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This work originated from the need to functionalize surfactant-coated inorganic nanoparticles for biomedical applications, a process that is limited by excess unbound surfactant. These limitations are connected to the bioconjugation of targeting molecules that are often in equilibrium between the free aliquot in solution and that which binds the surface of the nanoparticles. The excess in solution can play a role in the biocompatability in vitro and in vivo of the final nanoparticles stock. For this purpose, we tested the ability of common surfactants - monothiolated polyethylene glycol and amphiphilic polymers - to colloidally stabilize nanoparticles as excess surfactant is removed and compared them to newly appearing multidentate surfactants endowed with high avidity for inorganic nanoparticles. Our results showed that monothiolated polyethylene glycol or amphiphilic polymers have an insufficient affinity to the nanoparticles and as the excess surfactant is removed the colloidal stability is lost, while multidentate high-avidity surfactants excel in the same regard, possibly allowing improvement in an array of nanoparticle applications, especially in those stated.

The green synthesis of gold nanoparticles (Au-NPs) was carried out by pouring the aqueous extract of East Anatolian origin Asphodelus aestivus plant onto aqueous gold metal ions and reducing them via single-step one- pot method. The absorption peak of the synthesized nanoparticles gave a maximum at 575 nm. All the X-ray diffraction peaks at 2θ = 38.25 , 44.46 , 64.64 and 77.20 that index to (111), (200), (220), and (311) planes verify the successful synthesis of Au-NPs. Mostly spherical shape particles showed a homogeneous distribution with size range 20±5 nm are measured using TEM. From the FTIR spectrum, the peaks are seems to be related to phenolic compounds, flavonoids, benzophenones, terpenoids and anthocyanins which assume that they could act as the reducing agents. The plant extraction, one-pot, single-step method used is environmentally safe without the role of synthetic materials which is highly potential in mild and green synthesis applications. The Au-NPs were coated with chitosan biopolymer in aquatic solution medium and verified by SEM. Then, cytotoxic investigations of the biosynthesized Au-NPs were carried out by HUVEC cells. Au-NPs were showed toxic effects on cell culture, even if in a small amount. However, chitosan biopolymer coating increased cell viability.Keywords: Gold nanoparticle, Biosynthesis, Asphodelus aestivus, Biopolymer coating, Cytotoxicity

Nanotechnology has played a critical role in the last years due its fight towards coronavirus disease (COVID-19), with highly effective nanotechnology-based vaccines. However, no successful advances have been observed in the development of nanodrugs to target other global leading causes of death such as autoimmune diseases or cancer. The tropism of nanomaterials towards the liver cells upon intravenous administration is a challenge for its clinical translation, which enhances the need for more selective-targeting strategies. Nonetheless, this can be an opportunity to exploit hepatic diseases such as primary biliary cholangitis (PBC) which have just one therapeutic option, liver transplantation. In this context, the aim of the present PhD was to design a targeting strategy towards macrophages which are involved in adaptive and innate immune responses of several pathophysiological diseases, by using nanoparticles functionalized with glycans for a more selective targeting. The repolarization of macrophages towards a restorative phenotype may lead to an amelioration of the events by approaching novel targeting strategies for clinical translation. For this reason, to deeper understand the life cycle of nanoparticles in the body after intravenous injection in immunocompetent mice, a short and long-term fate study using gold nanoparticles was done. In order to study “if and how” nanoparticles accumulate in the liver cells, different physicochemical parameters were evaluated such as different geometrical shapes, size and polymer coatings. This study was used as a screening to choose the nanoparticles with a higher tropism towards the liver to functionalize the nanoparticles surface with glycans, which have a pivotal role in regulating physiological and pathophysiological conditions, offering a remarkable opportunity to tune immunological responses and inflammation. The design of novel NPs functionalized with a N-glycan that expresses terminal sialic acids may mask NPs from the immune cell response and hepatic degradation. Finally, an innovative approach to design, synthesize and evaluate their biological therapeutic effect on macrophages from PBC by using two different monosaccharides: 1) mannose, which have shown to have anti-inflammatory properties in several autoimmune diseases and be involved in the differentiation of T regulatory cells and; 2) sialic acid, which is also involved in the development of an anti-inflammatory response and suppression of tumour growth. The advancement of nanotechnology-based strategies, provides a new direction in the design of multifunctional nanodevices with a more predictable fate. Nanotechnology has played a critical role in the last years due its fight towards coronavirus disease (COVID-19), with highly effective nanotechnology-based vaccines. However, no successful advances have been observed in the development of nanodrugs to target other global leading causes of death such as autoimmune diseases or cancer. The tropism of nanomaterials towards the liver cells upon intravenous administration is a challenge for its clinical translation, which enhances the need for more selective-targeting strategies. Nonetheless, this can be an opportunity to exploit hepatic diseases such as primary biliary cholangitis (PBC) which have just one therapeutic option, liver transplantation. In this context, the aim of the present PhD was to design a targeting strategy towards macrophages which are involved in adaptive and innate immune responses of several pathophysiological diseases, by using nanoparticles functionalized with glycans for a more selective targeting. The repolarization of macrophages towards a restorative phenotype may lead to an amelioration of the events by approaching novel targeting strategies for clinical translation. For this reason, to deeper understand the life cycle of nanoparticles in the body after intravenous injection in immunocompetent mice, a short and long-term fate study using gold nanoparticles was done. In order to study “if and how” nanoparticles accumulate in the liver cells, different physicochemical parameters were evaluated such as different geometrical shapes, size and polymer coatings. This study was used as a screening to choose the nanoparticles with a higher tropism towards the liver to functionalize the nanoparticles surface with glycans, which have a pivotal role in regulating physiological and pathophysiological conditions, offering a remarkable opportunity to tune immunological responses and inflammation. The design of novel NPs functionalized with a N-glycan that expresses terminal sialic acids may mask NPs from the immune cell response and hepatic degradation. Finally, an innovative approach to design, synthesize and evaluate their biological therapeutic effect on macrophages from PBC by using two different monosaccharides: 1) mannose, which have shown to have anti-inflammatory properties in several autoimmune diseases and be involved in the differentiation of T regulatory cells and; 2) sialic acid, which is also involved in the development of an anti-inflammatory response and suppression of tumour growth. The advancement of nanotechnology-based strategies, provides a new direction in the design of multifunctional nanodevices with a more predictable fate.

Understanding the patterns of noncovalent adsorption of double-stranded nucleic acids (dsDNA) on gold nanoparticles (GNPs) was the aim of this study. It was found that the high-affinity motifs in DNA can and do act as an “anchor” for the fixation of the whole molecule on the GNP (up to 98 ± 2 single-stranded (ss)DNA molecules per particle with diameter of 13 ± 2 nm). At the same time, the involvement of an “anchor” in the intramolecular DNA interaction can negatively affect the efficiency of the formation of ss(ds)DNA–GNP structures. It has been shown that the interaction of GNP with DNA duplexes is accompanied by their dissociation and competitive adsorption of ssDNAs on GNP, wherein the crucial factor of DNA adsorption efficiency is the intrinsic affinity of ssDNA to GNP. We propose a detailed scheme for the interaction of dsDNA with GNPs, which should be taken into account in studies of this type. Researchers focused on this field should accept the complicated nature of such objects and take into account the many competing processes, including the processes of adsorption and desorption of DNA on gold as well as the formation of secondary structures by individual DNA strands.

In this study, we investigated the use of porous silicon (PSi) fabricated using metal-assisted chemical etching (MACE) as a substrate for the deposition of Au nanoparticles (NPs) for the reduction of nitroaromatic compounds. PSi provides a high surface area for the deposition of Au NPs, and MACE allows for the fabrication of a well-defined porous structure in a single step. We used the reduction of p-nitroaniline as a model reaction to evaluate the catalytic activity of Au NPs on PSi. The results indicate that the Au NPs on the PSi exhibited excellent catalytic activity, which was affected by the etching time. Overall, our results highlighted the potential of PSi fabricated using MACE as a substrate for the deposition of metal NPs for catalytic applications.

Lateral flow nucleic acid biosensors (LFNABs) have attracted extensive attention due to their rapid turnaround time, low cost, and results that are visible to the naked eye. One of the key steps to develop LFNABs is to prepare DNA–gold nanoparticle (DNA–AuNP) conjugates, which affect the sensitivity of LFNABs significantly. To date, various conjugation methods—including the salt-aging method, microwave-assisted dry heating method, freeze–thaw method, low-pH method, and butanol dehydration method—have been reported to prepare DNA–AuNP conjugates. In this study, we conducted a comparative analysis of the analytical performances of LFNABs prepared with the above five conjugation methods, and we found that the butanol dehydration method gave the lowest detection limit. After systematic optimization, the LFNAB prepared with the butanol dehydration method had a detection limit of 5 pM for single-strand DNA, which is 100 times lower than that of the salt-aging method. The as-prepared LFNAB was applied to detect miRNA-21 in human serum, with satisfactory results. The butanol dehydration method thus offers a rapid conjugation approach to prepare DNA–AuNP conjugates for LFNABs, and it can also be extended to other types of DNA biosensors and biomedical applications.

Au/TiO2 catalytic coatings have been developed onto the inner surface of a quartz tube for photocatalytic applications. Gold nanoparticles with diameter 3–5 nm were synthesised using the citrate method, with sodium borohydride as a reducing agent. The nanoparticles were characterised by UV–vis spectroscopy, small angle X-ray scattering (SAXS), dynamic light scattering (DLS), and transmission electron microscopy (TEM). The photocatalytic activity of gold nanoparticles and Au/TiO2 catalytic coatings was studied in the reduction of 4-nitrophenol (4-NP) with green LEDs. The reaction rate follows Langmuir-Hinshelwood kinetics and increases with the light intensity until a plateau at 3 mW cm−2. The photocatalytic activity of gold nanoparticles was fully preserved in the Au/TiO2 coatings.

