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We have synthesized L-cysteine and oleylamine stabilized CsPbBr3 perovskite quantum dots (PQDs) and coupled them with gold nanoparticles (AuNPs). The PQDs and AuNPs, as well as their hybrid nanostructures (HNS), were characterized using UV–visible (UV–vis) and photoluminescence (PL) spectroscopy. The UV–vis spectra show absorption bands of the HNS at 503 and 520 nm, attributed mainly to PQDs and AuNPs, respectively. The PQDs show a strong excitonic PL band peaked at 513 nm from PQDs. The HR-TEM results show the formation of hybrid structures between PQDs and AuNPs, which is also supported by the PL quenching of the PQDs by the coupled AuNPs. Ultrafast dynamics of the exciton and charge carriers in the HNS and pristine PQD were studied using femtosecond transient absorption. Multiexponential fitting of the dynamic data revealed the existence of shallow and deep trap states in pristine PQDs and ultrafast electron transfer from PQDs to AuNPs in the HNS. A kinetic model was proposed to account for the key dynamic processes involved and to extract the time for electron transfer from PQDs to AuNPs in the HNS, found to be ∼2 ps. Dynamic processes in pristine PQDs are largely unchanged by HNS formation with AuNPs. [ABSTRACT FROM AUTHOR]

Gold nanoparticles synthesized via honey-mediated chemical reduction have desirable features that make them ideal candidates for nanoparticle-assisted photothermal therapy (N-PTT). However, their photothermal properties have not been previously explored. In this study, after synthesis and characterization (structural and optical) of the HM-AuNPs, we investigated their photothermal conversion efficiency (η) and absorption cross section (σ a b s ) in aqueous solution, cytotoxic effects in in vitro MDA-MB-468 breast cancer cell culture, and temperature profiles in agarose gel under 810 nm NIR irradiation. The results showed that ≈ 15 nm and primarily spherical HM-AuNPs had η values of up to 40% and an average σ a b s of 2.15 ± 0.08 × 10 − 18 m 2. Furthermore, cell viability was reduced to about 52% and the temperature profile in agarose gel had the typical radially increasing topology. Collectively, the findings show that HM-AuNPs can be used in N-PTT. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction reaction (CO2RR) for CH4 production presents a promising strategy to address carbon neutrality, and the incorporation of a second metal has been proven effective in enhancing catalyst performance. Nevertheless, there remains limited comprehension regarding the fundamental factors responsible for the improved performance. Herein, the critical role of Pd in electrocatalytic CO2 reduction to CH4 on Cu-based catalysts has been revealed at a molecular level using in situ surface-enhanced Raman spectroscopy (SERS). A "borrowing" SERS strategy has been developed by depositing Cu–Pd overlayers on plasmonic Au nanoparticles to achieve the in situ monitoring of the dynamic change of the intermediate during CO2RR. Electrochemical tests demonstrate that Pd incorporation significantly enhances selectivity toward CH4 production, and the Faradaic efficiency (FE) of CH4 is more than two times higher than that for the catalysts without Pd. The key intermediates, including *CO2−, *CO, and *OH, have been directly identified under CO2RR conditions, and their evolution with the electrochemical environments has been determined. It is found that Pd incorporation promotes the activation of both CO2 and H2O molecules and accelerates the formation of abundant active *CO and hydrogen species, thus enhancing the CH4 selectivity. This work offers fundamental insights into the understanding of the molecular mechanism of CO2RR and opens up possibilities for designing more efficient electrocatalysts. [ABSTRACT FROM AUTHOR]

In this work, we have implemented the time-dependent density functional theory approximate auxiliary s function (TDDFT-aas) method, which is an approximate TDDFT method. Instead of calculating the exact two-center electron integrals in the K coupling matrix when solving the Casida equation, we approximate the integrals, thereby reducing the computational cost. In contrast to the related TDDFT plus tight-binding (TDDFT+TB) method, a new type of gamma function is used in the coupling matrix that does not depend on the tight-binding parameters. The calculated absorption spectra of silver and gold nanoparticles using TDDFT-aas show good agreement with TDDFT and TDDFT+TB results. In addition, we have implemented the analytical excited-state gradients for the TDDFT-aas method, which makes it possible to calculate the emission energy of molecular systems. [ABSTRACT FROM AUTHOR]

Photosensitization of semiconductors by excitation of chiral plasmonic metallic nanostructures has attracted much attention, not only for the analysis and detection of circularly polarized light but also for its potential applications in chiral photosynthesis. Although there have been reports on the detection of semiconductor-sensitized current in chiral nanostructures precisely fabricated by physical vapor deposition and/or lithography techniques, there have been no studies using plasmonic metal nanocolloids synthesized by chemical processes. In this study, we report the establishment of a fabrication method for large-area chiral photoelectrodes and the semiconductor photosensitization phenomenon realized using chiral plasmonic nanoparticles. Chiral plasmonic Au nanoparticles prepared by previously reported colloidal methods were immobilized onto a TiO2 thin film electrode by electrophoresis. When TiO2 electrodes loaded with chiral Au nanoparticles synthesized using L-cysteine were irradiated with circularly polarized light, left circularly polarized light irradiation at a wavelength of 500–600 nm generated a larger anodic photocurrent than right circularly polarized light irradiation at the same wavelength. This trend was reversed for TiO2 electrodes immobilized with colloidal Au nanoparticles synthesized with D-cysteine. From these results, we conclude that the efficiency of photocurrent generation by chiral plasmon excitation can be controlled by the polarization direction of the incident light. [ABSTRACT FROM AUTHOR]

We energetically predict the morphology of Pd, Ag, Au, and Pt nanoparticles on (0001) sapphire substrates, using density functional theory (DFT) simulations and the well-known Young–Dupre equation. In all cases, the contact angles exceed 90 ° , indicating that the nanoparticles are spherical. Notably, Au nanoparticles exhibit a higher contact angle than those of their counterparts. The validity of the proposed a b i n i t i o nanoparticle morphology prediction approach based on DFT simulations was assessed in comparison with our previous experimental findings pertaining to the time variation of the full width at half maximum (FWHM) of the resonant peak. Furthermore, the diffusivities of single Pd, Ag, Au, and Pt atoms on the substrate were evaluated by calculating the activation energy, offering insights into the underlying physics governing the timing of FWHM peaks. The analysis confirms a higher diffusivity of Au and Ag compared with Pd and Pt. According to the comparison between DFT and experiment results, although no clear relation is observed between the contact angles and timing of FWHM peaks, the diffusivity of sputtered atoms may influence the timing of FWHM peaks. Thus, timing can help to clarify the nanoparticle size, rather than shape. [ABSTRACT FROM AUTHOR]

The surface-enhanced Raman scattering (SERS) technique provides outstanding molecular fingerprint identification and high sensitivity of analytes. Herein, colloidal sphere-shaped gold nanoparticles (Au-NPs) trapped in concentric rings of the Bessel beam generated from the optical fiber-based negative axicon has been reported as a SERS substrate. With the trapping of Au-NPs, the SERS ability of colloidal Au-NPs improved, and the average enhancement factor (AEF) of the rhodamine-6G (R6G) and 4-aminothiophenol (4-ATP) molecules can reach up to the order of 107. Control experiments were also carried out with the trapping of Au-NPs by Gaussian beam illumination, without any illumination of the light and with the trapping of Au-NPs by the Bessel beam illumination on a silver (Ag)-coated silicon (Si) substrate with a self-assembled monolayer (SAM) of 4-ATP. Theoretical studies were also carried out using the finite element method (FEM) to identify the hotspots generated in the gaps formed between the Au-NPs, leading to an enhancement in the SERS signal of the molecules, and the results were consistent with the experimentally determined AEFs. The obtained results demonstrate that the proposed SERS technique is stable. This study has significant potential applications in clinical diagnosis, food safety, environment safety, chemical sensing, and biosensing. [ABSTRACT FROM AUTHOR]

