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Recent studies have identified gold nanoparticles in ores in a range of deposit types, but little is known about their formation processes. In this contribution, gold-bearing magnetite from the well-documented, world-class Beiya Au deposit, China, was investigated in terms of microstructure and crystallography at the nanoscale. We present the first three-dimensional (3D) focused ion beam/scanning electron microscopy (FIB/SEM) tomography of the distribution of gold nanoparticles in nanopores in the low-Si magnetite. The porous low-Si magnetite, which overprints an earlier generation of silician magnetite, was formed by a coupled dissolution-reprecipitation reaction (CDRR). The extrinsic changes in thermodynamic conditions (e.g., S content and temperature) of the hydrothermal fluids resulted in the CDRR in magnetite and the disequilibrium of Au-Bi melts. The gold nanoparticles crystallized from Au-supersaturated fluids originating from the disequilibrium of Au-Bi melts and grew in two ways depending on the intrinsic crystal structure and pore textures: (1) heteroepitaxial growth utilizing the (111) lattice planes of magnetite, and (2) randomly oriented nucleation and growth. Therefore, this study unravels how intrinsic and extrinsic factors drove the formation of gold nanoparticles at fluid-mineral interfaces. [ABSTRACT FROM AUTHOR]

Phototherapy is a type of medical treatment that involves exposure to ultraviolet-visible (UV–Vis) region or near-infrared (NIR) region light to treat certain medical conditions. Compared to other treatment methods such as chemotherapy and radiotherapy, it attracts a lot of attention today due to its lower cost, more effect on the tumor cell, and less side effects. Today's clinical therapy research shows that combining chemotherapeutic methods and phototherapeutic methods on a single nanostructure increases the therapeutic effect that each method alone has, and this is even more effective in destroying cancer cells. The emergence of nanomaterials recently opens up new opportunities to increase therapeutic efficacy and overcome limitations in current phototherapy techniques. Gold nanostars (GNSs) are a kind of promising photothermal agent recently in the biomedical field with its strong absorption in the NIR field, high photothermal conversion efficiency, excellent photothermal stability, and biocompatibility. In this study, the synthesis methods, optical properties of GNSs, and their current studies on cancer diagnosis and treatments are summarized. [ABSTRACT FROM AUTHOR]

Biologically, there exist two kinds of syntheses: photosynthesis and ATP-driven biosynthesis. The light harvesting of photosynthesis is known to achieve an efficiency of ∼ 95% by the quantum energy transfer of photons. However, how the ATP-driven biosynthesis reaches its high efficiency still remains unknown. Deoxynucleotide triphosphates (dNTPs) in polymerase chain reaction (PCR) adopt the identical way of ATP to release their energy, and thus can be employed to explore the ATP energy process. Here, using a gold nanoparticle (AuNP) enhanced PCR (AuNP-PCR), we demonstrate that the energy released by phosphoanhydride-bond (PB) hydrolysis of dNTPs is in form of photons (PB-photons) to drive DNA replication, by modulating their resonance with the average inter-AuNP distance (D). The experimental results show that both the efficiency and yield of PCR periodically oscillate with D increasing, indicating a quantized process, but not simply a thermal one. The PB-photon wavelength is further determined to 8.4 µm. All these results support that the release, transfer and utilization of bioenergy are in the form of photons. Our findings of ATP-energy quantum conversion will open a new avenue to the studies of high-efficiency bioenergy utilization, biochemistry, biological quantum physics, and even brain sciences. [ABSTRACT FROM AUTHOR]

The understanding of amphiphilic block copolymers (ABC) in encapsulation and transport of inorganic nanomedicines is highly desired. Still, it remains limited due to the challenges in the fabrication of nanoassemblies (NAs) with highly-controlled shape and loading of nanoparticles. Herein, through growth regulation of luminescent gold nanoparticles (AuNPs) by different reductants with ABC pluronic F127 as a template, a straightforward strategy is reported for in-situ fabrication of three well-controlled gold NAs (AuNAs) that display tunable shapes from spherical to elongated nanostructures and controllable surface chemistry and loading of AuNPs with distinct emissions but identical individual AuNP size. The three AuNAs exhibit tailored in-vivo transport behaviours: those with spherical shape and more hydrophilic surface show longer blood retention with higher tumor-targeting efficiency (∼25.3% injection dose/g) and excellent long-term near-infrared tumor imaging even after 96 h post-injection. These findings provide a useful guidance in designing specific nanostructures for future nanomedicine transport. [ABSTRACT FROM AUTHOR]

Loop-mediated isothermal amplification (LAMP) is a molecular diagnosis technology with the advantages of isothermal reaction conditions and high sensitivity. However, the LAMP reactions are prone to producing false-positive results and thus are usually less reliable. This study demonstrates a gold nanoparticle (AuNP)-assisted colorimetric LAMP technique for diagnosing SARS-CoV-2, which aims to overcome the false-positive results. The AuNPs were functionalized with E gene probes, specifically tailored to bind to the amplified E-gene LAMP product, using the freezing method. Varied salt concentration and AuNP/probe combinations were tested for the highest visual performance. The experiments were conducted on synthetic SARS-CoV-2 RNA (Omicron variant), as well as on clinical samples. The assay showed an exceptional sensitivity of 8.05 fg of LAMP amplicon mixture (0.537 fg/µL). The average reaction time was ~ 30 min. In conclusion, AuNP-assisted LAMP detection will not identify any potential unspecific amplification, which helps to improve the efficiency and reliability of LAMP assays in point-of-care applications. The freezing method to functionalize the AuNPs with probes simplifies the assay, which can be utilized in further diagnostic studies., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Fentanyl (FTN) and synthetic analogs of FTN continue to ravage populations across the globe, including in the United States where opioids are increasingly being used and abused and are causing a staggering and growing number of overdose deaths each year. This growing pandemic is worsened by the ease with which FTN can be derivatized into numerous derivatives. Understanding the chemical properties/behaviors of the FTN class of compounds is critical for developing effective chemical detection schemes using nanoparticles (NPs) to optimize important chemical interactions. Halogen bonding (XB) is an intermolecular interaction between a polarized halogen atom on a molecule and e - -rich sites on another molecule, the latter of which is present at two or more sites on most fentanyl-type structures. Density functional theory (DFT) is used to identify these XB acceptor sites on different FTN derivatives. The high toxicity of these compounds necessitated a "fragmentation" strategy where smaller, non-toxic molecules resembling parts of the opioids acted as mimics of XB acceptor sites present on intact FTN and its derivatives. DFT of the fragments' interactions informed solution measurements of XB using 19 F NMR titrations as well as electrochemical measurements of XB at self-assembled monolayer (SAM)-modified electrodes featuring XB donor ligands. Gold NPs, known as monolayer-protected clusters (MPCs), were also functionalized with strong XB donor ligands and assembled into films, and their interactions with FTN "fragments" were studied using voltammetry. Ultimately, spectroscopy and TEM analysis were combined to study whole-molecule FTN interactions with the functionalized MPCs in solution. The results suggested that the strongest XB interaction site on FTN, while common to most of the drug's derivatives, is not strong enough to induce NP-aggregation detection but may be better exploited in sensing schemes involving films.

