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Objective(s): Several studies reported the apoptotic and lytic activity of melittin (Mel) in different tumor cells. In this study, a novel nano-complex was developed composed of AS1411aptamers, melittin and gold nanoparticle for the treatment of breast cancer cells. Materials and Methods: Gold nanoparticles (GNP) were synthesized using reduction of tetrachloroauric acid (HAuCl4). Melittin modified with cysteine and AS1411aptamer conjugated to the gold nanoparticle. Gel retardation assay was used to prove the formation of GNP-Mel-AS1411 complex. Physicochemical properties of complex were investigated by Dynamic Light Scattering (DLS). The cytotoxicity of Mel and GNP-Mel-AS1411 complex were evaluated in both MCF-7 (target) and L929 (non-target) cells by the MTT assay. Results: The average size of GNP and GNP-Mel-AS1411 complex were 20 ± 2.5 and 270.5± 3.2 respectively. The results of MTT assay revealed that this nanocomplex was more cytotoxic in MCF-7 (cell viability = 19% ± 2%) and less cytotoxic in L929 cells (cell viability = 73% ± 1.6%). Conclusion: The results of this study indicated that the gold nanoparticle-melittin-AS1411 complex had a potential value in cancer cell targeted delivery of melittin. [ABSTRACT FROM AUTHOR]

In this research, the Au nanoparticle was synthesized using a biosynthesized strategy by Mentha aquatic extract and characterized by Uv-vis spectroscopic method. The synthesized Au/NPs were used as a conductive mediator for the modification of the tramadol electrochemical sensor. The modified paste electrode with Au/NPs and 1-butyl-3-methylimidazolium tetrachloroborate (BMTCB) showed high catalytic activity for the determination of tramadol in aqueous solution. When compared to the bare electrode, the Au/NPs/BMTCB/CPE increased tramadol oxidation current by 8.8 times and lowered drug oxidation potential by 20 mV. The diffusion coefficient (D) ~ 2.55 × 10− 5 cm2/s was calculated for electro-oxidation of tramadol at surface of Au/NPs/BMTCB/CPE. With a detection limit of 6.0 nM, the Au/NPs/BMTCB/CPE revealed a linear relationship between tramadol oxidation current and concentration in the range of 0.01–400.0 M. [ABSTRACT FROM AUTHOR]

[Display omitted] • Systematically forming gold nanoparticles within a polymer particle under light irradiation. • Examining the structural properties and encapsulation degree of gold nanoparticles. • Testing physically encapsulated gold nanoparticles as reactive quasi-homogeneous catalysts. • Observing size-independent activation energies for encapsulated gold nanoparticles. The reduction of gold ions using four different types of mild reducing agents was carried out in the presence of poly(n-isopropylacrylamide), PNIPAM, particles under light irradiation at room temperature. Simply controlling the concentration ratios of the gold ions to reductants allowed for the systematic formation of physically encapsulated gold nanoparticles (AuNPs) within the PNIPAM particles due to the presence of weak interactions between the guest AuNPs and host PNIPAM particles. After the examination of the structural and physical properties of the AuNPs and their loading efficiency, the composite particles were extensively utilized in the aerobic homocoupling of phenylboronic acid in EtOH to examine their catalytic properties associated with the rate of reaction, selectivity, and activation energy (E a). All composite particles showed the highly selective formation of the biphenyl product and comparable E a values, regardless of the size and distribution of the encapsulated AuNPs as catalysts. However, the way the AuNPs were formed within the PNIPAM particles notably influenced the rate of reaction. As such, developing a simple approach to optimize the encapsulation degree of AuNPs and their structural features in the presence of polymer particles can be applied to designing diverse metal-polymer composite particles for rapid and effective catalytic systems. [ABSTRACT FROM AUTHOR]

Introduction: Plants containing aristolochic acid and its derivatives are nephrotoxic, mutagenic, and carcinogenic to humans; chronic diet poisoning caused by the aristolochic acid is the cause of endemic (Balkan) nephropathy and related cancers. Objective: To develop a colloidal gold immunochromatographic test strip (ICS) based on the competitive format for the rapid detection of aristolochic acid A (AA‐A) in herbal medicinal materials. Materials and methods: For the ICS based on gold nanoparticles (AuNPs), the antigen [AA‐A–bovine serum albumin (BSA)], and goat anti‐mouse IgG were drawn on the nitrocellulose membrane as the test line (T line) and the control line (C line), respectively. Monoclonal antibody (MAb)–AuNP conjugates were sprayed onto the conjugate pad. The sensitivity of the ICS was 6 ng/mL, and the test was completed in 10 min. The analysis of AA‐A in traditional Chinese medicine samples showed that the ICS results were in good agreement with those obtained by high‐performance liquid chromatography methods. Conclusion: These results demonstrated that the ICS test could be used as a reliable, rapid, cost‐effective, and convenient qualitative tool for on‐site screening techniques to detect AA‐A in herbal medicinal materials without any special instrumentation. An immunochromatographic strip (ICS) test for aristolochic acid was developed, and the ICS of aristolochic acid showed sensitivity of 6.0 ng/mL. The ICS is a rapid, cost‐effective, for on‐site screening technique for AA, and could detect aristolochic acid (AA) in herbal medicinal materials and food. [ABSTRACT FROM AUTHOR]

The use of nanoparticles for developing vaccines has become a routine process for researchers and pharmaceutical companies. Gold nanoparticles (GNPs) are chemical inert, have low toxicity, and are easy to modify and functionalize, making them an attractive choice for nanovaccine development. GNPs are modified for diagnostics and detection of many pathogens. The biocompatibility and biodistribution properties of GNPs render them ideal for use in clinical settings. They have excellent immune modulatory and adjuvant properties. They have been used as the antigen carrier for the delivery system to a targeted site. Tagging them with antibodies can direct the drug or antigen-carrying GNPs to specific tissues or cells. The physicochemical properties of the GNP, together with its dynamic immune response based on its size, shape, surface charge, and optical properties, make it a suitable candidate for vaccine development. The clear outcome of modulating dendritic cells, T and B lymphocytes, which trigger cytokine release in the host, indicates GNPs' efficiency in combating pathogens. The high titer of IgG and IgA antibody subtypes and their enhanced capacity to neutralize pathogens are reported in multiple studies on GNP-based vaccine development. The major focus of this review is to illustrate the role of GNPs in developing nanovaccines against multiple infectious agents, ranging from viruses to bacteria and parasites. Although the use of GNPs has its shortcomings and a low but detectable level of toxicity, their benefits warrant investing more thought and energy into the development of novel vaccine strategies. [ABSTRACT FROM AUTHOR]

