Incorporation Of Gold Nanoparticles Research Articles

Light-Sheet Skew Ray-Based Microbubble Chemical Sensor for Pb2+ Measurements

A multimode fiber-based sensor is proposed and demonstrated for the detection of lead traces in contaminated water. The sensing mechanism involves using a light sheet to excite a specific group of skew rays that optimizes light absorption. The sensing region features an inline microbubble structure that funnels the skew rays into a tight ring, thereby intensifying the evanescent field. The sensitivity is further refined by incorporating gold nanoparticles, which amplify the evanescent field strength through localized surface plasmon resonance. The gold nanoparticles are functionalized with oxalic acid to improve specificity for lead ion detection. Experiment results demonstrated the significantly enhanced absorption sensitivity of the proposed sensing method for large center offsets, achieving a detection limit of 0.1305 ng/mL (the World Health Organization safety limit is 10 ng/mL) for concentrations ranging from 0.1 to 10 ng/mL.

Software Integrated Personalized Biosensing Device for Serum Creatinine Detection Based on Boron doped MXene Nanohybrid.

In recent years, an increase in the number of chronic kidney disease (CKD) cases has led to a global health burden majorly affecting underdeveloped and developing nations. A key biomarker for assessing the kidneys' normal functioning is creatinine, which is filtered out from the blood by the kidney. Thus, timely and specific detection of creatinine becomes necessary for diagnosis and subsequent treatment of CKD. Hence, in this study, we have tried to develop a field-deployable, software-integrated immunosensor for the detection of creatinine in a serum sample. The immunosensor was developed by incorporating gold nanoparticles, boron doped MXene, polyaniline, and anticreatinine antibody using an appropriate bioconjugation reaction. The developed sensor was able to detect creatinine in a linear dynamic range of 10 nM to 0.1 M with a limit of detection of 1.72 (±0.07) nM. The sensor was integrated with an indigenously developed software named "CretCheck" which simplifies the process of data analysis. The software integrated personalized biosensing device was used to find the creatinine concentrations directly from the obtained analytical signals. The developed immunosensor with the integrated software can also be implemented directly in primary health care facilities for creatinine detection in the future.

Incorporation of Gold Nanoparticle into ZnO Electron Transport Layer to Improve Performance of Hybrid Bulk Heterojunction Solar Cell

Abstract We have investigated the effect of localized surface plasmon resonance (LSPR) from gold nanoparticles incorporated into the electron transport layer (ETL) of zinc oxide (ZnO) on charge carrier transport in order to improve the performance of inverted hybrid bulk-heterojunction solar cells. Synthesis of gold nanoparticles capped by 3-mercaptopropionic acid (AuMPA) and oleylamine (AuOA) was carried out by use of the reduction method and the fabrication of solar cell device with the configuration of ITO/ZnO:AuNPs/P3HT:PCBM/PEDOT:PSS/Ag was done by spin coating and thermal evaporation techniques. The absorbance spectra show a plasmonic peak of AuMPA in solution at 521 nm, while AuOA has a plasmonic peak at 531 nm, with both solutions showing a red-wine color. In our investigation, the incorporation of AuMPA about 2.65wt% or AuOA about 3.5 wt% in the ZnAc solution is quite stable. With the addition of 1.77 wt% AuMPA, the fabricated devices show a significant improvement at short circuit condition (JSC) from 46.67 mA/cm2 to 83.11 mA/cm2, resulting in an increase in power conversion efficiency (PCE) from 5.64% to 9.00% under the illumination of 100 mW/cm2 simulated solar irradiation. While the AuOA addition of 2.65 wt%, the JSC increased from 22.67 mA/cm2 to 44.12 mA/cm2 along with an improvement of PCE from 2.71% to 5.32%. The experiment results suggest that the electron mobility or charge carrier transport to the indium tin oxide (ITO) cathode is improved by the local electric field enhancement around the zinc oxide (ZnO) electron transport layer due to the effect of gold nanoparticles (AuNPs).