Gold nanoparticles (AuNPs) possess attractive electronic, optical, and catalytic properties, enabling many potential applications. Poly( N -isopropyl acrylamide) (PNIPAAm) is a temperature-responsive polymer that changes its hydrophilicity upon a slight temperature change, and combining PNIPAAm with AuNPs allows us to modulate the properties of AuNPs by temperature. In a previous study, we proposed a simpler method for designing PNIPAAm-AuNP hybrid microgels, which used an AuNP monomer with polymerizable groups. The size of AuNPs is the most important factor influencing their catalytic performance, and numerous studies have emphasized the importance of controlling the size of AuNPs by adjusting their stabilizer concentration. This paper focuses on the effect of AuNP size on the catalytic activity of PNIPAAm-AuNP hybrid microgels prepared via the copolymerization of N -isopropyl acrylamide and AuNP monomers with different AuNP sizes. To quantitatively evaluate the catalytic activity of the hybrid microgels, we monitored the reduction of 4-nitrophenol to 4-aminophenol using the hybrid microgels with various AuNP sizes. While the hybrid microgels with an AuNP size of 13.0 nm exhibited the highest reaction rate and the apparent reaction rate constant ( k app ) of 24.2 × 10 -3 s -1 , those of 35.9 nm exhibited a small k app of 1.3 × 10 -3 s -1 . Thus, the catalytic activity of the PNIPAAm-AuNP hybrid microgel was strongly influenced by the AuNP size. The hybrid microgels with various AuNP sizes enabled the reversibly temperature-responsive on-off regulation of the reduction reaction., Competing Interests: The authors declare no conflicts of interest.

DNA is an ideal template for the design of nanoarchitectures with molecular-like features. Here, we present an optimized assembly strategy for the concatenation of DNA quasi-rings into long scaffolds. Ionic strength, which played a major role during self-assembly, produced the expected high quality only at 15 mM MgCl 2 . Atomic force microscopy (AFM) characterization showed several micrometer long tubular structures that were used as templates for the positioning of plasmonic nanoparticles (NPs) along a three-dimensional helical path using DNA tethers. As imaged by high-resolution scanning transmission electron microscopy (HR-STEM) and modeled by theoretical calculations, the NPs distributed into a "fusilli" fashion (i.e., a helical pasta shape), displaying chiroptical activity as revealed by a bisignated CD absorption, centered at the plasmon resonance wavelength. The present structures contribute to enrich the ever-developing arena of chiroplasmonic DNA-based nanomaterials and demonstrate that large assemblies are attainable for their future application to develop metamaterials.

Gold nanoparticles (AuNPs) have unique features that might lead to the development of a new class of diabetic medicines. AuNPs were biosynthesized utilizing sodium-alginate. UV-Vis-spectroscopy, Fourier transforms infrared, field emission scanning electron microscopy (FESEM), and energy dispersive X-ray were used to examine the particles. The potential of AuNPs for improving the diabetes condition was examined along with swimming in rats. FESEM image revealed the spherical morphology with an average particle size of 106.6 ± 20.8 nm. In the diabetic group, serum glucose, blood urea nitrogen (BUN), creatinine, cholesterol, and triglyceride (TG) levels were significantly higher than the control group. Low-density lipoprotein (LDL) was significantly higher and high-density lipoprotein (HDL) was significantly lower in the diabetic group compared to the control group. Malondialdehyde (MDA) levels were also significantly higher in the D group. However, in the groups treated with swimming and gold, these parameters were significantly improved. Specifically, serum-glucose, BUN, creatinine, cholesterol, and TG levels were significantly reduced, while LDL was significantly decreased in the diabetic + swimming + AuNPs group and HDL was significantly increased in the diabetic + AuNPs group. MDA levels were significantly decreased in the treated groups, and other antioxidants were significantly improved in the diabetic + swimming + AuNPs group. Catalase levels were also significantly improved in the D + gold group. It can be concluded that both AuNPs and swimming can decrease diabetic complications., Competing Interests: Conflict of interest: Authors state no conflict of interest., (© 2024 the author(s), published by De Gruyter.)

Enzymes in nature efficiently catalyze chiral organic molecules by elaborately tuning the geometrical arrangement of atoms in the active site. However, enantioselective oxidation of organic molecules by heterogeneous electrocatalysts is challenging because of the difficulty in controlling the asymmetric structures of the active sites on the electrodes. Here, we show that the distribution of chiral kink atoms on high-index facets can be precisely manipulated even on single gold nanoparticles; and this enabled stereoselective oxidation of hydroxyl groups on various sugar molecules. We characterized the crystallographic orientation and the density of kink atoms and investigated their specific interactions with the glucose molecule due to the geometrical structure and surface electrostatic potential.

The invasive plant, Sphagneticola trilobata (L.) J. F. Pruski, has been known for its bioactivities and used to synthesize gold nanoparticles (AuNPs). Nonetheless, previous research has not directly compared the effectiveness of the plant parts in producing the AuNPs. The objective of this study was to compare the effectiveness of the flower and leaf of S. trilobata in synthesizing AuNPs. S. trilobata leaves and flowers were separately extracted using distilled water at 60°C for 30 min. The leaf and flower extracts were mixed with the HAuCl. 3H 2 O and heated to 60°C for 30 min to yield AuNPs-ALSt and AuNPs-AFSt, respectively. AuNPs were also prepared using trisodium citrate (Na 3 C 6 H 5 O 7 ) as a control. The resultant AuNPs were characterized using an ultraviolet-visible spectrophotometer, particle size analyzer, and scanning electron microscope. Antioxidant activity was evaluated based on 1-diphenyl-2-picrylhydrazyl (DPPH) inhibition and anticancer activity- 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide assay against MCF-7 cells. The AuNPs-ALSt and AuNPs-AFSt were revealed to have better stability and smaller particle diameters. AuNPs-ALSt and AuNPs-AFSt had average particle diameters of 11.86 ± 3.37 and 34.86 ± 23.56 nm, respectively. Agglomeration was predominantly observed in AuNPs synthesized using the flower or leaf extract as stipulated to be affected by the insufficient capping agent and intense hydrolytic reaction. AuNPs-AFSt had higher DPPH antioxidant activity than AuNPs-ALSt with half-maximal inhibitory concentrations of IC 50 123.44 and 168.83 ppm, respectively. Both AuNPs-ALSt and AuNPs-AFSt could inhibit 80% growth of the MCF-7; however, at lower concentrations, inhibitory effects were more pronounced in AuNPs-AFSt. Aqueous extracts of S. trilobata flowers and leaves could be used to synthesize AuNPs, whereas the former yielded AuNPs with higher biological activities., Competing Interests: There are no conflicts of interest., (Copyright: © 2024 Journal of Advanced Pharmaceutical Technology & Research.)