Rapid, sensitive, and reliable detection of high mobility group box 1 (HMGB1) is essential for medical and diagnostic applications due to its important role as a biomarker of chronic inflammation. Here, we report a facile method for the detection of HMGB1 using carboxymethyl dextran (CM-dextran) as a bridge molecule modified on the surface of gold nanoparticles combined with a fiber optic localized surface plasmon resonance (FOLSPR) biosensor. Under optimal conditions, the results showed that the FOLSPR sensor detected HMGB1 with a wide linear range (10−10 to 10−6 g/mL), fast response (less than 10 min), and a low detection limit of 43.4 pg/mL (1.7 pM) and high correlation coefficient values (>0.9928). Furthermore, the accurate quantification and reliable validation of kinetic binding events measured by the currently working biosensors are comparable to surface plasmon resonance sensing systems, providing new insights into direct biomarker detection for clinical applications.

Eco-friendly chemical methods using FDA-approved Pluronic F127 (PLU) block copolymer have garnered much attention for simultaneously forming and stabilizing Au nanoparticles (AuNPs). Given the remarkable properties of AuNPs for usage in various fields, especially in biomedicine, we performed a systematic study to synthesize AuNP-PLU nanocomposites under optimized conditions using UV irradiation for accelerating the reaction. The use of UV irradiation at 254 nm resulted in several advantages over the control method conducted under ambient light (control). The AuNP-PLU-UV nanocomposite was produced six times faster, lasting 10 min, and exhibited lower size dispersion than the control. A set of experimental techniques was applied to determine the structure and morphology of the produced nanocomposites as affected by the UV irradiation. The MTT assay was conducted to estimate IC50 values of AuNP-PLU-UV in NIH 3T3 mouse embryonic fibroblasts, and the results suggest that the sample is more compatible with cells than control samples. Afterward, in vivo maternal and fetal toxicity assays were performed in rats to evaluate the effect of AuNP-PLU-UV formulation during pregnancy. Under the tested conditions, the treatment was found to be safe for the mother and fetus. As a proof of concept or application, the synthesized Au:PLU were tested as contrast agents with an X-ray computed tomography scan (X-ray CT).

In the present study, the various concentrations of AuNP (1.25, 2.5, 5, 10 ppm) were prepared to investigate the biocompatibility, biological performances and cell uptake efficiency via Wharton’s jelly mesenchymal stem cells and rat model. The pure AuNP, AuNP combined with Col (AuNP-Col) and FITC conjugated AuNP-Col (AuNP-Col-FITC) were characterized by Ultraviolet–visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR) and Dynamic Light Scattering (DLS) assays. For in vitro examinations, we explored whether the Wharton’s jelly MSCs had better viability, higher CXCR4 expression, greater migration distance and lower apoptotic-related proteins expression with AuNP 1.25 and 2.5 ppm treatments. Furthermore, we considered whether the treatments of 1.25 and 2.5 ppm AuNP could induce the CXCR4 knocked down Wharton’s jelly MSCs to express CXCR4 and reduce the expression level of apoptotic proteins. We also treated the Wharton’s jelly MSCs with AuNP-Col to investigate the intracellular uptake mechanisms. The evidence demonstrated the cells uptake AuNP-Col through clathrin-mediated endocytosis and the vacuolar-type H+-ATPase pathway with good stability inside the cells to avoid lysosomal degradation as well as better uptake efficiency. Additionally, the results from in vivo examinations elucidated the 2.5 ppm of AuNP attenuated foreign body responses and had better retention efficacy with tissue integrity in animal model. In conclusion, the evidence demonstrates that AuNP shows promise as a biosafe nanodrug delivery system for development of regenerative medicine coupled with Wharton’s jelly MSCs.

Interactions between fluorephores and surface plasmon was investigated by a custom-built fluorescence lifetime system. Gold nanoparticle with double-stranded DNA on the surface was utilized to exactly control the distance between fluorephores and the nanoparticle. We calculated surface plasmon-induced changes in the radiative decay rate constant and the quenching rate constant. The results revealed that the distance between the fluorephore and the nanoparticle strongly affected the radiative decay rate and the quenching rate. With an increase in the distance, the radiative decay rate decreased while the quenching rate increased. This suggests that the distance between fluorephores and surface plasmon plays an important role in fluorescence lifetime modification. The results also indicated that the fluorescence lifetime of the fluorephores can be significantly modified by surface plasmon resonance. This indicates that surface plasmon resonance can be used as a tool to control the fluorescence lifetime of fluorephores for sensing applications.

In this work, two human epidermal growth factor receptors, HER-1 and HER-2, were selected as biomarkers to enable the detection of breast cancer. Therefore, two biosensors were developed using gold sensor chips coupled with amperometric detection of the enzyme label horse radish peroxidase (HRP). The biosensors/immunosensors relied on indirect sandwich enzyme-linked immunosorbent assays with monoclonal antibodies (Ab) against HER-1 and HER-2 attached to the sensors to capture the biomarkers. Detection polyclonal antibodies followed by secondary anti-rabbit (for HER-1) and anti-goat (for HER-2) IgG antibody-HRP were then applied for signal generation. In buffer, the developed sensors showed limits of detections (LOD) of 1.06 ng mL−1 and 0.95 ng mL−1 and limits of quantification (LOQ) of 2.1 ng mL−1 and 1.5 ng mL−1 for HER-1 and HER-2, respectively. In 100% (undiluted) serum, LODs of 1.2 ng mL−1 and 1.47 ng mL−1 and LOQs of 1.5 ng mL−1 and 2.1 ng mL−1 were obtained for HER-1 and HER-2, respectively. Such limits of detections are within the serum clinical range for the two biomarkers. Furthermore, gold nanoparticles (AuNP) labelled with secondary anti-rabbit and anti-goat IgG antibody-HRP were then used to enhance the assay signal and increase the sensitivity. In buffers, LODs of 30 pg mL−1 were seen for both sensors and LOQs of 98 pg mL−1 and 35 pg mL−1 were recorded for HER-1 and HER-2, respectively. For HER-2 the AuNPs biosensor was also tested in 100% serum obtaining a LOD of 50 pg mL−1 and a LOQ of 80 pg mL−1. The HER-2 AuNP electrochemical immunosensor showed high specificity with very low cross-reactivity to HER-1. These findings demonstrate that the two developed sensors can enable early detection as well as monitoring of disease progression with a beneficial impact on patient survival and clinical outcomes.

Tuberculosis (TB) has been a devastating human illness for thousands of years. According to the WHO, around 10.4 million new cases of tuberculosis are identified every year, with 1.8 million deaths. To reduce these statistics and the mortality rate, an early and accurate TB diagnosis is essential. This study offers a highly sensitive and selective electrochemical biosensor for Mycobacterium tuberculosis (MTB) detection based on a ternary nanocomposite of reduced graphene oxide, polydopamine, and gold nanoparticles (rGO-PDA-AuNP). Avidin-biotin coupling was used to bind the MTB probe DNA onto the rGO-PDA-AuNP modified glassy carbon electrode (ssDNA/avidin/rGO-PDA-AuNP). UV-Visible, Raman, XRD, and TEM were used to evaluate the structural and morphological characteristics of rGO-PDA-AuNP. Furthermore, DNA immobilization is validated using FESEM and FT-IR techniques. The modified electrodes were electrochemically analyzed using cyclic voltammetry (CV) and linear sweep voltammetry (LSV), and the results indicate that the produced electrode can detect target DNA up to 0.1 × 10−7 mM with 2.12 × 10−3 mA µM−1 sensitivity and a response time of 5 s. The constructed genosensor displayed high sensitivity and stability, and it also provides a unique strategy for diagnosing MTB at an early stage. Furthermore, our rGO-PDA-AuNP/GCE-based electrochemical platform has broad potential for creating biosensor systems for detecting various infectious pathogens and therapeutically significant biomarkers.

Stem cell (SC)-based therapies hold the potential to revolutionize therapeutics by enhancing the body's natural repair processes. Currently, there are only three SC therapies with marketing authorization within the European Union. To optimize outcomes, it is important to understand the biodistribution and behavior of transplanted SCs in vivo. A variety of imaging agents have been developed to trace SCs; however, they mostly lack the ability to simultaneously monitor the SC function and biodistribution at high resolutions. Here, we report the synthesis and application of a nanoparticle (NP) construct consisting of a gold NP core coated with rhodamine B isothiocyanate (RITC)-doped mesoporous silica (AuMS). The MS layer further contained a thiol-modified internal surface and an amine-modified external surface for dye conjugation. Highly fluorescent AuMS of three different sizes were successfully synthesized. The NPs were non-toxic and efficiently taken up by limbal epithelial SCs (LESCs). We further showed that we can functionalize AuMS with a reactive oxygen species (ROS)-sensitive fluorescent dye using two methods, loading the probe into the mesopores, with or without additional capping by a lipid bilayer, and by covalent attachment to surface and/or mesoporous-functionalized thiol groups. All four formulations displayed a ROS concentration-dependent increase in fluorescence. Further, in an ex vivo SC transplantation model, a combination of optical coherence tomography and fluorescence microscopy was used to synergistically identify AuMS-labeled LESC distribution at micrometer resolution. Our AuMS constructs allow for multimodal imaging and simultaneous ROS sensing of SCs and represent a promising tool for in vivo SC tracing.

The use of gold nanoparticles as drug delivery systems has received increasing attention due to their unique properties, such as their high stability and biocompatibility. However, gold nanoparticles have a high affinity for proteins, which can result in their rapid clearance from the body and limited drug loading capabilities. To address these limitations, we coated the gold nanoparticles with silica and PEG, which are known to improve the stability of nanoparticles. The synthesis of the nanoparticles was carried out using a reduction method. The nanoparticles’ size, morphology, and drug loading capacity were also studied. The SEM images showed a spherical and homogeneous morphology; they also showed that the coatings increased the average size of the nanoparticles. The results of this study provide insight into the potential of gold nanoparticles coated with silica and PEG as drug delivery systems. We used ibuprofen as a model drug and found that the highest drug load occurred in PEG-coated nanoparticles and then in silica-coated nanoparticles, while the uncoated nanoparticles had a lower drug loading capacity. The coatings were found to significantly improve the stability and drug load properties of the nanoparticles, making them promising candidates for further development as targeted and controlled release drug delivery systems.