Understanding the influence of a crowded intracellular environment on the structure and solvation of DNA functionalized gold nanoparticles (ss-DNA AuNP) is necessary for designing applications in nanomedicine. In this study, the effect of single (Gly, Ser, Lys) and mixture of amino acids (Gly+Ser, Gly+Lys, Ser+Lys) at crowded concentrations is examined on the structure of the ss-DNA AuNP using molecular dynamics simulations. Using the structural estimators such as pair correlation functions and ligand shell positional fluctuations, the solvation entropy is estimated. Combining the AuNP–solvent interaction energy with the solvation entropy estimates, the free energy of solvation of the AuNP in crowded solutions is computed. The solvation entropy favours the solvation free energy which becomes more favourable for larger effective size of AuNP in crowded solutions relative to that in water. The effective size of AuNP depends on the different propensity of the crowders to adsorb on Au surface, with the smallest crowder (Gly) having the highest propensity inducing the least effective AuNP size as compared to other single crowder solutions. In mixed crowded solutions of amino acids of variable size and chemistry, distinctive local adsorption of the crowders on the gold surface is observed that controls the additive or non-additive crowding effects which govern an increase (in Gly+Ser) or decrease (in Gly+Lys) in nanoparticle effective size respectively. The results shed light into the fundamental understanding of the influence of intracellular crowding on structure of ss-DNA AuNP and plausible employability of crowding as a tool to design programmable self-assembly of functionalized nanoparticles. [ABSTRACT FROM AUTHOR]

Structural parameters play a crucial role in determining the electromagnetic and thermal responses of gold nanoconstructs (GNCs) at near-infrared (NIR) wavelengths. Therefore, developing GNCs for reliable, high-contrast photoacoustic imaging has been focused on adjusting structural parameters to achieve robust NIR light absorption with photostability. In this study, we introduce an efficient photoacoustic imaging contrast agent: gold sphere chains (GSCs) consisting of plasmonically coupled gold nanospheres. The chain geometry results in enhanced photoacoustic signal generation originating from outstanding photothermal characteristics compared to traditional gold contrast agents, such as gold nanorods. Furthermore, the GSCs produce consistent photoacoustic signals at laser fluences within the limits set by the American National Standards Institute. The exceptional photoacoustic response of GSCs allows for high-contrast photoacoustic imaging over multiple imaging sessions. Finally, we demonstrate the utility of our GSCs for molecular photoacoustic cancer imaging, both in vitro and in vivo, through the integration of a tumor-targeting moiety.

Exocytosis is a critical factor for designing efficient nanocarriers and determining cytotoxicity. However, the research on the exocytosis mechanism of nanoparticles, especially the role of long non-coding RNAs (lncRNA), has not been reported. In this study, the exocytosis of AuNPs in the KYSE70 cells and the involved molecular pathways of exocytosis are analyzed. It demonstrates that nanoparticles underwent time-dependent release from the cells by exocytosis, and the release of β-hexosaminidase confirms that AuNPs are excreted through lysosomes. Mechanistic studies reveal that lncRNA ESCCAL-1 plays a vital role in controlling the exocytosis of AuNPs through activation of the MAPK pathway, including the phosphorylation of ERK and JNK. The study implies that the ESCCAL-1-mediated pathway plays an important role in the exocytosis of AuNPs in KYSE70 cells. This finding has implications for the role of ESCCAL-1 on the drug resistance of esophagus cancer by controlling lysosome-mediated exocytosis.

Modeling light–matter interactions in hybrid plasmonic materials is vital to their widening relevance from optoelectronics to photocatalysis. Here, we explore photoluminescence (PL) from ZnO nanorods (ZNRs) embedded with gold nanoparticles (Au NPs). A progressive increase in Au NP concentration introduces significant structural disorder and defects in ZNRs, which paradoxically quenches defect related visible PL while intensifying the near band edge (NBE) emission. Under UV excitation, the simulated semi-classical model realizes PL from ZnO with sub-bandgap defect states, eliciting visible emissions that are absorbed by Au NPs to generate a non-equilibrium hot carrier distribution. The photo-stimulated hot carriers, transferred to ZnO, substantially modify its steady-state luminescence, reducing NBE emission lifetime and altering the abundance of ionized defect states, finally reducing visible emission. The simulations show that the change in the interfacial band bending at the Au–ZnO interface under optical illumination facilitates charge transfer between the components. This work provides a general foundation to observe and model the hot carrier dynamics and strong light–matter interactions in hybrid plasmonic systems. [ABSTRACT FROM AUTHOR]

We examine the aggregation behavior of AuNPs of different sizes on graphene as function of temperature using molecular dynamic simulations with Reax Force Field. In addition, the consequences of such aggregation on the morphology of AuNPs and the charge transfer behavior of AuNP-Graphene hybrid structure are analyzed. The aggregation of AuNPs on graphene is confirmed from the center of mass distance calculation. The simulation results indicate that the size of AuNPs and temperature significantly affect the aggregation behavior of AuNPs on graphene. The strain calculation showed that shape of AuNPs changes due to the aggregation and the smaller size AuNPs on graphene exhibit more shape changes than larger AuNPs at all the temperatures studies in this work. The charge transfer calculation reveals that, the magnitude of charge transfer is higher for larger AuNPs-graphene composite when compared with smaller AuNPs-graphene composite. The charge transfer trend and the trends seen in the number of Au atoms directly in touch with graphene are identical. Hence, our results conclude that, quantity of Au atoms directly in contact with graphene during aggregation is primarily facilitates charge transfer between AuNPs and graphene. Our results on the size dependent strain and charge transfer characteristics of AuNPs will aid in the development of AuNPs-graphene composites for sensor applications. [ABSTRACT FROM AUTHOR]

Photoinduced force microscopy (PiFM) is a technique for nanoscale characterization of optically active materials. For correct data analysis, it is important to understand and recognize potential artifacts. In this study, we provide a Fourier-based framework for the different origins of the photoinduced force, including the photothermal motion of the atomic force microscopy (AFM) tip in PiFM measurements. We use individual gold nanoparticles as a model system to explore such tip-related phenomena and to demonstrate the benefits of three-dimensional analysis of the photoinduced force. Comparison of the in-phase heterodyne PiFM signal and the derivative of the tip–sample interaction, ∂ ⟨ k ts ⟩ / ∂ z c , directly reveals a photothermal origin for the PiFM signal in our experiments. Furthermore, we observe a lateral photothermal vibration of the tip apex induced by tip asymmetry. This lateral vibration emphasizes the importance of considering the motion of the AFM tip during data analysis. The improved lateral resolution conferred by ∂ ⟨ k ts ⟩ / ∂ z c can lead to misinterpretation. Our findings highlight that meticulous data analysis is required to ensure the correct interpretation of PiFM data. [ABSTRACT FROM AUTHOR]

Difficulty in heating tumors with high spatial selectivity while protecting surrounding healthy tissues from thermal harm is a challenge for cancer photothermal treatment (PTT). To mitigate this problem, PTT mediated by photothermal agents (PTAs) has been established as a potential therapeutic technique to boost selectivity and reduce damage to surrounding healthy tissues. Various gold nanoparticles (AuNP) have been effectively utilized as PTAs, mainly using strategies to target cancerous tissue and increase selective thermal damage. Meanwhile, imaging can be used in tandem to monitor the AuNP distribution and guide the PTT. Mainly, the parameters impacting the induced temperature can be determined using simulation tools before treatment for effective PTT. However, accurate simulations can only be performed if the amount of AuNPs accumulated in the tumor is known. This study introduces Photo-Magnetic Imaging (PMI), which can appropriately recover the AuNP concentration to guide the PTT. Using multi-wavelength measurements, PMI can provide AuNP concentration based on their distinct absorption spectra. Tissue-simulating phantom studies are conducted to demonstrate the potential of PMI in recovering AuNP concentration for PTT planning. The recovered AuNP concentration is used to model the temperature increase accurately in a small inclusion representing tumor using a multiphysics solver that takes into account the light propagation and heat diffusion in turbid media.