The discrimination and recognition of biological targets, such as proteins, cells, and bacteria, are of utmost importance in various fields of biological research and production. These include areas like biological medicine, clinical diagnosis, and microbiology analysis. In order to efficiently and cost-effectively identify a specific target from a wide range of possibilities, researchers have developed a technique called differential sensing. Unlike traditional "lock-and-key" sensors that rely on specific interactions between receptors and analytes, differential sensing makes use of cross-reactive receptors. These sensors offer less specificity but can cross-react with a wide range of analytes to produce a large amount of data. Many pattern recognition strategies have been developed and have shown promising results in identifying complex analytes. To create advanced sensor arrays for higher analysis efficiency and larger recognizing range, various nanomaterials have been utilized as sensing probes. These nanomaterials possess distinct molecular affinities, optical/electrical properties, and biological compatibility, and are conveniently functionalized. In this review, our focus is on recently reported optical sensor arrays that utilize nanomaterials to discriminate bioanalytes, including proteins, cells, and bacteria.

Cancer has been the most deadly disease, and 13 million cancer casualties are estimated to occur each year by 2030. Gold nanoparticles (AuNPs)-based photothermal therapy (PTT) has attracted great interest due to its high spatiotemporal controllability and noninvasiveness. Due to the trade-off between particle size and photothermal efficiency of AuNPs, rational design is needed to realize aggregation of AuNPs into larger particles with desirable NIR adsorption in tumor site. Exploiting the bioorthogonal "Click and Release" (BCR) reaction between iminosydnone and cycloalkyne, aggregation of AuNPs can be achieved and attractively accompanied by the release of chemotherapeutic drug purposed to photothermal synergizing. We synthesize iminosydnone-lonidamine (ImLND) as a prodrug and choose dibenzocyclooctyne (DBCO) as the trigger of BCR reaction. A PEGylated AuNPs-based two-component nanoplatform consisting of prodrug-loaded AuNPs-ImLND and tumor-targeting peptide RGD-conjugated AuNPs-DBCO-RGD is designed. In the therapeutic regimen, AuNPs-DBCO-RGD are intravenously injected first for tumor-specific enrichment and retention. Once the arrival of AuNPs-ImLND injected later at tumor site, highly photothermally active nanoaggregates of AuNPs are formed via the BCR reaction between ImLND and DBCO. The simultaneous release of lonidamine further enhanced the therapeutic performance by sensitizing cancer cells to PTT., (© 2024 Wiley-VCH GmbH.)

Aptamers are widely used in biosensing due to their specific sensitivity toward many targets. Thus, gold nanoparticle (AuNP) aptasensors are subject to intense research due to the complementary properties of aptamers as sensing elements and AuNPs as transducers. We present herein a novel method for the functional coupling of thrombin-specific aptamers to AuNPs via an anionic, redox-active poly(ferrocenylsilane) (PFS) polyelectroyte. The polymer acts as a co-reductant and stabilizer for the AuNPs, provides grafting sites for the aptamer, and can be used as a redox sensing element, making the aptamer-PFS-AuNP composite (aptamer-AuNP) a promising model system for future multifunctional sensors. The aptamer-AuNPs exhibit excellent colloidal stability in high ionic strength environments owing to the combined electrosteric stabilizing effects of the aptamer and the PFS. The synthesis of each assembly element is described, and the colloidal stability and redox responsiveness are studied. As an example to illustrate applications, we present results for thrombin sensitivity and specificity using the specific aptamer., (© 2024 Wiley‐VCH GmbH.)

Purpose: Gold nanoparticles (GNPs) as pharmaceutical and drug delivery tools exhibited harmful effects on human health and other living species. Quercetin (Qur) reveals various pharmacological effects specially antioxidant, anti-inflammatory and antiapoptotic. This study is directed to investigate hepatotoxicity of GNPs, in addition, to assess the impact of Qur in mitigating the toxicological effects of GNPs., Methods: Groups of rats were treated with or without sphere GNPs (10, 20 and 50 nm) and Qur (200 mg/kg b.wt.). Blood and liver samples from euthanized rats were subjected to biochemical, hematological, histopathological, and immunohistochemical investigations., Results: In comparison with 20 and 50 nm treated groups, the 10 nm GNPs significantly increased serum hepatic enzymes, aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and bilirubin. These 10 nm GNPs were associated with oxidative stress and markedly decreased antioxidant enzymes: catalase (CAT), glutathione peroxidase (GPX) and superoxide dismutase (SOD). Immunohistochemically, 10 nm GNPs expressed intense positive signals in nuclei of hepatocytes when stained with anti-caspase-3 antibody confirming extensive apoptosis. Pre-cotreatment with Qur decreased all tested hepatic enzymes and increased serum level of antioxidant enzymes compared to 10 nm GNPs. Qur treatment strongly exhibited anti-Ki67 antibody (proliferative marker) indicating high proliferation of hepatic parenchyma. Histopathologically, 10 nm GNPs revealed diffuse hydropic degenerations, severe sinusoidal congestion, coagulative necrosis, sever steatosis and diffuse hemosiderosis within the hepatic parenchyma. Qur treatment ameliorated most of these pathological effects., Conclusion: The smaller diameters of GNPs induce potential oxidative stress, cytotoxic, and apoptotic effects in hepatic tissues rather than larger ones. In addition, Qur demonstrated a significant prophylactic role against hepatotoxicity of GNPs., Competing Interests: The authors declare that they have no competing interests., (©2024 The Authors.)

Glioblastoma multiforme (GBM) is a glioma and the most aggressive type of brain tumor with a dismal average survival time, despite the standard of care. One promising alternative therapy is boron neutron capture therapy (BNCT), which is a noninvasive therapy for treating locally invasive malignant tumors, such as glioma. BNCT involves boron-10 isotope capturing neutrons to form boron-11, which then releases radiation directly into tumor cells with minimal damage to healthy tissues. This therapy lacks clinically approved targeted blood-brain-barrier-permeating delivery vehicles for the central nervous system (CNS) entry of therapeutic boron-10. Gold nanoparticles (GNPs) are selective and effective drug-delivery vehicles because of their desirable properties, facile synthesis, and biocompatibility. This review discusses biomedical/therapeutic applications of GNPs as a drug delivery vehicle, with an emphasis on their potential for carrying therapeutic drugs, imaging agents, and GBM-targeting antibodies/peptides for treating glioma. The constraints of GNP therapeutic efficacy and biosafety are discussed.

