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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.

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.

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]

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]

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]

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]

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]

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]

Exosomes as new biomarkers for cancer diagnosis have attracted attention because they are highly released by tumor cells in various biological fluids. In this study, an electrochemical paper-based immunosensor device (Exo-sensing paper) is introduced for the detection of exosome in the serum. The Exo-sensing paper is a three-electrode system that is prepared using pattern paper and carbon and silver inks. The sensor part of this immunosensor contains a three-dimensional porous nanocomposite of nickel nanofoam coupled with graphene oxide and gold nanoparticles. The high specific surface area of this nanocomposite increases the antibody loading on the sensor surface significantly and consequently leads to obtaining a wide linear range of 500–1 × 107 Exospore µL−1 with a detection limit of 110 Exosome µL−1. Due to some advantages of this constructed Exo-sensing paper such as easy storage, simple application, low cost and good selectivity in the real samples, this system has a good potential to be used as a point of care testing for in situ detection of the exosomes and is a promising strategy for minimally invasive liquid biopsy. [ABSTRACT FROM AUTHOR]

[Display omitted] Regulating the electron structure and precise loading sites of metal-active sites within the highly conjugated and porous covalent-triazine frameworks (CTFs) is essential to promoting the nitrogen reduction reaction (NRR) performance for electrocatalytic ammonia (NH 3) synthesis under ambient conditions. Herein, experimental method and density functional theory (DFT) calculations were conducted to deeply probe the effect on NRR of the modulation of modulating the electron structure and the loading site of gold nanoparticles (Au NPs) in a two-dimensional (2D) CTF. 2D CTF synthesized using melem and hexaketocyclohexane octahydrate as building blocks (denoted as M−HCO−CTF) served as a robust scaffold for loading Au NPs to form an M−HCO−CTF@AuNP hybrid. DFT results uncovered that well-defined Au sites with tunable local structure were the active site for driving the NRR, which can significantly suppress the conversion of H+ into *H adsorption and enhance the nitrogen (N 2) adsorption/activation. The overlapped Au (3 d) and *N 2 (2 p) orbitals lowered the free energy of the rate-determining step to form *NNH, thereby accelerating the NRR. The M−HCO−CTF@AuNPs electrocatalyst exhibited a large NH 3 yield rate of 66.3 μg h−1 mg−1 cat. and a high Faraday efficiency of 31.4 % at − 0.2 V versus reversible hydrogen electrode in 0.1 M HCl, superior to most reported CTF-based ones. This work can provide deep insights into the modulation of the electron structure of metal atoms within a porous organic framework for artificial NH 3 synthesis through NRR. [ABSTRACT FROM AUTHOR]

Featured Application: The work presents information on the potential for the synthesis of hydrogels comprising gold nanoparticles coated with itraconazole, together with an evaluation of their potential utility. Gold nanoparticles have been identified as a promising avenue for the development of drug carriers, particularly in the context of antimicrobial drug delivery, where limited solubility represents a significant challenge. The ability of gold nanoparticles to penetrate biofilms and disrupt fungal cell membranes makes them an effective tool to support antifungal therapy, especially against resistant strains. Gold nanoparticles also demonstrate synergistic effects with chemotherapeutics and can influence the release profile of the active substances. This study aimed to develop a topical hydrogel drug formulation containing itraconazole (ITZ), with the addition of gold nanoparticles, to enhance its therapeutic properties. Due to ITZ's poor water solubility, three types of the gold nanoparticles (AuNPs) of different sizes were synthesized and subsequently coated with itraconazole. The resulting formulations were incorporated into carbopol gels and their ability to diffuse through semipermeable membranes was assessed. The findings demonstrated that the combination of gold nanoparticles and itraconazole elevated the diffusion coefficient to twice the level observed in gels without nanoparticles. Furthermore, the combined effect of gold nanoparticles and itraconazole against a reference Candida albicans strain was investigated. The combination of gold nanoparticles and itraconazole demonstrated a growth-inhibitory effect on this strain, indicating that this formulation could potentially be employed in the treatment of fungal infections. The study confirms that hydrogels with itraconazole and gold nanoparticles can be obtained, offering enhanced drug diffusion. [ABSTRACT FROM AUTHOR]

