Incorporation Of Gold Nanoparticles Research Articles

Effect of gold nanoparticle dispersion on the structural, optical and radiation shielding parameters of sodium Borate glass

Abstract Borate-derived radiation shielding glasses have been thoroughly explored, yet the effects of gold nanoparticle (GNP) dispersion on sodium borate glasses remain unstudied. This study investigates the impact of GNP dispersion and varying GNP concentrations on the radiation shielding properties and other parameters of sodium borate glass. All the glasses were prepared using the melt-quench technique with a composition of 30Na₂O-70B₂O₃, containing 0, 3 × 10⁸, and 3 × 10⁹ nanoparticles. The X-ray diffractogram confirmed the amorphous nature of the prepared glass samples, while Fourier Transform Infrared Spectroscopy (FTIR) confirmed structural modifications, indicated by the formation of non-bridging oxygens due to the incorporation of GNPs. High-resolution transmission electron microscopy (HR-TEM) confirmed the presence of GNPs with an average size of 1.317 nm, and Field Emission Scanning Electron Microscopy (FESEM) revealed further coagulation of GNPs into tiny grains to alleviate surface stresses. Density measurements showed a clear decrease from 2.3051 to 2.1363 g/cm³ with the incorporation of gold nanoparticles. Additionally, a localized surface plasmon resonance peak centered at 612 nm was observed in the UV‒Vis spectrogram of the glass with the highest GNP concentration. Radiation shielding parameters, including the mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), half-value layer (HVL), tenth-value layer (TVL), mean free path (MFP), and effective atomic number (Zeff), were analyzed using Phy-X/PSD software. The LAC value initially decreases from 78.046 to 72.330 cm⁻¹ with the incorporation of GNPs but increases to 77.846 cm⁻¹ with a higher GNP concentration. This glass system exhibited superior radiation shielding parameters compared to various reported glass systems, indicating its potential for shielding applications.

An advanced 3D DNA nanoplatform for spatiotemporally confined enhanced dual-mode biosensing MicroRNA in cancer cell

Dual-mode signal output platforms have demonstrated considerable promise due to their improved anti-interference capability and inherent signal self-correction. Nevertheless, traditional discrete-distributed signal probes often encounter significant drawbacks, including limited mass transfer efficiency, diminished signal strength, and instability in intricate biochemical environments. In response to these challenges, a scalable and hyper-compacted 3D DNA nanoplatform resembling “periodic focusing heliostat” has been developed for synergistically enhanced fluorescence (FL) and surface-enhanced Raman spectroscopy (SERS) biosensing of miRNA in cancer cells. Our approach utilized a distinctive assembly strategy integrating gold nanostars (GNS) as fundamental “heliostat units” linked by palindromic DNA sequences to facilitate each other hand-in-hand cascade alignment and condensed into large scale nanostructures. This configuration was further augmented by the incorporation of gold nanoparticles (GNP) via strong Au–S bonds, resulting in a sturdy framework for improved signal transduction. The initiation of this assembly process was mediated by the hybridization of dsDNA to miRNA-21, which served as a primer for polymerization and nicking reactions, thus generating a multifunctional T2 probe. This probe is intricately designed with three distinct parts: a 3′-palindromic end for structural integrity, a central region for capturing SERS-active probes (Cy3-P2), and a 5′-segment for attaching fluorescence reporters. Upon integration T2 into the GNS-based heliostat unit, it promotes palindromic arm-induced aggregation and plasma exciton coupling between plasma nanoparticles and signal transduction tags. This clustered arrangement creates a high-density “hot spot” array that maximizes the local electromagnetic fields necessary for enhanced SERS and FL response. This superstructure supports enhanced aggregation-induced signal amplification for both SERS and FL, offering exceptional sensitivity with LOD as low as 0.0306 pM and 0.409 pM. The efficacy of this method was demonstrated in the evaluation of miRNA-21 in various cancer cell lines.