The utilization of contrast agents in magnetic resonance imaging (MRI) has become increasingly important in clinical diagnosis. However, the low diagnostic specificity of this technique is a limiting factor for the early detection of tumors. To develop a new contrast agent with a specific target for early stage tumors, we present the synthesis and characterization of a nanocontrast composed of gold nanoparticles (AuNPs), gadopentetic acid (Gd-DTPA), and epidermal growth factor (EGF). Carbodiimide-based chemistry was utilized to modify Gd-DTPA for functionalization with AuNPs. This resulted in the formation of the Au@Gd-EGF nanocontrast. The relaxation rate (1/T1) of the nanocontrast was analyzed using MRI, and cytotoxicity was determined based on cell viability and mitochondrial activity in a human breast adenocarcinoma cell line. Fourier-transform infrared spectroscopy analysis confirmed the effectiveness of carbodiimide in the formation of the Gd-DTPA-cysteamine complex in the presence of bands at 930, 1042, 1232, 1588, and 1716 cm -1 . The complexes exhibited good interactions with the AuNPs. However, the signal intensity of the Au@Gd-EGF nanocontrast was lower than that of the commercial contrast agent because the r1/r2 relaxivities of the Gd-DTPA-based contrast agents were lower than those of the gadoversetamide-based molecules. The Au@Gd-EGF nanocontrast agent exhibited good biocompatibility, low cytotoxicity, and high signal intensity in MRI with active targeted delivery, suggesting significant potential for future applications in the early diagnosis of tumors., (© 2023. The Author(s), under exclusive licence to Japanese Society of Radiological Technology and Japan Society of Medical Physics.)

Gold nanoparticles (Au-NPs) seeded plasmonic nanofluids (PNFs) have shown promising results in overall performance enhancement of direct absorption solar collector (DASC) due to localized surface plasmon resonance (LSPR) effect. For the work presented here, Au-NPs were synthesized by the wet chemical method and were utilized to prepare plasmonic nanofluid. The surface plasmon resonance peak of Au-NPs was observed at 531 nm using UV–Visible spectrophotometer study. The testing for performance enhancement of gold plasmonic nanofluid (GPNF) laden DASC so far is limited to laboratory scale setups or simulation studies. Considering the dearth of outdoor experimental studies, an attempt has been made in the present study to evaluate the thermal performance of Au-NPs (∼40 nm) based nanofluid (∼0.0002 wt%) in full scale DASC. The experiments have been performed at different flow rates under clear sky outdoor conditions in winter season at Jalandhar, India. The maximum collector outlet temperature was measured to be 55 °C with GPNF which is about 7 °C higher than the maximum outlet temperature obtained with de-ionized water as working fluid. Thermal efficiency with GPNF is about 33% higher than de-ionized water at the optimal flow rate of 0.030 kg/s. • Au nanoparticles of average sizes ∼40 nm synthesized by a facile chemical route. • Au plasmonic nanofluid showed better absorption properties due to surface plasmon enhancement. • Performance analysis of Au nanofluid laden DASC carried out during winter season in India. • Study results showed maximum efficiency improvement of ∼33% over DI water. [ABSTRACT FROM AUTHOR]

In this work, a versatile method to increase the optical response of oxide nanostructures is described. Thin TiO2 films with buried gold nanoparticles (TiO2-AuNP) were synthesized on a crystalline Si surface. The localized surface plasmon resonance reflection maximum is formed around 720–750 nm. Current-voltage characteristics of planar structures formed by use of different contact materials were measured. Spectral features of an optical response of TiO2-AuNP is discussed. The results obtained indicate a broad prospect of using the formed structures in the field of integrated optoelectronic devices. [ABSTRACT FROM AUTHOR]

Prostate cancer is a leading health burden, the third most common cancer in a man. High accuracy detection and screening methods with a suitable biomarker can significantly reduce the risk of mortality. Prostate specific antigen (PSA) is the efficient and acceptable biomarker due to its level of increment in the biological fluid with the prostate cancer patient. This research was focused to establish a sensitive method of PSA detection by using gold nanoparticle (GNP) conjugated PSA specific aptamer on interdigitated mini-electrode. GNP allowed to capture higher number of aptamers on the surface and enhanced the interaction of PSA. This good detection method can determine PSA at 45 aM with the sensitivity of 30 aM. A linear range was noticed from 60 until 2000 aM on the regression curve at y = 0. 1 5 6 8 x + 0. 1 4 3 ; R 2 = 0. 9 5 5. Moreover, spiking PSA in human serum enhances the current response with increasing PSA concentrations. This method of determination helps to quantify the PSA level and diagnose the prostate cancer at different stages. This study uses the properly fabricated interdigitated mini-electrode for identifying the prostate specific antigen. Aptamer has been used as the probe and numbers of aptamer immobilization enhanced by gold nanoparticle conjugation. To minimize the biofouling, PEGylated metal oxide was layered on the sensing surface. By using this set-up, the sensitivity and limit of detection were attained at attomolar range with higher selectivity. [ABSTRACT FROM AUTHOR]

Amyloidosis are a hereditary or acquired disorders, which are associated with misfolding of normally soluble, functional peptides and proteins, and their conversion into contentious aggregation can cause amyloid fibrils. These fibrils reduce function of the proteins and with generation of toxic intermediates in the process of self-assembly cause amyloid diseases such as Alzheimer, Parkinson, etc. Nanoparticles are materials with a dimension of 1–100 nm that influence the process of protein fibrillation since nanoparticles mediated by chemical methods have been show side effects, biological methods have been preferred due to its safety for human therapeutic use. In this study, the effect of gold nanoparticle produced from hibiscus on the amyloid formation of α-lactalbumin was evaluated using light scattering absorption, fluorescence (ThT assay, intrinsic fluorescence assay and ANS binding assay), TEM, CD spectroscopy and SDS-PAGE. α -Lactalbumin has been chose as a good sample for study the amyloid formation due to the formation of molten globule state. The results show that AuNPs inhibit formation of amyloid fibrils in reduced α-lactalbumin. This protective effect resulted are due to increase protein adsorption to the surface of the nanoparticles and therefore prevents their structural changes. Nanoparticle by binding to the monomer prevented them from join together and elongation the core of amyloid fibrils. Finally, the results show that biosynthesized AuNPs mediated by hibiscus can be used as effective therapeutic agent for prevention of formation amyloid and treatment of amyloid disease. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study purposed to evaluate the efficacy of brachytherapy with the modality of ultrasonic hyperthermia in the presence of gold nanoparticles (GNPs) on an ocular retinoblastoma tumor in an animal model of the rabbit. A retinoblastoma tumor was induced by the injection of the human cell line of Y79 in rabbit eyes (n = 41). After two weeks, tumor size reached a diameter of about 5–7 mm. Seven groups were involved: control, GNPs injection, hyperthermia, hyperthermia with GNPs injection, brachytherapy with I-125, a combination of hyperthermia and brachytherapy, and a combination of brachytherapy, hyperthermia and, GNPs. The tumor area was measured using B-mode ultrasound images on the zero-day and at the end of the third week. The groups were evaluated for a histopathological study of tumor necrosis. There was a significant difference between the relative area changes of tumor in the combination group with the other study groups (p <.05). The results of histopathologic studies confirmed the necrosis of living retinoblastoma cells. Combination therapy of brachytherapy and hyperthermia with GNPs reduces the relative size of the tumor. This method increases the necrosis percentage of retinoblastoma and significantly reduces the retinoblastoma mass in the rabbit eyes. [ABSTRACT FROM AUTHOR]