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major causative agents in human and animal and the alarming growth of vancomycin resistant MRSA is the main driving force for the development of a new methodology to restore the antibacterial activity against MRSA. In the present study, gold nanoparticles (GNP) were synthesized using the chlorauric acid and trisodium citrate dehydrate. The gold nanoparticles and vancomycin bound gold nanoparticles (VBGNP) were characterized by using UV-vis spectrophotometer, SEM, TEM, AFM and XRD. The nanoparticles exhibit maximum absorbance at 520-524 nm in the UV spectrum. In SEM the size of the (GNP) and (VBGNP) decreases from 40 to 20 nm. The TEM average diameter of the VBGNPs was found to be (10-40) as the size of the particles was asymmetrical. A thin layer around 1-2 nm of drug which indicates the adsorption of vancomycin on the surface of GNPs. The antibacterial mechanism of GNPs particles interact with the building elements of the bacterial cell outer membrane, causing structural changes, and increase the adsorption of VBGNPs showed high antibacterial activity against Methicillin-resistant S. aureus. [ABSTRACT FROM AUTHOR]

Breast cancer remains the most common malignancy among women worldwide. Although the implementation of mammography has dramatically increased the early detection rate, conventional treatments like chemotherapy, radiation therapy, and surgery, have significantly improved the prognosis for breast cancer patients. However, about a third of treated breast cancer patients are known to suffer from disease recurrences and progression to metastasis. Immunotherapy has recently gained traction due to its ability to establish long-term immune surveillance, and response for the prevention of disease recurrence and extension of patient survival. Current research findings have revealed that gold nanoparticles can enhance the safety and efficacy of cancer immunotherapy, through their unique intrinsic properties of good biocompatibility, durability, convenient surface modification, as well as enhanced permeability and retention effect. Gold nanoparticles are also able to induce innate immune responses through the process of immunogenic cell death, which can lead to the establishment of lasting adaptive immunity. As such gold nanoparticles are considered as good candidates for next generation immunotherapeutic strategies. This mini review gives an overview of gold nanoparticles and their potential applications in breast cancer immunotherapeutic strategies. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A simple and label-free electrochemical aptasensor was developed for ultra-sensitive determination of chloramphenicol (CAP) based on a 2D transition of metal carbides (MXene) loaded with gold nanoparticles (AuNPs). The embedded AuNPs not only inhibit the aggregation of MXene sheets, but also improve the quantity of active sites and electronic conductivity. The aptamers (Apts) were able to immobilize on the MXene–AuNP modified electrode surface through Au–S interaction. Upon specifically binding with CAP with high affinity, the CAP–Apt complexes produced low conductivity on the aptasensor surface, leading to a decreased electrochemical signal. The resulting current change was quantitatively correlated with CAP concentration. Under optimized experimental conditions, the constructed aptasensor exhibited a good linear relationship within a wide range of 0.0001–10 nM and with a low detection limit of 0.03 pM for CAP. Moreover, the developed aptasensor has been applied to the determination of CAP concentration in honey samples with satisfactory results. [ABSTRACT FROM AUTHOR]

Background: To take advantages, such as multiplex capacity, non-photobleaching property, and high sensitivity, of surface-enhanced Raman scattering (SERS)-based in vivo imaging, development of highly enhanced SERS nanoprobes in near-infrared (NIR) region is needed. A well-controlled morphology and biocompatibility are essential features of NIR SERS nanoprobes. Gold (Au)-assembled nanostructures with controllable nanogaps with highly enhanced SERS signals within multiple hotspots could be a breakthrough. Results: Au-assembled silica (SiO2) nanoparticles (NPs) (SiO2@Au@Au NPs) as NIR SERS nanoprobes are synthesized using the seed-mediated growth method. SiO2@Au@Au NPs using six different sizes of Au NPs (SiO2@Au@Au50–SiO2@Au@Au500) were prepared by controlling the concentration of Au precursor in the growth step. The nanogaps between Au NPs on the SiO2 surface could be controlled from 4.16 to 0.98 nm by adjusting the concentration of Au precursor (hence increasing Au NP sizes), which resulted in the formation of effective SERS hotspots. SiO2@Au@Au500 NPs with a 0.98-nm gap showed a high SERS enhancement factor of approximately 3.8 × 106 under 785-nm photoexcitation. SiO2@Au@Au500 nanoprobes showed detectable in vivo SERS signals at a concentration of 16 μg/mL in animal tissue specimen at a depth of 7 mm. SiO2@Au@Au500 NPs with 14 different Raman label compounds exhibited distinct SERS signals upon subcutaneous injection into nude mice. Conclusions: SiO2@Au@Au NPs showed high potential for in vivo applications as multiplex nanoprobes with high SERS sensitivity in the NIR region. [ABSTRACT FROM AUTHOR]

The rampant use of cyanide in mining activities has posed a substantial hazard to aquatic ecosystems and human health. Herein, a composite film of poly(vinyl alcohol)/chitosan (PVA/CS) with gold nanoparticles was synthesized as a potential colorimetric sensor for cyanide ions detection in water. The utilized AuNPs with a mean diameter of 14.32±3.49 nm were synthesized by chemical reduction using polyethyleneimine. Ultraviolet-visible spectroscopy revealed the characteristic peak of AuNPs at around 530 nm in the spectrum of PVA/CS/AuNP film, while SEM microscopy revealed the integration AuNPs across the polymer substrate. A color change from red to colorless was observed on the composite film after the addition of water samples with cyanide ions with a visual detection limit between 0.1-1 ppm. The sensor also exhibited good selectivity towards cyanide against the tested water samples containing various metal ions. This study reveals the potential of the fabricated PVA/CS/AuNP composite film as a simple, affordable, and environmentally benign material for on-site detection of cyanide in water and other related application. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) show unique size‐ and shape‐dependent photosensitive properties resulting from localized surface plasmon resonance, which can be exploited in colorimetric sensors. Polyamidoamine (PAMAM) dendrimers are suitable nanotemplates of AuNPs and nanoplatforms of some stimuli‐responsive materials. In this study, AuNP was loaded in phenylalanine (Phe)‐modified PAMAM dendrimers with dual pH‐ and temperature‐sensitive properties to produce a naked‐eye colorimetric sensor with responsivity to both pH and temperature. The ultraviolet‐visible (UV‐Vis) spectra of AuNP‐loaded PAMAM‐Phe‐Suc were changed by heating at pH 4 and 5, but unchanged at pH above 5.5. The UV‐Vis spectra of AuNP‐loaded PAMAM‐Phe and PAMAM‐Suc were only slightly changed by heating at pH above 5.5 and at pH 4 and 5, respectively. In solution, AuNP‐loaded PAMAM‐Phe‐Suc changed color (from brown to gray) under high temperature (≥50 °C) and acidic (pH≤5) conditions, suggesting its functionality as a naked‐eye colorimetric dual pH and temperature sensor. [ABSTRACT FROM AUTHOR]

Metasurfaces composed of regularly arranged and deliberately oriented metallic nanoparticles can be employed to manipulate the amplitude, phase and polarization of an incident electromagnetic wave. The metasurfaces operating in the visible to near infrared spectral range rely on the modern fabrication technologies which offer a spatial resolution beyond the optical diffraction limit. Although direct laser writing is an alternative to the fabrication of nanostructures, the achievement of regular nanostructures with deep-subwavelength periods by using this method remains a big challenge. Here, we proposed and demonstrated a novel strategy for regulating disordered plasmonic nanoparticles into nanogratings with deep-subwavelength periods and reshaped nanoparticles by using femtosecond laser pulses. The orientations of the nanogratings depend strongly on the polarization of the femtosecond laser light. Such nanogratings exhibit reflection and polarization control over the reflected light, enabling the realization of polarization sensitive optical memory and color display with high spatial resolution and good chromacity.