Developing successful nanomedicine hinges on regulating nanoparticle surface interactions within biological systems, particularly in intravenous nanotherapeutics. We harnessed the surface interactions of gold nanoparticles (AuNPs) with serum proteins, incorporating a γ-globulin (γG) hard surface corona and chemically conjugating Doxorubicin to create an innovative hybrid anticancer nanobioconjugate, Dox-γG-AuNPs. γG (with an isoelectric point of ~7.2) enhances cellular uptake and exhibits pH-sensitive behaviour, favouring targeted cancer cell drug delivery. In cell line studies, Dox-γG-AuNPs demonstrated a 10-fold higher cytotoxic potency compared to equivalent doxorubicin concentrations, with drug release favoured at pH 5.5 due to the γ-globulin coronas inherent pH sensitivity. This bioinspired approach presents a novel strategy for designing hybrid anticancer therapeutics. Our study also explored the intricacies of the p53-mediated ROS pathways role in regulating cell fate, including apoptosis and necrosis, in response to these treatments. The pathways delicate balance of ROS emerged as a critical determinant, warranting further investigation to elucidate its mechanisms and implications. Overall, leveraging the robust γ-globulin protein corona on AuNPs enhances biostability in harsh serum conditions, augments anticancer potential within pH-sensitive environments, and opens promising avenues for bioinspired drug delivery and the design of novel anticancer hybrids with precise targeting capabilities.

Clinical drug administration aims to deliver drugs efficiently and safely to target tissues, organs, and cells, with the objective of enabling their therapeutic effects. Currently, the main approach to enhance a drugs effectiveness is ensuring its efficient delivery to the intended site. Due to the fact that there are still various drawbacks of traditional drug delivery methods, such as high toxicity and side effects, insufficient drug specificity, poor targeting, and poor pharmacokinetic performance, nanocarriers have emerged as a promising alternative. Nanocarriers possess significant advantages in drug delivery due to their size tunability and surface modifiability. Moreover, nano-drug delivery systems have demonstrated strong potential in terms of prolonging drug circulation time, improving bioavailability, increasing drug retention at the tumor site, decreasing drug resistance, as well as reducing the undesirable side effects of anticancer drugs. Numerous studies have focused on utilizing polysaccharides as nanodelivery carriers, developing delivery systems based on polysaccharides, or exploiting polysaccharides as tumor-targeting ligands to enhance the precision of nanoparticle delivery. These types of investigations have become commonplace in the academic literature. This review aims to elucidate the preparation methods and principles of polysaccharide gold nanocarriers. It also provides an overview of the factors that affect the loading of polysaccharide gold nanocarriers with different kinds of drugs. Additionally, it outlines the strategies employed by polysaccharide gold nanocarriers to improve the delivery efficiency of various drugs. The objective is to provide a reference for further development of research on polysaccharide gold nanodelivery systems.

A plasmonic nanosensor is proposed and investigated its sensitivity using the optical properties of plasmonic nanoparticles. To this end, we first consider the nanosensor consisting of bowtie nanoparticles. Then, the nanosensor performance is examined under different factors such as the refractive index of the background environment, the height, and length of the nanoparticles. The proposed bowtie nanoparticles, in this work, are made of gold. The boundary element method is used to simulate the nanosensor. The extinction cross-section is computed in terms of wavelength and the effect of various factors on the resonance wavelength of localized surface plasmon is investigated. It is shown that the nanosensor investigated in this research has a high sensitivity to the changes in the refractive index of the studied sample. The sensitivity of the nanosensor is obtained as 650 nm/RIIU. In addition, the required spectral range can be arbitrarily adjusted by the type of nanoparticles. [ABSTRACT FROM AUTHOR]

The development of an effective catalytic system for the dehydrogenative coupling of hydrosilanes with alcohols remains an ongoing challenge, particularly for alcohol protection applications. In this study, we report the development and optimization of a highly efficient gold catalyst supported on fibrillated cellulose modified with citric acid. The catalyst exhibited remarkable catalytic activity under mild conditions with 0.01–0.05 mol% of Au loading, facilitating the formation of silyl ethers with excellent yield. Notably, our catalytic system overcomes the need for excess alcohol, typically required in such reactions, making it highly practical for alcohol protection applications. This work represents a significant advancement in the field of dehydrosilylation catalysis, offering a sustainable, efficient, and environmentally friendly approach for the synthesis of functional silanol-based materials and alcohol protection applications. The scope of substrates and the utility of the catalyst have been thoroughly studied. [ABSTRACT FROM AUTHOR]

An immunochromatographic test system based on the indirect competitive format has been developed for the rapid control of cyanotoxin microcystin-LR (MC-LR) in drinking water. To increase the assay sensitivity, a hydroquinone-based reduction of silver ions on the surface of gold nanoparticles as part of the immune complexes formed on the immunochromatographic membrane has been carried out. This stage allows for the enhancement of the colouration in test strip zones. The developed test system is characterised by an instrumental limit of detection of 0.05 ng/mL, a cut-off of 0.5 ng/mL, and a working range of the detectable concentrations of 0.08–0.42 ng/mL. The assay duration was 17 min. The applicability of the test system for MC-LR detection in drinking water is demonstrated. The assay recoveries vary from 90% to 120%. [ABSTRACT FROM AUTHOR]

Au@Pt core-satellite nanoparticles (CSNPs) with dual-functionality as both catalyst and surface-enhanced Raman scattering (SERS) substrate are successfully synthesized by decorating Pt nanocrystals on plasmonic Au colloids. The coupling "hotspot" structures at the Au-Pt interface significantly promotes the catalytic decarboxylation reaction, and provides spectroscopic insights into the molecule-plasmon interface in universal plasmon-promoted catalytic reactions. [Display omitted] Plasmon-induced hot carriers are a promising "active" energy source, attracting increasing attention for their potential applications in photocatalysis and photodetection. Here, we hybridize plasmonic Au spherical nanoparticles (SNPs) with catalytically active Pt nanocrystals to form Au@Pt core-satellite nanoparticles (CSNPs), which act as both an efficient catalyst for plasmon-promoted decarboxylation reaction and a robust surface-enhanced Raman scattering (SERS) substrate for plasmon-enhanced molecular spectroscopic detection. By regulating the coverage of Pt nanocrystals on the Au SNPs, we modulated the "hotspot" structures of the Au@Pt CSNPs to optimize the SERS detecting capability and catalytic decarboxylation performance. The coupling functionalities enable us with unique opportunities to in-situ SERS monitor universal reactions catalyzed by active catalysts (e.g. Pt, Pd) in the chemical industry in real-time. The decarboxylation rate of 4-mercaptophenylacetic acid was dynamically controlled by the surface catalytic decarboxylation step, following first-order overall reaction kinetics. Moreover, the reaction rate exhibited a strong correlation with the local field enhancement |E/E 0 |4 of the hotspot structure. This work provides spectroscopic insights into the molecule-plasmon interface under the plasmon-promoted catalytic reactions, guiding the rational design of the plasmonic interface of nanocatalysts to achieve desired functionalities. [ABSTRACT FROM AUTHOR]