The challenges of a heme protein and enzyme-based H2O2 sensor was subdued by developing a highly sensitive and practically functional amperometric gold nanoparticles (Au NPs)/SnO2 nanofibers (SnO2 NFs) composite sensor. The composite was prepared by mixing multiporous SnO2 NFs (diameter: 120–190 nm) with Au NPs (size: 3–5 nm). The synthesized Au NPs/SnO2 NFs composite was subsequently coated on a glassy carbon electrode (GCE) and displayed a well-defined reduction peak during a cyclic voltammetry (CV) analysis. The SnO2 NFs prevented the aggregation of Au NPs through its multiporous structure and enhanced the catalytic response by 1.6-fold. The SnO2 NFs-supported GCE/Au NPs/SnO2 NFs composite sensor demonstrated a very good catalytic activity during the reduction of hydrogen peroxide (H2O2) that displayed rapid amperometric behavior within 6.5 s. This sensor allowed for highly sensitive and selective detection. The sensitivity was 14.157 µA/mM, the linear detection range was from 49.98 µM to 3937.21 µM (R2 = 0.99577), and the lower limit of detection was 6.67 µM. Furthermore, the developed sensor exhibited acceptable reproducibility, repeatability, and stability over 41 days. In addition, the Au NPs/SnO2 NFs composite sensor was tested for its ability to detect H2O2 in tap water, apple juice, Lactobacillus plantarum, Bacillus subtilis, and Escherichia coli. Therefore, this sensor would be useful due to its accuracy and sensitivity in detecting contaminants (H2O2) in commercial products.

Dacarbazine (DB) is an antineoplastic drug extensively used in cancer therapy. However, present limitations on its performance are related to its low solubility, instability, and non-specificity. To overcome these drawbacks, DB was included in β-cyclodextrin (βCD), which increased its aqueous solubility and stability. This new βCD@DB complex has been associated with plasmonic gold nanoparticles (AuNPs), and polyethylene glycol (PEG) has been added in the process to increase the colloidal stability and biocompatibility. Different techniques revealed that DB allows for a dynamic inclusion into βCD, with an association constant of 80 M−1 and a degree of solubilization of 0.023, where βCD showed a loading capacity of 16%. The partial exposure of the NH2 group in the included DB allows its interaction with AuNPs, with a loading efficiency of 99%. The PEG-AuNPs-βCD@DB nanosystem exhibits an optical plasmonic absorption at 525 nm, a surface charge of −29 mV, and an average size of 12 nm. Finally, laser irradiation assays showed that DB can be released from this platform in a controlled manner over time, reaching a concentration of 56 μg/mL (43% of the initially loaded amount), which, added to the previous data, validates its potential for drug delivery applications. Therefore, the novel nanosystem based on βCD, AuNPs, and PEG is a promising candidate as a new nanocarrier for DB.

A key process in the development of atherosclerotic plaques is the recruitment of monocytes into the artery wall. Using spectral photon-counting computed tomography we examine whether monocyte deposition within the artery wall of ApoE-/- mouse can be detected. Primary mouse monocytes were labelled by incubating them with 15 nm gold nanoparticles coated with 11-mercaptoundecanoic acid The monocyte uptake of the particle was confirmed by electron microscopy of the cells before injection into 6-week-old apolipoprotein E deficient (ApoE-/-) mouse that had been fed with the Western diet for 10 weeks. Four days following injection, the mouse was sacrificed and imaged using a MARS spectral photon counting computed tomography scanner with a spectral range of 7 to 120 KeV with five energy bins. Imaging analysis showed the presence of X-ray dense material within the mouse aortic arch which was consistent with the spectral characteristic of gold rather than calcium. The imaging is interpreted as showing the deposition of gold nanoparticles containing monocytes within the mouse aorta. The results of our study determined that spectral photon-counting computed tomography could provide quantitative information about gold nanoparticles labelled monocytes in voxels of 90 × 90 × 90 µm3. The imaging was consistent with previous micro-CT and electron microscopy of mice using the same nanoparticles. This study demonstrates that spectral photon-counting computed tomography, using a MARS small bore scanner, can detect a fundamental atherogenic process within mouse models of atherogenesis. The present study demonstrates the feasibility of spectral photon-counting computed tomography as an emerging molecular imaging modality to detect atherosclerotic disease.

Breast cancer is the first leading tumor in women in terms of incidence worldwide. Seventy percent of cases are estrogen receptor (ER) α-positive. In these malignancies, 17β-estradiol (E2) via ERα increases the levels of neuroglobin (NGB), a compensatory protein that protects cancer cells from stress-induced apoptosis, including chemotherapeutic drug treatment. Our previous data indicate that resveratrol (RSV), a plant-derived polyphenol, prevents E2/ERα-induced NGB accumulation in this cellular context, making E2-dependent breast cancer cells more prone to apoptosis. Unfortunately, RSV is readily metabolized, thus preventing its effectiveness. Here, four different RSV analogs have been developed, and their effect on the ERα/NGB pathway has been compared with RSV conjugated with highly hydrophilic gold nanoparticles as prodrug to evaluate if RSV derivatives maintain the breast cancer cells’ susceptibility to the chemotherapeutic drug paclitaxel as the original compound. Results demonstrate that RSV conjugation with gold nanoparticles increases RSV efficacy, with respect to RSV analogues, reducing NGB levels and enhancing the pro-apoptotic action of paclitaxel, even preventing the anti-apoptotic action exerted by E2 treatment on these cells. Overall, RSV conjugation with gold nanoparticles makes this complex a promising agent for medical application in breast cancer treatment.

This work demonstrates the incorporation of gold nanoparticles (AuNPs) into crosslinker-free poly(N-isopropylacrylamide), PNIPAM, particles in situ and the examination of their structural and catalytic properties. The formation process of the AuNPs across the crosslinker-free PNIPAM particles are compared to that of crosslinked PNIPAM particles. Given the relatively larger free volume across the crosslinker-free polymer network, the AuNPs formed by the in situ reduction of gold ions are detectably larger and more polydisperse, but their overall integration efficiency is slightly inferior. The structural features and stability of these composite particles are also examined in basic and alcoholic solvent environments, where the crosslinker-free PNIPAM particles still offer comparable physicochemical properties to the crosslinked PNIPAM particles. Interestingly, the crosslinker-free composite particles as a colloidal catalyst display a higher reactivity toward the homocoupling of phenylboronic acid and reveal the importance of the polymer network density. As such, the capability to prepare composite particles in a controlled polymer network and reactive metal nanoparticles, as well as understanding the structure-dependent physicochemical properties, can allow for the development of highly practical catalytic systems.

A promising therapeutic strategy to delay and/or prevent the onset of neurodegenerative diseases (NDs) could be to restore neuroprotective pathways physiologically triggered by neurons against stress injury. Recently, we identified the accumulation of neuroglobin (NGB) in neuronal cells, induced by the 17β-estradiol (E2)/estrogen receptor β (ERβ) axis, as a protective response that increases mitochondria functionality and prevents the activation of apoptosis, increasing neuron resilience against oxidative stress. Here, we would verify if resveratrol (Res), an ERβ ligand, could reactivate NGB accumulation and its protective effects against oxidative stress in neuronal-derived cells (i.e., SH-SY5Y cells). Our results demonstrate that ERβ/NGB is a novel pathway triggered by low Res concentrations that lead to rapid and persistent NGB accumulation in the cytosol and in mitochondria, where the protein contributes to reducing the apoptotic death induced by hydrogen peroxide (H2O2). Intriguingly, Res conjugation with gold nanoparticles increases the stilbene efficacy in enhancing neuron resilience against oxidative stress. As a whole, ERβ/NGB axis regulation is a novel mechanism triggered by low concentration of Res to regulate, specifically, the neuronal cell resilience against oxidative stress reducing the triggering of the apoptotic cascade.

International audience; Hybrid aluminosilicate nanotubes (Imo-CH3) have the ability to trap small organic molecules inside their hydrophobic internal cavity while being dispersed in water owing to their hydrophilic external surface. They also display a curvature-induced polarization of their wall, which favors reduction outside the nanotubes and oxidation inside. Here, we coupled bare plasmonic gold nanoparticles (GNPs) with Imo-CH3 and analyzed for the first time the redox reactivity of these hybrid nano-reactors upon UV illumination. We show that the coupling between GNPs and Imo-CH3 significantly enhances the nanotube photocatalytic activity, with a large part of water reduction occurring directly on the gold surface. The coupling mechanism strongly influences the initial H2 production rate, which can go from ×10 to more than ×90 as compared to bare Imo-CH3 depending on the synthesis route of the GNPs. The present results show that this hybrid photocatalytic nano-reactor benefits from a synergy of polarization and confinement effects that facilitate efficient H2 production.

Aβ42 is one of the most extensively studied blood and Cerebrospinal fluid (CSF) biomarkers for the diagnosis of symptomatic and prodromal Alzheimer’s disease (AD). Because of the heterogeneity and transient nature of Aβ42 oligomers (Aβ42Os), the development of technologies for dynamically detecting changes in the blood or CSF levels of Aβ42 monomers (Aβ42Ms) and Aβ42Os is essential for the accurate diagnosis of AD. The currently commonly used Aβ42 ELISA test kits usually mis-detected the elevated Aβ42Os, leading to incomplete analysis and underestimation of soluble Aβ42, resulting in a comprised performance in AD diagnosis. Herein, we developed a dual-target lateral flow immunoassay (dLFI) using anti-Aβ42 monoclonal antibodies 1F12 and 2C6 for the rapid and point-of-care detection of Aβ42Ms and Aβ42Os in blood samples within 30 min for AD diagnosis. By naked eye observation, the visual detection limit of Aβ42Ms or/and Aβ42Os in dLFI was 154 pg/mL. The test results for dLFI were similar to those observed in the enzyme-linked immunosorbent assay (ELISA). Therefore, this paper-based dLFI provides a practical and rapid method for the on-site detection of two biomarkers in blood or CSF samples without the need for additional expertise or equipment. Graphical Abstract