Abstract Background Gene and chemical therapy has become one of the rising stars in the field of molecular medicine during the last two decades. However, there are still numerous challenges in the development of efficient, targeted, and safe delivery systems that can avoid siRNA degradation and reduce the toxicity and adverse effects of chemotherapy medicine. Results In this paper, a highly efficient AS1411 aptamer modified, dsDNA and MMP-2 cleavable peptide-fabricated gold nanocage vehicle, which could load doxorubicin hydrochloride (DOX) and siRNAs to achieve a combination of tumor responsive genetic therapy, chemotherapy, and photothermal treatment is presented. Our results show that this combined treatment achieved targeted gene silencing and tumor inhibition. After nearly one month of treatment with DOX-loaded Au-siRNA-PAA-AS1411 nanoparticles with one dose every three days in mice, a synergistic effect promoting the eradication of long-lived tumors was observed along with an increased survival rate of mice. The combined genetic, chemotherapeutic, and photothermal treatment group exhibited more than 90% tumor inhibition ratio (tumor signal) and a ~ 67% survival rate compared with a 30% tumor inhibition ratio and a 0% survival rate in the passive genetic treatment group. Conclusions The development of nanocarriers with double-stranded DNA and MMP-2 cleavable peptides provides a new strategy for the combined delivery of gene and chemotherapy medicine. Au-siRNA-PAA-AS1411 exerts high anticancer activities on lung cancer, indicating immense potentials for clinical application.

We report the effects of gold nanoparticles (GNP) on the enhancement of the dose effect and double-strand break (DSB) induction for X-ray monoenergies (10 keV–2 MeV). The overall relative biological effectiveness (RBE) was defined as the product of dose and DSB enhancement. The cellular doses and energy spectra were computed using the PENELOPE (PENetration and Energy LOss of Positrons and Electrons) code. The DNA damage yields were estimated using the MCDS (Monte Carlo damage simulation) code. Considering the production of Auger electrons induced by 7mg/ml GNP, we found that dose enhancement at the 30 keV was ~4.0 for cells with radius $4~\mu \text{m}$ . The DSB induction increased as GNP concentrations increased and was dependent on X-ray energy. These findings demonstrated that the maximum RBE was attained at 30–40 keV and therefore this energy range would be more efficient in cancer cell killing.

Yonghui Liu,1 Zhaoyu Wang,1 Fan Yu,2 Mingjing Li,1 Haomiao Zhu,1 Kun Wang,1 Meng Meng,1 Wei Zhao1 1State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and KLMDASR of Tianjin, Nankai University, Tianjin 300353, People’s Republic of China; 2College of Life Sciences, Nankai University, Tianjin 300071, People’s Republic of ChinaCorrespondence: Meng Meng; Wei ZhaoState Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and KLMDASR of Tianjin, Nankai University, No. 38 Tongyan Road, Haihe Education Park, Tianjin 300353, People’s Republic of ChinaTel/Fax +86 22-23507760Email mengmeng@nankai.edu.cn; wzhao@nankai.edu.cnBackground: Therapeutic tumor vaccines are one of the most promising strategies and have attracted great attention in cancer treatment. However, most of them have shown unsatisfactory immunogenicity, there are still few available vaccines for clinical use. Therefore, there is an urgent demand to develop novel strategies to improve the immune efficacy of antitumor vaccines.Purpose: This study aimed to develop novel adjuvants and carriers to enhance the immune effect of MUC1 glycopeptide antigen-based antitumor vaccines.Methods: An antitumor vaccine was developed, in which MUC1 glycopeptide was used as tumor-associated antigen, α-GalCer served as an immune adjuvant and AuNPs was a multivalent carrier.Results: Immunological evaluation results indicated that the constructed vaccines enabled a significant antibody response. FACS analysis and immunofluorescence assay showed that the induced antisera exhibited a specific binding with MUC1 positive MCF-7 cells. Moreover, the induced antibody can mediate CDC to kill MCF-7 cells. Besides stimulating B cells to produce MUC1-specific antibodies, the prepared vaccines also induced MUC1-specific CTLs in vitro. Furthermore, the vaccines significantly delayed tumor development in tumor-bearing mice model.Conclusion: These results showed that the construction of vaccines by presenting α-GalCer adjuvant and an antigen on gold nanoparticles offers a potential strategy to improve the antitumor response in cancer immunotherapy.Keywords: MUC1 glycopeptide, α-galactosylceramide, gold nanoparticle, antitumor vaccine

Breast cancer remains the most common malignancy among women worldwide. Although the implementation of mammography has dramatically increased the early detection rate, conventional treatments like chemotherapy, radiation therapy, and surgery, have significantly improved the prognosis for breast cancer patients. However, about a third of treated breast cancer patients are known to suffer from disease recurrences and progression to metastasis. Immunotherapy has recently gained traction due to its ability to establish long-term immune surveillance, and response for the prevention of disease recurrence and extension of patient survival. Current research findings have revealed that gold nanoparticles can enhance the safety and efficacy of cancer immunotherapy, through their unique intrinsic properties of good biocompatibility, durability, convenient surface modification, as well as enhanced permeability and retention effect. Gold nanoparticles are also able to induce innate immune responses through the process of immunogenic cell death, which can lead to the establishment of lasting adaptive immunity. As such gold nanoparticles are considered as good candidates for next generation immunotherapeutic strategies. This mini review gives an overview of gold nanoparticles and their potential applications in breast cancer immunotherapeutic strategies.