Integration of gold nanoparticles onto electrochemical biosensor electrodes has been widely conducted to improve the performance of biosensors. Gold nanospikes (AuNS), as one of the gold nanoparticle morphologies, can be integrated into biosensors through electrodeposition and has the potential to immobilize bioreceptor on biosensors using the self-assembled monolayer (SAM) method. This paper examines the potential of AuNS-deposited Screen-Printed Carbon Electrodes (SPCEs) on immobilizing enzymes as label-based electrochemical biosensor by evaluating the optimum parameter for glucose oxidase (GOx) enzyme immobilization on the SPCE that consists of incubation time and concentration of SAM molecule—L-cysteine—and GOx enzyme, then reviews its performances. The developed biosensor exhibits excellent performance in detecting glucose (linear range of 0.2–15 mM and limit of detection (LOD) of 116 µM), with good selectivity against uric acid, urea, ascorbic acid, dopamine, and lactic acid, and superiority towards gold nanosphere modified biosensor. [ABSTRACT FROM AUTHOR]

In the present work, a host network of bismuth borate glass with composition (30-x)Bi2O3-70B2O3-xHAuCl4⋅3H2O where x = 0, 0.01, 0.1, and 1 mol% was prepared through a conventional melt-quench technique. The influence of gold nanoparticles on the structural, thermal, and optical properties of these bismuth borate glasses was investigated by preparing and comparing a series of glass samples containing varying concentrations of gold ranging from 0 to 1 mol%. No post-treatment was applied to ensure a fair comparison of previously reported results. X-ray diffraction analysis confirmed the amorphous nature of the glasses, with noticeable changes in peak broadening indicating varying degrees of disorderness with gold incorporation. Fourier Transform Infrared spectroscopy revealed modifications in structural groups and bonding due to gold doping. High-resolution Transmission Electron Microscopy and Selected Area Electron Diffraction confirmed the formation of gold nanoparticles within the glass matrix. Thermal analysis demonstrated altered glass stability with varying gold concentrations making them potent applicants for fiber drawing. UV–Vis absorption spectra exhibited reduced transparency with increasing gold content, along with the appearance of a localized surface plasmon resonance peak at 580, 600, and 605 nm for 0.01-, 0.1-, and 1-mol% gold, respectively. These results confirm the successful incorporation of gold nanoparticles and their significant impact on the optical properties, particularly in tailoring the plasmonic behavior of the glasses, offering potential for photonic applications. [ABSTRACT FROM AUTHOR]

This work uses the polymeric reduction method to explore the in-situ synthesis of gold nanoparticles (AuNPs) within 3D-printed optical fiber probes (OFPs). Digital light processing (DLP) 3D printing is employed to fabricate the OFPs using a resin consisting of hydroxyethyl methacrylate (HEMA) and polyethylene glycol diacrylate (PEGDA). After printing, OFPs were immersed in a boiling gold precursor solution to facilitate the synthesis of AuNPs inside the polymer matrix. We produced single material (HEMA/PEGDA) and multimaterial (HEMA/PEGDA + Dentaclear) OFPs loaded with AuNPs at different concentrations. Scanning electron microscopy analysis confirmed the effective distribution and dispersion of AuNPs within the polymer matrix. The optical properties, including reflection and transmission spectra, are comprehensively measured using customized setups. The localized surface plasmon resonance of the embedded AuNPs created a distinct dip in the 500–600 nm wavelength range. Higher AuNP concentrations and longer dipping times enhanced light absorption, reducing reflection and transmission intensities. Multimaterial OFPs also exhibited tunable wavelength filtering capabilities based on the AuNP concentration. The AuNP-loaded OFPs demonstrated stable optical performance across varying temperatures and pH environments, highlighting their potential for diverse applications. [ABSTRACT FROM AUTHOR]