Theeranan Tangthong,1,2 Thananchai Piroonpan,2 Velaphi C Thipe,3,4 Menka Khoobchandani,4,5 Kavita Katti,4,5 Kattesh V Katti,4– 6 Wanvimol Pasanphan1,2 1Department of Materials Science, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand; 2Center of Radiation Processing for Polymer Modification and Nanotechnology (CRPN), Department of Materials Science, Faculty of Science, Kasetsart University Chatuchak, Bangkok, 10900, Thailand; 3Department of Chemistry, University of Missouri, Columbia, MO, 65211, USA; 4Institute of Green Nanotechnology, University of Missouri, Columbia, MO, 65211, USA; 5Department of Radiology, University of Missouri, Columbia, MO, 65211, USA; 6Department of Physics, University of Missouri, Columbia, MO, 65211, USACorrespondence: Wanvimol PasanphanDepartment of Materials Science, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok, 10900, ThailandTel +66 2562 5555 (Ext. 646518)Email wanvimol.p@ku.ac.thKattesh V KattiInstitute of Green Nanotechnology, University of Missouri, Columbia, MO, 65211, USATel +1 573 882-5656Fax +1 573 884-5679Email KattiK@health.missouri.eduPurpose: We report herein bombesin peptide conjugated water-soluble chitosan gallate as a template for rapid one-pot synthesis of gold nanoparticles (AuNPs) with capabilities to target receptors on prostate cancer cells.Methods: Water-soluble chitosan (WCS), anchored with gallic acid (GA) and LyslLys3 (1,4,7,10-tetraazacyclo dodecane-1,4,7,10-tetraacetic acid) bombesin 1– 14 (DBBN) peptide, provides a tumor targeting nanomedicine agent. WCS nanoplatforms provide attractive strategies with built-in capabilities to reduce gold (III) to gold nanoparticles with stabilizing and tumor-targeting capabilities. WCS-GA-DBBN encapsulation around gold nanoparticles affords optimum in vitro stability.Results: The DBBN content in the WCS-GA-DBBN sample was ∼ 27%w/w. The antioxidant activities of WCS-GA and WCS-GA-DBBN nanocolloids were enhanced by 12 times as compared to the nascent WCS. AuNPs with a desirable hydrodynamic diameter range of 40– 60 nm have been efficiently synthesized using WCS-GA and WCS-GA-DBBN platforms. The AuNPs were stable over 4 days after preparation and ∼ 3 days after subjecting to all relevant biological fluids. The AuNPs capped with WCS-GA-DBBN peptide exhibited superior cellular internalization into prostate tumor (PC-3) cells with evidence of receptor mediated endocytosis.Conclusion: The AuNPs capped with WCS-GA-DBBN exhibited selective affinity toward prostate cancer cells. AuNPs conjugated with WCS-GA-DBBN serve as a new generation of theranostic agents for treating various neoplastic diseases, thus opening-up new applications in oncology.Keywords: water-soluble chitosan, gallic acid, bombesin, one-pot synthesis, gold nanoparticle, prostate cancer

This paper reported a real-time detection strategy for Hg2+ inspired by the visible spectrophotometer that used a smartphone as a low-cost micro-spectrometer. In combination with the smartphone’s camera and optical accessories, the phone’s built-in software can process the received light band image and then read out the spectral data in real time. The sensor was also used to detect gold nanoparticles with an LOD of 0.14 μM, which are widely used in colorimetric biosensors. Ultimately, a gold nanoparticles-glutathione (AuNPs-GSH) conjugate was used as a probe to detect Hg2+ in water with an LOD of 1.2 nM and was applied successfully to natural mineral water, pure water, tap water, and river water samples.

Extracellular vesicles (EVs) exist in biological fluids such as blood, urine, and cerebrospinal fluid and are promising cancer biomarkers. Attempts to isolate and analyze trace EVs, however, have been a challenge for researchers studying their functions and secretion mechanisms, which has stymied the options for diagnostic application. This study demonstrated a collection of EVs that was enhanced by gold nanoparticles (AuNPs) via the use of optical force. The collection system consists of an inverted microscope equipped with a CCD camera, a square capillary connected with a PTFE tube, and an Nd:YAG laser that generates optical force. The laser beam was focused on a capillary wall in which a cell culture medium containing EVs flowed continuously. Control of the surface charges on both the capillary wall and the AuNPs achieved the collection and retention of EVs on the capillary wall. The positively charged capillary wall retained EVs even after the laser irradiation was halted due to the negative charges inherent on the surface of EVs. Conversely, positively charged AuNPs had a strong electrostatic interaction with EVs and enhanced the optical force acting on them, which made collecting them a much more efficient process.

Metal nanoparticles are effective radiosensitizers that locally enhance radiation doses in targeted cancer cells. Compared with other metal nanoparticles, gold nanoparticles (GNPs) exhibit high biocompatibility, low toxicity, and they increase secondary electron scatter. Herein, we investigated the effects of active-targeting GNPs on the radiation-induced bystander effect (RIBE) in prostate cancer cells. The impact of GNPs on the RIBE presents implications for secondary cancers or spatially fractionated radiotherapy treatments. Anti-prostate-specific membrane antigen (PSMA) antibodies were conjugated with PEGylated GNPs through EDC–NHS chemistry. The media transfer technique was performed to induce the RIBE on the non-irradiated bystander cells. This study focused on the LNCaP cell line, because it can model a wide range of stages relating to prostate cancer progression, including the transition from androgen dependence to castration resistance and bone metastasis. First, LNCaP cells were pretreated with phosphate buffered saline (PBS) or PSMA-targeted GNPs (PGNPs) for 24 h and irradiated with 160 kVp X-rays (0–8 Gy). Following that, the collected culture media were filtered (sterile 0.45 µm polyethersulfone) in order to acquire PBS- and PGNP- conditioned media (CM). Then, PBS- and PGNP-CM were transferred to the bystander cells that were loaded with/without PGNPs. MTT, γ-H2AX, clonogenic assays and reactive oxygen species assessments were performed to compare RIBE responses under different treatments. Compared with 2 Gy-PBS-CM, 8 Gy-PBS-CM demonstrated a much higher RIBE response, thus validating the dose dependence of RIBE in LNCaP cells. Compared with PBS-CM, PGNP-CM exhibited lower cell viability, higher DNA damage, and a smaller survival fraction. In the presence of PBS-CM, bystander cells loaded with PGNPs showed increased cell death compared with cells that did not have PGNPs. These results demonstrate the PGNP-boosted expression and sensitivity of RIBE in prostate cancer cells.

Active targeting gold nanoparticles (AuNPs) are a very promising avenue for cancer treatment with many publications on AuNP mediated radiosensitization at kilovoltage (kV) photon energies. However, uncertainty on the effectiveness of AuNPs under clinically relevant megavoltage (MV) radiation energies hinders the clinical translation of AuNP-assisted radiation therapy (RT) paradigm. The aim of this study was to investigate radiosensitization mediated by PSMA-targeted AuNPs irradiated by a 6 MV radiation beam at different depths to explore feasibility of AuNP-assisted prostate cancer RT under clinically relevant conditions. PSMA-targeted AuNPs (PSMA-AuNPs) were synthesized by conjugating PSMA antibodies onto PEGylated AuNPs through EDC/NHS chemistry. Confocal fluorescence microscopy was used to verify the active targeting of the developed PSMA-AuNPs. Transmission electron microscopy (TEM) was used to demonstrate the intracellular biodistribution of PSMA-AuNPs. LNCaP prostate cancer cells treated with PSMA-AuNPs were irradiated on a Varian 6 MV LINAC under varying depths (2.5 cm, 10 cm, 20 cm, 30 cm) of solid water. Clonogenic assays were carried out to determine the in vitro cell survival fractions. A Monte Carlo (MC) model developed on TOPAS platform was then employed to determine the nano-scale radial dose distribution around AuNPs, which was subsequently used to predict the radiation dose response of LNCaP cells treated with AuNPs. Two different cell models, with AuNPs located within the whole cell or only in the cytoplasm, were used to assess how the intracellular PSMA-AuNP biodistribution impacts the prostate cancer radiosensitization. Then, MC-based microdosimetry was combined with the local effect model (LEM) to calculate cell survival fraction, which was benchmarked against the in vitro clonogenic assays at different depths. In vitro clonogenic assay of LNCaP cells demonstrated the depth dependence of AuNP radiosensitization under clinical megavoltage beams, with sensitization enhancement ratio (SER) of 1.14 ± 0.03 and 1.55 ± 0.05 at 2.5 cm depth and 30 cm depth, respectively. The MC microdosimetry model showed the elevated percent of low-energy photons in the MV beams at greater depth, consequently resulting in increased dose enhancement ratio (DER) of AuNPs with depth. The AuNP-induced DER reached ~5.7 and ~8.1 at depths of 2.5 cm and 30 cm, respectively. Microdosimetry based LEM accurately predicted the cell survival under 6 MV beams at different depths, for the cell model with AuNPs placed only in the cell cytoplasm. TEM results demonstrated the distribution of PSMA-AuNPs in the cytoplasm, confirming the accuracy of MC microdosimetry based LEM with modelled AuNPs distributed within the cytoplasm. We conclude that AuNP radiosensitization can be achieved under megavoltage clinical radiotherapy energies with a dependence on tumor depth. Furthermore, the combination of Monte Carlo microdosimetry and LEM will be a valuable tool to assist with developing AuNP-aided radiotherapy paradigm and drive clinical translation.

Gold nanoparticles (AuNPs) were the basis for the earliest research in the field of surface enhanced Raman scattering (SERS). Coupling of their surface plasmon resonances creates hot-spots of high electromagnetic intensities found to be very useful for sensing applications. However, chemically synthesized AuNPs in suspension are usually polydisperse and when arranged on a SERS substrate, lack periodic spatial organization. This leads to large variations in the enhancement factor (EF) which is detrimental to the sensing capabilities of the SERS substrate. Here, we showcase reproducible fabrication of an array of spherical AuNPs at the apices of shell isolated silicon nanocones with a homogeneous EF for SERS. The AuNPs are produced through discrete rotation glancing angle deposition of Au on shell isolated silicon nanocones (SI-SiNC) with square lattice periodicity and 250 nm pitch. By tuning the substrate tilt angle, substrate rotation angle and deposition thickness, the location and the size of the AuNPs formed can be controlled. Using this method, we successfully fabricated 60 nm AuNPs positioned at the apices of the nanocone array. Finite-Difference Time-Domain (FDTD) simulations were performed to visualize the electric field enhancement and verify conditions such as tip radius and oxide shell thickness to optimize the same. The EF was then experimentally calculated by performing SERS measurements on benzenethiol (BT) functionalized AuNPs at 400 unique points over the SI-SiNC substrate and compared to measurements of pure BT solution. A homogeneous substrate EF of (2.05 ± 0.05) ∙107 (99% confidence interval) at par with literature was calculated for the C-S in-plane deformation mode, δCS, of the BT molecule excited at 1077 cm-1. Our work highlights the advantages of nanofabrication for homogeneous SERS EF substrates.