This work is devoted to the kinetic analysis and modeling of patterns of the formation of nanoforms of metallic gold and mechanisms of the formation of metal macroparticles. The kinetics of the process in a steady state in solution and in a flow simulating the processes of deposit formation is considered. The autocatalytic nature of the synthesis of gold nanoparticles is shown, where the reverse oxidation of Au0 by strong oxidizer Au3+ is of fundamental importance. The kinetic behavior of the system is modeled, depending on the initial concentration of the reagent (Au3+), concentrations of autocatalytic seeds (Au1+, Au0), and the concentration of the reducing agent. The dependence of the multi-stage process on temperature is analyzed. The formation of a gold placer in a flow is modeled mathematically, based on the theory of ideal displacement reactors. The model includes a zone of dispersed mineral gold (or nanodistributed gold), a zone of the hydroflow, and a zone of coagulation in the formation of macroparticles on a metal nucleus (a zone of precipitation). Calculations are made of the dependence of reagent distribution on the concentration of the reducing component, the rate of hydraulic flow, the concentration of coagulants, and the precipitation of seeds. [ABSTRACT FROM AUTHOR]

An anatase/TiO2(B) homojunction loaded with Au nanoparticles was synthesized, achieving a C2H6 yield rate of 170 μmol g−1 h−1 in a flow photoreactor. The homojunction reduces TiO2(B)'s strong oxidative ability, offering a more moderate environment for methane dehydrogenation, while Au aids in charge mitigation and methyl radical coupling. The catalyst highlights homojunction engineering and a ternary synergistic effect in photocatalytic CH4 coupling. [ABSTRACT FROM AUTHOR]

C-reactive protein (CRP) is a protein made by the liver, which is released into the bloodstream in response to inflammation. Furthermore, CRP is a potential risk factor for heart disease. Hence, it is of great importance to develop a rapid, sensitive, accurate, and cost-effective method for CRP detection. Herein, we report an enzyme-free fluorescent assay for the rapid and ultra-sensitive detection of CRP with a limit of detection (LOD) reaching as low as 3.08 pg/mL (i.e., ~ 27 fM). The high sensitivity of our method was simply achieved via dual-functionalized gold nanoparticles (AuNPs). By regulating the molar ratio of DNA to CRP antibody immobilized on the AuNP surface, hundreds to thousands-fold amplification in the analyte signal could be instantly accomplished. Furthermore, our sensor was selective: non-target proteins such as interleukin-6, interleukin-1β, procalcitonin, bovine serum albumin, and human serum albumin did not interfere with the target CRP detection. Moreover, simulated serum samples were successfully analyzed. Given the excellent sensitivity, selectivity, and high resistance to complicated matrices, the enzyme-free CRP detection strategy developed in this work can be used as a generic platform to construct sensors for a wide variety of protein biomarkers and hence offers potential as a tool for rapid, accurate, and low-cost medical diagnosis. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) exhibit great promise in cancer therapy and drug delivery due to their unique physicochemical properties. The utilization of plant extracts and phytochemicals for the synthesis of AuNPs offers a simple, rapid, eco-friendly, and cost-effective alternative. This review provides an in-depth analysis of the role of plant-mediated AuNPs in cancer treatment, focusing on their core mechanisms, drug delivery applications, and future potential. It emphasizes the advantages of green synthesis methods for cancer therapy, detailing the processes involved and highlighting various plants used for nanoparticle biosynthesis. The review also explores the anti-cancer effects of plant-mediated AuNPs, such as their ability to selectively target cancer cells and induce apoptosis, supported by both in vitro and in vivo studies. Additionally, the application of these nanoparticles in targeted drug delivery for cancer therapy is examined. The review addresses biocompatibility and toxicity concerns, providing insights into the safety of these nanoparticles. Future research directions and challenges are discussed to overcome current limitations and maximize their clinical applicability. In summary, plant-mediated AuNPs offer a sustainable and effective approach for cancer therapy and drug delivery, with their green synthesis and diverse anti-cancer properties highlighting their potential. Further research is essential to fully realize their clinical benefits. [ABSTRACT FROM AUTHOR]

The Zika virus (ZIKV) is a global health threat due to its rapid spread and severe health implications, including congenital abnormalities and neurological complications. Differentiating ZIKV from other arboviruses such as dengue virus (DENV) is crucial for effective diagnosis and treatment. This study presents the development of a biosensor for detecting the ZIKV non‐structural protein 1 (NS1) using gold nanoparticles (AuNPs) functionalized with monoclonal antibodies employing dynamic light scattering (DLS). The biosensor named ZINS1‐mAb‐AuNP exhibited specific binding to the ZIKV NS1 protein, demonstrating high colloidal stability indicated by a hydrodynamic diameter (DH) of 140 nm, detectable via DLS. In the absence of the protein, the high ionic strength medium caused particle aggregation. This detection method showed good sensitivity and specificity, with a limit of detection (LOD) of 0.96 μg mL−1, and avoided cross‐reactivity with DENV2 NS1 and SARS‐CoV‐2 spike proteins. The ZINS1‐mAb‐AuNP biosensor represents a promising tool for the early and accurate detection of ZIKV, facilitating diagnostic and treatment capabilities for arboviral infections. [ABSTRACT FROM AUTHOR]

Nowadays, rapid and facile diagnosis of cancer using user friendly processes has attracted much attention. In this regard, an electrochemical (EC) biosensor with high sensitivity was fabricated by merging MIL156 MOF@COF nanocomposite with Au nanoparticles for the detection of CA15-3. Herein, metal clusters of MIL-156 as a Metal organic frameworks (MOF) were coated by a crystalline covalent organic frameworks (COF) through covalent bonding and created core-shell-like structures. The active part of the working electrode was modified in two consecutive steps. First, MIL-156 MOF@COF and then Au nanoparticles were electrodeposited on the glassy carbon electrode (GCE). The porosity of nanocomposite has significantly increased the surface area and improved the conductivity. Au nanoparticles also form an acceptable substrate for bonding antibodies due to their high affinity with amino groups. In addition, Au nanoparticles amplify the EC signal of the biosensor with their undeniable conductivity. Nanocomposite was characterized with XRD, SEM, and EDAX techniques. To investigate the proposed biosensor, differential pulse voltammetry (DPV) was used as an analytical technique. The CA15-3 calibration provided a linear range between concentrations of 30 and 100 nU/mL, thus expressing the powerful diagnostic potential of the designed biosensor. Furthermore, the suggested biosensor has been used in serum samples and discriminate breast cancer sufferers from healthy individuals with high confidence levels. [ABSTRACT FROM AUTHOR]