This study explores the synthesis and characterization of gold nanoparticles (AuNPs) using green and chemical methods, employing ginger extract and curcumin as reducing agents, in comparison to sodium citrate reduction. The biosynthesized AuNPs synthesized with ginger extract exhibited an average hydrodynamic diameter of 15 and 10 nm for curcumin-conjugated AuNPs, while chemically synthesized AuNPs with sodium citrate displayed an average size of 10 nm. Assessments via Zeta potential measurements revealed negative surface charges across all samples, with the curcumin-conjugated AuNPs showing −36.3 mV, ginger extract-synthesized AuNPs showing −31.7 mV, and chemically produced gold nanoparticles having a surface charge of −40.4 mV. Transmission Electron Microscopy (TEM) confirmed spherical morphologies for the synthesized nanoparticles,and it revealed the presence of biomolecules embedded within the nanoparticles synthesized using biological materials, whereas chemically synthesized AuNPs lacked such features. The FTIR spectra of the biosynthesized AuNPs highlighted the presence of phenolic and aromatic compounds from the ginger extract and curcumin, indicating their role in coating the nanoparticles. Gas chromatography-mass spectrometry (GC-MS) analysis identified gingerol as a key component in the ginger extract, contributing to nanoparticle capping. The antimicrobial efficacy of the AuNPs was evaluated against P. aeruginosa , E. coli , and S. aureus , revealing superior activity for curcumin-AuNPs, with ginger-AuNPs also outperforming chemically synthesized counterparts. These findings confirm the advantages of biological approaches, using a plant extract like ginger and pure curcumin suspension, for better size distribution when used as reducing agents, along with improved antimicrobial efficacy compared to chemically produced gold nanoparticles synthesized with sodium citrate. This study also highlight the potential of green-synthesized AuNPs in biomedical applications, due to their enhanced stability from higher surface charge and the repeatability of biological methods. [ABSTRACT FROM AUTHOR]

Rapid virus identification is crucial for preventing outbreaks. The COVID-19 pandemic has highlighted the critical nature of rapid virus detection. Here, we designed a label-free electrochemical biosensor modified with gold nanoparticles (AuNPs) to detect IgG antibodies from human serum, enabling rapid point-of-care diagnostics. AuNPs were synthesized and characterized. A multivariate optimization was carried out to determine the optimal condition for functionalizing AuNPs with anti-IgG. Subsequently, using a glassy carbon electrode (GCE), a modified AuNPs/GCE electrochemical biosensor was developed for IgG detection. The results indicated that AuNPs displayed a spherical morphology with a size distribution of 19.54 nm. Additionally, the zeta potential was recorded at −7.84 mV. Central composite design (CCD) analysis determined the optimal conditions for functionalizing AuNPs to be an anti-IgG concentration of 320 µg mL−1, a temperature of 25 °C, and pH of 7.4. The characterization study confirmed the successful synthesis and functionalization of AuNPs. Through electrochemical impedance spectroscopy measurement, the biosensor demonstrated a limit of detection (LOD) of 0.2 ng mL−1 and limit of quantification (LOQ) of 0.8 ng mL−1. Furthermore, tests in real samples showed the interaction between IgG antibodies in serum samples and AuNPs/GCE, confirming the biosensor's ability to detect and quantify IgG in clinical samples. [ABSTRACT FROM AUTHOR]

Detection of microRNA-196a (miRNA-196a) is crucial in cancer research, enabling early diagnosis and providing guidance for individualized treatment. In this work, we employed a naturally occurring negatively charged nano silk fibroin (NSF) with high mechanical properties, biocompatibility, and conductivity to be encapsulated with a positively charged gold nanoparticles (AuNPs) were used as film-forming materials for electrostatic layer-by-layer self-assembly to modify the working electrode of the screen-printed carbon electrode (SPCE). Under the optimized experimental conditions, the uniformly distributed AuNPs on the surface of the multilayer film modified SPCE (AuNPs/NSF)5.5/SPCE combined with the sulfhydryl-modified capture probe cp-DNA through gold-sulfur bonds. Furthermore, miRNA-196a is specifically captured through complementary base pairing to achieve highly sensitive and specific detection. (AuNPs/NSF)5.5/SPCE electrode can detect miRNA-196a in a concentration range of 1.0 × 10−13 to 1.0 × 10−6 M, and the calculated detection limit is 4.63 × 10−14 M when the signal-to-noise ratio is 3. The obtained results showed that the (AuNPs/NSF)5.5/SPCE has excellent selectivity and good stability over time. [ABSTRACT FROM AUTHOR]