Development of a sensitive ds-DNA/Au NPs/ PGE biosensor for determination of Buprenorphine using electrochemical and molecular dynamic simulation investigation

A sensitive electrochemical DNA biosensor has been developed for the detection of Buprenorphine (Bu), a narcotic pain reliever. To achieve this, double-stranded DNA (ds-DNA) was immobilized on a pencil graphite electrode that was modified with gold nanoparticles (Au NPs/PGE). The gold nanoparticles enhanced the performance of the DNA biosensor. The constructed ds-DNA/Au NPs/ PGE exhibited a linear detection range spanning from 0.05 to 100 μM with an impressive detection limit of 20 nM for Bu detection. Additionally, the DNA biosensor demonstrated good response in real samples evaluations. Finally, the interaction between carbon and gold atoms with DNA was confirmed through molecular dynamics simulation, while the interaction between DNA and the Bu drug was confirmed through molecular docking method. In conclusion, the electrochemical DNA biosensor presented in this study demonstrates exceptional sensitivity and reliability in the detection of buprenorphine. The incorporation of gold nanoparticles, as well as the use of molecular dynamics simulations and docking methods, contributes to a comprehensive understanding of the interactions involved in this detection process.

Enhancing Laser-Induced Graphene via Integration of Gold Nanoparticles and Titanium Dioxide for Sensing and Robotics Applications.

Laser-induced graphene (LIG) is a promising material for various applications due to its unique properties and facile fabrication. However, the electrochemical performance of LIG is significantly lower than that of pure graphene, limiting its practical use. Theoretically, integrating other conductive materials with LIG can enhance its performance. In this study, we investigated the effects of incorporating gold nanoparticles (AuNPs) and titanium dioxide (TiO2) into LIG on its electrochemical properties using ReaxFF molecular dynamics (MD) simulations and experimental validation. We found that both AuNPs and TiO2 improved the work function and surface potential of LIG, resulting in a remarkable increase in output voltage by up to 970.5% and output power density by 630% compared to that of pristine LIG. We demonstrated the practical utility of these performance-enhanced LIG by developing motion monitoring devices, self-powered sensing systems, and robotic hand platforms. Our work provides new insights into the design and optimization of LIG-based devices for wearable electronics and smart robotics, contributing to the advancement of sustainable technologies.

Physicochemical Properties of Inorganic and Hybrid Hydroxyapatite-Based Granules Modified with Citric Acid or Polyethylene Glycol.

This study delves into the physicochemical properties of inorganic hydroxyapatite (HAp) and hybrid hydroxyapatite-chitosan (HAp-CTS) granules, also gold-enriched, which can be used as aggregates in biomicroconcrete-type materials. The impact of granules' surface modifications with citric acid (CA) or polyethylene glycol (PEG) was assessed. Citric acid modification induced increased specific surface area and porosity in inorganic granules, contrasting with reduced parameters in hybrid granules. PEG modification resulted in a slight increase in specific surface area for inorganic granules and a substantial rise for hybrid granules with gold nanoparticles. Varied effects on open porosity were observed based on granule type. Microstructural analysis revealed increased roughness for inorganic granules post CA modification, while hybrid granules exhibited smoother surfaces. Novel biomicroconcretes, based on α-tricalcium phosphate (α-TCP) calcium phosphate cement and developed granules as aggregates within, were evaluated for compressive strength. Compressive strength assessments showcased significant enhancement with PEG modification, emphasizing its positive impact. Citric acid modification demonstrated variable effects, depending on granule composition. The incorporation of gold nanoparticles further enriched the multifaceted approach to enhancing calcium phosphate-based biomaterials for potential biomedical applications. This study demonstrates the pivotal role of surface modifications in tailoring the physicochemical properties of granules, paving the way for advanced biomicroconcretes with improved compressive strength for diverse biomedical applications.

Gold doped Wollastonite hybrid nanocomposites as a candidate for bone regeneration/healing applications: Biocompatibility and antimicrobial efficacy