Attaching DNA oligonucleotides to gold nanoparticles (AuNPs) to prepare spherical nucleic acids (SNAs) has offered tremendous insights into surface chemistry with resulting bioconjugates serving as critical reagents in biosensors and nanotechnology. While thiolated DNA is generally required to achieve stable conjugates, we herein communicate that using a thermal drying method, a high DNA density and excellent SNA stability was achieved using nonthiolated DNA, rivaling the performance of thiolated DNA such as surviving 1 M NaCl, 2 month stability in 0.3 M NaCl and working in 50 % serum. A poly‐adenine block with as few as two consecutive terminal adenine bases is sufficient for anchoring on AuNPs. By side‐by‐side comparison with the salt‐aging method, the conjugation mechanism was attributed to competitive adenine adsorption at high temperature along with an extremely high DNA concentration upon drying. Bioanalytical applications of nonthiolated SNAs were validated in both solution and paper‐based sensor platforms, facilitating cost‐effective applications for SNAs. [ABSTRACT FROM AUTHOR]

A robust catalyst for the electrochemical oxidation of formic acid (EOFA) was develop by depositing semi-spherical platinum nanoparticles (nano-Pt, <37 nm in diameters) as connected aggregates (ca. 106 nm in an average diameter) onto the surface of a glassy carbon (GC) rod (Pt/GC catalyst). This Pt/GC catalyst was further amended sequentially with spherical gold nanoparticles (nano-Au, ca. 50 nm in an average diameter) and iron oxide nanowires (nano-FeOx, ca. 30 nm in average diameter and 194 nm in average length). The layers' sequencing of the catalyst was critical in optimizing the catalyst's efficiency. Surprisingly, the modification of the Pt/GC catalyst first with nano-Au and next with nano-FeOx (FeOx/Au/Pt/GC catalyst) decreased the electrochemical surface area of nano-Pt ca. 16-times, which is highly desirable. Besides, it increased tremendously the activity (two-orders of magnitude), stability (ca. 18-fold) and tolerance against CO poisoning (7-times) of the catalyst for EOFA. Moreover, it saved up to ca. −236 mV in the onset potential of the "non-poisoning" dehydrogenation pathway of EOFA. It further retained a high mass activity of 300 A g−1. With the aid of multiple materials and electrochemical inspections, the catalyst's development was confirmed and the role of catalytic ingredients was elucidated. Interestingly, nano-Au hindered geometrically the adsorption of poisoning CO molecules onto the Pt surface, whereas nano-FeOx improved significantly the charge transfer kinetics of EOFA while mediating a faster mechanism. [Display omitted] • A nanostructured FeOx/Au/Pt/GC catalyst was successfully developed. • It boosted (2 order of magnitude) the activity toward the electrochemical oxidation of formic acid (EOFA). • It owned an improved stability (ca. 18-fold) and tolerance against CO poisoning (7-times), in relative to the Pt/GC catalyst. • It saved up to ca. −236 mV in the onset potential of the "non-poisoning" dehydrogenation pathway of EOFA. [ABSTRACT FROM AUTHOR]

In this contribution, facile synthesis of gold nanoparticles (AuNPs) at ambient conditions is reported based on the use of the polyphenolic compound quercetin (QT) as the reducing and stabilizing agent at room temperature (RT). Under alkali-induced pH adjustment of QT solution and stirring conditions at RT, QT could quickly reduce gold salt (Au3+) into its nanoparticle form (Au0), resulting in the formation of a sparkling red color colloidal solution (AuNPs) with an absorption maximum at 520 nm. Further, Fourier transform infrared spectroscopy (FTIR) was employed to showcase the role of QT in the nanomaterial's synthesis process. The formed QT-AuNPs responded swiftly to Al3+ charging with color perturbation from red to grayish-purple, coupled with an absorption spectra red shift, owing to Al3+-induced aggregation of QT-AuNPs. However, when fluoride ion (F−) was pre-mixed with an optimized Al3+ concentration, reversed color changes from grayish-purple to red were observed with a blue shift in the absorption spectra. Simply put, F− formed a complex with Al3+, thus preventing Al3+-induced aggregation of QT-AuNPs. The analytical response A520/A650 was linear with F− concentration ranging from 25.0 to 250.0 µM and 250.0–600.0 µM, with a detection limit of 7.5 µM. The developed QT-AuNPs/Al3+ detection probe was selective to only F− charging, in comparison with other possible interfering anions. Real sample potentiality of the developed sensor was demonstrated on tap water samples, toothpaste, and fluoride-rich mouthwash, with reliable accuracy. [ABSTRACT FROM AUTHOR]

Telomerase presents over-expression in most cancer cells and has been used as a near-universal marker of cancer. Studies have revealed that inhibiting telomerase activity by utilizing oligonucleotides to down-regulate the expression of intracellular human telomerase reverse-transcriptase (hTERT) mRNA is an effective method of achieving anti-tumor therapy. Considering that oncogenic microRNA-21 has been proven to indirectly up-regulate hTERT expression and drive cancer metastasis and aggression through increased telomerase activity, here, we constructed an AS1411-functionallized oligonucleotide-conjugated gold nanoprobe (Au nanoprobe) to simultaneously down-regulate intracellular microRNA-21 and hTERT mRNA by using anti-sense oligonucleotide technology to explore their targeted anti-tumor therapy effect. In vitro cell studies demonstrated that Au nanoprobes could effectively induce apoptosis and inhibit the proliferation of cancer cells by down-regulating intracellular hTERT activity. In vivo imaging and anti-tumor studies revealed that Au nanoprobes could accumulate at the tumor site and inhibit the growth of MCF-7 tumor xenografted on balb/c nude mice, thus having potential for anti-tumor therapy. [ABSTRACT FROM AUTHOR]

Hydrogel nanocomposites that respond to external stimuli and possess switchable electrical properties are considered as emerging materials with potential uses in electrical, electrochemical, and biological devices. This work reports the synthesis and characterization of thermo-responsive and electroconductive hydrogel nanocomposites based on poly(N-isopropylacrylamide) (PNiPAAm) and gold nanoparticles (nanospheres—AuNPs and nanorods—AuNRs) using two different synthetic techniques. Method I involved γ-irradiation-induced crosslinking of a polymer matrix (hydrogel), followed by radiolytic in situ formation of gold nanoparticles, while Method II included the chemical synthesis of nanoparticles, followed by radiolytic formation of a polymer matrix around the gold nanoparticles. UV–Vis spectral studies revealed the presence of local surface plasmon resonance (LSPR) bands characteristic of nanoparticles of different shapes, confirming their formation and stability inside the polymer matrix. Morphological, structural, and physicochemical analyses indicated the existence of a stable porous polymer matrix, the formation of nanoparticles with a face-centered cubic structure, increased swelling capacity, and a slightly higher volume phase transition temperature (VPTT) for the hydrogel nanocomposites. Comparative electrochemical impedance spectroscopy (EIS) showed an increase in conductivity for the nano Au-PNiPAAm hydrogel nanocomposites compared to the PNiPAAm hydrogel, with a considerable rise detected above the VPTT. By reverting to room temperature, the conductivity decreased, indicating that the investigated hydrogel nanocomposites exhibited a remarkable reversible "on–off" thermo-switchable mechanism. The highest conductivity was observed for the sample with rod-shaped gold nanoparticles. The research findings, which include optical, structural, morphological, and physicochemical characterization, evaluation of the efficiency of the chosen synthesis methods, and conductivity testing, provide a starting point for future research on the given nanocomposite materials with integrated multifunctionality. [ABSTRACT FROM AUTHOR]