A simple and sensitive AuNP-coated magnetic beads (AMB)-based electrochemical biosensor platform was fabricated for bioassay. In this study, AuNP-conjugated magnetic particles were successfully prepared using biotin–streptavidin conjugation. The morphology and structure of the nanocomplex were characterized by scanning electron microscopy (SEM) with energy-dispersive X-ray analysis (EDX) and UV–visible spectroscopy. Moreover, cyclic voltammetry (CV) was used to investigate the effect of AuNP-MB on alkaline phosphatase (ALP) for electrochemical signal enhancement. An ALP-based electrochemical (EC) immunoassay was performed on the developed AuNP-MB complex with indium tin oxide (ITO) electrodes. Subsequently, the concentration of capture antibodies was well-optimized on the AMB complex via biotin–avidin conjugation. Lastly, the developed AuNP-MB immunoassay platform was verified with extracellular vesicle (EV) detection via immune response by showing the existence of EGFR proteins on glioblastoma multiforme (GBM)-derived EVs (108 particle/mL) spiked in human plasma. Therefore, the signal-enhanced ALP-based EC biosensor on AuNP-MB was favorably utilized as an immunoassay platform, revealing the potential application of biosensors in immunoassays in biological environments.

The global pandemic of COVID-19 has created an unrivalled need for sensitive and rapid point-of-care testing (POCT) methods for the detection of infectious viruses. For the novel coronavirus SARS-CoV-2, the nucleocapsid protein (N-protein) is one of the most abundant structural proteins of the virus and it serves as a useful diagnostic marker for detection. Herein, we report a fiber optic particle plasmon resonance (FOPPR) biosensor which employed a single-stranded DNA (ssDNA) aptamer as the recognition element to detect the SARS-CoV-2 N-protein in 15 min with a limit of detection (LOD) of 2.8 nM, meeting the acceptable LOD of 106 copies/mL set by the WHO target product profile. The sensor chip is a microfluidic chip based on the balance between the gravitational potential and the capillary force to control fluid loading, thus enabling the power-free auto-flowing function. It also has a risk-free self-contained design to avoid the risk of the virus leaking into the environment. These findings demonstrate the potential for designing a low-cost and robust POCT device towards rapid antigen detection for early screening of SARS-CoV-2 and its related mutants.

Metallic plasmonic substrates such as gold nanoparticles (AuNPs) have fascinated researchers due to their usefulness in verious interdisciplinary studies at the interface between applied physics, biochemistry, engineering, and medicine. A good understanding of the physics of these noble nanostructures, particularly the plasmonic and optical properties, can be employed to improve a wide range of sensors and electronic devices. The relevance of molecular recognition and the binding of biological and chemical entities to diagnostics, biosensors, and drug delivery has attracted significant research interest. By addressing material functionalization design and advanced characterization methods, this doctoral work aims to highlight efforts to exploit the surface modification strategies to enhance the responsiveness of nanoparticle substrates for improved detection of health-relevant biomolecules. The self-assembly of small ligands, such as alkanethiols, and oligonucleotides on the surface of AuNPs provided a possible starting route for the preparation of bio-nanomaterials with precise physicochemical properties. The versatile AuNPs were optimized and thoroughly characterized by employing electron microscopy techniques such as transmission electron microscope (TEM), atomic force microscopy (AFM), and scanning electron microscopy (SEM), spectroscopic techniques, including ultraviolet/visible (UV/Vis), dynamic light scattering (DLS), and thermal lens spectrometry (TLS), and biochemical assays (gel electrophoresis, Dot plot, Western plot, and the Enzyme Linked Immunosorbent Assay (ELISA)). Subsequently, the molecular recognition capabilities of functionalized AuNPs were investigated using multiple techniques, including novel detection routes such as the electrophoresis approach coupled with online TLS. This work establishes a versatile platform for AuNP engineering with controlled size and surface functionality. The strategies presented in this thesis aim to improve medical diagnostics to make them affordable for point-of-care scenarios to enhance the quality of human health. wide range of sensors and electronic devices. The relevance of molecular recognition and the binding of biological and chemical entities to diagnostics, biosensors, and drug delivery has attracted significant research interest. By addressing material functionalization design and advanced characterization methods, this doctoral work aims to highlight efforts to exploit the surface modification strategies to enhance the responsiveness of nanoparticle substrates for improved detection of health-relevant biomolecules. The self-assembly of small ligands, such as alkanethiols and oligonucleotides on the surface of AuNPs provided a possible starting route for the preparation of bio-nanomaterials with precise physicochemical properties. The versatile AuNPs were optimized and thoroughly characterized by employing electron microscopy techniques such as transmission electron microscope (TEM), atomic force microscopy (AFM), and scanning electron microscopy (SEM), spectroscopic techniques, including ultraviolet/visible (UV/Vis), dynamic light scattering (DLS), and thermal lens spectrometry (TLS), and biochemical assays (gel electrophoresis, Dot plot, Western plot, and the Enzyme Linked Immunosorbent Assay (ELISA)). Subsequently, the molecular recognition capabilities of functionalized AuNPs were investigated using multiple techniques, including novel detection routes such as the electrophoresis approach coupled with online TLS. This work establishes a versatile platform for AuNP engineering with controlled size and surface functionality. The strategies presented in this thesis aim to improve medical diagnostics to make them affordable for point-of-care scenarios to enhance the quality of human health.

In this paper, polystyrene microspheres were firstly prepared by seeded emulsion polymerization, and the uniform monolayer of polystyrene microspheres was prepared on the substrate by the dipping method. Then, polystyrene monolayer film was used as a mask and a low dimensional array structure of gold was prepared by bottom-up self-assembly process. After that, the method of solution etching and annealing was used, and the gold nanoparticle array was post-processed. As a result, gold nanoparticles were recrystallized, with an average diameter of about 50 nm. Subsequently, the semiconductor process was adopted, with focused ion beams induced deposition and electron beam evaporation, and single electron transistors were fabricated, based on self-assembled gold nanoparticles. Finally, the devices were fixed in a liquid helium cryostat and Coulomb blockade was observed at 320 mK. It is a novel fabrication of a single electron transistor based on gold nanoparticle array template and prepared with polystyrene nanospheres.

Single domain antibodies (sdAb) are the recombinant variable heavy domains derived from camelid heavy-chain antibodies. While they have binding affinities equivalent to conventional antibodies, sdAb are only one-tenth the size and possess numerous advantages such as excellent thermal stability with the ability to refold following denaturation, and inexpensive production in Escherichia coli or yeast. However, their small size does have drawbacks, one being that they can lose activity upon attachment or adsorption to surfaces, or may fail to adsorb efficiently, as they are highly soluble. This can make the transition from using conventional antibodies to sdAb nontrivial for assay development. Specifically, it is often necessary to re-optimize the protocols and tailor the recombinant sdAb through protein engineering to function efficiently in handheld assays, which currently are utilized for point of care testing and field applications. This work focuses on optimizing the integration of sdAb into rapid vertical flow assays. To achieve this goal, we engineered sdAb-based constructs and developed general protocols for the attachment of the sdAb to both gold nanoparticles and a support membrane. We achieved a limit of detection of 0.11 µg/mL for toxins staphylococcal enterotoxin B and ricin, both potential biothreat agents. Additionally, we demonstrated the ability to detect the nucleocapsid protein of SARS-CoV-2, a common target of antigen tests for COVID-19.

The development of a rapid, sensitive, and straightforward detection method of prostate‐specific antigen (PSA) is indispensable for the early diagnosis of prostate cancer (PCa). This work relates an electrochemical method using functionalized single‐stranded DNA aptamer to diagnose PCa and benign prostate hyperplasia. The sensing platform relies on PSA recognition by aptamer/Au/GO‐nanohybrid‐modified glassy carbon electrode. Besides ferrocyanide TiO2/carbon quantum dots (CQDs) probe is used to investigate the effect of nanoparticle‐containing electrolyte. Optimization of incubation time of aptamer/Au/GO‐nanohybrid and volume fraction of nafion were done using Design Expert 10 software reporting 42.4 h and 0.095% V/V, respectively. In ferrocyanide medium, PSA detection as low as 3, 2.96, and 0.85 ng mL−1 was achieved with a dynamic range from 0.5 to 7 ng ml−1, in accord with clinical values, using cyclic voltammetry, square wave voltammetry, and electrochemical impedance spectroscopy, respectively. Moreover, this sensor exhibited conspicuous performance in TiO2/CQDs‐containing medium with different pH values of 5.4 and 8 to distinguish total PSA and free PSA, resulting in very low limit of detections, 0.028, and 0.007 ng ml−1, respectively. The results manifested the proposed system as a forthcoming sensor in a clinical and point of care analysis of PSA.