Versatile methods for the quantification of intracellular cholesterol are essential for understanding cellular physiology and for diagnosing disorders linked to cholesterol metabolism. Here we used Raman spectroscopy (RS) and surface-enhanced Raman spectroscopy (SERS) to measure changes in cholesterol after incubating human fibroblasts with increasing concentrations of cholesterol-methyl-β-cyclodextrin. RS and SERS were sensitive and accurate enough to detect high levels of cholesterol in fibroblasts from patients affected by type C Niemann-Pick disease (NPC), a lysosomal storage disorder characterized by the primary accumulation of cholesterol. Moreover, SERS was able to distinguish between fibroblasts from different NPC patients, demonstrating higher accuracy than RS and standard fluorescent labeling of cholesterol with filipin III. We show that the type of gold nanoparticles used as signal enhancer surfaces in our SERS measurements are internalized by the cells and are eventually found in lysosomes, the main site of accumulation of cholesterol in NPC fibroblasts. The higher sensitivity of SERS can thus be attributed to the specific trafficking of our gold nanoparticles into these organelles. Our results indicate that RS and SERS can be used as sensitive and accurate methods for the evaluation of intracellular cholesterol content, allowing for the potential development of an optical detection tool for the ex-vivo screening and monitoring of those diseases characterized by abnormal modification in cholesterol levels. [ABSTRACT FROM AUTHOR]

The paper presents an investigation on the optoelectronic and photocatalytic properties of titanium-nitride (TiN) thin films, modified through the introduction of metal ions (Au, Ag, and Cu) during implantation, followed by thermal annealing. Employing high-resolution microscopic and spectroscopic techniques, we examined the microstructural and compositional features of the films in detail. The films exhibited a crystalline structure with distinct columnar patterns, attributed to defect release and recovery during annealing. Furthermore, metal nanoparticles were detected in samples implanted with gold and silver ions, indicating coalescence processes, while no such particles were observed in the case of Cu ions. Post-implantation annealing also led to surface oxidation and the formation of anatase TiO 2 , with a coexistence of TiO 2 , TiN, metallic Au and Ag, and CuO phases in subsurface regions. Comparative optical measurements revealed significant changes in photoluminescence efficiency and photocatalytic response of modified TiN. All implanted samples showed reduced photoluminescence intensity compared to pristine titanium-nitride, with the Au-implanted film exhibiting the most significant decrease, due to the presence of surface Au nanoparticles, thus resulting in the slower electron-hole recombination rates and enhanced photocatalytic activity. [ABSTRACT FROM AUTHOR]

We investigated the design and characterization of a Lab-On-a-Chip (LoC) cell detection system primarily designed to support immunotherapy in cancer treatment. Immunotherapy uses Chimeric Antigen Receptors (CARs) and T Cell Receptors (TCRs) to fight cancer, engineering the response of the immune system. In recent years, it has emerged as a promising strategy for personalized cancer treatment. However, it requires bioreactor-based cell culture expansion and manual quality control (QC) of the modified cells, which is time-consuming, labour-intensive, and prone to errors. The miniaturized LoC device for automated QC demonstrated here is simple, has a low cost, and is reliable. Its final target is to become one of the building blocks of an LoC for immunotherapy, which would take the place of present labs and manual procedures to the benefit of throughput and affordability. The core of the system is a commercial, on-chip-integrated capacitive sensor managed by a microcontroller capable of sensing cells as accurately measured charge variations. The hardware is based on standardized components, which makes it suitable for mass manufacturing. Moreover, unlike in other cell detection solutions, no external AC source is required. The device has been characterized with a cell line model selectively labelled with gold nanoparticles to simulate its future use in bioreactors in which labelling can apply to successfully engineered CAR-T-cells. Experiments were run both in the air—free drop with no microfluidics—and in the channel, where the fluid volume was considerably lower than in the drop. The device showed good sensitivity even with a low number of cells—around 120, compared with the 107 to 108 needed per kilogram of body weight—which is desirable for a good outcome of the expansion process. Since cell detection is needed in several contexts other than immunotherapy, the usefulness of this LoC goes potentially beyond the scope considered here. [ABSTRACT FROM AUTHOR]