• 17β-Estradiol(17β-E2) is a reproductive hormone & quantified by colorimetry. • NaCl-induced (from 60 mM) gold nanoparticle (GNP) immunoassay was demonstrated. • Antibody (50 nM) was stable on GNP, dispersed with red color & spectral changes. • Sensitivity at 10 pM, controls didn't show color changes with specific detection. • Selective experiments were done with small, macromolecules and the serum. 17β-Estradiol (17β-E2) is the reproductive hormone playing a major role in female reproductive system and acts as an important component of metabolic processes. Quantifying 17β-E2 level helps to identify the reproductive endocrine related problems. Herein, a salt-induced (from 60 mM) gold nanoparticle (GNP) based immunoassay was introduced to quantify 17β-E2. Polyclonal antibody (50 nM) was immobilized on the surface of GNP and the color with GNPs was changed (blue to red shift) upon adding the target in the presence of high monovalent salt (NaCl) concentration. The sensitivity was at 10 pM with the point of GNPs assembly to disassembly. Negative control experiments did not show any color changes with GNPs indicate the specific detection of 17β-E2. In addition, selective detection was proved in the presence of other organic-, inorganic-, biological-molecules and the serum. This simple bare eye detection is quantifying the level of 17β-E2 and diagnosing the reproductive endocrine related disorders. [ABSTRACT FROM AUTHOR]

Gold nanoparticle–decorated metal organic frameworks (MOF@AuNPs) with significantly enhanced color signal intensity were synthesized through in situ growth of AuNPs on the MOF skeleton. The resultant MOF@AuNP nanocomposites were characterized with 16.7-fold higher absorbance than conventional 40 nm AuNPs (AuNP40). Thus, for the first time, we applied it as a signal amplification label to improve the immunochromatographic assay (ICA) of human chorionic gonadotropin (HCG). The detection limit of our enhanced ICA was 1.69 mIU/mL, which is ca. 10.6-fold improvement in sensitivity compared to traditional AuNP40-ICA. The recoveries of this MOF@AuNPs-ICA ranged from 86.03 to 119.22%, with coefficients of variation of 3.05 to 13.74%. The reliability and practicability were further validated by the clinically used chemiluminescence immunoassay method. Given their excellent signal amplification ability, the proposed MOF@AuNPs could serve as an ideal ICA label for rapid and sensitive detection of disease biomarkers. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Techniques such as Fourier transform infrared (FTIR), ultraviolet–visible (UV–vis) spectra, fluorescence, circular dichroism (CD) and spectroscopy were applied to elucidate the formation, structure and physicochemical properties of levobupivacaine–gold nanoparticle (LGN) binding to human serum albumin (HSA). Thermodynamic parameters (ΔG = −2.58 × 104 J·mol−1, ΔS = −7.80 J·mol−1·K−1, and ΔS = −2.82 × 104 J·mol−1 at 305 K) suggested one weak binding site on HSA, which was governed by van der Waals forces as well as hydrogen bonds. Moreover, the outcomes of UV–vis, CD, FTIR, synchronous and three‐dimensional fluorescence suggested that the microenvironment of HSA had been changed with addition of LGN. Based on the results of fluorescence resonance energy transfer, a distance of 2.8 nm between the LGN and HSA was observed. This approach has potential value for illustrating the pharmacodynamics of LGN when in combination with transmembrane transport, biomolecular function effect, and other experiments. [ABSTRACT FROM AUTHOR]

In this work, gold nanoparticles were biosynthesized via Plectranthus amboinicus leaf extract as the reducing agent. A series of techniques were used for sample analysis. The biosynthesized gold nanoparticles (bAuNPs) are a uniform size with a spherical shape. The FTIR analysis reveals the presence of many oxygen-containing functional groups on the bAuNP surface. The cyclic voltammetry and electrochemical impedance spectroscopic characterizations reveal that while the bAuNPs have a slightly lower conductivity than chemically synthesized AuNPs (cAuNPs). However, the bAuNPs have a superior electrocatalytic performance toward nicotine reduction. After optimization, the bAuNP-modified SPE could detect nicotine linearly from 10 to 2,000 μM with a low detection limit of 2.33 μM. In addition, the bAuNPs/SPE have been successfully used for nicotine-containing-product analysis.

This report describes strategies to increase the reactive surfaces of integrated gold nanoparticles (AuNPs) by employing two different types of host materials that do not possess strong electrostatic and/or covalent interactive forces. These composite particles are then utilized as highly reactive and recyclable quasi-homogeneous catalysts in a C-C bond forming reaction. The use of mesoporous TiO2 and poly(N-isopropylacrylamide), PNIPAM, particles allows for the formation of relatively small and large guest AuNPs and provides the greatly improved stability of the resulting composite particles. As these AuNPs are physically incorporated into the mesoporous TiO2 (i.e., supported AuNPs) and PNIPAM particles (i.e., encapsulated AuNPs), their surfaces are maximized to serve as highly reactive catalytic sites. Given their increased physicochemical properties (e.g., stability, dispersity, and surface area), these composite particles exhibit notably high catalytic activity, selectivity, and recyclability in the homocoupling of phenylboronic acid in water and EtOH. Although the small supported AuNPs display slightly faster reaction rates than the large encapsulated AuNPs, the apparent activation energies (Ea) of both composite particles are comparable, implying no obvious correlation with the size of guest AuNPs under the reaction conditions. Investigating the overall physical properties of various composite particles and their catalytic functions, including the reactivity, selectivity, and Ea, can lead to the development of highly practical quasi-homogeneous catalysts in green reaction conditions.

We explore a sandwich-type gold nanoparticle coated reduced graphene oxide (rGO-AuNP) as an effective nanotheranostic platform for the second near-infrared (NIR-II) window photoacoustic (PA) imaging-guided photothermal therapy (PTT) in ovarian cancer. The PEG was loaded onto the AuNPs surface to increase the stability of nanostructure. The forming rGO-AuNPs- PEG revealed very strong SERS signal, NIR-II PA signal and high photothermal efficiency against tumor upon 1,061 nm laser irradiation. The prominent performance was attributed to the plasmonic coupling of AuNPs, and the enhanced response of rGO and the plasmonic AuNP. Thus, our study demonstrates that the rGO-AuNP nanocomposite could promise to be a potential photothermal agent and pave the way for the diagnosis and therapy of ovarian cancer in the future.