This work investigates the bioactivity of pure Wollastonite and gold-doped Wollastonite nanohybrids synthesized via a wet chemical technique. Doping with gold nanoparticles at different ratios for Wollastonite, where a dramatic decrease in the respective average particle sizes at the lowest doping ratio of 1.25 wt./v%, then the particle size raised gradually with an increase in the content of gold nanoparticles. In addition, a significant increase in the calculated surface area and the cumulative pore volume upon incorporating gold nanoparticles with the lowest doping ratio of 1.25 wt./v% is associated with a slight decrease in the average pore size. Then, a gradual decrease in the calculated surface area and cumulative pore volume with the increase of doping ratio with gold nanoparticles is associated with an increase in average pore size. The results revealed that after two days of incubation for treated MG-63 cells, the W/Au 5 wt./v% showed the significantly highest alkaline phosphatase (ALP) activity among all other concentrations and the control cells. The ALP activity exceeded four mU/mL. After four days of incubation, the ALP activity in all doping ratios was significantly higher than the control cells, with no significant difference among other groups, but lower than ALP levels after two days of incubation. Also, pure Wollastonite and gold-doped Wollastonite nanohybrids, especially the lowest doping ratio of 1.25 wt./v%, have remarkable efficacy in combating E. coli (Gram-negative), S. aureus (Gram-positive) and Candida albicans. In vitro studies showed that pure Wollastonite and gold-doped Wollastonite nanohybrids had minimal cytotoxic effects on osteosarcoma MG-63 cells, while they showed remarkable cell proliferation even at low concentrations. Based on the in-vitro ALP, bioactivity and biocompatibility results, the content of ALP can directly reflect the activity or function of osteoblasts and is positively correlated with the mineralization ability of cells, which shows that pure and gold-doped Wollastonite nanohybrids were suitable candidates for bone regeneration/healing applications.

In English

Artificial implants are a favorable environment for bacterial adhesion and subsequent biofilm formation, thereby accelerating the development of infection in the area of implant incorporation. Despite significant progress in the development of various endoprostheses over the past decades, bacterial periprosthetic infection is one of the main factors leading to complications in their use, prolongation of rehabilitation, and significant economic losses. The present work is devoted to the creation of hybrid hydrogel nanocomposites with complex antimicrobial action for endoprosthetics in the maxillofacial region and for filling postoperative cavities (primarily after tumor removal). These nanocomposites were created on the basis of pre-synthesized spongy polyvinylformal with encapsulated gold nanoparticles, the pore space of which was partially filled with pH-sensitive hydrogels based on acrylic acid (or copolymers based on acrylamide and acrylic acid) with sorbed Albucid. The structure of the synthesized hybrid hydrogel materials was confirmed by IR spectroscopy. Studies of the kinetics of hydrogel swelling in buffer solutions with different pH values have shown that the sample filled with a copolymer of acrylamide and acrylic acid with their ratio 95:5 has the optimal properties for preserving the geometric dimensions of the material for endoprosthetics, while in the case of incorporation of 100 % acrylic acid, the degree of swelling of the material (and, respectively, its dimensions) can vary significantly with a change of рН. Antimicrobial effect of the developed hybrid hydrogel materials was investigated using the following bacterial cultures: Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 29213, Staphylococcus aureus ATCC 25923, and Pseudomonas aeruginosa ATCC 27853. The antibacterial effect of polyvinylformal-based composites with incorporated gold nanoparticles that were saturated with Albucid on all test microorganisms was demonstrated (growth inhibition zones ranged from 15 to 35 mm), which will prevent microbial contamination of the developed hybrid hydrogel material when it is used in endoprosthesis.

Recycled gold-reduced graphene oxide nanocomposite for efficient adsorption and photocatalytic degradation of crystal violet

In this study, gold-reduced graphene oxide (Au@rGO) nanocomposite has been synthesized by repurposing electronic waste and dry batteries. This innovative approach involved utilizing the graphite rod from dry batteries to produce reduced graphene oxide (rGO), which was subsequently modified through the incorporation of gold nanoparticles obtained from recycled electronic waste. This methodology marks a significant breakthrough in electronic waste recycling, presenting a cost-effective and sustainable means of creating novel nanocomposites for applications in photocatalysis and adsorption, particularly in the removal of crystal violet (CV) from aqueous media. The synthesized Au@rGO nanocomposite was characterized using X-ray diffraction, scanning electron microscopy, energy dispersed X-ray, and N2 adsorption/desorption. Parameters that affect the adsorption and photocatalytic degradation of CV dye have been studied in detail. The optimal conditions for CV adsorption and photocatalytic degradation were pH of 10, equilibrium time of 30 min, CV concentration of 10 mg/L and adsorbent dosage of 40 mg. Furthermore, the isotherm and kinetics of CV removal were also studied. The removal of CV dye using adsorption and photocatalytic degradation techniques reached 95% and 99%, respectively. Consequently, the results showed that photocatalytic degradation of CV dye onto the mesoporous Au@rGO nanocomposite is more proper way than the adsorption technique for removing the CV dye from aqueous media. The designed photocatalyst has high efficiency and it can be reused and activated several times so it can be used in real water treatment applications.