Enhanced enzymatic electrochemical detection of an organophosphate Pesticide: Achieving Wide linearity and femtomolar detection via gold nanoparticles growth within polypyrrole films

The indiscriminate use of pesticides in agriculture demands the development of devices capable of monitoring contaminations in food supplies, in the environment and biological fluids. Simplicity, easy handling, high sensitivities, and low limits-of-detection (LOD) and quantification are some of the required properties for these devices. In this work, we evaluated the effect of incorporating gold nanoparticles into indigo carmine-doped polypyrrole during the electropolymerization of films for use as an acetylcholinesterase (AChE) enzyme-based biosensor. As proof of concept, the pesticide methyl parathion was tested towards the inhibition of AChE. The enzyme was immobilized simply by drop-casting a solution, eliminating the need for any prior surface modification. The biosensors were characterized with cyclic voltammetry, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The assays for the detection of methyl parathion with films containing polypyrrole, indigo carmine and AChE (PPy–IC–AChE) presented a sensitivity of 5.7 μA cm−2 g−1 mL and a LOD of 12 nmol L−1 (3.0 ng L−1) with a linear range from 1.3 x 10−7 mol L−1 to 1.0 x 10−5 mol L−1. The introduction of gold nanoparticles (AuNP) into the film (PPy–IC–AuNP-AChE) led to remarkable improvements on the overall performance, such as a lower redox potential for the enzymatic reaction, a 145 % increase in sensitivity (14 μA cm−2 g−1 mL), a wider detection dynamic range (from 1.3x10−7 to 1.0x10−3 mol L−1), and a very low LOD of 24 fmol L−1 (64 ag mL−1). These findings underscore the potential of using AuNPs to improve the enzymatic performance of biosensor devices.

Gold Nanoparticles for Retinal Molecular Optical Imaging.

The incorporation of gold nanoparticles (GNPs) into retinal imaging signifies a notable advancement in ophthalmology, offering improved accuracy in diagnosis and patient outcomes. This review explores the synthesis and unique properties of GNPs, highlighting their adjustable surface plasmon resonance, biocompatibility, and excellent optical absorption and scattering abilities. These features make GNPs advantageous contrast agents, enhancing the precision and quality of various imaging modalities, including photoacoustic imaging, optical coherence tomography, and fluorescence imaging. This paper analyzes the unique properties and corresponding mechanisms based on the morphological features of GNPs, highlighting the potential of GNPs in retinal disease diagnosis and management. Given the limitations currently encountered in clinical applications of GNPs, the approaches and strategies to overcome these limitations are also discussed. These findings suggest that the properties and efficacy of GNPs have innovative applications in retinal disease imaging.

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

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, 2 × 10−10, and 2 × 10−9 mol% of nanoparticles. The x-ray diffractogram (XRD) 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 cm−3 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 76.073 to 70.502 cm−1 with the incorporation of GNPs but increases to 75.878 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.

Exploring the Relationship between Mechanical Properties and Electrical Impedance in Cement-Based Composites Incorporating Gold Nanoparticles.

Structural health monitoring applications have gained significant attention in recent research, particularly in the study of the mechanical-electrical properties of materials such as cement-based composites. While most researchers have focused on the piezoresistive properties of cement-based composites under compressive stress, exploring the electrical impedance of such materials can provide valuable insights into the relationship between their mechanical and electrical characteristics. In this study, we investigated the connection between the mechanical properties and electrical impedance of cement-based composites modified with Au nanoparticles. Cylindrical samples with dimensions of 3 cm in diameter and 6 cm in length were prepared with a ratio of w/c = 0.47. The Au nanoparticles (Au NPs) were synthesized using pulsed laser ablation in liquids, and their size distribution was analyzed through dynamical light scattering. Mechanical properties were evaluated by analyzing the Young modulus derived from strain-stress curves obtained at various force rates. Electrical properties were measured by means of electrical impedance spectroscopy. The experimental results revealed a notable reduction of 91% in the mechanical properties of Au NPs-cement compounds, while their electrical properties demonstrated a significant improvement of 65%. Interestingly, the decrease in mechanical properties resulting from the inclusion of gold nanoparticles in cementitious materials was found to be comparable to that resulting from variations in the water/cement ratios or the hydration reaction.

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.