Immune responses are involved in the pathogenesis of many diseases, including cancer, autoimmune diseases, and chronic inflammation. These responses are attributed to immune cells that produce cytokines, mediate cytotoxicity, and synthesize antibodies. Gold nanoparticles (GNPs) are novel agents that intervene with immune responses because of their unique physical‐chemical properties. In particular, GNPs enhance anti‐tumour activity during immunotherapy and eliminate excessive inflammation in autoimmune diseases. However, GNPs synthesized by conventional methods are toxic to living organisms. Green biosynthesis provides a safe and eco‐friendly method to obtain GNPs from microbes or plant extracts. In this review, we describe several patterns for green GNP biosynthesis. The applications of GNPs to target immune cells and modulate the immune response are summarized. In particular, we elaborate on how GNPs regulate innate immunity and adaptive immunity, including inflammatory signaling and immune cell differentiation. Finally, perspectives and challenges in utilizing green biosynthesized GNPs for novel therapeutic approaches are discussed. [ABSTRACT FROM AUTHOR]

Acute myocardial infarction (AMI) is the heart attack happening when the blood flow is terminated to the heart muscles. C-reactive protein (CRP) level is raising significantly in AMI patients after the onset of symptom; also, temporal variations of CRP in plasma of AMI patient have also been found. Quantifying the concentration of CRP helps to identify the condition associated with AMI. Plasmonic enzyme-linked immunosorbent assay (ELISA) was utilized here to identify CRP by the sandwich of aptamer and antibody. Bare-eye CRP detection was achieved by plasmonic ELISA through the aggregation (blue color) of gold nanoparticle in the presence of CRP, whereas in the absence of CRP, it retains its red color (dispersion). Depending on the catalase presence on the ELISA surface, hydrogen peroxide (H2O2) controls gold growth and differentiates with color changes. To achieve the lowest detection limit of CRP, H2O2 (200 µM), gold seed (0.2 µM), and streptavidin-catalase (1:500) were found optimal. The detection limit was reached at 0.25 µg/mL, whereas it was 0.5 µg/mL in the CRP-spiked serum. This method of detection system is easier to detect the levels of CRP and helps diagnosing AMI. [ABSTRACT FROM AUTHOR]

Here, gold nanoparticles (AuNPs) were synthesized upon exposure to nano-pulsed Nd-YAG laser irradiation in de-ionized water (PLAL) and functionalized with levan polysaccharide for assessing the anticancer efficacy of doxorubicin (DOX)-conjugated levan-capped AuNPs complexes to MCF-7 breast cancer cells. According to the physicochemical test results, the increments in levan amount enhanced the colloidal stability and the drug encapsulation efficiency (DEE) significantly. For the 10L-AuNP group having the highest levan amount (10 mg/mL levan), DEE was calculated as 92.21 ± 0.56%. The lean levan, uncapped AuNPs, and 10L-AuNP were found non-cytotoxic (>80% cell viability) in the studied concentrations with 48 h MTT assays. At higher DOX loadings (25, 50, and 100 μg/mL) of 10L-AuNP, the cell viability reduced significantly compared to free DOX. Overall, these nanoparticle complexes could be proposed as potent drug delivery vehicles for cancer drugs such as DOX, as well as other drugs in the prospective studies. • Gold nanoparticle (AuNP) synthesis in levan solution via pulsed laser ablation • Levan increased the Doxorubicin (DOX) encapsulation efficiency of AuNP. • Levan, AuNP, and levan-capped AuNP were biocompatible in the concentrations used. • Levan-capped AuNP increased the cytotoxicity of DOX in higher concentrations. • Necrosis and apoptosis in MCF-7 cells were dependent on dosages of DOX/AuNP. [ABSTRACT FROM AUTHOR]

Electrochemical immunosensors enable rapid analyte quantification in small sample volumes, and have been demonstrated to provide high sensitivity and selectivity, simple miniaturization, and easy sensor production strategies. As a point-of-care (POC) format, user-friendliness is equally important and most often not combinable with high sensitivity. As such, we demonstrate here that a sequence of metal oxidation and reduction, followed by stripping via differential pulse voltammetry (DPV), provides lowest limits of detection within a 2-min automatic measurement. In exchanging gold nanoparticles (AuNPs), which dominate in the development of POC sensors, with silver nanoparticles (AgNPs), not only better sensitivity was obtained, but more importantly, the assay protocol could be simplified to match POC requirements. Specifically, we studied both nanoparticles as reporter labels in a sandwich immunoassay with the blood protein biomarker NT-proBNP. For both kinds of nanoparticles, the dose-response curves easily covered the ng∙mL−1 range. The mean standard deviation of all measurements of 17% (n ≥ 4) and a limit of detection of 26 ng∙mL−1 were achieved using AuNPs, but their detection requires addition of HCl, which is impossible in a POC format. In contrast, since AgNPs are electrochemically less stable, they enabled a simplified assay protocol and provided even lower LODs of 4.0 ng∙mL−1 in buffer and 4.7 ng∙mL−1 in human serum while maintaining the same or even better assay reliability, storage stability, and easy antibody immobilization protocols. Thus, in direct comparison, AgNPs clearly outperform AuNPs in desirable POC electrochemical assays and should gain much more attention in the future development of such biosensors. [ABSTRACT FROM AUTHOR]

Silica coating on a gold nanoparticle can improve its thermal application in cancer thermotherapy. In this paper, the interfacial thermal conductance between gold and silica is calculated utilizing classical non-equilibrium molecular dynamics. It is revealed that the results of molecular dynamics are different from what has been predicted by the conventional diffuse mismatch model. Furthermore, the interfacial thermal conductance between amorphous SiO2 and gold is approximately twice that of crystalline silica, which is explained by calculating the vibrational density of state mismatches. The interfacial thermal conductance variations in terms of van der Waals interaction strength between gold and silica are also investigated. It is revealed that the conductance increases by about 30% by increasing the simulation temperature from 300 to 700 K. The results of this paper can be useful in nanofluid systems, in addition to the application of silica-coated gold nanoparticles in cancer thermal therapy. [ABSTRACT FROM AUTHOR]

The current study intended to evaluate two types of biorecognition element (BRE), namely recombinant antibody fragments and M13 bacteriophage-displayed antibody fragments, where protein L and electrostatic interactions were used to respectively conjugated antibodies and bacteriophages on AuNPs. The functionalization process was examined by DLS to monitor the changes in the size and zeta potential. The formation of the BRE-G17-Gly immunological complexes was manifested by aggregation (confirmed by FE-SEM) and color change from red to dark blue visible to the naked eye. Local refractive index variations of functionalized AuNPs were monitored by a UV − vis spectrophotometer, showing increasing size and decreasing zeta potential in all stages. The calibration plot was developed in the concentration range 1–5 µg/mL and the limit of detection (LOD) was 1 µg/mL. The LSRP nanobiosensor in combination with the phage-based BRE was an affordable and simple approach, as it was able to eliminate the time-consuming and costly step of extracting antibodies. Contrary to the traditional immunoassays, this method does not require additional amplification, e.g., enzymatic, to read the result. The proposed LSPR nanobiosensor model can be adapted to detect a wide range of pathogens, viruses, and biomarkers in the shortest possible time. [ABSTRACT FROM AUTHOR]

Acinetobacter baumannii causes multidrug resistance, leading to fatal infections in humans. In this study, we showed that Lys AB2 P3-His-a hexahistidine-tagged form of an antimicrobial peptide (AMP) loaded onto DNA aptamer-functionalized gold nanoparticles (AuNP-Apt)-can effectively inhibit A. baumannii infection in mice. When A. baumannii-infected mice were intraperitoneally injected with AuNP-Apt loaded with Lys AB2 P3-His, a marked reduction in A. baumannii colonization was observed in the mouse organs, leading to prominently increased survival time and rate of the mice compared to those of the control mice treated with AuNP-Apt or Lys AB2 P3-His only. This study shows that AMPs loaded onto AuNP-Apt could be an effective therapeutic tool against infections caused by multidrug-resistant pathogenic bacteria in humans. [ABSTRACT FROM AUTHOR]