Temperature detection is particularly important in the medical and scientific fields. Although there are various temperature detection methods, most of them focus on broad temperature detection, and basic research in specific fields, especially the detection of subtle temperature changes (32–34 °C) during wound infection, is still insufficient. For this purpose, a novel colorimetric temperature sensing probe is designed in this paper, which can quickly and intuitively respond to small temperature changes within a specific range through color changes. In this paper, hyperbranched polyethyleneimine (HPEI) was modified by isobutyrylation to prepare hyperbranched temperature-sensitive polymer (HPEI-IBAm). And it was combined with gold nanoparticles (AuNPs) prepared by a sodium citrate reduction method to construct an HPEI-IBAm-AuNP colorimetric probe. The probe exhibits excellent stability, even at salt concentrations of up to 12 g/L, thanks to the abundant amino functional groups and the large steric hindrance effect unique to HPEI-IBAm. In particular, the temperature detection range of the probe is precisely locked within 32–34 °C, enabling it to respond quickly and accurately to small temperature changes of only 2 °C. This feature is perfectly suited to the practical needs of temperature detection in infected wounds. The linear fitting coefficient of the temperature response is as high as 0.9929, ensuring the accuracy of the test results. The detection performance of the probe remained highly consistent over 10 cycles, fully proving its excellent reusability and durability. In addition, a flexible colorimetric sensor was prepared by combining the probe with polydimethylsiloxane (PDMS) film. This sensor is capable of rapidly detecting human skin temperature in real time, achieving an accuracy of 99.07% to 100.61%. It can provide a possible solution to the challenges of delayed and difficult temperature detection caused by different body parts and uneven surfaces, among others. This demonstrates its extensive practical value and potential, and it is expected to be further applied in the monitoring of wound infections. [ABSTRACT FROM AUTHOR]

