Search Results (165)

This study presents a comparative investigation of plasmonic sensing platforms based on colloidal gold nanoparticle (AuNP) suspensions and gold film over nanosphere (AuFoN) solid substrates for the detection of epidermal growth factor receptor (EGFR), an essential biomarker and therapeutic target in oncology. The strategy relies on fluorescence emission modulation of an Atto647N-labeled DNA oligomer competitively bound to an EGFR-specific aptamer. Our results demonstrate that the colloidal AuNPs can function as competitive binding sensors, leading to fluorescence quenching upon fluorophore attachment to the surface of the NPs and partial fluorescence recovery due to EGFR-induced displacement of the fluorophore–aptamer complex. This specificity was confirmed by reversed binding experiments. However, the system proved highly sensitive to the experimental design: excessive washing (centrifugation) led to unspecific aggregation and signal loss, while reduced washing steps improved signal retention and revealed EGFR-induced fluorophore displacement into the supernatant. On the contrary, film-based substrates exhibited strong initial fluorescence, but failed to retain the fluorophore–aptamer complex after washing, resulting in fluorescence decay independent of EGFR incubation. This indicates that AuFoN lacked the binding stability necessary for specific displacement-based sensing. These findings highlight that while colloidal AuNPs can support competitive binding detection, their reproducibility is limited by colloidal stability and protocol sensitivity, whereas AuFoN substrates require improved surface functionalization strategies. The study emphasizes the critical role of surface chemistry, aptamer–fluorophore affinity, and washing protocols in determining the success or failure of plasmon-enhanced aptamer-based biosensing systems and suggests opportunities for improving specificity and robustness in future designs. Full article

This study considered and compared silver, gold, and their combination of nanoparticles (AgNPs, AuNPs, and Au-AgNPs) with biocompatible material mesoporous silica SBA-15 as potential antibacterial agents. A facile, one-pot “green” methodology, utilizing L-histidine as a reducing agent and bridge between components, was employed to obtain Ag@SBA-15, Au@SBA-15, and Au-Ag@SBA-15 nanocomposites without the use of external additives. Various physicochemical tools (UV-Vis, TEM, SAED, FESEM, XPS, BET, XRD, and FTIR) presented SBA-15 as a good carrier for spherical AgNPs, AuNPs, and Au-AgNPs with average diameters of 8.5, 16, and 9 nm, respectively. Antibacterial evaluations of Escherichia coli and Staphylococcus aureus showed that only Ag@SBA-15, at a very low Ag concentration (1 ppm) during 2 h of contact, completely reduced the growth (99.99%) of both strains, while the Au@SBA-15 nanocomposite required higher concentrations (5 ppm) and time (4 h) to reduce 99.98% E. coli and 94.54% S. aureus. However, Au introduction in Ag@SBA-15 to form Au-Ag@SBA-15 negatively affected its antibacterial potential, lowering it due to the galvanic replacement reaction. Nevertheless, the rapid and effective combating of two bacteria at low NPs concentrations, through the synergistic effects of mesoporous silica and AgNPs or AuNPs, in Ag@SBA-15 and Au@SBA-15 nanocomposites, provides a potential substitute for existing bacterial disinfectants. Full article

(1) Background: gold nanoparticles (AuNPs) are of particular interest in biomedical research because they possess unique optical properties. In particular, its localized surface plasmon resonance is widely used for photothermal therapy and for detecting molecular interactions at nanoparticle surfaces. To enhance circulation time and biocompatibility, nanoparticles are often coated to shield their hydrophobic character. (2) Methods: we explored the seed-growth method to coat AuNPs with phospholipids to improve colloidal stability. (3) Results: various charged phospholipids were tested, and particle size and zeta potential were characterized. The monodispersity of the coated nanoparticles strongly depends on the narrow size distribution of both gold nanoparticles seeds and lipid vesicles. Achieving stable coated AuNPs with zwitterionic lipids such as phosphatidylcholine was challenging, whereas coatings containing phosphatidylglycerol did not compromise nanoparticle stability. (4) Conclusions: coating AuNPs with phospholipids via the seed-growth method has potential but requires further optimization to improve reproducibility and achieve stable nanoparticles with near-neutral surface charge. Full article