Simple Summary: Oesophageal adenocarcinoma (OAC), an aggressive cancer of the food pipe, often responds poorly to current chemo-radiotherapy, with only 20–30% of patients achieving a complete response. Improving tumour sensitivity to radiation could greatly benefit patient outcomes. This study explores a new approach using pyrazinib (P3), a compound previously shown to enhance radiation sensitivity in OAC. By combining P3 with gold nanoparticles (AuNP-P3), we created a formulation that improves delivery and retains P3's cancer-fighting properties. Tests demonstrated that AuNP-P3 enhances radiation sensitivity in cancer cells, reduces tumour-supporting factors, and prevents blood vessel formation, which is needed for tumour growth. These results suggest AuNP-P3 as a promising, targeted treatment to boost radiation effectiveness in OAC, potentially leading to more successful treatment outcomes for patients. Background/Objectives: Only 20–30% of oesophageal adenocarcinoma (OAC) patients achieve a complete response to neoadjuvant chemo-radiotherapy for locally advanced tumours. Enhancing the response to radiation therapy is critical for improving outcomes in this aggressive cancer. Pyrazinib (P3) is a promising compound with radiosensitizing, anti-angiogenic, anti-inflammatory, and anti-metabolic properties. However, its limited solubility and bioavailability have hindered its therapeutic potential. Methods: To overcome these limitations, pyrazinib was conjugated with gold nanoparticles (AuNP-P3), creating a novel formulation designed to enhance solubility, maintain bioactivity, and enable targeted delivery to tumour sites. Results: In an isogenic model of OAC radioresistance, AuNP-P3 significantly reduced the surviving fraction following irradiation, demonstrating its radiosensitizing properties. It also reduced mitochondrial metabolism and modulated the secretion of inflammatory mediators in both in vitro models of OAC radioresistance and human ex vivo OAC tumour explants. Furthermore, AuNP-P3 exhibited potent anti-angiogenic activity, significantly inhibiting blood vessel formation in vivo using zebrafish embryo models. Conclusions: These results collectively confirm that P3, in its conjugated formulation with gold nanoparticles, retains its therapeutic properties, highlighting the potential of AuNP-P3 as a novel therapeutic radiosensitizer for oesophageal adenocarcinoma and supporting its further development for clinical applications. [ABSTRACT FROM AUTHOR]

In radiation tumor therapy, irradiation, on one hand, should cause cell death to the tumor. On the other hand, the surrounding non-tumor tissue should be maintained unaffected. Therefore, methods of local dose enhancements are highly interesting. Gold nanoparticles, which are preferentially uptaken by very-fast-proliferating tumor cells, may enhance damaging. However, the results in the literature obtained from cell culture and animal tissue experiments are very contradictory, i.e., only some experiments reveal increased cell killing but others do not. Thus, a better understanding of cellular mechanisms is required. Using the breast cancer cell model SkBr3, the effects of gold nanoparticles in combination with ionizing radiation on chromatin network organization were investigated by Single-Molecule Localization Microscopy (SMLM) and applications of mathematical topology calculations (e.g., Persistent Homology, Principal Component Analysis, etc.). The data reveal a dose and nanoparticle dependent re-organization of chromatin, although colony forming assays do not show a significant reduction of cell survival after the application of gold nanoparticles to the cells. In addition, the spatial organization of γH2AX clusters was elucidated, and characteristic changes were obtained depending on dose and gold nanoparticle application. The results indicate a complex response of ALU-related chromatin and heterochromatin organization correlating to ionizing radiation and gold nanoparticle incorporation. Such complex whole chromatin re-organization is usually associated with changes in genome function and supports the hypothesis that, with the application of gold nanoparticles, not only is DNA damage increasing but also the efficiency of DNA repair may be increased. The understanding of complex chromatin responses might help to improve the gold nanoparticle efficiency in radiation treatment. [ABSTRACT FROM AUTHOR]

Natural polyphenolic compounds play a pivotal role in biological processes and exhibit notable antioxidant activity. Among these compounds, chlorogenic acid stands out as one of the most widespread and important polyphenols. The accurate detection of chlorogenic acid is crucial for ensuring the quality and classification of the raw materials used in its extraction, as well as the final products in the food, pharmaceutical, and cosmetics industries that contain this bioactive compound. Raman spectroscopy emerges as a powerful analytical tool, particularly in field applications, due to its versatility and sensitivity, offering both qualitative and quantitative analyses. By using the self-assembly of gold nanoparticles at liquid–liquid interfaces and the developed "aqua-print" process, we propose a facile and inexpensive route to fabricate enhanced substrates for surface-enhanced Raman spectroscopy with high reproducibility. To ensure substrate reliability and accurate molecule detection in SERS experiments, a benchmarking procedure was developed. This process involved the use of non-resonant rhodamine 6G dye in the absence of charge transfer and was applied to all synthesized nanoparticles and fabricated substrates. The latter revealed the highest enhancement factor of 4 × 104 for 72 nm gold nanoparticles among nanoparticle diameters ranging from 14 to 99 nm. Furthermore, the enhanced substrate was implemented in the detection of chlorogenic acid with a concentration range from 10 μM to 350 μM, demonstrating high accuracy (R2 > 99%). Raman mapping was employed to validate the good uniformity of the signal (the standard deviation was below 15%). The findings of this study were also supported by DFT calculations of the theoretical Raman spectra, demonstrating the formation of the chlorogenic acid dimer. The proposed method is strategically important for the development of the class of in-field methods to detect polyphenolic compounds in raw materials such as plants, extracted plant proteins, and polyphenolic compounds. [ABSTRACT FROM AUTHOR]

Gold nanoparticles have diverse applications, requiring advancements in their synthesis that facilitate scale up, size control and reproducibility. Using a seeded-growth method in a 20 mL two-phase flow reactor (ID 2.4 mm) at 35 °C, highly monodisperse gold nanoparticles of any chosen size from 20 to 60 nm were produced. Heptane was utilised as the segmenting fluid to transport the aqueous reagent-containing droplets through a coiled PTFE reactor preventing their interaction with the reactor walls and thus reactor fouling. Gold seeds ~ 12 nm were produced via a passivated Turkevich synthesis by reduction of high pH Au(III) solution using citric acid as reducing agent. For the seeded-growth in flow, the reagents utilised were the seed solution (diluted accordingly), a stabilising Tris base solution, tetrachloroauric(III) acid trihydrate and hydrogen peroxide as reducing agent. Seeded-growth synthesis was also performed using as seeds commercial 10 nm gold nanoparticles, with excellent Coefficient of Variation (CoV) and Optical Density (OD) of the grown particles (CoV < 8% and OD ≥ 1) demonstrating that they are monodisperse and have high concentration. The synthesis was able to produce 18 mL/h of grown nanoparticles solution at 2.2–2.8 mg Au/h without any divergence in the quality of the produced particles for over eight hours. [ABSTRACT FROM AUTHOR]

The utilization of carbon-based materials in biomedicine, especially graphene derivatives, has garnered significant interest. However, the concern about the necessity of removing oxygen containing functional groups in graphene oxide (GO) modification for biomedical applications has not been extensively studied. Here, we synthesized graphene oxide (GO) and reduced graphene oxide (rGO) modified with small gold nanoparticles (AuNPs) below 10 nm, referred to as GO-Au and rGO-Au, respectively, and subsequently their antioxidant capability, antibacterial activity, and cytotoxicity were directly compared. The rapid microwave-assisted synthesis method was employed to produce GO-Au and rGO-Au nanocomposites. Structural and compositional analyses using various characterization techniques revealed distinctive properties between GO-Au and rGO-Au. Interestingly, antioxidant assays employing DPPH and ABTS methods demonstrated that GO-Au exhibited higher antioxidant activity than rGO-Au with IC50 values of 98.5 and 202.8 μg/mL, respectively. Antibacterial assays showed that GO-Au was more effective at inhibiting E. coli growth (52% growth inhibition), while rGO-Au was significantly better against S. aureus (99% growth inhibition) due to the distinct mechanisms of action. On the other hand, cytotoxicity assays performed on Vero cells revealed that GO-Au exhibited greater biocompatibility compared to rGO-Au with IC50 values of 31.3 μg/mL and 23.4 μg/mL, respectively. These findings emphasize the crucial role of oxygen-containing functional groups in GO-based materials, particularly in GO-Au nanocomposites, for enhanced biocompatibility and bioactivity. Removing oxygen groups, as seen in rGO-Au, is unnecessary, unless in cases targeting specific bacteria like S. aureus. This suggests that preserving the oxygen-containing functional groups in other GO modifications is preferable in the biomedical field to maintain the low toxicity of graphene-based materials and their bioavailability. [ABSTRACT FROM AUTHOR]