Background Discovery of early-stage biomarkers is a long-sought goal of Alzheimer’s disease (AD) diagnosis. Age is the greatest risk factor for most AD and accumulating evidence suggests that age-dependent elevation of asparaginyl endopeptidase (AEP) in the brain may represent a new biological marker for predicting AD. However, this speculation remains to be explored with an appropriate assay method because mammalian AEP exists in many organs and the level of AEP in body fluid isn’t proportional to its concentration in brain parenchyma. To this end, we here modified gold nanoparticle (AuNPs) into an AEP-responsive imaging probe and choose transgenic APPswe/PS1dE9 (APP/PS1) mice as an animal model of AD. Our aim is to determine whether imaging of brain AEP can be used to predict AD pathology. Results This AEP-responsive imaging probe AuNPs-Cy5.5-A&C consisted of two particles, AuNPs-Cy5.5-AK and AuNPs-Cy5.5-CABT, which were respectively modified with Ala–Ala–Asn–Cys–Lys (AK) and 2-cyano-6-aminobenzothiazole (CABT). We showed that AuNPs-Cy5.5-A&C could be selectively activated by AEP to aggregate and emit strong fluorescence. Moreover, AuNPs-Cy5.5-A&C displayed a general applicability in various cell lines and its florescence intensity correlated well with AEP activity in these cells. In the brain of APP/PS1 transgenic mice , AEP activity was increased at an early disease stage of AD that precedes formation of senile plaques and cognitive impairment. Pharmacological inhibition of AEP with δ-secretase inhibitor 11 (10 mg kg−1, p.o.) reduced production of β-amyloid (Aβ) and ameliorated memory loss. Therefore, elevation of AEP is an early sign of AD onset. Finally, we showed that live animal imaging with this AEP-responsive probe could monitor the up-regulated AEP in the brain of APP/PS1 mice. Conclusions The current work provided a proof of concept that assessment of brain AEP activity by in vivo imaging assay is a potential biomarker for early diagnosis of AD. Graphical abstract

Bijon Kumar Sil,1 Mohd Raeed Jamiruddin,2 Md Ahsanul Haq,1 Mohib Ullah Khondoker,3 Nowshin Jahan,1 Shahad Saif Khandker,1 Tamanna Ali,1 Mumtarin Jannat Oishee,1 Taku Kaitsuka,4 Masayasu Mie,5 Kazuhito Tomizawa,6 Eiry Kobatake,5 Mainul Haque,7 Nihad Adnan8 1Gonoshasthaya-RNA Molecular Diagnostic and Research Center, Dhaka, 1205, Bangladesh; 2Department of Pharmacy, BRAC University, Dhaka, 1212, Bangladesh; 3Gonoshasthaya Samaj Vittik Medical College, Savar, Dhaka, 1344, Bangladesh; 4School of Pharmacy, International University of Health and Welfare, Okawa, Fukuoka, 831-8501, Japan; 5School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa, 226-8502, Japan; 6Department of Molecular Physiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, 860-0811, Japan; 7The Unit of Pharmacology, Faculty of Medicine and Defence Health Universiti Pertahanan, Nasional Malaysia (National Defence University of Malaysia), Kuala Lumpur, 57000, Malaysia; 8Department of Microbiology, Jahangirnagar University, Savar, Dhaka, 1342, BangladeshCorrespondence: Nihad AdnanDepartment of Microbiology, Jahangirnagar University, Savar, Dhaka, 1342, BangladeshTel +8801705709910Email nihad@juniv.eduMainul HaqueThe Unit of Pharmacology, Faculty of Medicine and Defence Health, Universiti Pertahanan, Nasional Malaysia (National Defence University of Malaysia), Kem Perdana Sungai Besi, Kuala Lumpur, 57000, MalaysiaTel +60109265543Email runurono@gmail.comBackground: Serological tests detecting severe acute respiratory syndrome coronavirus− 2 (SARS-CoV-2) are widely used in seroprevalence studies and evaluating the efficacy of the vaccination program. Some of the widely used serological testing techniques are enzyme-linked immune-sorbent assay (ELISA), chemiluminescence immunoassay (CLIA), and lateral flow immunoassay (LFIA). However, these tests are plagued with low sensitivity or specificity, time-consuming, labor-intensive, and expensive. We developed a serological test implementing flow-through dot-blot assay (FT-DBA) for SARS-CoV-2 specific IgG detection, which provides enhanced sensitivity and specificity while being quick to perform and easy to use.Methods: SARS-CoV-2 antigens were immobilized on nitrocellulose membrane to capture human IgG, which was then detected with anti-human IgG conjugated gold nanoparticle (hIgG-AuNP). A total of 181 samples were analyzed in-house. Within which 35 were further evaluated in US FDA-approved CLIA Elecsys SARS-CoV-2 assay. The positive panel consisted of RT-qPCR positive samples from patients with both < 14 days and > 14 days from the onset of clinical symptoms. The negative panel contained samples collected from the pre-pandemic era dengue patients and healthy donors during the pandemic. Moreover, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of FT-DBA were evaluated against RT-qPCR positive sera. However, the overall efficacies were assessed with sera that seroconverted against either nucleocapsid (NCP) or receptor-binding domain (RBD).Results: In-house ELISA selected a total of 81 true seropositive and 100 seronegative samples. The sensitivity of samples with < 14 days using FT-DBA was 94.7%, increasing to 100% for samples > 14 days. The overall detection sensitivity and specificity were 98.8% and 98%, respectively, whereas the overall PPV and NPV were 99.6% and 99%. Moreover, comparative analysis between in-house ELISA assays and FT-DBA revealed clinical agreement of Cohen’s Kappa value of 0.944. The FT-DBA showed sensitivity and specificity of 100% when compared with commercial CLIA kits.Conclusion: The assay can confirm past SARS-CoV-2 infection with high accuracy within 2 minutes compared to commercial CLIA or in-house ELISA. It can help track SARS-CoV-2 disease progression, population screening, and vaccination response. The ease of use of the assay without requiring any instruments while being semi-quantitative provides the avenue of its implementation in remote areas around the globe, where conventional serodiagnosis is not feasible.Keywords: COVID-19, SARS-CoV-2, dot-blot immunoassay, AuNP, gold nanoparticle, serosurveillance, nucleocapsid, receptor binding domain

International audience; Organizing nanoparticles in a controlled way allows us to monitor their optical properties. It is particularly interesting to organize them on top of liquid crystal films to take advantage, in a second step, of the easy actuation of liquid crystals with external parameters such as temperature, electric fields, and so forth. We show that despite their fluidity, nematic and smectic films allow the formation of well-ordered hexagonal domains of gold spherical nanoparticles (AuNPs) at their surface, but we also show that both nematic films and AuNP domains impact each other. Using optical microscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), and spectrophotometry, we compare nematic, polymer-stabilized nematic, and smectic films with AuNP domains made of NPs of diameter 6 nm. On the liquid crystal films, depressions are revealed below the AuNP domains, whereas the AuNP domains appear well-organized but with a hexagonal period shortened with respect to AuNP monolayers formed on hard substrates. We interpret these features by the anchoring tilt imposed by the AuNP domains on the liquid crystal molecules. The smectic-A layers characteristic of the nematic surface transform into smectic-C layers, which induce the formation of depression. The energy penalty associated with the local smectic-A/smectic-C transition induces the shortening of the AuNP domain period in order to decrease the AuNP domain surface. The observed large depth of the polymer-stabilized nematic depressions below AuNP domains may be explained either by an increased size of the polymer-stabilized smectic layers close to the surface or by an increased number of polymer-stabilized smectic liquid crystal smectic layers close to the surface with respect to pure nematic films.

The iron superoxide dismutase (FeSOD) is a first barrier to defend photosynthetic organisms from superoxide radicals. Although it is broadly present in plants and bacteria, FeSODs are absent in animals. They belong to the same phylogenic family as Mn-containing SODs, which are also highly efficient at detoxifying superoxide radicals. In addition, SODs can react with peroxynitrite, and FeSOD enzyme has already been used to evaluate the anti-nitrative capacity of plant antioxidants. Gold nanoparticles (AuNPs) have been shown to significantly improve the functionality and the efficiency of ligands, providing they are properly assembled. In this work, the characteristics of the recombinant cowpea (Vigna unguiculata) FeSOD (rVuFeSOD) immobilized onto AuNPs were investigated as a function of (1) NP surface chemistry and (2) biofunctionalization methods, either physical adsorption or covalent bonding. The NP surface chemistry was studied by varying the concentration of the ligand molecule 11-mercaptoundecanoic acid (MUA) on the NP surface. The coverage and activity of the protein on AuNPs was determined and correlated to the surface chemistry and the two biofunctionalization methods. rVuFeSOD–AuNPs conjugate stability was monitored through absorption measurements, agarose gel electrophoresis and DLS, enzymatic activity by a colorimetric assay and by in-gel activity assay, and coverage was measured by colorimetric assay. When using physical adsorption, the NP is the most perturbing agent for the activity of the enzyme. In contrast, only the NP coverage was affected by MUA ligand concentration. However, during covalent attachment, both the NP and the concentration of MUA on the surface influenced the enzyme activity, while the coverage of the NP remained constant. The results evidence the importance of the biomolecule and AuNP interaction for the functionality of the hybrid. These strategies can be used to develop electrochemical biosensors for O2•− and for peroxynitrite in biomedical applications.

Gold nanoparticles (GNPs) are used in proton therapy radio-sensitizers to help increase the dose of radiation to targeted tumors by the emission of secondary electrons. Thus, this study aimed to investigate the link between secondary electron yields produced from a nanoshell of GNPs and dose absorption according to the distance from the center of the nanoparticles by using a Monte Carlo model. Microscopic evaluation was performed by modeling the interactions of secondary electrons in a phase-space file (PSF), where the number of emitted electrons was calculated within a spherical GNP of 15 nm along with the absorbed dose near it. Then, the Geant4-DNA physics list was used to facilitate the tracking of low-energy electrons down to an energy below 50 eV in water. The results show a remarkable change in the number of secondary electrons, which can be compared at concentrations less than and greater than 5 mg/mL, with increased secondary electron production exhibited around NPs within a distance of 10–100 nm from the surface of all nanospheres. It was found that there was a steep dose enhancement drop-off up to a factor of dose enhancement factor (DFE) ≤ 1 within a short distance of 100 nm from the surface of the GNPs, which revealed that the dose enhancement existed locally at nanometer distances from the GNPs. Overall, our results indicate that the physical interactions of protons with GNP clusters should not be considered as being directly responsible for the radio-sensitization effect, but should be regarded as playing a major role in NP properties and concentrations, which has a subsequent impact on local dose enhancement.