Gold nanoparticles (AuNPs) can be used with megavolt (MV) X-rays to exert radiosensitization effects, as demonstrated in cell survival assays and mouse experiments. However, the detailed mechanisms are not clear; besides physical dose enhancement, several chemical and biological processes have been proposed. Reducing the AuNP concentration while achieving sufficient enhancement is necessary for the clinical application of AuNPs. Here, we used positively charged (+) AuNPs to determine the radiosensitization effects of AuNPs combined with MV X-rays on DNA damage in vitro. We examined the effect of low concentrations of AuNPs on DNA damage and reactive oxygen species (ROS) generation. DNA damage was promoted by 1.4 nm +AuNP with dose enhancement factors of 1.4 ± 0.2 for single-strand breaks and 1.2 ± 0.1 for double-strand breaks. +AuNPs combined with MV X-rays induced radiosensitization at the DNA level, indicating that the effects were physical and/or chemical. Although −AuNPs induced similar ROS levels, they did not cause considerable DNA damage. Thus, dose enhancement by low concentrations of +AuNPs may have occurred with the increase in the local +AuNP concentration around DNA or via DNA binding. +AuNPs showed stronger radiosensitization effects than −AuNPs. Combining +AuNPs with MV X-rays in radiation therapy may improve clinical outcomes.

The pathology of Alzheimer’s disease (AD), the most common cause of dementia, is considered to be mainly driven by two major hallmarks (tau and amyloid beta). It is highly desirable to develop an affordable medicinal diagnostic that can be utilized worldwide for the early diagnosis of AD. Hence, p-tau231 was selected as a specific target, which appears both in AD serum and cerebrospinal fluid, for the development of a sensing platform for the diagnosis of AD. To the best of our knowledge, these are the first aptamer-mediated biosensors that rely on sensitive fluorescent and colorimetric aptasensors for the rapid monitoring of p-tau231. The nitrogen-doped carbon dot-based turn-on fluorescent aptasensor could rapidly analyze p-tau231 down to 3.64 ng/mL within 40 min, and the colorimetric Cu-enhanced-Au aptablot displayed high sensitivity at 4.71 pg/mL through a digital camera, with visibility to the naked eye down to 8 ng/mL p-tau231 within 140 min. Owing to their advantages, which include affordability, rapidity, high sensitivity, and dependence on complicated instruments, these aptamer-based biosensors offer significant potential for the early diagnosis of AD worldwide.

Nanoparticles with oligonucleotides bound to the outside or incorporated into the matrix can be used for gene editing or to modulate gene expression in the CNS. These nanocarriers are usually optimised for transfection of neurons or glia. They can also facilitate transcytosis across the brain endothelium to circumvent the blood-brain barrier. This review examines the different formulations of nanocarriers and their oligonucleotide cargoes, in relation to their ability to enter the brain and modulate gene expression or disease. The size of the nanocarrier is critical in determining the rate of clearance from the plasma as well as the intracellular routes of endothelial transcytosis. The surface charge is important in determining how it interacts with the endothelium and the target cell. The structure of the oligonucleotide affects its stability and rate of degradation, while the chemical formulation of the nanocarrier primarily controls the location and rate of cargo release. Due to the major anatomical differences between humans and animal models of disease, successful gene therapy with oligonucleotides in humans has required intrathecal injection. In animal models, some progress has been made with intraventricular or intravenous injection of oligonucleotides on nanocarriers. However, getting significant amounts of nanocarriers across the blood-brain barrier in humans will likely require targeting endothelial solute carriers or vesicular transport systems.

With recent advances in nanotechnology, various nanomaterials have been used as drug carriers in molecular imaging for the treatment of cancer. The unique physiochemical properties and biocompatibility of gold nanoparticles have developed a breakthrough in molecular imaging, which allows exploration of gold nanoparticles in drug delivery for diagnostic purpose. The conventional gold nanoparticles synthetisation methods have limitations with chemical contaminations during the synthesisation process and the use of higher energy. Thus, various innovative approaches in gold nanoparticles synthetisation are under development. Recently, studies have been focused on the development of eco-friendly, non-toxic, cost-effective and simple gold nanoparticle synthesisation. The pulsed laser ablation in liquid (PLAL) technique is a versatile synthetic and convincing technique due to its high efficiency, eco-friendly and facile method to produce gold nanoparticle. Therefore, this study aimed to review the eco-friendly gold nanoparticle synthesisation method via the PLAL method and to characterise the gold nanoparticles properties for molecular imaging. This review paper provides new insight to understand the PLAL technique in producing gold nanoparticles and the PLAL parameters that affect gold nanoparticle properties to meet the desired needs in molecular imaging.

Pengfei Zhang,1,* Peicheng Wang,2,* Lei Yan,3 Lifeng Liu1 1Department of Otolaryngology – Head and Neck Surgery, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi 710061, China; 2Department of Otolaryngology – Head and Neck Surgery, Weihai Municipal Hospital, Weihai, Shandong 264200, China; 3Innoscience Research Sdn. Bhd, Subang Jaya, Selangor 47500, Malaysia *These authors contributed equally to this work Background: Nasopharyngeal cancer (NPC) is one of the subtypes of head and neck cancers. It occurs rarely, and its prevalence depends mainly on geographical location. Modern-day research is focused on coupling nanotechnology and traditional medicine for combating cancers. Gold nanoparticles (AuNPs) were synthesized from Solanum xanthocarpum (Sx) leaf extract using reduction method. Methods: Characterization of the synthesized AuNPs was done by different techniques such as ultraviolet–visible spectrum absorption, X-ray diffraction, dynamic light scattering, Fourier transform infrared spectroscopy, transmission electron microscopy, and energy-dispersive X-ray analysis. Results: All the results showed the successful green synthesis of AuNPs from Sx, which induced apoptosis of C666-1 cell line (NPC cell line). There was a decline in both cell viability and colony formation in C666-1 cells upon treatment with Sx-AuNPs. The cell death was proved to be caused by autophagy and mitochondrial-dependent apoptotic pathway. Conclusion: Thus, due to their anticancer potential, these nanoparticles coupled with Sx can be used for in vivo applications and clinical research in future. Keywords: Solanum xanthocarpum, gold nanoparticle, C666-1 cells, ROS, apoptosis

Purpose: Molecular imaging is one of the import methods for recognition of cancer at the early stage in order to enhance the capacity of remedy. This study was aimed to introduce a new contrast agent that was targeted with CD24 so as to improve the CT scan detection of cancer cells with higher CD24 expression. Methods: The surface modifications of gold nanoparticles (Au-NPs) were done with long PEG (HS-PEG-CH3O) and short PEG (HS-PEG-COOH) chains to enhance their stability and capacity for immobilization of different antibodies. MTT assay was carried out to assess the biocompatibility of the NPs. The obtained contrast agent was implemented in the targeted CT imaging based on in vitro and in vivo studies of breast cancer. Results: The results revealed that the attached CD24 to the cell surface of PEGylated Au-NPs could enhance significantly the cells CT number (40.45 HU in 4T1, while it was 16.61 HU in CT26) It was shown that the attenuation coefficient of the molecularly targeted cells was more than 2 times excessive than the control groups. Further, the tumor region in model of xenograft tumor has higher density compare to the omnipaque groups, 60 min after injection (45 Hu vs.81 Hu). These results showed that the nanoparticles stayed in tumor region for longer time. Conclusion: It is predicted that the synthesized nanoparticle can be used as computed tomography contrast agent. Also, it can be used to identify the tumor cells with higher expression of CD24 at the early stages more efficiently compare to the other routine methods.