Plasmonic-enhanced photoluminescence in porous silicon with pore-embedded gold nanoparticles fabricated by direct reduction of chloroauric acid

The low efficiency of porous silicon (p-Si) luminescence hinders the development of silicon-based optoelectronic devices. The increase in p-Si emission using near-field enhancement, owing to the incorporation of gold nanoparticles (AuNPs) into the photonic structure, is probably the most viable alternative. However, the coupling of plasmon resonance to p-Si emission is challenging because of the difficulty in controlling the size and location of the AuNPs with respect to the emissive p-Si layer. In this study, AuNPs were synthesized by clean direct reduction of chloroauric acid inside a p-Si photonic structure. As a result, AuNPs could be synthesized all along the pores of the p-Si structure, allowing for a six-fold enhancement of the p-Si photoluminescence, specifically for the emission band at 567 nm owing to the plasmon effect. Possible applications of this hybrid material include light-emitting devices and photoluminescence-based sensors.

Mussel-inspired electroactive, antibacterial and antioxidative composite membranes with incorporation of gold nanoparticles and antibacterial peptides for enhancing skin wound healing

Large skin wounds are one of the most important health problems in the world. Skin wound repair and tissue regeneration are complex processes involving many physiological signals, and effective wound healing remains an enormous clinical challenge. Therefore, there is an urgent need for a strategy to rapidly kill bacteria, promote cell proliferation and accelerate wound healing. At present, electrical stimulation (ES) is often used in the clinical treatment of skin wounds and can simulate the endogenous biological current of the body and accelerate the repair process of skin wounds. However, a single ES strategy has difficulty covering the entire wound area, which may lead to unsatisfactory therapeutic effects. To overcome this deficiency, it is essential to develop a collaborative treatment strategy that combines ES with other treatments. In this study, gold nanoparticles and antibacterial peptides (Os) were loaded on the surface of poly(lactic-co-glycolic acid) (PLGA) material through the reducibility and adhesion of polydopamine (PDA) and improved the electrical activity, anti-inflammatory, antibacterial and biocompatibility properties of the polymer material. At the same time, this composite membrane material (Os/Au-PDA@PLGA) combined with ES was used in wound therapy to improve the wound healing rate. The results show that the new wound repair material has good biocompatibility and can effectively promote cell proliferation and migration. Through the combined application of gold nanoparticles and antibacterial peptides Os, the polymer materials have more efficient bactericidal and antioxidant effects. The antibacterial experiment results showed that gold nanoparticles could further enhance the antibacterial activity of antibacterial peptides. Furthermore, the Os/Au-PDA@PLGA composite membrane has good hydrophilicity and electrical activity, which can provide a more favorable cell microenvironment for wound healing. In vivo studies using a full-thickness skin defect model in rats showed that the Os/Au-PDA@PLGA composite membrane had a better therapeutic effect than the pure PLGA material. More importantly, the combination of the Os/Au-PDA@PLGA composite with ES significantly accelerated the rate of vascularization and collagen deposition and promoted wound healing compared with non-ES controls. Therefore, the combination of the Au/Os-PDA@PLGA composite membrane with ES may provide a new strategy for the effective treatment of skin wounds.