Background and Objective:In recent years, the use of nanoparticles (NPs), especially gold nanoparticles (GNPs) in radiotherapy, has been repeatedly studied by in-vitro, in-vivo experiments, and Monte Carlo simulation. Some studies declare that specific absorption of GNPs (with a higher atomic number) by cancerous cells increases radiations’ lethal effect compared to normal cells. This review article aimed to investigate the radiosensitizing effect of GNPs in cancer radiotherapy. Materials and Methods:Research databases such as Web of Science, PubMed, and Scopus were examined from December 2019. All Gold Nanoparticles Radiation Therapy (GNRT) articles that studied the radiosensitization of gold nanoparticles in radiotherapy were involved in the assessment. Among 706 chosen articles, 52 documents were included in this investigation. Results:The results of all these studies indicate that an increase in tumor mortality happens due to higher radiation absorption by nanoparticles entering the tumor; however, the relationship between the interaction of radiant energy and the size of gold nanoparticles is controversial. Conclusion:This review article will discuss recent advances in the development of gold-based NPs to improve radiotherapy. Keywords:Gold Nanoparticle,Radiotherapy,Radio sensitization,Cancer

Many cancer therapeutics are tested in vitro using only tumour cells. However, the tumour promoting effect of cancer associated fibroblasts (CAFs) within the tumour microenvironment (TME) is thought to reduce cancer therapeutics’ efficacy. We have chosen pancreatic ductal adenocarcinoma (PDAC) as our tumor model. Our goal is to create a co-culture of CAFs and tumour cells to model the interaction between cancer and stromal cells in the TME and allow for better testing of therapeutic combinations. To test the proposed co-culture model, a gold nanoparticle (GNP) mediated-radiation response was used. Cells were grown in co-culture with different ratios of CAFs to cancer cells. MIA PaCa-2 was used as our PDAC cancer cell line. Co-cultured cells were treated with 2 Gy of radiation following GNP incubation. DNA damage and cell proliferation were examined to assess the combined effect of radiation and GNPs. Cancer cells in co-culture exhibited up to a 23% decrease in DNA double strand breaks (DSB) and up to a 35% increase in proliferation compared to monocultures. GNP/Radiotherapy (RT) induced up to a 25% increase in DNA DSBs and up to a 15% decrease in proliferation compared to RT alone in both monocultured and co-cultured cells. The observed resistance in the co-culture system may be attributed to the role of CAFs in supporting cancer cells. Moreover, we were able to reduce the activity of CAFs using GNPs during radiation treatment. Indeed, CAFs internalize a significantly higher number of GNPs, which may have led to the reduction in their activity. One reason experimental therapeutics fail in clinical trials relates to limitations in the pre-clinical models that lack a true representation of the TME. We have demonstrated a co-culture platform to test GNP/RT in a clinically relevant environment.

Sodium citrate-stabilized gold nanoparticles (AuNPs) are destabilized when dispersed in cell culture media (CCMs). This may promote their aggregation and subsequent sedimentation, or under the proper conditions, their interaction with dispersed proteins can lead to the formation of a NP-stabilizing protein corona. CCMs are ionic solutions that contain growth substances which are typically supplemented, in addition to serum, with different substances such as dyes, antioxidants, and antibiotics. In this study, the impact of phenol red, penicillin–streptomycin, l-glutamine, and β-mercaptoethanol on the formation of the NP–protein corona in CCMs was investigated. Similar protein coronas were obtained except in the presence of antibiotics. Under these conditions, the protein corona took more time to be formed, and its density and composition were altered, as indicated by UV–vis spectroscopy, Z potential, dynamic light scattering, and liquid chromatography–mass spectrometry analyses. As a consequence of these modifications, a significantly different AuNP cellular uptake was measured, showing that NP uptake increased as did the NP aggregate formation. AuNP uptake studies performed in the presence of clathrin- and caveolin-mediated endocytosis inhibitors showed that neither clathrin receptors nor lipid rafts were significantly involved in the internalization mechanism. These results suggest that in these conditions, NP aggregation is the main mechanism responsible for their cellular uptake., We acknowledge financial support from the Pandora European Training Network (GA-671881) funded in the framework of H2020 Marie Skłodowska-Curie ITN programme, Spanish Ministerio de Ciencia, Innovación y Universidades (MCIU) (RTI2018-099965-B-I00, AEI/FEDER, UE), and Catalan Agència de Gestió d’Ajuts Universitaris i de Recerca (AGAUR) (2017-SGR-1431). L.M. thanks the financial support from AGAUR by means of the grants for the incorporation of post-doctoral research staff into the Catalan science and technology system within the Beatriu de Pinós program (grant no. 2016 BP 00350). N.G.B. acknowledges financial support by MINECO through the Ramon y Cajal program (RYC-2012-10991). ICN2 is supported by the Severo Ochoa program from Spanish MINECO (grant no. SEV-2017-0706) and is funded by the CERCA Programme/Generalitat de Catalunya. The present work has been performed in the framework of the doctorate in Chemistry and Materials Science at the Autonomous University of Barcelona (UAB) and has been supported by the Priority program ACBN, University of Salzburg. O.H.M. acknowledges financial support from the Spanish Ministry of Science and Innovation (MICINN) through a FPI fellowship, resolved by the Agencia Estatal de Investigación (AEI) with reference (BES-2017-083043). The Proteomics Unit at VHIO is a member of Proteored, PRB3, supported by grant PT17/0019 and funded by ISCIII and ERDF.

Active targeting is a promising approach for the treatment of viral infections. In particular, site-specific formulations for the treatment of HIV infection may overcome challenges associated with current ARV regimens. In this study we explored active targeting by synthesizing a gold nanoparticle construct decorated with an anti-CD4 cyclic peptide. The aim was to demonstrate selectivity of the system for the CD4 receptor and to deliver the RNA payload into T-lymphocytes. Colloidal gold nanoparticles functionalized withN-succinimidyl 3-(2-pyridyldithio) propionate (SPDP) were formed by a one-pot synthesis method where thiol modified polyethyleneimine (PEI) was mixed with chloroauric acid. PEI-SPDP AuNPs (gold nanoparticles) were conjugated to an anti-CD4 peptide and loaded with RNA. We measured toxicity and uptake using TZM-bl and HeLa cells. Our findings show that the nanoparticles bind selectively to CD4 + cells. UV-vis characterisation of the nanoparticles revealed a surface plasmon resonance (SPR) peak at 527 nm, corresponding to a 6 nm diameter. HRTEM of the complete nanoparticles visualised circular shaped particles with average diameter of ∼7 nm. The polydispersity index was calculated to be 0.08, indicating monodispersity of complete NPS in solution. Through the pyridine-2-thione assay each nanoparticle was calculated to carry 1.37 × 105SPDP molecules available for peptide binding. Flow cytometry showed that 13.6% of TZM-bl cells, and 0.14% of HeLa cells retained fluorescence after an overnight incubation, an indication of system binding. No internal RNA delivery was demonstrated. Further work is required to improve internalization.

Flavivirus detection in humans and mosquito reservoirs has been an important issue since it can cause a variety of illnesses and could represent a health problem in geographical zones where the vector is endemic. In this work, we designed and characterized a biosensor based on gold nanoparticles (AuNPs) and antibody 4G2 for the detection of dengue virus (DENV) in vitro, obtaining different conjugates (with different antibody concentrations). The AuNP–4G2 conjugates at concentrations of 1, 3, and 6 µg/mL presented an increase in the average hydrodynamic diameter compared to the naked AuNPs. Also, as part of the characterization, differences in the UV-Vis absorbance spectrum and electrophoretic migration were observed between the conjugated AuNPs (with BSA or antibody) and naked AuNPs. Additionally, we used this biosensor (AuNP–4G2 conjugate with 3 µg/mL antibody) in the assembly of a competitive lateral flow assay (LFA) for the development of an alternative test to detect the flavivirus envelope protein in isolated DENV samples as a future tool for dengue detection (and other flaviviruses) in the mosquito vector (Aedesaegypti) for the identification of epidemic risk regions. Functionality tests were performed using Dengue virus 2 isolated solution (TCID50/mL = 4.58 × 103) as a positive sample and PBS buffer as a negative control. The results showed that it is possible to detect Dengue virus in vitro with this gold nanoparticle-based lateral flow assay with an estimated detection limit of 5.12 × 102 PFU. We suggest that this biosensor could be used as an additional detection tool by coupling it to different point-of-care tests (POCT) for the easy detection of other flaviviruses.

Zhenrui Xue,1– 3,* Minli You,2,3,* Ping Peng,1– 3,* Haoyang Tong,2,3 Wanghong He,2– 4 Ang Li,4 Ping Mao,1– 3 Ting Xu,1 Feng Xu,2,3 Chunyan Yao1 1Department of Transfusion Medicine, Southwest Hospital, Third Military Medical University, Army Medical University, Chongqing, 400038, People’s Republic of China; 2The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, 710049, People’s Republic of China; 3Bioinspired Engineering and Biomechanics Center (BEBC), Xi’an Jiaotong University, Xi’an, 710049, People’s Republic of China; 4Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, Xi’an, 710049, People’s Republic of China*These authors contributed equally to this workCorrespondence: Chunyan Yao; Feng XuDepartment of Transfusion Medicine, Southwest Hospital, Third Military Medical University, Army Medical University, Chongqing, 400038, People’s Republic of ChinaTel +64 389 619 2922Email yao_yao24@yahoo.com; fengxu@mail.xjtu.edu.cnPurpose: Detection of single-base mutations is important for real-time monitoring of tumor progression, therapeutic effects, and drug resistance. However, the specific detection of single-base mutations from excessive wild-type background sequences with routine PCR technology remains challenging. Our objective is to develop a simple and highly specific qPCR-based single-base mutation detection method.Methods: Using EGRF T790M as a model, gold nanoparticles at different concentrations were separately added into the Taqman-MGB qPCR system to test specificity improvement, leading to the development of the optimal Taqman-MGB nanoPCR system. Then, these optimal conditions were used to test the range of improvement in the specificity of mutant-type and wild-type templates and the detection limit of mutation abundances in a spiked sample.Results: The Taqman-MGB nanoPCR was established based on the traditional qPCR, with significantly suppressed background noise and improved specificity for single-base mutation detection. With EGFR T790M as a template, we demonstrated that our Taqman-MGB nanoPCR system could improve specificity across a wide concentration range from 10− 9 μM to 10 μM and detect as low as 0.95% mutation abundance in spiked samples, which is lower than what the traditional Taqman-MGB qPCR and existing PCR methods can detect. Moreover, we also proposed an experimentally validated barrier hypothesis for the mechanism of improved specificity.Conclusion: The developed Taqman-MGB nanoPCR system could be a powerful tool for clinical single-base mutation detection.Keywords: nanoparticle-assisted PCR, point mutation, gold nanoparticle, specificity