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Viruses are infectious agents that pose significant threats to plants, animals, and humans. The current coronavirus disease 2019 pandemic, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has spread globally and resulted in over 2 million deaths and immeasurable financial losses. Rapid and sensitive virus diagnostics become crucially important in controlling the spread of a pandemic before effective treatment and vaccines are available. Gold nanoparticle (AuNP)‐based testing holds great potential for this urgent unmet biomedical need. In this review, we describe the most recent advances in AuNP‐based viral detection applications. In addition, we discuss considerations for the design of AuNP‐based SARS‐CoV‐2 testings. Finally, we highlight and propose important parameters to consider for the future development of effective AuNP‐based testings that would be critical for not only this COVID‐19 pandemic, but also potential future outbreaks. This article is categorized under:Diagnostic Tools > BiosensingDiagnostic Tools > In Vitro Nanoparticle‐Based Sensing [ABSTRACT FROM AUTHOR]

Studies are presented in the context of the past attempts at finding nanocatalysts that can boost the performance of microbial fuel cells (MFCs) -- in terms of waste treatment and energy generation. Given the great potential of biomimetically synthesized nanoparticles (BMNPs) in providing less expensive and more environmentally friendly alternatives to NPs synthesized by physical and chemical methods, as well as a near-total lack of previous work in this area, the current research was undertaken. Effect of gold and silver nanoparticles (NPs), synthesized biomimetically using five freely available weeds, was assessed as catalysts in the MFCs. In all cases, the nanoparticles were seen to enhance the coulombic efficiency (reflective of the reduction in the waste's organic carbon load), maximum attainable power density, and overall energy yield of the MFCs by >200% relative to the uncatalyzed MFCs. Gold nanoparticles were more effective than silver nanoparticles by ≥ 20%. The results reveal that biomimetically synthesized NPs can be highly effective in reducing the operational costs as well as ecological footprints of MFCs and further work should be focused on NPs of non-precious metals. [ABSTRACT FROM AUTHOR]

We have developed a gold nanoparticle‐based surface‐assisted laser desorption/ionization mass spectrometric (SALDI‐MS) method for the analysis of amphetamine‐type stimulants (ATS), including methamphetamine (MA), 3,4‐methylenedioxy‐N‐methamphetamine (MDMA), 3,4‐methylenedioxy‐N‐ethylamphetamine (MDEA), and 4‐fluoromethamphetamine (4‐FMA), by derivatization to form quaternary ammonium species. After derivatization, the ion signal intensities of the derivatives of MA, MDMA, MDEA, and 4‐FMA significantly increase as compared to that without derivatization. Moreover, there is no analyte suppression effect in our samples after derivatization. The limits of detection (LODs) for MA, MDMA, MDEA, and 4‐FMA are 0.1, 1.0, 91, and 44 ppb, respectively, with the correlation coefficients of these regressions in the calibration curves higher than 0.99. The optimal experimental conditions, including concentration of gold nanoparticles and sample preparation method, were then applied to urine samples. After a simple sample pretreatment, including extraction and derivatization, results show that the average recoveries of the SALDI‐MS method for MA and MDMA are 100.87 ± 5.8% and 98.28 ± 2.9%, respectively. In summary, we have demonstrated a method to improve the sensitivity of the SALDI method for determination of ATS by derivatization and the method has been validated in the determination of MA and MDMA in urine samples. [ABSTRACT FROM AUTHOR]

Background and Aim: Multidrug-resistant (MDR) pathogenic microorganisms have become a global problem in ruminants as a result of the intensive use of antibiotics, causing the development of resistance among gut microbiota. The antibioticresistant microorganisms can be transferred from diseased animals to humans. This study aimed to determine the prevalence of MDR Escherichia coli and Salmonella spp. isolated from cattle, buffaloes, sheep, and goats suffering from respiratory signs, diarrhea, and mastitis and to screen the antibiotic sensitivity of selected isolated bacteria. It also detected antibioticresistance genes by polymerase chain reaction (PCR), produced green gold nanoparticles (AuNPs) using plant extracts (Artemisia herba-alba and Morus alba), and evaluated the antimicrobial activities of these biosynthesized nanoparticles on selected pathogens (E. coli and Salmonella spp.). Materials and Methods: MDR E. coli and Salmonella spp. were investigated using fecal samples (n=408), nasal swabs (n=358), and milk samples (n=227) of cattle, buffaloes, sheep, and goats with or without clinical signs, including respiratory manifestations, pneumonia, diarrhea, and mastitis, from different governorates in Egypt. E. coli and Salmonella spp. were isolated and identified on selective media, which were confirmed by biochemical reactions and PCR. Antimicrobial susceptibility testing against 10 commonly used antibiotics was performed using the Kirby-Bauer disk diffusion method. Antibiotic resistance genes blaTEM, blaSHV, blaOXA, and blaCTX-M were detected by PCR. The antibacterial effect of the biosynthesized AuNPs was evaluated by MIC and well diffusion assay. The biosynthesized AuNPs were also characterized by ultraviolet-visible spectrophotometry and transmission electron microscopy (TEM). Results: Among all fecal samples, the prevalence of E. coli was 18.4% (183/993) and that of Salmonella spp. was 16.7% (66/408), as determined by cultural and molecular tests. All isolates of E. coli and Salmonella spp. were 100% resistant to ampicillin (AM) and amoxicillin and highly resistant to cefoxitin and AM-sulbactam. The total rate of resistance genes in E. coli was 61.2% (112/183), while that in Salmonella was 63.6% (42/66) for pathogens isolated from ruminants with respiratory manifestations, pneumonia, diarrhea, and mastitis. Among the resistance genes, blaTEM had the highest prevalence rate in E. coli (25.9%, 21/81) while blaSHV had the lowest (9.8%, 8/81) in fecal swabs. AuNPs were successfully synthesized using aqueous leaf extract of A. herba-alba and M. alba as bioreducing agents. TEM analysis showed particle size of 10-42 nm for A. herba-alba and M. alba AuNPs. The biosynthesized AuNPs showed antibacterial activity against MDR E. coli and Salmonella spp. Conclusion: Rapid and accurate diagnostic methods are the cornerstone for effective treatment to reduce the risk of antimicrobial-resistant pathogenic microorganisms. This is particularly important for overcoming the increasing rate of MDR in ruminants with respiratory manifestations, pneumonia, diarrhea, and mastitis. This can be complemented by the development of AuNPs synthesized in an environmentally friendly manner AuNPs using natural plant extracts for the treatment of antibiotic-resistant microorganisms. [ABSTRACT FROM AUTHOR]