NEAR INFRARED-RESPONSIVE HYDROGELS CONTAINING ADENOVIRAL VECTORS: APPLICATION IN BONE REGENERATION

We have developed plasmonic fibrin-based hydrogels that incorporate gold nanoparticles which transduce incident near-infrared (NIR) light into heat. Human adenovirus serotype type-5 vectors encoding a firefly luciferase (fLuc) coding sequence driven by a heat-inducible promoter were incorporated into the hydrogels. Transmission electronic microscopic analysis revealed that the adenoviral vectors were associated to the fibrin fibers. In vitro experiments in which human cells were cultured with plasmonic hydrogels showed that the adenoviral vectors can diffuse from the hydrogels, transduce the cells, and stimulate heat-induced transgene expression upon NIR irradiation. The hydrogels were implanted in 4.2 mm drill hole defects generated in the humerus of male rabbits. Three days after implantation, the defects were NIR-irradiated. Six h later, the animals were euthanized and samples from the bone defect zone were processed for immunohistochemical analyses using a specific fLuc antibody. The results showed strong expression of fLuc in tissues surrounding the implants of NIR-irradiated rabbits, while non- irradiated animals exhibited negligible expression. We next aimed to use the temperature increase to induce the production of transgenic bone morphogenetic protein 6 (BMP-6), using safe gene switches that can provide tighter control of in vivo transgene expression than heat-inducible promoters. These switches are only activated by heat in the presence of rapamycin and maintain a high level of targeted transgene expression for several days after heat activation. Adenoviral vectors encoding the safe switches that control the expression of BMP-6 were incorporated to the composites. The resulting NIR-responsive hydrogels were implanted in the bone defects generated in rabbits and used as a platform to transduce host cells, generate local hyperthermia and stimulate BMP-6 production.Acknowledgements: This research was supported by grants RTI2018-095159-B-I00 and PID2021-126325OB-I00 (MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe”), by grant P2022/BMD- 7406 (Regional Government of Madrid). M.A.L-J. is the recipient of predoctoral fellowship PRE2019-090430 (MCIN/AEI/10.13039/501100011033).

Gold nanostructures/quantum dots for the enhanced efficiency of organic solar cells.

Incorporating gold nanoparticles (AuNPs) into organic solar cell (OSC) structures provides an effective means to manipulate light-matter interactions. AuNPs have been used as plasmonic-enhancement and light-trapping materials in OSCs and exhibit diverse single and mixed morphologies. Substantial near-field enhancement from metal periodic structures has consistently demonstrated high enhancement in solar cell efficiency. Additionally, coupling with atomic gold clusters in the form of gold quantum dots holds promise for light harvesting through fluorescence phenomena. The configured devices optimize light utilization in OSCs by considering factors such as the morphology, position, and hybridization of localized surface plasmon resonance, propagating surface plasmon resonance, and fluorescence phenomena. This optimization enhances light absorption, scattering, and efficient trapping facilitated by gold nanostructures/quantum dots. The configured setup exhibits multiple effects, concurrently improving plasmonic and fluorescence responses under solar irradiation, thereby enhancing energy conversion performance. Integrating plasmonic nanostructures with OSCs can address fundamental issues, providing opportunities to enhance the light-absorption intensity and charge transfer efficiency at intra and intermolecular levels. This comprehensive review demonstrates that the greatest improvement in solar cell efficiency exceeded 30% compared with the reference cells.

Carboxyl-functionalized two-dimensional MXene-Au nanocomposites were prepared as SERS substrates for the detection of melamine in dairy products.

In the present study, we address the limitations of conventional surface-enhanced Raman scattering (SERS) techniques for sensitive and stable detection of melamine in food products, especially dairy. To overcome these challenges, we developed a novel SERS-active substrate by incorporating gold nanoparticles (AuNPs) onto carboxyl-functionalized two-dimensional (2D) MXene material doped with nitrides, specifically Au-Ti2N-COOH. Our strategy leverages the unique physicochemical properties of MXene, a class of atomically thin, 2D transition metal carbides/nitrides, with tunable surface functionalities. By modifying the MXene surface with AuNPs and introducing carboxyl groups (-COOH), we successfully enhanced the interaction between the substrate and melamine molecules. The carboxyl groups form hydrogen bonds with the amino groups on the melamine's triazine ring, facilitating the adsorption of melamine molecules within the 'hotspot' regions responsible for SERS signal amplification. A series of characterization methods were used to confirm the successful synthesis of Au-Ti2N-COOH composites.Using Au-Ti2N-COOH as the SERS substrate, we detected melamine in spiked dairy product samples with significantly enhanced sensitivity and stability compared to nitride-doped MXene alone. The detection limit in liquid milk stands at 3.7008 μg kg-1, with spike recovery rates ranging from 99.84% to 107.55% and an approximate RSD of 5%. This work demonstrates the effectiveness of our approach in designing a label-free, rapid, and robust SERS platform for the accurate quantitation of melamine contamination in food, thereby mitigating health risks associated with melamine adulteration.