Gold nanoparticles (GNPs) are proven effective heavy-atom radiosensitizers to produce imaging contrast and dose enhancement in radiotherapy. To understand the physical and biological effect of adding GNPs to the tumour cells, Monte Carlo simulation based on particle tracking and transport, is employed to predict the dosimetry in the cellular and DNA scale. In this review, we first explore the recent advances in Monte Carlo simulation on GNP radiosensitisation. The development of particle tracking algorithm for very low energy electron in the simulation is discussed, followed by some results regarding the prediction of dose enhancement (microscopic and macroscopic). We then review different Monte Carlo cell models with GNPs in the simulation, the biological effect resulting from DNA damage, and the effects of increasing imaging contrast in the tumour cell due to photoelectric enhancement. Moreover, we explain and look at different studies and results on GNP-enhanced radiotherapy using gamma rays (brachytherapy), megavoltage photon, kilovoltage photon, electron and proton beams.

Abstract Tuberculosis (TB) is a highly contagious life-threatening disease caused by the bacterial pathogen Mycobacterium tuberculosis. ESAT-6, an abundant early secretory antigenic target protein by M. tuberculosis, found to play a vital role in virulence. Developing a friendly method for the detection of ESAT-6 at the lower concentration facilitates to treat TB at an earlier stage and helps to control the spreading of disease. Herein, a new single-step approach was designed and was done by pre-mixing ESAT-6 and antibody before being added to the gold nanoparticle (GNP) followed by the salt-induced aggregation. We could attain the detection limit of 1.25 pM, showing the aggregation of GNP and the red spectral shift. Further, a higher specificity was demonstrated with the lack of electrostatic biofouling by ESAT-6 on GNP and retained the dispersed GNP in the presence of 10-kDa culture filtrate protein from M. tuberculosis. The required precise antibody concentration for this assay was found to be 60 nM. The increment in the antibody concentration from 75 nM drastically diminishes the sensitivity to ~ 680-fold, due to the crowding effect. With this assay, we attested the suitability of colorimetric assay for efficiently detecting the smaller-sized protein.

Abstract Background Gold nanoparticles (AuNPs) are promising candidates to design the next generation NP-based drug formulations specifically treating maternal, fetal or placental complications with reduced side effects. Profound knowledge on AuNP distribution and effects at the human placental barrier in dependence on the particle properties and surface modifications, however, is currently lacking. Moreover, the predictive value of human placental transfer models for NP translocation studies is not yet clearly understood, in particular with regards to differences between static and dynamic exposures. To understand if small (3–4 nm) AuNPs with different surface modifications (PEGylated versus carboxylated) are taken up and cross the human placental barrier, we performed translocation studies in a static human in vitro co-culture placenta model and the dynamic human ex vivo placental perfusion model. The samples were analysed using ICP-MS, laser ablation-ICP-MS and TEM analysis for sensitive, label-free detection of AuNPs. Results After 24 h of exposure, both AuNP types crossed the human placental barrier in vitro, although in low amounts. Even though cellular uptake was higher for carboxylated AuNPs, translocation was slightly increased for PEGylated AuNPs. After 6 h of perfusion, only PEGylated AuNPs were observed in the fetal circulation and tissue accumulation was similar for both AuNP types. While PEGylated AuNPs were highly stable in the biological media and provided consistent results among the two placenta models, carboxylated AuNPs agglomerated and adhered to the perfusion device, resulting in different cellular doses under static and dynamic exposure conditions. Conclusions Gold nanoparticles cross the human placental barrier in limited amounts and accumulate in placental tissue, depending on their size- and/or surface modification. However, it is challenging to identify the contribution of individual characteristics since they often affect colloidal particle stability, resulting in different biological interaction in particular under static versus dynamic conditions. This study highlights that human ex vivo and in vitro placenta models can provide valuable mechanistic insights on NP uptake and translocation if accounting for NP stability and non-specific interactions with the test system.

Background: Presurigical planning for glioma tumor resection and radiotherapy treatment require proper delineation of tumoral and peritumoral areas of brain. Diffusion tensor imaging (DTI) is the most common mathematical model applied for diffusion weighted MRI data. Neurite orientation dispersion and density imaging (NODDI) is another mathematical model for DWI data modeling. Objective: We studied whether extracted parameters of DTI, and NODDI models can be used to differentiate between edematous, tumoral, and normal areas in brain white matter (WM). Material and Methods: 12 patients with peritumoral edema underwent 3T multi-shell diffusion imaging with b-values of 1000 and 2000 smm-2 in 30 and 64 gradient directions, respectively. We fitted DTI and NODDI to data in manually drawn regions of interest and used their derived parameters to characterize edematous, tumoral and normal brain areas. Results: We found that DTI parameters fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) all significantly differentiated edematous from contralateral normal brain WM (p

Introduction: Electrical impedance of tissues on low frequencies includes useful information about functional and structural changes in tissues. This property is used in Electrical Impedance Tomography (EIT) imaging modality for the detection of lesions in tissues. Objective: The goal of this article is to study changes in electrical impedance of tissues in the presence of gold nanoparticles. Materials and Methods: Spherical gold nanoparticles with size of 20-25 nm were synthesized with Turkevich method. Size distribution and shape of nanoparticles were characterized by transmission electron microscopy (TEM). Electrical impedance of two types of phantoms (chicken fat and muscle paste tissues) was measured by 4-electrode method with and without gold nanoparticles. Results: Results demonstrate a reduction in electrical impedance of tissues in the presence of gold nanoparticles. However, this reduction is not the same for fat and muscle tissues. Reductions in resistive impedance are for fat and muscle tissues on the frequency of 1 KHz, respectively. A reduction in electrical impedance is accompanied by a rise in electrical conductance leading to increase in EIT signal. Conclusion: As signal enhancement is different for fat and muscle tissues; presence of gold nanoparticles could be used to improve EIT image contrast.