To obtain versatile nanoplatforms comparable for various bio-applications, synthesis and functionalization of two inorganic nanoparticles (NPs), i.e., gold (AuNPs) and iron oxide (SPIONs), are described for different NP diameters. Chosen ligands have adapted chemical function to graft to the surfaces of the NPs (thiols and phosphonates, respectively) and the identical frequently used external carboxyl group for comparison of the NPs' material effect on their final behavior. To further evaluate molecular length effect, AuNPs are functionalized by different ligands. Numerous characterizations highlight the colloidal stability when grafting organic molecules on NPs. The potentiality of the functionalized NPs to react efficiently with a protein monolayer is finally evaluated by grafting them on a protein covered chip, characterized by atomic force microscopy. Comparison of the NPs' surface densities and measured heights enable observation of different NPs' reactivity and infer the influence of the inorganic core material, as well as the NPs' size and ligand length. AuNPs have higher affinities to biomolecules, especially when covered by shorter ligands. NP ligands should be chosen not only based on their length but also on their chemical chain, which affects proteic layer interactions. This original multiplex comparison method using AFM is of great interest to screen the effects of used NP materials and functionalization when developing theranostic nanoplatforms. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (NPs) have demonstrated significance in several important fields, including drug delivery and anticancer research, due to their unique properties. Gold NPs possess significant optical characteristics that enhance their application in biosensor development for diagnosis, in photothermal and photodynamic therapies for anticancer treatment, and in targeted drug delivery and bioimaging. The broad surface modification possibilities of gold NPs have been utilized in the delivery of various molecules, including nucleic acids, drugs, and proteins. Moreover, gold NPs possess strong localized surface plasmon resonance (LSPR) properties, facilitating their use in surface-enhanced Raman scattering for precise and efficient biomolecule detection. These optical properties are extensively utilized in anticancer research. Both photothermal and photodynamic therapies show significant results in anticancer treatments using gold NPs. Additionally, the properties of gold NPs demonstrate potential in other biological areas, particularly in antimicrobial activity. In addition to delivering antigens, peptides, and antibiotics to enhance antimicrobial activity, gold NPs can penetrate cell membranes and induce apoptosis through various intracellular mechanisms. Among other types of metal NPs, gold NPs show more tolerable toxicity capacity, supporting their application in wide-ranging areas. Gold NPs hold a special position in nanomaterial research, offering limited toxicity and unique properties. This review aims to address recently highlighted applications and the current status of gold NP research and to discuss their future in nanomedicine. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) are highly attractive for applications in the field of biosensing, particularly for colorimetric nucleic acid detection. Their unique optical properties, which are highly sensitive to changes in their environment, make them ideal candidates for developing simple, rapid, and cost-effective assays. When functionalized with oligonucleotides (Au-nanoprobes), they can undergo aggregation or dispersion in the presence of complementary sequences, leading to distinct color changes that serve as a visual signal for detection. Aggregation-based assays offer significant advantages over other homogeneous assays, such as fluorescence-based methods, namely, label-free protocols, rapid interactions in homogeneous solutions, and detection by the naked eye or using low-cost instruments. Despite promising results, the application of Au-nanoprobe-based colorimetric assays in complex biological matrices faces several challenges. The most significant are related to the colloidal stability and oligonucleotide functionalization of the Au-nanoprobes but also to the mode of detection. The type of functionalization method, type of spacer, the oligo–AuNPs ratio, changes in pH, temperature, or ionic strength influence the Au-nanoprobe colloidal stability and thus the performance of the assay. This review elucidates characteristics of the Au-nanoprobes that are determined for colorimetric gold nanoparticles (AuNPs)-based nucleic acid detection, and how they influence the sensitivity and specificity of the colorimetric assay. These characteristics of the assay are fundamental to developing low-cost, robust biomedical sensors that perform effectively in biological fluids. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (NPs) are among the most commonly employed metal NPs in biological applications, with distinctive physicochemical features. Their extraordinary optical properties, stemming from strong localized surface plasmon resonance (LSPR), contribute to the development of novel approaches in the areas of bioimaging, biosensing, and cancer research, especially for photothermal and photodynamic therapy. The ease of functionalization with various ligands provides a novel approach to the precise delivery of these molecules to targeted areas. Gold NPs' ability to transfer heat and electricity positions them as valuable materials for advancing thermal management and electronic systems. Moreover, their inherent characteristics, such as inertness, give rise to the synthesis of novel antibacterial and antioxidant agents as they provide a biocompatible and low-toxicity approach. Chemical and physical synthesis methods are utilized to produce gold NPs. The pursuit of more ecologically sustainable and economically viable large-scale technologies, such as environmentally benign biological processes referred to as green/biological synthesis, has garnered increasing interest among global researchers. Green synthesis methods are more favorable than other synthesis techniques as they minimize the necessity for hazardous chemicals in the reduction process due to their simplicity, cost-effectiveness, energy efficiency, and biocompatibility. This article discusses the importance of gold NPs, their optical, conductivity, antibacterial, antioxidant, and anticancer properties, synthesis methods, contemporary uses, and biosafety, emphasizing the need to understand toxicology principles and green commercialization strategies. [ABSTRACT FROM AUTHOR]

This study compares the mobility behaviour, in a H2O2 environment, of three different geometries of hybrid particle made of silica core functionalized by gold (nanoparticles or layer). It is known that the decomposition of H2O2 on gold surfaces drives mobility; however, the link between mobility orientation and the organization of gold on silica surfaces is still questionable. While conventional wisdom posits that asymmetric designs are crucial for generating phoretic forces or localized bubble propulsion, recent research suggests that symmetrical particles may also exhibit motility. To address this debate, we developed a robust workflow for synthesizing gold grafted silica nanoparticles with precise control over size and shape, enabling the direct comparison of their motile behaviour by dynamic light scattering and particle tracking velocimetry. Our results indicate, first, that a combination of techniques is necessary to overcome their intrinsic limitation and, second, that the inherent asymmetry generated by isotropic gold nanoparticle deposition onto silica surfaces may enable particle motility. [ABSTRACT FROM AUTHOR]