Preparation of gastrodin modified P(VDF-TrFE)-Eudragit L100-AuNPs nanofiber membranes with piezoelectric property

In recent years, electroactive nerve conduits made from a blend of P(VDF-TrFE) (poly (vinylidene fluoride-trifluoroethylene)) with other materials have shown significant progress. However, research combining P(VDF-TrFE) conduits with drug delivery systems remains sparse. In this study, we developed a novel gastrodin-loaded P(VDF-TrFE)-Eudragit L100-gold nanoparticles (Gas@PT-EL100-AuNPs) nanofiber membrane. Fabricated through electrospinning technique, this composite membrane aimed to investigate the impacts of gastrodin and AuNPs on its properties. Experimental results indicated that the incorporation of gold nanoparticles significantly reduced the fiber diameter of the membrane and enhanced the overall performance by improving hydrophilicity and piezoelectric properties. Specifically, the addition of AuNPs substantially enhanced the piezoelectric performance of the nanofiber membrane. Furthermore, the inclusion of gastrodin not only improved the membrane's hydrophilicity but also enabled effective release of the neuroprotective drug. These findings suggest that the Gas@PT-EL100-AuNPs nanofiber membrane is a novel biomaterial with potential applications in the repair and treatment of nerve injuries.

Unraveling Plasmonic Effects in Plasmon-Enhanced Lithium–Oxygen Batteries

Rechargeable lithium–oxygen batteries have high theoretical energy density compared to the conventional Li–ion batteries. However, the recharging process is primarily disturbed by the large overpotential caused by sluggish OER kinetics. Plasmonic materials have unique properties with light, known as surface plasmon resonance (SPR). In this study, we demonstrate plasmonic effect in the Li–O2 battery system by incorporating gold nanoparticles on the Ketjen Black (KB) cathode. During discharge, plasmonic Au NPs induce a Li2O2 morphology change to small particles, which are easily decomposed during recharge. Most importantly, the SPR-induced hot carriers help to form and decompose Li2O2 and suppress carboxylate side-products, decreasing recharge voltages and increasing the round-trip efficiency up to 80.2%. Meticulous analyses of the catalytic properties of the Au NPs and the SPR-induced near-field enhancement and local heat effects are here additionally shared.Keywords: Li–O2 battery, Plasmonics, Light-enhanced batteries, Hot carriers, Near-field enhancement

Ultra-thin vertical tft photosensor and photosynapse based on au-doped- graphene under transition metal selenide reaction

The development of artificial photosensitive synapses with high sensitivity and biomimetic properties that combine innovative concepts and neuromorphic architectures is crucial to achieving highly integrated and flexible intelligent visual systems. Recently, graphene heterostructure-based photosensitive synaptic transistors have been extensively studied for this purpose. However, compared to traditional transistors, vertical structure thin film transistors (VTFTs) with ultra-short channels and advantages, such as high integration, have yet to be investigated in photosensitive synapses. Here, we report an ultra-thin VTFT featuring a graphene/WxSex–1 van der Waals heterostructure that combines photonic and neuromorphic elements. We demonstrate a VTFT in which the channel layer is formed by covalently bonded WxSex–1 nanomaterials produced by introducing Se atoms on the surface of a tungsten metal thin film deposited via radio-frequency sputtering. This structure successfully simulated the main synaptic function, exhibited photosensitive synaptic responses to ultraviolet (λ = 365 nm) light, and demonstrated highly reliable electrical performance. Furthermore, the incorporation of gold nanoparticles changed the photosensitive synaptic response properties of the graphene/WxSex–1 heterostructure from excitatory to inhibitory, showing a responsivity of about ∼14 A W–1, which was attributed to the heterojunction interface resonant effects and efficient charge transfer induced by localized surface plasmons. This further enabled optical artificial synaptic applications while operating with low voltage spikes and low light intensity. This work provides a novel strategy for integrating and developing biological and nano-electronic systems.

Antimicrobial effects of hydrogel implants incorporating gold nanoparticles and albucide and developed for reconstructive surgery in the orbit and periorbital area