Strongly concentrated optical fields around a metal nanoparticle in the close vicinity of a dipole noticeably facilitate dramatic changes in the localized density of states due to hybrid photonic–plasmonic mode couplings as compared to that of the pure cavity mode fields. Significant variations of the field intensity in the presence of the metal nanoparticle elucidate enhanced light–matter interaction in a hybrid structure. The enhancement factor of the light–matter interaction is studied through the single-atom cooperativity parameter, which is directly proportional to the ratio of the fluorescence lifetimes of the off-resonant and on-resonant emission. A compact and cost-effective hybrid device, which includes a microfiber cavity, supporting whispering gallery modes, and a well-defined solid nanostructure, consisting of a gold nanoparticle core, overcoated by a silica shell, and decorated with CdS/CdSe quantum dots, is demonstrated to offer an outstanding potential for the enhancement of light–matter interaction. Surface plasmons of a gold nanoparticle, placed inside a hollow cylindrical nanostructure at the surface of a microfiber, are activated upon excitation of the dipoles of the quantum emitters, which are on-resonance with the whispering gallery mode. Time-resolved experiments demonstrate that the single-atom cooperativity parameter of the quantum dots is enhanced by a factor of about 4.8 in the presence of the gold nanoparticle being simultaneously in strong interaction with the cavity mode field and the metal nanoparticle's surface plasmons. [ABSTRACT FROM AUTHOR]

• This study reports a sensitivity enhancement of Au-coated lens-type dosimeter. • A layer of Au was attached to the upstream of lens-type dosimeter. • The dose enhancement factor of 5- μ m thick gold layers was 5.4 for 120 kVp X-ray tube. • Au-coated CLODs can measure a few cGy dose delivered to patients during CT imaging. This study reports a sensitivity enhancement of gold-coated contact lens-type ocular in vivo dosimeters (CLOD s) for low-dose measurements in computed tomography (CT). Monte Carlo (MC) simulations were conducted to evaluate the dose enhancement from the gold (Au) layers on the CLOD s. The human eye and CLOD s were modeled, and the X-ray tube voltages were defined as 80, 120, and 140 kVp. The thickness of the Au layer attached to a CLOD ranged from 100 nm to 10 μm. The thickness of the active layer ranged from 20 to 140 μm. The dose ratio between the active layer of the Au-coated CLOD and a CLOD without a layer, i.e., the dose enhancement factor (DEF), was calculated. The DEFs of the first 20-μm thick active layer of the 5-μm thick Au-coated CLOD were 18.4, 19.7, 20.2 at 80, 120, and 140 kVp, respectively. The DEFs decreased as the thickness of the active layer increased. The DEFs of 100-nm to 5-μm thick Au layers increased from 1.7 to 5.4 for 120-kVp X-ray tube voltage when the thickness of the active layer was 140 μm. The MC results presented a higher sensitivity of Au-coated CLODs (∼20-times higher than that of CLODs without a gold layer). Au-coated CLODs can be applied to an evaluation of very low doses (a few cGy) delivered to patients during CT imaging. [ABSTRACT FROM AUTHOR]

Background: Cell penetrating peptides (CPPs) can enter a cell through the cell membrane, and used in the fields of drug delivery, gene therapy, and cancer therapy by their property transporting various molecules into cytoplasm. Gold nanospheres (GNSs) are a useful tool for molecular imaging, because they are not cytotoxic and have high solubility, excellent light scattering property and ease of synthesis. We constructed a drug delivery system by developing gold nanospheres conjugated to MCaUF1-9-C, a CPP derived from maurocalcine (MCa) scorpion toxin. We examined the applicability of this cell-selective anti-cancer drug delivery system by evaluating its cell-penetrating and cell death activities. Methods: Cell viability of HeLa and MDA-MB-231 cells, against 500 nanomolar concentration of doxorubicin (DOX)-conjugated gold nanoparticles (DOX-GNPs, and DOX-MCaUF1–9-C-GNP) were evaluated using MTT assay. Cell penetrability of MCaUF1-9-C peptide conjugated to gold nanoparticles investigated using of dark field imaging and atomic absorption spectroscopy (AAS). Results: HeLa cell viability was about 87% when treated with DOX-GNP and DOX-MCaUF1-9-C-GNP, whereas DOX-MCaUF1–9-C-GNP induced high cytotoxicity in MDA-MB-231 cells (30%). Dark field imaging demonstrated higher affinity of MCaUF1–9-C-GNP for the MDA-MB-231 cell compared with HeLa cells. Moreover, atomic absorption spectrometry data analysis showed that 33% of the total amounts of the applied MCaUF1–9-C-GNP were internalized in MDA-MB-231 cells. Conclusion: These results demonstrated that peptide conjugated GNP would be a useful tool for the development of a cell-selective drug delivery system.

Abstract Background With the enormous increment of globalization and global warming, it is expected that the number of newly evolved infectious diseases will continue to increase. To prevent damage due to these infections, the development of a diagnostic method for detecting a virus with high sensitivity in a short time is highly desired. In this study, we have developed a disposable electrode with high-sensitivity and accuracy to evaluate its performances for several target viruses. Results Conductive silicon rubber (CSR) was used to fabricate a disposable sensing matrix composed of nitrogen and sulfur-co-doped graphene quantum dots (N,S-GQDs) and a gold-polyaniline nanocomposite (AuNP-PAni). A specific anti-white spot syndrome virus (WSSV) antibody was conjugated to the surface of this nanocomposite, which was successfully applied for the detection of WSSV over a wide linear range of concentration from 1.45 × 102 to 1.45 × 105 DNA copies/ml, with a detection limit as low as 48.4 DNA copies/ml. Conclusion The engineered sensor electrode can retain the detection activity up to 5 weeks, to confirm its long-term stability, required for disposable sensing applications. This is the first demonstration of the detection of WSSV by a nanofabricated sensing electrode with high sensitivity, selectivity, and stability, providing as a potential diagnostic tool to monitor WSSV in the aquaculture industry.

Abstract Radiotherapy is an essential step during the treatment of glioblastoma multiforme (GBM), one of the most lethal malignancies. The survival in patients with GBM was improved by the current standard of care for GBM established in 2005 but has stagnated since then. Since GBM is a radioresistant malignancy and the most of GBM recurrences occur in the radiotherapy field, increasing the effectiveness of radiotherapy using high-Z metal nanoparticles (NPs) has recently attracted attention. This review summarizes the progress in radiotherapy approaches for the current treatment of GBM, the physical and biological mechanisms of radiosensitization through high-Z metal NPs, and the results of studies on radiosensitization in the in vitro and in vivo GBM models using high-Z metal NPs to date.