In the current research, a successful and fast synthesis of gold nanoparticles (AuNPs) by utilizing the leaf extract of Eryngium planum is reported. In order to analyze the influential synthesis parameters, the Plackett-Burman (PB) design was utilized, while the response surface methodology (RSM) was employed for optimization purposes. Furthermore, the achieved AuNPs were applied in the production of the Au-MoS2 nanocomposite. The efficiency of the visible-light photocatalyst was examined in the photocatalytic decolorization of the refractory azo dye, Acid Blue 113 (AB113). A high dye removal efficiency (94%) was observed under the optimal conditions of pH 7.6 using 15.5 mg of Au-MoS2, and 14 min. These results proved that the fabricated Au-MoS2 photocatalyst using biogenic AuNPs was more efficient than pure MoS2 and could be used as a promising catalyst for the degradation of dye-containing effluents. [ABSTRACT FROM AUTHOR]

Oral squamous cell carcinoma (OSCC) is a disease of significant concern with higher mortality rates. Conventional treatment approaches have several drawbacks, leading to the opening of new research avenues in the field of nanoparticle-based cancer therapeutics. The study aimed at the synthesis of gold nanoparticles (Pm-AuNPs) from the aqueous bark extract of Pterocarpus marsupium, followed by its characterization and in vitro anticancer evaluation against OSCC. The synthesized Pm-AuNPs were characterized using UV–visible spectroscopy, particle size analyser, zeta potential, FTIR and SEM techniques. The anticancer potential of the Pm-AuNPs was evaluated against OSCC cell lines (SCC29b, SSC154 and OECM-1) through in vitro assays. The IC50 value was found to be 25 ± 1.2, 45 ± 1.5 and 75 ± 2.1 µg/mL for the three OSCC cell lines, elucidating Pm-AuNPs cytotoxic effects and mechanism of action. Intracellular ROS and SOX detection, mitochondrial transmembrane potential analysis and apoptosis detection were used to confirm the activity of Pm-AuNPs against OSCC. Acute toxicity studies on Wistar rats confirmed the non-toxic nature of the Pm-AuNPs at a higher dose concentration up to 2000 mg/kg body weight. The findings underscore Pm-AuNPs as promising candidates for future anticancer therapeutics, providing insights into their mechanism of action and therapeutic efficacy against OSCC. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) were synthesized using three red wine extracts (RW-Es); by varying temperature, pH, concentrations of RW-Es and gold salt. The RW-AuNPs were characterized by UV–vis, transmission electron microscopy (TEM), dynamic light scattering (DLS), and the Fourier Transform Infra-red Spectroscopy (FT–IR). Their stability was evaluated in water, foetal bovine serum (FBS), phosphate-buffered saline (PBS), and Dulbecco's Modified Eagle Medium (DMEM) by UV–Vis. The effect of the RW-Es and RW-AuNPs on KMST-6 cell cell viability was evaluated by MTT assay; and their wound healing effects were monitored by scratch assay. RW-AuNPs synthesis was observed by colour change, and confirmed by UV–Vis spectrum, with an absorption peak around 550 nm. The hydrodynamic sizes of the RW-AuNPs ranged between 10 and 100 nm. Polyphenols, carboxylic acids, and amino acids are some of functional groups in the RW-Es that were involved in the reduction of RW-AuNPs. The RW-AuNPs were stable in test solutions and showed no cytotoxicity to the KMST-6 cells up to 72 h. AuNPs synthesized from Pinotage and Cabernet Sauvignon enhanced proliferation of KMST-6 cells and showed potential as wound healing agents. Further studies are required to investigate the molecular mechanisms involved in the potential wound-healing effect of the RW-AuNPs. [ABSTRACT FROM AUTHOR]

Locally advanced head and neck squamous cell carcinoma (LA-HNSCC) is characterized by high rate of recurrence, resulting in a poor survival. Standard treatments are associated with significant toxicities that impact the patient's quality of life, highlighting the urgent need for novel therapies to improve patient outcomes. On this regard, noble metal nanoparticles (NPs) are emerging as promising agents as both drug carriers and radiosensitizers. On the other hand, co-treatments based on NPs are still at the preclinical stage because of the associated metal-persistence. In this bioconvergence study, we introduce a novel strategy to exploit tumour chorioallantoic membrane models (CAMs) in radio-investigations within clinical equipment and evaluate the performance of non-persistent nanoarchitectures (NAs) in combination with radiotherapy with respect to the standard concurrent chemoradiotherapy for the treatment of HPV-negative HNSCCs. A comparable effect has been observed between the tested approaches, suggesting NAs as a potential platinum-free agent in concurrent chemoradiotherapy for HNSCCs. On a broader basis, our bioconvergence approach provides an advance for the translation of Pt-free radiosensitizer to the clinical practice, positively shifting the therapeutic vs. side effects equilibrium for the management of HNSCCs. [ABSTRACT FROM AUTHOR]

Methotrexate (MTX) is a folic acid antagonist routinely used in cancer treatment, characterized by poor water solubility and low skin permeability. These issues could be mitigated by using drug delivery systems, such as functionalized gold nanoparticles (AuNPs), known for their versatility and unique properties. This study aimed to develop multi-shell AuNPs functionalized with MTX for the improvement of MTX antitumoral, antioxidant, and biocompatibility features. Stable phosphine-coated AuNPs were synthesized and functionalized with tailored polyethylene glycol (PEG) and short-branched polyethyleneimine (PEI) moieties, followed by MTX covalent binding. Physicochemical characterization by UV–vis and Fourier-transform infrared spectroscopy (FTIR) spectroscopy, dynamic light scattering (DLS), scanning transmission electron microscopy (STEM), and X-ray photoelectron spectroscopy (XPS) confirmed the synthesis at each step. The antioxidant activity of functionalized AuNPs was determined using DPPH radical scavenging assay, ferric ions' reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC) assays. Biocompatibility and cytotoxicity were assessed using MTT and LDH assays on HaCaT human keratinocytes and CAL27 squamous cell carcinoma. MTX functionalized AuNPs demonstrated enhanced antioxidant activity and a pronounced cytotoxic effect on the tumoral cells compared to their individual components, highlighting their potential for improving cancer therapy. [ABSTRACT FROM AUTHOR]