Background: It is important to develop orbital hydrogel implants capable of depositing drugs (particularly, antimicrobial and anticancer drugs). Purpose: To assess antimicrobial effects of hybrid hydrogel implants containing gold nanoparticles and albucide and developed for reconstructive surgery in the orbit and periorbital area. Material and Methods: A 30% aqueous solution of albucide was used in the study. Antimicrobial activity of synthesized hydrogels was determined using Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 29213, Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 strains. Results: All the synthesized samples of orbital hydrogel implants were sterile. The synthesized hydrogels and hydrogel nanocomposites with incorporated Au nanoparticles demonstrated bacteriostatic effects against E. Coli ATCC 25922, E. Faecalis ATCC 29213, and S. Aureus ATCC 25923 strains, and bactericidal effects against P. Aeruginosa ATCC 27853 strain. This study also demonstrated marked bactericidal effects of hybrid hydrogel implants incorporating both Au nanoparticles and albucide. Conclusion: Orbital hydrogel implants were found to be sterile after being sealed into polypropylene bags and steam sterilized at 121 °C for 20 minutes. Our findings of bacteriostatic and bactericidal effects of the synthesized hydrogels and hydrogel nanocomposites containing Au nanoparticles and albucide against bacterial strains of interest will allow for the absence of, or low probability of bacterial contamination in applications of these hydrogels in implants.

Nanofibrous polycaprolactone/gelatin scaffold containing gold nanoparticles: Physicochemical and biological characterization for wound healing.

In this study, gold nanoparticles were loaded into poly (ε-caprolactone) (PCL)/gelatin nanofibrous matrices to fabricate a potential wound dressing. The mats were produced by electrospinning of PCL/gelatin solution supplemented with synthesizedgold nanoparticles (200, 400 and 800 ppm). Prepared scaffolds were investigated regarding their chemical properties, morphology, mechanical properties, surface wettability, water-uptake capacity, water vapor permeability, porosity, blood compatibility, microbial penetration test and cellular response. In addition to in vivo study, a full-thickness excisional wound in a rat model was used to evaluate the healing effect of prepared scaffolds. Results showed appropriate mechanical properties and porosity of prepared scaffolds. With L929 cells, the PCL/gelatin scaffold containing 400 ppm gold nanoparticles demonstrated the greatest cell growth. In vivo results validated the favorable wound-healing benefits of the scaffold incorporating gold nanoparticles, which triggered wound healing compared to sterile gauze. Our results showed the capability of nanofibrous matrices containing gold nanoparticles for successful wound treatment.

Controlled Encapsulation of Gold Nanoparticles into Zr-Metal-Organic Frameworks with Improved Detection Limitation of Volatile Organic Compounds via Surface-Enhanced Raman Scattering.

Volatile organic compounds (VOCs) have harmful effects on human health and the environment but detecting low levels of VOCs is challenging due to a lack of reliable biomarkers. However, incorporating gold nanoparticles (Au NPs) into metal-organic frameworks (MOFs) shows promise for VOC detection. In this study, we developed nanoscale Au@UiO-66 that exhibited surface-enhanced Raman scattering (SERS) activity even at very low levels of toluene vapors (down to 1.0 ppm) due to the thickness of the shell and strong π-π interactions between benzenyl-type linkers and toluene. The UiO-66 shell also increased the thermal stability of the Au NPs, preventing aggregation up to 550 °C. This development may be useful for sensitive detection of VOCs for environmental protection purposes.

Flexible Humidity Sensor Based on Au Nanoparticles/Organosilica-Containing Polyelectrolyte Composite

A novel flexible humidity sensor incorporating gold nanoparticles (Au NPs) and a trifunctional organosilica compound has been developed through the integration of sol–gel processing, free radical polymerization, and self-assembly techniques. The trifunctional organosilica was initially synthesized by modifying (3-mercaptopropyl)trimethoxysilane (thiol-MPTMS) with 3-(trimethoxysilyl)propyl methacrylate (vinyl-TMSPMA). Subsequently, a hydrophilic polyelectrolyte, [3(methacryloylamino)propyl]trimethyl ammonium chloride (MAPTAC), was grafted onto the MPTMS-TMSPMA gel. The Au NPs were assembled onto the thiol groups present in the MPTMS-TMSPMA-MAPTAC gel network. The compositional and microstructural properties of the Au NPs/MPTMS-TMSPMA-MAPTAC composite film were investigated utilizing Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The presence of thiol groups and mesoporous silica skeletons ensured the stability of the humidity-sensing film on the substrate under highly humid conditions, while the hydrophilic groups functioned as humidity-sensitive sites. This innovative humidity sensor demonstrated high sensitivity, acceptable linearity, minimal hysteresis, and rapid response time across a broad range of working humidity levels. Based on the complex impedance spectra analysis, hydronium ions (H3O+) were determined to govern the conductance process of the flexible humidity sensor.