A wearable non-enzymatic sensor for continuous monitoring of glucose in human sweat

To enhance personalized diabetes management, there is a critical need for non-invasive wearable electrochemical sensors made from flexible materials to enable continuous monitoring of sweat glucose levels. The main challenge lies in developing glucose sensors with superior electrochemical characteristics and high adaptability. Herein, we present a wearable sensor for non-enzymatic electrochemical glucose analysis. The sensor was synthesized using hydrothermal and one-pot preparation methods, incorporating gold nanoparticles (AuNPs) functionalized onto aminated multi-walled carbon nanotubes (AMWCNTs) as an efficient catalyst, and crosslinked with carboxylated styrene butadiene rubber (XSBR) and PEDOT:PSS. The sensors were then integrated onto screen-printed electrodes (SPEs) to create flexible glucose sensors (XSBR-PEDOT:PSS-AMWCNTs/AuNPs/SPE). Operating under neutral conditions, the sensor exhibits a linear range of 50 μmol/L to 600 μmol/L, with a limit of detection limit of 3.2 μmol/L (S/N = 3), enabling the detection of minute glucose concentrations. The flexible glucose sensor maintains functionality after 500 repetitions of bending at a 180° angle, without significant degradation in performance. Furthermore, the sensor exhibits exceptional stability, repeatability, and resistance to interference. Importantly, we successfully monitored changes in sweat glucose levels by applying screen-printed electrodes to human skin, with results consistent with normal physiological blood glucose fluctuations. This study details the fabrication of a wearable sensor characterized by ease of manufacture, remarkable flexibility, high sensitivity, and adaptability for non-invasive blood glucose monitoring through non-enzymatic electrochemical analysis. Thus, this streamlined fabrication process presents a novel approach for non-invasive, real-time blood glucose level monitoring.

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.

High efficient dip catalyst for nitrophenol reduction using bacterial cellulose impregnated self-crosslinked glycol chitosan via formation of gold nanoparticles

A simple approach was used to create an environmentally friendly dip catalyst by incorporating gold nanoparticles (AuNPs) into bacterial cellulose (BC) via glycol chitosan (GCS), which acted as both a reducing and self-crosslinking agent. The BC-GCS-AuNPs dip catalyst was analyzed using UV–Vis spectroscopy, FTIR, SEM, XRD, and TEM to confirm the formation of AuNPs and GCS self-crosslinking within the BC network. The catalyst efficacy was tested for converting 4-nitrophenol (NP) to 4-amino phenol (AP). Results demonstrated excellent catalytic performance, achieving up to 98 % within 5 min. The dip catalyst present an appealing option for green and sustainable catalysis due to its outstanding performance, stability, and reusability.

Straightforward microwave-assisted synthesis of ultrasmall gold nanoparticles acnhored on reduced graphene oxide for enhanced antibacterial application

Graphene derivative materials, such as graphene oxide (GO) and reduced graphene oxide (rGO), have garnered significant attention from scientists for over two decades due to their distinctive characteristics and versatile applications across various fields, particularly in biomedical applications. Incorporating gold nanoparticles (AuNPs) into rGO sheets as rGO-Au nanocomposites further enhances its performance in biomedical applications. This study presents a rapid and efficient method for synthesizing ultrasmall AuNPs anchored on reduced graphene oxide (rGO-Au) using microwave irradiation and ascorbic acid. The optimum microwave treatment was 4 min, ensuring the highest GO reduction degree. Structural characterization by TEM reveals a distinctive architecture with ultrasmall AuNPs (average size of 2.2 nm) distributed on the rGO sheets. Interestingly, while the synthesized rGO-Au did not exhibit any antibacterial activities against both Escherichia coli and Staphylococcus aureus in disk diffusion assays, it demonstrated bacteriostatic effect at remarkably low concentrations when assessed by optical density measurement. The effective concentration of rGO-Au to inhibit E. coli growth was determined to be 2.5 ppm, while for S. aureus, it was 5 ppm, resulting in growth inhibition of 53.1% and 50.0%, respectively. These findings provide a straightforward synthesis route for rGO-Au nanocomposites and underscore the importance of AuNPs’ size and quantity in modulating antibacterial properties.

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).