Prevalent contamination of water by cadmium ion (Cd2+) brings environmental risk, which threatening to human health including renal dysfunction, reduced lung capacity, and some cancers. It calls for rapid, sensitive and selective protocol to analyze Cd2+ on field. In this work, specific Raman probe is rationally designed by gold nanoparticles (AuNPs) functionalized with tripeptide glutathione (GSH) and Rhodamine 6G (R6G) (denoted as R6G/GSH/AuNPs), which is explored for indirectly determining trace Cd2+ in river water. Based on chelating interaction between GSH and Cd2+ to form tetrahedral Cd(SG)4, which trends easy detachment from R6G/GSH/AuNPs. With increasing Cd2+ concentration, the Raman probe without protection of GSH happens due aggregation and Raman signal of R6G increases correspondingly. The R6G/GSH/AuNPs-based Raman detection of Cd2+ in river water shows rapidness, excellent sensitivity, selectivity and good repeatability. Limit of detection of 10 ppb with a widely linear range of 0.5–20 ppm could be achieved. It could be perspective that such Raman probe could be extended to be used for on-site monitoring trace Cd2+ in river water system.

A small water-soluble phosphorus-containing dendrimer was engineered for the complexation of gold(I) and for its reduction under mild conditions. Gold nanoparticles were obtained as colloidal suspensions simply and only when the powdered form of this dendrimer was dissolved in water, as shown by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX) analyses. The dendrimers acted simultaneously as mild reducers and as nanoreactors, favoring the self-assembly of gold atoms and promoting the growth and stabilization of isolated gold nanoparticles. Thus, an unprecedented method for the synthesis of colloidal suspensions of water-soluble gold nanoparticles was proposed in this work.

Arek M Engstrom,1 Ryan A Faase,2 Grant W Marquart,3 Joe E Baio,2 Marilyn R Mackiewicz,3 Stacey L Harper1,2,4 1Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR, United States; 2School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, OR, United States; 3Department of Chemistry, Portland State University, Portland, OR, United States; 4Oregon Nanoscience and Microtechnologies Institute, Corvallis, OR, United StatesCorrespondence: Stacey L Harper Email Stacey.Harper@oregonstate.eduIntroduction: Humans are intentionally exposed to gold nanoparticles (AuNPs) where they are used in variety of biomedical applications as imaging and drug delivery agents as well as diagnostic and therapeutic agents currently in clinic and in a variety of upcoming clinical trials. Consequently, it is critical that we gain a better understanding of how physiochemical properties such as size, shape, and surface chemistry drive cellular uptake and AuNP toxicity in vivo. Understanding and being able to manipulate these physiochemical properties will allow for the production of safer and more efficacious use of AuNPs in biomedical applications.Methods and Materials: Here, AuNPs of three sizes, 5 nm, 10 nm, and 20 nm, were coated with a lipid bilayer composed of sodium oleate, hydrogenated phosphatidylcholine, and hexanethiol. To understand how the physical features of AuNPs influence uptake through cellular membranes, sum frequency generation (SFG) was utilized to assess the interactions of the AuNPs with a biomimetic lipid monolayer composed of a deuterated phospholipid 1.2-dipalmitoyl-d62-sn-glycero-3-phosphocholine (dDPPC).Results and Discussion: SFG measurements showed that 5 nm and 10 nm AuNPs are able to phase into the lipid monolayer with very little energetic cost, whereas, the 20 nm AuNPs warped the membrane conforming it to the curvature of hybrid lipid-coated AuNPs. Toxicity of the AuNPs were assessed in vivo to determine how AuNP curvature and uptake influence cell health. In contrast, in vivo toxicity tested in embryonic zebrafish showed rapid toxicity of the 5 nm AuNPs, with significant 24 hpf mortality occurring at concentrations ≥ 20 mg/L, whereas the 10 nm and 20 nm AuNPs showed no significant mortality throughout the five-day experiment.Conclusion: By combining information from membrane models using SFG spectroscopy with in vivo toxicity studies, a better mechanistic understanding of how nanoparticles (NPs) interact with membranes is developed to understand how the physiochemical features of AuNPs drive nanoparticle–membrane interactions, cellular uptake, and toxicity.Keywords: gold nanoparticle, vibrational spectroscopy, nanoparticle–biological interactions, hybrid lipid-coated nanoparticle, toxicity, size-dependent interaction, zebrafish

Yersinia enterocolitica (Y. enterocolitica), Enterobacteriaceae ailesinin bir üyesi olan Yersinia cinsi’ne ait, en yaygın görülen gıda kaynaklı zoonotik patojenlerden üçüncüsüdür. Havyan dışkısı ile kontamine olan kirli sular ile veya enfekte hayvan ile iletişimin bir sonucu olarak, insanlarda enfeksiyona sebep olabilir. Düşük sıcaklıklara dayanabilme özelliği sayesinde, buzdolabında bulunan yiyeceklerde de üremeye devam edebilmektedir. Bu sebep ile patojenin hızlı ve hassas tespiti sağlık açısında önemlidir. Bu çalışmada, elektrokimyasal sistem kullanılarak, Y. enterocolitica’nın tespiti için altın nanopartikül ile güçlendirilmiş bir immünosensörün geliştirilmesi hedeflenmiştir. Çalışmada ticari olarak temin edilen Y. enterocolitica pozitif kontrol ve antikor kullanılmıştır. Standard sandvich assay kullanılarak sensör yüzeye uygulanan immünoassay ile en düşük tespit limiti 102 cfu/ml, altın nanoparçacıklar ile güçlendirilen antikor sensörü ile 37 cfu/ml Y. enterocolitica tampon çözelti içerisinde tespit edilebilmiştir. İmmünoassay’in özgüllüğü, antikora özgül olmayan antijenlerin çapraz reaksiyon oranı ile tespit edilmiştir. Bu çalışma da, standard sandvich assay ve altın nanopartiküller ile güçlendirilmiş sandvich assay prensibi geliştirilmiş ve Y. enterocolitica’nın tespiti için kullanmıştır. Bunun ile birlikte, antikor tabanlı bir enzimatik sensör de, altın nanoparçacıkların ölçüm duyarlılığına etkisi belirlenmiştir. Çalışmada ölçüm için elektrokimyasal sensör cihazı kullanılmış olup, Y. enterocolitica’nın tespitinde kullanılan immünosensör birçok elektrokimyasal biyosensör ile birleştirilebilir.

Abstract This study proposes the synthesis of a type of anticancer nanoparticle, aptamers and Au nanoparticle (Apt-Au)-modified Morin pH-sensitive liposome (MSL), which exhibits targeting properties. Tumors are difficult to cure because their microenvironment varies from that of normal tissue; its pH is lower than that of normal tissue, which generally impedes the effectiveness of drugs. Thus, pH-responsive drugs have attracted extensive attention. Gold nanoparticles (AuNPs) show potential as drug carriers because of their small size, good biocompatibility, easy surface modification, and strong cell penetration. Apt-Au@MSL exhibits excellent monodispersity and tumor-targeting properties and can be released in partly acidic environment via dialysis. We screened our model cancer cell by MTT assay and found that SGC-7901 cells can effectively suppress proliferation. In vivo results demonstrate that the administration of Apt-Au@MSL could inhibit tumor growth in xenograft mouse models. H&E staining and TUNEL assay further confirmed that Apt-Au@MSL can promote tumor apoptosis. Apt-Au@MSL may induce apoptosis by triggering overproduction of reactive oxygen species (ROS) and regulating multiple signal crosstalk. Both blood biochemistry tests and H&E staining suggested that these materials exhibit negligible acute toxicity and good biocompatibility in vivo. With its powerful function, Apt-Au@MSL can be used as a target-based anticancer material for future clinical cancer treatment.