Zhenrui Xue,1– 3,* Minli You,2,3,* Ping Peng,1– 3,* Haoyang Tong,2,3 Wanghong He,2– 4 Ang Li,4 Ping Mao,1– 3 Ting Xu,1 Feng Xu,2,3 Chunyan Yao1 1Department of Transfusion Medicine, Southwest Hospital, Third Military Medical University, Army Medical University, Chongqing, 400038, People’s Republic of China; 2The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, 710049, People’s Republic of China; 3Bioinspired Engineering and Biomechanics Center (BEBC), Xi’an Jiaotong University, Xi’an, 710049, People’s Republic of China; 4Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, Xi’an, 710049, People’s Republic of China*These authors contributed equally to this workCorrespondence: Chunyan Yao; Feng XuDepartment of Transfusion Medicine, Southwest Hospital, Third Military Medical University, Army Medical University, Chongqing, 400038, People’s Republic of ChinaTel +64 389 619 2922Email yao_yao24@yahoo.com; fengxu@mail.xjtu.edu.cnPurpose: Detection of single-base mutations is important for real-time monitoring of tumor progression, therapeutic effects, and drug resistance. However, the specific detection of single-base mutations from excessive wild-type background sequences with routine PCR technology remains challenging. Our objective is to develop a simple and highly specific qPCR-based single-base mutation detection method.Methods: Using EGRF T790M as a model, gold nanoparticles at different concentrations were separately added into the Taqman-MGB qPCR system to test specificity improvement, leading to the development of the optimal Taqman-MGB nanoPCR system. Then, these optimal conditions were used to test the range of improvement in the specificity of mutant-type and wild-type templates and the detection limit of mutation abundances in a spiked sample.Results: The Taqman-MGB nanoPCR was established based on the traditional qPCR, with significantly suppressed background noise and improved specificity for single-base mutation detection. With EGFR T790M as a template, we demonstrated that our Taqman-MGB nanoPCR system could improve specificity across a wide concentration range from 10− 9 μM to 10 μM and detect as low as 0.95% mutation abundance in spiked samples, which is lower than what the traditional Taqman-MGB qPCR and existing PCR methods can detect. Moreover, we also proposed an experimentally validated barrier hypothesis for the mechanism of improved specificity.Conclusion: The developed Taqman-MGB nanoPCR system could be a powerful tool for clinical single-base mutation detection.Keywords: nanoparticle-assisted PCR, point mutation, gold nanoparticle, specificity

Theeranan Tangthong,1,2 Thananchai Piroonpan,2 Velaphi C Thipe,3,4 Menka Khoobchandani,4,5 Kavita Katti,4,5 Kattesh V Katti,4– 6 Wanvimol Pasanphan1,2 1Department of Materials Science, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand; 2Center of Radiation Processing for Polymer Modification and Nanotechnology (CRPN), Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand; 3Laboratório de Ecotoxicologia - Centro de Química e Meio Ambiente - Instituto de Pesquisas Energéticase Nucleares (IPEN) - Comissão Nacional de Energia Nuclear- IPEN/CNEN-SP, São Paulo, Brasil; 4Institute of Green Nanotechnology, University of Missouri, Columbia, MO, 65211, USA; 5Department of Radiology, University of Missouri, Columbia, MO, 65211, USA; 6Department of Physics, University of Missouri, Columbia, MO, 65211, USACorrespondence: Wanvimol PasanphanDepartment of Materials Science, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok, 10900, ThailandTel +66 2562 5555 (Ext. 646518)Email wanvimol.p@ku.ac.thKattesh V KattiInstitute of Green Nanotechnology, University of Missouri, Columbia, MO, 65211, USATel +1 573 882-5656Fax +1 573 884-5679Email KattiK@health.missouri.eduIntroduction: Functionalization of water-soluble chitosan (WSCS) nanocolloids with, gold nanoparticles (AuNPs), and LyslLys3 (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid)-bombesin 1– 14 (DOTA-BBN) peptide affords an innovative pathway to produce prostate tumor cell-specific nanomedicine agents with potential applications in molecular imaging and therapy.Methods: The preparation involves the production and full characterization of water-soluble chitosan (WSCS), via gamma (γ) rays (80 kGy) irradiation, followed by DOTA-BBN conjugation for subsequent use as an effective template toward the synthesis of tumor cell-specific AuNPs-WSCS-DOTA-BBN.Results: The WSCS-DOTA-BBN polymeric nanoparticles (86 ± 2.03 nm) served multiple roles as reducing and stabilizing agents in the overall template synthesis of tumor cell-targeted AuNPs. The AuNPs capped with WSCS and WSCS-DOTA-BBN exhibited average Au-core diameter of 17 ± 8 nm and 20 ± 7 nm with hydrodynamic diameters of 56 ± 1 and 67± 2 nm, respectively. The AuNPs-WSCS-DOTA-BBN showed optimum in vitro stability in biologically relevant solutions. The targeted AuNPs showed selective affinity toward GRP receptors overexpressed in prostate cancer cells (PC-3 and LNCaP).Discussion: The AuNPs-WSCS-DOTA-BBN displayed cytotoxicity effects against PC-3 and LNCaP cancer cells, with concomitant safety toward the HAECs normal cells. The AuNPs-WSCS-DOTA-BBN showed synergistic targeting toward tumor cells with selective cytotoxicity of AuNPs towards PC-3 and LNCaP cells. Our investigations provide compelling evidence that AuNPs functionalized with WSCS-DOTA-BBN is an innovative nanomedicine approach for use in molecular imaging and therapy of GRP receptor-positive tumors. The template synthesis of AuNPs-WSCS-DOTA-BBN serves as an excellent non-radioactive surrogate for the development of the corresponding 198AuNPs theragnostic nanoradiopharmaceutical for use in cancer diagnosis and therapy.Keywords: DOTA-bombesin, gold nanoparticle, water-soluble chitosan, nanoradiopharmaceutical, prostate cancer

Theeranan Tangthong,1,2 Thananchai Piroonpan,2 Velaphi C Thipe,3,4 Menka Khoobchandani,4,5 Kavita Katti,4,5 Kattesh V Katti,4– 6 Wanvimol Pasanphan1,2 1Department of Materials Science, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand; 2Center of Radiation Processing for Polymer Modification and Nanotechnology (CRPN), Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand; 3Laboratório de Ecotoxicologia - Centro de Química e Meio Ambiente - Instituto de Pesquisas Energéticase Nucleares (IPEN) - Comissão Nacional de Energia Nuclear- IPEN/CNEN-SP, São Paulo, Brasil; 4Institute of Green Nanotechnology, University of Missouri, Columbia, MO, 65211, USA; 5Department of Radiology, University of Missouri, Columbia, MO, 65211, USA; 6Department of Physics, University of Missouri, Columbia, MO, 65211, USACorrespondence: Wanvimol PasanphanDepartment of Materials Science, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, Bangkok, 10900, ThailandTel +66 2562 5555 (Ext. 646518)Email wanvimol.p@ku.ac.thKattesh V KattiInstitute of Green Nanotechnology, University of Missouri, Columbia, MO, 65211, USATel +1 573 882-5656Fax +1 573 884-5679Email KattiK@health.missouri.eduIntroduction: Functionalization of water-soluble chitosan (WSCS) nanocolloids with, gold nanoparticles (AuNPs), and LyslLys3 (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid)-bombesin 1– 14 (DOTA-BBN) peptide affords an innovative pathway to produce prostate tumor cell-specific nanomedicine agents with potential applications in molecular imaging and therapy.Methods: The preparation involves the production and full characterization of water-soluble chitosan (WSCS), via gamma (γ) rays (80 kGy) irradiation, followed by DOTA-BBN conjugation for subsequent use as an effective template toward the synthesis of tumor cell-specific AuNPs-WSCS-DOTA-BBN.Results: The WSCS-DOTA-BBN polymeric nanoparticles (86 ± 2.03 nm) served multiple roles as reducing and stabilizing agents in the overall template synthesis of tumor cell-targeted AuNPs. The AuNPs capped with WSCS and WSCS-DOTA-BBN exhibited average Au-core diameter of 17 ± 8 nm and 20 ± 7 nm with hydrodynamic diameters of 56 ± 1 and 67± 2 nm, respectively. The AuNPs-WSCS-DOTA-BBN showed optimum in vitro stability in biologically relevant solutions. The targeted AuNPs showed selective affinity toward GRP receptors overexpressed in prostate cancer cells (PC-3 and LNCaP).Discussion: The AuNPs-WSCS-DOTA-BBN displayed cytotoxicity effects against PC-3 and LNCaP cancer cells, with concomitant safety toward the HAECs normal cells. The AuNPs-WSCS-DOTA-BBN showed synergistic targeting toward tumor cells with selective cytotoxicity of AuNPs towards PC-3 and LNCaP cells. Our investigations provide compelling evidence that AuNPs functionalized with WSCS-DOTA-BBN is an innovative nanomedicine approach for use in molecular imaging and therapy of GRP receptor-positive tumors. The template synthesis of AuNPs-WSCS-DOTA-BBN serves as an excellent non-radioactive surrogate for the development of the corresponding 198AuNPs theragnostic nanoradiopharmaceutical for use in cancer diagnosis and therapy.Keywords: DOTA-bombesin, gold nanoparticle, water-soluble chitosan, nanoradiopharmaceutical, prostate cancer

Here, we report a switching method of singlet oxygen (1O2) generation based on the adsorption/desorption of porphyrins to gold nanoparticles driven by sulfide (thiol or disulfide) compounds. The generation of 1O2 by photosensitization is effectively suppressed by the gold nanoparticles and can be restored by a sulfide ligand exchange reaction. The on/off ratio of 1O2 quantum yield (ΦΔ) reached 7.4. By examining various incoming sulfide compounds, it was found that the ligand exchange reaction on the gold nanoparticle surface could be thermodynamically or kinetically controlled. The remaining gold nanoparticles in the system still suppress the generation of 1O2, which can be precipitated out simultaneously with porphyrin desorption by the proper polarity choice of the incoming sulfide to restore the 1O2 generation.