Background: Cervical cancer is the fourth leading cause of death among women worldwide, with human papillomavirus (HPV) identified as a major contributing factor. This study investigates the immunostimulatory activity and antigen delivery efficiency of Glycyrrhiza uralensis polysaccharide gold nanoparticles (GUPS-AuNPs) and assesses the antitumor efficacy of an HPV dendritic cell (DC) vaccine using GUPS-AuNPs as a delivery system. Methods: GUPS-AuNPs were synthesized via a green reduction method and characterized using advanced techniques, including SEM, EDS, TEM, UV, and FT-IR spectroscopy. DCs served as the primary experimental model, with flow cytometry employed to evaluate the immunostimulatory activity and antigen delivery effectiveness of GUPS-AuNPs. Additionally, a TC-1 tumor-bearing mouse model was established to assess the immunostimulatory and antitumor effects of the HPV-DC vaccine facilitated by GUPS-AuNPs. Results: The synthesized GUPS-AuNPs exhibited a particle size of 120.77 ± 3.13 nm, a surface charge of −11.9 ± 2.1 mV, and excellent stability. Flow cytometry analysis demonstrated that GUPS-AuNPs significantly enhanced DC maturation and promoted T cell proliferation. Furthermore, antigen delivery experiments revealed that GUPS-AuNPs improved the antigen capture capabilities of DCs. Confocal imaging confirmed that GUPS-AuNPs extended the intracellular retention time of antigens. In vivo studies showed that the HPV-DC vaccine formulated with GUPS-AuNPs as carriers effectively suppressed tumor growth, elevated the populations of CD4⁺ T and CD8⁺ T cells in the spleen, and induced a robust antigen-specific immune response. Conclusions: GUPS-AuNPs effectively enhance DC maturation and antigen delivery, significantly boosting the adaptive immune response triggered by HPV vaccines and leading to the inhibition of tumor progression. This research introduces GUPS-AuNPs as a novel, safe, and efficient antigen delivery platform with promising potential for vaccine development. Full article

The development of low-background, facile, and robust fluorescent nanoprobes for imaging and monitoring of intracellular mRNA changes remains a great challenge. Taking advantage of the high fluorescence quenching efficiency of core-shell gold@polydopamine (Au@PDA) nanocomposites and Ca²⁺-promoting DNA adsorption stability, a simple and universal bioconjugate strategy was designed to a construct fluorescent nanoprobe for highly efficient tumor-related mRNA imaging. The fluorescence of Cy5-labeled DNA was quenched up to 92.38% by the AuNP and PDA via nanometal surface energy transfer (NSET) and photoinduced electron transfer (PET), respectively. TK1 mRNA, a biomarker of tumor growth, initiates hybridization and results in fluorescence recovery, which built the foundation for identifying the expression level changes in living cells. More importantly, three kinds of tumor-related mRNA (TK1 mRNA, GalNAc-T mRNA, and C-myc mRNA) can be detected simultaneously with different fluorophore-modified recognition sequences, which can avoid false positive signals and improve the reliability of cancer diagnostic, holding great promise for cancer diagnosis, prognosis, and therapy. Full article

Interest in gold nanoclusters (AuNCs) has grown significantly in recent decades. AuNCs, with a core size smaller than 2 nm, represent a unique class of functional nanomaterials. Their distinctive properties enable innovative applications across various interdisciplinary fields. Here, we introduce BioGoldNCDB, a freely available, fully annotated, and manually curated database of mainly about AuNCs and related AuNPs. Despite the rapid growth in biomedical applications of gold nanoclusters (AuNCs), the lack of a centralized and structured data resource hinders comparative analysis and rational design. Researchers face challenges in accessing standardized information on AuNCs’ structures, properties, and biological activities, which limits data-driven development in this emerging field. The database provides essential information, including CAS numbers and PubMed IDs, as well as specific details such as biomedical applications, cell lines used in research, particle size, and excitation/emission wavelengths. It currently covers 247 articles from 104 journals. Designed with a user-friendly and intuitive web interface, BioGoldNCDB is accessible on multiple devices, including phones, tablets, and PCs. Users can refine searches with multiple filters, and a help page is available for guidance. While offering quick insights for newcomers, BioGoldNCDB also serves as a valuable resource for researchers across various fields. Full article