Metallic nanoparticles are small particles, with dimensions of less than 100 nm, which have unique characteristics. For example, the color of a nanoparticle solution is given by the surface plasmon resonance, in contrast to only absorbance of a molecule. Metallic nanoparticles have been used in the antiquity for the production of colored glass. Many of the medieval cathedral red windows are in fact, stained with gold nanoparticles. However, presenting just a red solution to a class and explaining that the solution contains gold nanoparticles can be disappointing as the red color can be obtained in many different ways without the need of nanoparticles. Something peculiar, like dichroism, can, on the other hand, shine the interest of an observer to the “nano-world”. Dichroic nanoparticles show different colors when illuminated from the front (scattering) or from the back (transmission). This effect is unique for nanoparticles and nanostructures in general and can generate the “WOW” effect in class or during public demonstrations. In this article we present a simple synthesis of dichroic silver and gold nanoparticles. Solutions of such nanoparticles are a stunning visual media for demonstrations, outreach and engaging audience in the “nano”world.

Abstract Background Macrophage polarization and reprogramming in the lung play a critical role in the initiation, development and progression of acute lung injury (ALI). Regulating the activation and differentiation of pulmonary macrophages may provide a potential therapeutic strategy to treat ALI. We previously developed a novel class of anti-inflammatory nanoparticles (P12) that can potently inhibit Toll-like receptor (TLR) signaling in macrophages. These bioactive nanodevices were made of gold nanoparticles (GNPs) coated with hexapeptides to not only ensure their physiological stability but also enable GNPs with TLR inhibitory activity. Results In this study, using a lipopolysaccharide (LPS) induced ALI mouse model, we showed that P12 was able to alleviate lung inflammation and damage through reducing the infiltration of inflammatory cells and increasing the anti-inflammatory cytokine (IL-10) in the lung. These results prompted us to investigate possible macrophage polarization by P12. We first confirmed that P12 primarily targeted macrophages in the lung to exert anti-inflammatory activity. We then showed that P12 could drive the polarization of mouse bone marrow-derived macrophages (BMDMs) toward anti-inflammatory M2 phenotype. Interestingly, in the ALI mouse model, P12 was able to increase the alveolar M2 macrophages and reduce both the alveolar and interstitial M1 macrophages in the bronchoalveolar lavage fluid (BALF) and lung tissues. Conclusion This study demonstrated that peptide-coated GNPs could induce M2 macrophage polarization in vitro and in vivo to effectively regulate lung inflammation, protect lung from injuries and promote inflammation resolution. The ability of regulating macrophage polarization together with TLR inhibition made such a bioactive nanodevice a new generation of potent therapeutics to treat ALI.

Colon cancer is one of the major prevailing types of cancer worldwide. It has been the most important public health difficulty. Thus, we planned phytoconstituents arbitrated synthesis of gold nanoparticles (AuNPs) and examined their curative efficacy against the colon cancer (HCT-116) cells. In this current study, we formulated the AuNPs by using Albizia lebbeck (AL) aqueous leaf extract by the green method and synthesized AL-AuNPs were distinguished by UV-visible spectroscopy (UV-vis), energy dispersive X-ray diffraction (XRD), selected area (electron) diffraction (SAED) pattern, Fourier transform infrared spectroscopy (FTIR) and high-resolution transmission electron microscopy (HR-TEM). Synthesized AL-AuNPs confirmed by the UV absorption highest at 535 nm and the crystal structure of AL-AuNPs was additionally established by XRD and SAED pattern. HR-TEM images explained the size and morphology allocation of nanoparticles. FTIR analysis confirmed the presence of alkynes, aromatic compounds, and alkenes of biomolecules in AL-AuNPs. Furthermore, AL-AuNPs induced cytotoxicity at the IC50 concentration 48 µg/ml and also induced apoptosis by enhanced ROS production, decreased ΔΨm, apoptotic morphological changes by AO/EtBr and altering pro and anti-apoptotic protein expressions were analyzed in HCT-116 colon cancer cells. The findings of this investigation proved that the AL-AuNPs were revealed the potential anticancer activity against colon cancer (HCT-116) cells.

Antibiotic resistance amongst microbial pathogens is a mounting serious issue in researchers and physicians. Various alternatives to overcome the multidrug-resistant bacterial infections are under search, and biofilm growth inhibition is one of them. In this investigation, a polymeric drug delivery system loaded with multi-serratial drugs to improve the delivery of drugs against urinary tract infection causative Serratia marcescens. The chitosan grafted pyromellitic dianhydride – cysteine (CS-g-PMDA-CYS) was conjugated with AuNPs by using the –SH group of CYS and RF (rifampicin) and INH (isoniazid) were loaded in AuNPs-fused CS-g-PMDA-CYS system. Several physicochemical techniques characterized this fabricated AuNPs/RF/INH/CS-g-PMDA-CYS system. The successful encapsulation of RF and INH in AuNPs-fused CS-g-PMDA-CYS polymer had confirmed, and it observed the loading capacity for RF and INH was 9.02% and 13.12%, respectively. The in vitro drug discharge pattern was perceived high in pH 5.5 compared with pH 7.4. The AuNPs/RF/INH/CS-g-PMDA-CYS escalates 74% of Caenorhabditis elegans survival during Serratia marcescens infection by aiming biofilm development and virulence in S. marcescens. Author postulate that the fabricated system is a promising drug carrier and delivery system for inhibition of multidrug-resistant bacterias like S. marcescens.

African swine fever is a widespread and highly contagious disease in the porcine population, which is caused by African swine fever virus (ASFV). The PCR and ELISA detection methods are the main conventional diagnostic methods for ASFV antigen/antibody detection in the field. However, these methods have limitations of expensive equipment, trained technicians, and time-consuming results. Thus, a rapid, inexpensive, accurate and on-site detection method is urgently needed. Here we describe a double-antigen-sandwich lateral-flow assay based on gold nanoparticle-conjugated ASFV major capsid protein p72, which can detect ASFV antibody in serum samples with high sensitivity and specificity in 10 min and the results can be determined by naked eyes. A lateral flow assay was established by using yeast-expressed and acid-treated ASFV p72 conjugated with gold nanoparticles, which are synthesized by seeding method. A high coincidence (97.8%) of the assay was determined using clinical serum compared to a commercial ELISA kit. In addition, our lateral flow strip can detect as far as 1:10,000 diluted clinically positive serum for demonstration of high sensitivity. In summary, the assay developed here was shown to be rapid, inexpensive, accurate and highly selective. It represents a reliable method for on-site ASFV antibody detection and may help to control the ASFV pandemic.

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.