Abstract Background Several studies have confirmed that gold nanoparticles (AuNPs) of specific concentration and size exert a boosting effect on cell proliferation; however, the mechanism through which this effect occurs remains unknown. This study explores the canonical Wnt signaling pathway in AuNP promotion of human periodontal ligament stem cell (hPDLSC) proliferation. Methods MTS was employed to evaluate hPDLSC proliferation. The interference of LRP5 and β-catenin was steered by shRNA plasmids and siRNA, respectively, at which point the expression of MYC, CCND1, AXIN2, and POU5F1 had been estimated via real-time PCR. The expressions of LRP5 and β-catenin were detected via western blot assay. Results The proliferation of hPDLSCs treated with 60 nm AuNPs at 56 μM was clearly elevated. In contrast, β-catenin siRNA significantly decreased cell viability. The LRP5 shRNA plasmid did not consistently impact cells. The expressions of these four genes downstream of the Wnt/β-catenin signaling pathway were not significantly overexpressed in response to the interference of shRNA plasmid/siRNA with the treatment of AuNPs. Conclusions These results suggest that the Wnt/β-catenin signaling pathway plays a significant role in the process of AuNP promotion of hPDLSC proliferation.

Crystals of M4Au12Ag32(p-MBA)30 bimetallic monolayer-protected clusters (MPCs), where p-MBA is p-mercaptobenzoic acid and M+ is a counter-cation (M = Na, Cs) have been grown and their structure determined. The molecular structure of triacontakis[(4-carboxylatophenyl)sulfanido]dodecagolddotriacontasilver, Au12Ag32(C7H5O2S)30 or C210H150Ag32Au12O60S30, exhibits point group symmetry \overline{3} at 100 K. The overall diameter of the MPC is approximately 28 Å, while the diameter of the Au12Ag20 metallic core is 9 Å. The structure displays ligand bundling and intermolecular hydrogen bonding, which gives rise to a framework structure with 52% solvent-filled void space. The positions of the M+ cations and the DMF solvent molecules within the void space of the crystal could not be determined. Three out of the five crystallographically independent ligands in the asymmetric unit cell are disordered over two sets of sites. Comparisons are made to the all-silver M4Ag44(p-MBA)30 MPCs and to expectations based on density functional theory.

Objective(s): The central role of molecular imaging modalities in cancer management is an undeniable fact that could help to diagnose cancer tumors in early stages. The main aim of this study is to prepare a novel targeted molecular imaging nanoprobe of CD24-PEGylated Au NPs to improve the ability of Computed tomography scanning (CT scan) outputs for both in vitro and in vivo detection of breast cancer (4T1) cells. Materials and methods: Gold nanoparticles (Au NPs) were synthesized and coated with polyethylene glycol (PEG) chains in order to improve the stability of the Au NPs and to provide bio modification points for antibody immobilization. The synthesized nanoprobe was used for both in vitro and in vivo targeted CT imaging breast cancer cells (4T1) and the xenograft tumor model. Results: Findings showed that the attenuation coefficient of 4T1 cells that were targeted by CD24-PEGylated Au NPs is calculated to be over two times higher than the untargeted 4T1 cells (15 HU vs 39 HU, respectively). Indeed, the results clearly reveal that the developed CD24-PEGylated Au NPs showed the tumor CT enhancement was higher than that of Omnipaqe which used as control. Also, the CT number values of the tumor area at different time points gradually increased after 60 min post injection and was significantly higher than before injection. Conclusions: Results showed the introduced CT imaging nanoprobe (Au NPs-PEGylated) could be useful for CT imaging of breast tumors under in vivo condition. Overall, it is concluded that Au NPs-PEGylated contrast media is able to detect breast cancer (4T1) cells and is more effective compared with other casual methods.

Abstract The phytochemicals present in the stem bark extract of Nerium oleander (commonly known as Karabi) have been utilized for the green synthesis of stable gold-conjugated nanoparticles at room temperature under very mild conditions. The green synthesized gold-conjugated nanoparticles were characterized by surface plasmon resonance spectroscopy, High resolution transmission electron microscopy, X-ray diffraction studies and dynamic light scattering. A mechanism for the synthesis and stabilization of gold-conjugated nanoparticles (AuNPs) has been proposed. Anticancer activity of the stabilized AuNPs studied against MCF-7 breast cancer cell line revealed that the stabilized AuNPs were highly effective for the apoptosis of cancer cells selectively. The antioxidant activity of the stem bark extract of Nerium oleander has also been studied against a long lived 2,2-diphenylpicrylhydrazyl radical at room temperature. Moreover, the utilization of the stabilized AuNPs as a catalyst has also been demonstrated.

Poulomi Sengupta, Sachin S Surwase, Bhagavatula LV Prasad Physical Chemistry Division, CSIR–National Chemical Laboratory, Pune, India Abstract: Synthetic polymers are widely researched for their use in tissue engineering. Control in size, surface area, pore size, and elasticity are the biggest advantages of using a man-made polymer. However, often the polymers are hydrophobic (do not encourage cell attachment); hence, it is hugely challenging to integrate them with the normal tissues. Herein, we have tried to overcome this disadvantage of polymers by coating them with citrate-stabilized gold nanoparticles and arginine. High-density polyethylene, upon multiple treatments, shows low water contact angle, which encourages cell attachment and proliferation in comparison to the untreated polymers. Keywords: tissue engineering, gold nanoparticle, HDPE hydrophilicity

Background: To enhance the dose to tumor, the use of high atomic number elements has been proposed. Objective: The aim of this study is to investigate the effect of gold nanoparticle distribution on dose enhancement in tumor when the tumor is irradiated by typical monoenergetic X-ray beams by considering homogeneous and inhomogeneous distributions of gold nanoparticles (GNPs) in the tumor. Methods: MCNP-4C Monte Carlo code was utilized for the simulation of a source, a phantom containing tumor and gold nanoparticles with concentrations of 10, 30 and 70 mg Au/g tumor. A 15 cm×15 cm×15 cm cubic water phantom was irradiated with a small planar source with four monoenergetic X-ray beams of 35, 55, 75 and 95 keV energy. Furthermore, tumor depths of 2.5 cm, 4.5 cm and 6.5 cm with homogeneous and inhomogeneous distributions of nanoparticles were studied. Each concentration, photon energy, tumor depth and type of distribution was evaluated in a separate simulation. Results: Results have shown that dose enhancement factor (DEF) in tumor increases approximately linearly with the concentration of gold nanoparticles. While DEF has fluctuations with photon energy, 55 keV photons have the highest DEF values compared to other energies. While DEF has relatively the same values with tumor located at various depths, inhomogeneous distribution of GNP has shown different results compared with the homogeneous model. Dose enhancement can be expected with relatively deep seated tumors in radiotherapy with low energy X-rays. Inhomogeneous model is recommended for the purpose of dose enhancement study because it mimics the real distribution of GNPs in tumor.

(Ag3AsS3)0.6(As2S3)0.4 thin films deposited using the thermal evaporation technique onto glass substrates previously covered with layers of gold nanoparticles were studied. Optical transmission spectra of the sandwich structure were studied within the temperature range 77…300 K. The absorption spectra in the region of its exponential behaviour were analyzed, the dispersion dependences of refractive index as well as the temperature dependences of the energy pseudogap and Urbach energy were investigated. The disordering processes in the sandwich structure were discussed. The comparative analyses of optical parameters in single (Ag3AsS3)0.6(As2S3)0.4 layer and in the sandwich structure were performed.