Osteosarcoma (OSA) is the most common primary bone malignancy in dogs, characterized by aggressive growth and high metastatic potential. Despite advances in treatment, the prognosis for affected animals remains poor, mainly due to metastatic disease. Metastasis is a complex process that involves forming new blood vessels in the primary tumor (angiogenesis), intravasation, the transport of cancer cells to other locations, extravasation, and the growth of cancer cells in the secondary site. Gold nanoparticles (AuNPs), due to their unique physicochemical properties, are considered promising tools in cancer therapy, both as drug delivery systems and potential anti-metastatic agents. Previously, it has been demonstrated that 500 µg/mL glutathione-stabilized gold nanoparticles (Au-GSH NPs) inhibit cancer cell extravasation—one of the steps of the metastatic cascade. This study aimed to evaluate the anti-metastatic properties of Au-GSH NPs through their influence on OSA cell migration, proliferation, and colony formation in vitro, as well as their antiangiogenic properties on the chick embryo chorioallantoic (CAM) model. Additionally, we investigated whether these effects are associated with changes in alpha-2-macroglobulin (A2M) expression, as it was previously demonstrated to play an essential role in the metastatic cascade. Au-GSH NPs significantly inhibited migration and colony formation in canine osteosarcoma cells (from OSCA-8, OSCA-32, and D-17 cell lines) at 200 µg/mL concentrations. Interestingly, at 500 µg/mL, Au-GSH NPs inhibited angiogenesis on the CAM model and cancer cell migration, but fewer colonies were formed. These results may be directly related to the higher efficiency of Au-GSH NPs uptake by OSA cells at the dose of 200 μg/mL than at the dose of 500 μg/mL, as demonstrated using Microwave Plasma Atomic Emission Spectroscopy (MP-AES). Moreover, this is the first study that demonstrates a significant increase in A2M expression in cancer cells after Au-GSH NPs treatment. This study provides new insight into the potential use of Au-GSH NPs as anti-metastatic agents in canine osteosarcoma, indicating that their anti-metastatic properties may be related to A2M. However, further in vitro and in vivo studies are needed to explore the molecular mechanism underlying these effects and to evaluate the clinical relevance of AuNPs in veterinary oncology. Full article

Gold nanoparticles (AuNPs) anchored on graphene oxide (GO) have had a significant interest for their unique optical, electrical, and catalytic properties. This study presents an eco-friendly and sustainable synthesis of AuNPs on GO sheets using L-ascorbic acid (L-aa) as a green reducing agent and polyvinylpyrrolidone (PVP) as a stabilizer. The effect of reductant concentration on nanoparticle morphology was systematically investigated using UV–Visible spectroscopy and transmission electron microscopy (TEM). Results indicate the formation of AuNPs anchored on GO sheets and that an increase in the L-aa amount leads to both an increase in nanoparticle size and a morphological transition from spherical to irregular structures. The simultaneous nucleation and growth processes result in the formation of multiple families of nanostructures, as confirmed by TEM analysis, which reveals two distinct size distributions. At higher L-aa concentrations, the nanoparticles shape evolves into irregular morphologies due to selective growth along a preferential facet. This approach not only enables precise control over AuNP size and shape but also aligns with green chemistry principles, making it a promising route for applications in plasmonics, sensors, and photothermal therapy. Full article

Targeting and multidrug resistance are the significant problems of current antitumor drugs, and these problems become the key factors in the design of nanomedicine. Herein, Au NRs and OPC-Au NPs were prepared via the hydroquinone seedless growth method and proanthocyanidin (OPC) one-pot method, and then pH-GSH-near-infrared ΙΙ (NIR-ΙΙ)-responsive nano-prodrugs Au/DOX-ss LNRs and OPC-Au/DOX-ss LNPs were designed by the encapsulation of doxorubicin prodrug DOX-ss with Au-S affinity and thermal-sensitive liposomes. Interestingly, OPC endowed OPC-Au NPs with reducibility and excellent performance in terms of particle size, zeta potential, encapsulation rate, and drug loading rate. In particular, the photothermal efficiencies of OPC-Au/DOX-ss LNPs increased to 59.22% under the 1064 nm NIR-ΙΙ irradiation. Compared with free DOX-ss and Lipid DOX-ss, the IC50 of OPC-Au/DOX-ss LNPs was decreased by 91.68% and 97.60%, respectively. Furthermore, the expression of P-gp in MCF-7/ADR was significantly inhibited (decreased by 65%). The potential of proanthocyanidin remodels the pH-GSH-NIR-ΙΙ responsiveness and drug resistance of OPC-Au/DOX-ss LNPs for breast cancer treatment in NIR-ΙΙ photodynamic/photothermal therapy. Full article

Multidrug-resistant (MDR) bacterial pathogens pose a serious threat to global health, underscoring the urgent need for innovative therapeutic strategies. In this work, we designed and characterized thiol-modified antisense oligonucleotide-capped gold nanoparticles (ASO-AuNPs) to resensitize antibiotic-resistant bacteria. Transmission electron microscopy and UV–Vis spectroscopy confirmed the morphology, size, and optical properties of AuNPs and ASO-AuNPs. Minimum inhibitory concentrations (MIC) of ampicillin were determined for non-resistant Escherichia coli DH5α (16 ppm) and an ampicillin-resistant E. coli DH5α strain (PSK, 32,768 ppm). When co-administered with ampicillin, ASO-AuNPs (0.1 and 0.2 nM) significantly reduced bacterial growth compared to the antibiotic-alone control (p < 0.05), demonstrating the capacity of ASO-AuNPs to restore antibiotic efficacy. These findings provide a proof of concept that antisense oligonucleotide-functionalized nanomaterials can be harnessed to overcome beta-lactam resistance, setting the stage for further optimization and translation into clinical applications. Full article