We describe an environmentally benign method for the synthesis of porous gold by gelation of a hydrophilic polymer bearing metal-coordination units (thiocarbonyl groups, denoted as HPMC) and Au(III) ions. The gelation was performed by dropwise addition of a dispersed aqueous solution of HPMC to an aqueous solution of Au(III) in a test tube. Concentrations of 15 and 20 wt% HPMC provided elongated and fibrous gels. Scanning electron microscopy and transmission electron microscopy analyses of the fibrous gels revealed the formation of porous gels containing Au nanoparticles. Calcination of the polymer parts in the porous gels at 550 °C for 7 h, followed by self-assembly of the remaining Au nanoparticles, provided the golds with micrometer-size pores. Thermogravimetric analysis of the porous golds indicated that its purity was high (96 ~ 99%). Because the metal-coordination unit has soft basic characteristics, it preferentially coordinate to soft acidic noble metal ions such as platinum group metal ions, Ag(I), and so on. Therefore, this method will be applied to synthesis of various porous metals. [ABSTRACT FROM AUTHOR]

The combination of conducting polymer and nanogold represents a cutting-edge approach in the development of efficient drug release control systems, particularly leveraging molecular imprinting technology. In this work, a conductive molecularly imprinted polymer (MIP) was electro-synthesized from 1,8-diaminonaphthalene monomers in the presence of amoxicillin as target molecule on gold nanoparticles (AuNPs). AuNPs play a crucial role in supporting the polymerization process and facilitating the characterization of material properties through various analytical techniques. Furthermore, the conductive MIP facilitates fabrication control through electrochemical parameters, enabling the specific and reversible capture and release of amoxicillin. A comprehensive drug release kinetic study was conducted, revealing a significant departure from the conventional release profile of commercial amoxicillin capsules. While typical capsules release the drug over 1 h, our conductive MIP material demonstrated a substantially prolonged release time, extending up to approximately 8 h. This prolonged-release duration holds promising implications for drug delivery applications, potentially offering improved therapeutic outcomes and patient adherence. [ABSTRACT FROM AUTHOR]

Magnetic molecularly imprinted polymers (MMIPs) are used as artificial antibody materials. MMIPs have attracted a great deal of interest because of their low cost, wide practicality, predetermination, stability and their ability to achieve rapid separation from complex sample environments by the action of external magnetic field. MMIPs can simulate the natural recognition of entities. They are widely used because of their great advantages in terms of high selectivity. In this review article, the preparation methods of Fe3O4 NPs and a detailed summary of the commonly used methods for amination modification of Fe3O4 NPs are introduced, preparation of Ag NPs of different sizes and Au NPs of various shapes and preparation methods of magnetic molecularly imprinted plasmonic SERS composite nanoparticles such as Fe3O4@Ag NPs, Fe3O4/Ag NPs, Fe3O4@Au NPs, Fe3O4/Au NPs, Fe3O4@Au/Ag NPs and Fe3O4@Ag@Au NPs are main summarized. In addition, preparation process and the current application of MMIPs prepared from magnetic molecularly imprinted plasmonic SERS composite nanoparticles incorporating different functional monomers in a nuclear-satellite structure are also presented. Finally, the existing challenges and future prospects of MMIPs in applications are discussed. [ABSTRACT FROM AUTHOR]

A highly sensitive label-free electrochemical aptamer biosensor with magnetically induced self-assembly had been developed to detect gastrin-releasing peptide precursor (ProGRP), which is not only a highly specific tumour marker for small-cell lung cancer (SCLC), but also very stable in serum, and thus had robust clinical utility. Based on the advantages of high specific surface area and facile separation and recycling, magnetic α-Fe 2 O 3 /Fe 3 O 4 nanorods with the average length of 175 nm, the average diameter of 28 nm, and the saturation magnetization of 66.9 emu/g were used as the matrix, and Au nanoparticles (AuNPs) were loaded on the surfaces of the nanorods to enhance the electrochemical signal. The aptamer double-stranded probe with high specificity to the target protein was bound to the surface of α-Fe 2 O 3 /Fe 3 O 4 @Au. The thiol-modified oligonucleotides could quickly and stably bind to AuNPs to form Au-S, which provided a guarantee for the immobilization of the probe and the controllable self-assembled molecular layer. Then, the sensor after capturing the target was self-assembled on the surface of the magnetic glassy carbon electrode (MGCE) by liquid phase incubation for electrochemical detection. The construction and detection performance of the sensor were evaluated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). Under the optimized conditions, the sensor had remarkable linearity in the range of 0.1 pg/mL - 100 ng/mL (R2 = 0.998), the limit of detection (LOD) was 17.51 fg/mL, while the limit of quantitation (LOQ) was 58.39 fg/mL. Additionally, the biosensor had excellent stability, reproducibility and anti-interference ability, as well as satisfactory recovery in spiked serum samples (99.46 %–103.32 %). The rod-like magnetic α-Fe 2 O 3 /Fe 3 O 4 @Au nanocomposites were employed as signal amplification substrates for electrochemical detection, and the aptamer double-stranded probes were bound to their surfaces via Au-S bonds to form the biosensor. The biosensor demonstrated low LOD, excellent selectivity, reproducibility, and stability, as well as satisfactory recovery in spiked serum samples, suggesting its promising potential for sensitive detection of ProGRP in the clinical. [Display omitted] • A label-free electrochemical biosensor with magnetic self-assembly was constructed for ultrasensitive detection of ProGRP. • The rod-like magnetic α-Fe 2 O 3 /Fe 3 O 4 @Au nanocomposites were fabricated to amplify signal and increase sensitivity. • The biosensor exhibited femtogram-level LOD, excellent specificity, reproducibility, stability and satisfactory recovery in human serum. [ABSTRACT FROM AUTHOR]

In this paper, Au-modified Co 3 O 4 hollow nanospheres/graphene composites (Au-Co 3 O 4 /rGO) were synthesized for the first time through a novel "one-pot cooking" method at ambient temperature. The hollow nanospheres exhibited a particle size of approximately 10–15 nm, while the modified Au nanoparticles were about 4–5 nm in diameter. A high-efficiency and high response H 2 S gas sensor was constructed based on Au-Co 3 O 4 /rGO ternary composites. The effects of different Au modifying mass ratios on the H 2 S gas-sensitive performance of the composites were systematically investigated. At an operational temperature of 92 °C, the Au-Co 3 O 4 /rGO sensor, incorporating an Au loading mass ratio of 1.3 wt%, exhibited a response value of 175.4 for H 2 S at 100 ppm, a recovery time of 30 s, and a detection limit reaching as low as 10 ppb. This response was tripled compared to the undoped Co 3 O 4 /rGO sensor. At the same time, the H 2 S sensing mechanism by Au-Co 3 O 4 /rGO was discussed in detail. [ABSTRACT FROM AUTHOR]

This paper aims to study the nanofluids with peristaltic flow motion in a confined length of non-uniform horizontal tube with an endoscope. In addition to wall properties and velocity slip effect, three geometries (i.e., sphere, cylinders, and blades) of Gold – blood MHD nanoparticles are also considered. To peruse the realistic study of the model, equations and boundary conditions are modeled and formed in dimensionless control equations. Expressions for the exact solutions of velocity, nanoparticle shape effects for temperature, heat transfer, and stream function are obtained. Visual depiction of these solutions is also demonstrated by carrying out various parameters. After analyzing, a few observations illustrate that platelet-shaped nanoparticles attain the highest thermal conductivity. The maximum temperature is experienced for sphere-shaped nanoparticles and the increasing behavior is also observed for higher values of thermal slip parameter. The conduct of velocity profile increases for greater values of the slip parameter. Sphere-shaped nanoparticles also show dominance compared to brick- and platelet- shaped particles. A trapping phenomenon is also discussed in the current study. The presented model can useful for applications associated with the metabolic structures that play a vital role in heat sources inside the human body. [ABSTRACT FROM AUTHOR]