This article presents an examination of well-controlled patterns created using a Ga+-based focused ion beam (FIB) on glass, while silicon substrates were used to evaluate the FIB performance by its achievable feature size versus time constraints. The pattern creation on glass was developed with the aim of studying potential surface-enhanced Raman spectroscopy (SERS) applications. Furthermore, the FIB was used to create dimer systems of periodically and randomly positioned dumbbell-shaped pits on the glass (each dimer occupies an area of 203 × 87 nm2). By following the bitmap pattern files, the FIB ensured there was 3000 dimer fabrication over a 20 × 20 μm2 large area, with a pit size and position variation below 10 nm. The article highlights that FIB can be used for precise large-area nano-fabrication. The gold nanoparticle dimers were formed on the prepatterned surface via capillary force-assisted deposition. The fabricated nanostructures were tested in SERS measurements. The enhancement factor for Rhodamine B molecule reached ~105, demonstrating the potential application of the method to create nanostructures in the sensor domain. [ABSTRACT FROM AUTHOR]

Tissue regeneration can be achieved by providing endogenous cells with a biomaterial scaffold that supports their adhesion and proliferation, as well as the synthesis and deposition of an extracellular matrix (ECM). In this work, silk fibroin protein foams were formed by lyophilization to generate tissue engineering scaffolds. Three types of medically relevant nanoparticles (NPs) (iron oxide, gold and silver) were added to this biomaterial to assess the ability of silk foams to be functionalized with these NPs. The structural and mechanical properties of the foams with and without the NPs were suitable for tissue support. The in vitro cytocompatibility of the scaffolds was confirmed according to the ISO 10993 guidelines. The biocompatibility of the scaffolds was investigated by assessing inflammation and endogenous cell colonization in a mouse subcutaneous model These in vivo experiments demonstrated a loss of acute inflammation and the absence of chronic inflammation in the grafted animals. The obtained results show that silk foams are good candidates for supporting soft tissue regeneration with the additional possibility of functionalization with NPs. [ABSTRACT FROM AUTHOR]

The goal of this work is to investigate the catalytic activities of low-coordination atoms located in gold nanoparticles. Gold nanoparticles with sizes from 0.7 to 40 nm deposited on γ-Al2O3 were used as a catalyst. Synthesized gold nanoparticles and prepared catalysts were characterized by HRTEM, SEM, XRD, DLS, and UV-Vis spectroscopy. The specific activity of gold nanoparticles towards the isotope exchange reaction at 77 K was studied as a function of nanoparticle size. The catalytic activity increases significantly when the particle size is less than 3 nm. The activities of low-coordination gold atoms located at the edges and in the corners are markedly different. Corner atoms (CN = 6) are more than 40 times more active in the reaction of hydrogen isotope exchange than edge atoms (CN = 7). TOF for atoms with coordination numbers CN = 6 and CN = 7 are 0.258 ± 0.020 and 0.006 ± 0.001 molecules site−1 s−1, respectively. An equation was proposed for the dependence of the catalytic activity of the reaction on the particle size, the number of atoms on the surface, and their activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • A gel based on pAAm and crosslinked with AuNPs decorated with an amino acid derivative was synthesized. • The presented gel is a reinforced, highly elastic, and conductive material with anti-freezing properties. • p(AAm–0.4%BISS)–Au (WG) shows elongation at break of 1000 % with a tensile strength of 35.0 kPa. • The obtained material exhibits sensitivity to various deformations: elongation, bending, and compression. • The obtained material allows for real-time monitoring of joint movements and speech recognition. In this study, we present a nanocomposite hydrogel designed for skin motion sensing. The hydrogel is based on poly(acrylamide) crosslinked with gold nanoparticles covalently bound to the polymer matrix, yielding a robust, highly elastic and conductive material. The choice of amino acid derivative – N,N' -diacryloylcystine salt (BISS) – as a crosslinker allows for the introduction of gold nanoparticles, due to the presence of sulfide groups in its structure. During the nanoparticle modification process, covalent bonds between gold and sulfur atoms are formed as the disulfide bond is cleaved. In result of this self-assembly process, a multifunctional Au–BISS crosslinker is formed, enhancing the material's mechanical properties and introducing electrical conductivity. To confer anti-freezing properties and limit water evaporation, a binary mixture of water and glycerol was used. The resultant hydrogel exhibits high elasticity, strain sensitivity across a wide strain range and various types of deformation (elongation, bending, compression) with exceptional response time (120 ms) and recovery time (90 ms). The material's cold-resistance, resilience, and conductivity make it well-suited for real-time monitoring of joint movements and speech recognition, with potential applications in electronic skin and healthcare monitoring devices. [ABSTRACT FROM AUTHOR]