Carcinoembryonic antigen (CEA) is an important tumor biomarker for the early clinical diagnosis of various cancers, and, therefore, the accurate and sensitive quantitative determination of CEA is of vital significance. In this study, we demonstrated the in situ growth of Au nanoparticles (AuNPs) on nitrogen-doped graphene quantum dots (N-GQDs) decorated reduced graphene oxide (rGO) nanocomposites by using simple drop-coating and electrochemical deposition methods. N-GQDs@rGO can be formed through the π–π stacking interaction and possesses a high specific surface area and many functional groups, providing lots of anchor sites (amino moieties in NGQDs) for the in situ electrochemical growth of AuNPs without the addition of reductants and protective agents. Such AuNPs/N-GQDs@rGO ternary nanocomposites combine the characteristics of three nanomaterials, showing a large surface area, excellent solubility, good conductivity, catalytic activity, a simple fabrication process, and notable stability, which are further used to construct a label-free electrochemical immunosensor for the determination of CEA. Under the optimized experimental conditions, the AuNPs/N-GQDs@rGO-based electrochemical immunosensor achieves a broad linear response, ranging from 1 pg/mL to 0.5 μg/mL and a low detection limit of 0.13 pg/mL. Moreover, the AuNPs/N-GQDs@rGO-based electrochemical immunosensor shows exceptional selectivity, anti-interference, and anti-fouling capabilities for the direct analysis of CEA amounts in fetal bovine serum samples, showing vast potential in the clinical screening of cancer. Full article

Targeting HER2-positive cancer cells with precision therapies is a critical challenge in oncology. Here, we present a study on gold nanoparticles (AuNPs) conjugated with DARPin_9-29, a designed ankyrin repeat protein with high specificity and affinity for HER2 receptors. In this study, we investigate the therapeutic potential of AuNP-DARPin_9-29 conjugates, which was synthesized and characterized by us earlier, for photothermal therapy (PTT). By combining AuNP-DARPin treatment with visible light illumination, we show selective inhibition of HER2-positive cancer cell proliferation and tumor progression in a murine model. The results highlight the effectiveness of AuNP-DARPin in disrupting cancer cell viability and reducing tumor growth, providing a cost-effective and targeted approach for combating HER2-positive cancers. Full article

Chiral molecules are ubiquitous in nature and biological systems, where the unique optical and physical properties of chiral nanoparticles are closely linked to their shapes. Synthesizing chiral plasmonic nanomaterials with precise structures and tunable sizes is essential for exploring their applications. This study presents a method for growing three-dimensional chiral gold nanoflowers (Au NFs) derived from trisoctahedral (TOH) nanocrystals using D-cysteine and L-cysteine as chiral inducers. By employing a two-step seed-mediated growth approach, stable chiral Au nanoparticles with customizable sizes, shapes, and optical properties were produced by adjusting the Au nanosphere (Au NP) seed concentration and cysteine dosage. These nanoparticles exhibited optical activity in both the visible and near-infrared regions, with a maximum anisotropy factor (g-factor) of 0.024. Furthermore, the PEG-modified chiral Au NFs demonstrated excellent biocompatibility. This approach provides a precise method for geometrically controlling the design of three-dimensional chiral nanomaterials, holding great potential for biomedical applications. Full article

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. Full article

Skin damage is one of the most prevalent human injuries, which affects the health of human beings. However, skin damage is often accompanied by bacterial infection and wound microenvironment changes, causing damage to normal cells and inhibiting wound healing. Herein, we designed a thermal-responsive antibacterial hydrogel (GAG hydrogel) loaded with catalase (CAT)-like Au@Pt@MgSiO₃ nanoparticles (APM NPs) and gentamicin (GM) to promote wound healing. The GAG hydrogel was used in a photothermal therapy (PTT)/antibiotic combination to kill bacteria, reduce the use of antibiotics, improve the wound microenvironment, promote cell proliferation, and accelerate wound healing. Under near-infrared laser irradiation, APM NPs in the hydrogel generated local hyperthermia to kill bacteria. Meanwhile, the generated heat led to a change in the hydrogel’s morphology, enabling it to release GM and APM NPs to prevent the overuse of antibiotics. Subsequently, the CAT-like ability of the APM NPs decreased the oxidative stress caused by hydrogen peroxide (H₂O₂), thus remodeling the wound microenvironment. Then, the weakly acidic microenvironment of the wound caused the decomposition of the APM NPs and the release of magnesium ions (Mg²⁺), promoting the growth and migration of cells for wound healing. Therefore, the studied thermal-responsive antibacterial (GAG) hydrogel has potential in the field of wound healing. Full article