Background: Brucellosis is a major worldwide zoonotic disease that is caused by Brucella spp. and threatens the health of communities. Novel methods for rapid detection of Brucella bacteria are beneficial and necessary in preventing infection and subsequent economic losses. Constructing biosensors with nanoparticles is a promising approach for identification of pathogenic bacteria in a short time. This study aimed to introduce a new detection method of Brucella cells using a biosensor, based on gold nanoparticles and a specific aptamer, via a colorimetric reaction. In this work, gold nanoparticles (GNPs) were synthesized and attached to the aptamer through electrostatic bonding. The binding of aptamer to gold nanoparticles was confirmed by Uv/vis spectrophotometry, FT-IR, transmission electron microscope (TEM) and zeta sizer (DLS). Results: In the presence of the bacterial cells, aptamers were bound to their targets, and the surfaces of the nanoparticles were depleted from aptamers resulting in intensified peroxidation activity of GNPs, and with the addition of 3, 3′, 5, 5′-tetramethylbenzidine (TMB), the color of the solution was changed from red to purple, which indicated the presence of Brucella. The sensitivity of the aptasensor was investigated using different concentrations of Brucella cells and its specificity was confirmed against several species of bacteria. The results showed that the designed aptasensor was more sensitive compared to PCR assay method with the ability to detect 1.5 × 101 CFU/mL of the bacterial cells. Conclusion: These findings indicate that the designed aptasensor can be used as a simple and rapid diagnostic tool to detect Brucella cells without need to experts and expensive laboratory equipment. [ABSTRACT FROM AUTHOR]

The colloidal gold nanoparticle (AuNP)‐based colorimetric lateral flow assay (LFA) is one of the most promising analytical tools for point‐of‐care disease diagnosis. However, the low sensitivity and insufficient accuracy still limit its clinical application. In this work, a machine learning (ML)‐optimized colorimetric LFA with ultrasound enrichment is developed to achieve the sensitive and accurate detection of tau proteins for early screening of Alzheimer's disease (AD). The LFA device is integrated with a portable ultrasonic actuator to rapidly enrich microparticles using ultrasound, which is essential for sample pre‐enrichment to improve the sensitivity, followed by ML algorithms to classify and predict the enhanced colorimetric signals. The results of the undiluted serum sample testing show that the protocol enables efficient classification and accurate quantification of the AD biomarker tau protein concentration with an average classification accuracy of 98.11% and an average prediction accuracy of 99.99%, achieving a limit of detection (LOD) as sensitive as 10.30 pg mL−1. Further point‐of‐care testing (POCT) of human plasma samples demonstrates the potential use of LFA in clinical trials. Such a reliable lateral flow immunosensor with high precision and superb sensing performance is expected to put LFA in perspective as an AD clinical diagnostic platform. [ABSTRACT FROM AUTHOR]

An electrochemical biosensor based on a polystyrene-gold nanocomposite was fabricated for the ultrasensitive sensing of clenbuterol. The PS-Au nanocomposite was synthesized by modifying polystyrene with triazine and aminothiazole groups, followed by the in-situ reduction of AuNPs. The PS-Au/SPCE exhibited a linear range (0.01–10 μM) with a limit of detection of 3.2 nM towards clenbuterol along with high selectivity and good stability. The sensor platform showcased its prowess by accurately quantifying clenbuterol in milk specimens fortified with known analyte concentrations, yielding recovery percentages within the range of 96.5–102.8 %, accompanied by relative standard deviations below 4.2 %. The superior performance of the PS-Au/SPCE is due to the synergistic effect of the high surface area and electrocatalytic activity of the AuNPs, the efficient adsorption of clenbuterol on the functionalized polystyrene matrix, and the enhanced electron transfer kinetics. [ABSTRACT FROM AUTHOR]