Novel Ag3PO4/ZnWO4-modified graphite felt electrode for photoelectrocatalytic removal of harmful algae: Performance and mechanism.

A novel Ag3PO4/ZnWO4-modified graphite felt electrode (AZW@GF) was prepared by drop coating method and applied to photoelectrocatalytic removal of harmful algae. Results showed that approximately 99.21% of chlorophyll a and 91.57% of Microcystin-LR (MCLR) were degraded by the AZW@GF-Pt photoelectrocatalytic system under the optimal operating conditions with a rate constant of 0.02617 min-1 and 0.01416 min-1, respectively. The calculated synergistic coefficient of photoelectrocatalytic algal removal and MC-LR degradation by the AZW@GF-Pt system was both larger than 1.9. In addition, the experiments of quenching experiments and electron spin resonance (ESR) revealed that the photoelectrocatalytic reaction mainly generated •OH and •O2- for algal removal and MC-LR degradation. Furthermore, the potential pathway for photoelectrocatalytic degradation of MC-LR was proposed. Finally, the photoelectrocatalytic cycle algae removal experiments were carried out on AZW@GF electrode, which was found to maintain the algae removal efficiency at about 91% after three cycles of use, indicating that the photoelectrocatalysis of AZW@GF electrode is an effective emergency algae removal technology.

Multielectrode Arrays at Wafer-Level for Miniaturized Sensors Applications: Electrochemical Growth of Ag/AgCl Reference Electrodes.

In this study, a range of miniaturized Ag/AgCl reference electrodes with various layouts were successfully fabricated on wafer-level silicon-based substrates with metallic intermediate layers by precisely controlling the electrochemical deposition of Ag, followed by electrochemical chlorination of the deposited Ag layer. The structure, as well as the chemical composition of the electrode, were characterized with SEM & EDS. The results showed that the chlorination is very sensitive to the applied electric field and background solution. Potentiostatic chlorination, in combination with an adjusted mushroom-shaped Ag sealing deposition, enabled the formation of electrochemical usable Ag/AgCl layers. The stability of the electrodes was tested using open circuit potential (OCP) measurement. The results showed that the reference electrodes stayed stable for 300 s under 3 M KCl solution. The first stage study showed that the stability of the Ag/AgCl reference electrode in a chip highly depends on chip size design, chlorination conditions, and a further protection layer.

Highly Enhanced Photocatalytic Performances of Composites Consisting of Silver Phosphate and N-Doped Carbon Nanomesh for Oxytetracycline Degradation.

Photocatalytic technology based on silver phosphate (Ag3PO4) has excellent potential in removing antibiotic pollutants, but the low separation rate of photogenerated hole-electron pairs restricts the application of the photocatalyst. In this study, it was found that the combination of nitrogen-doped carbon (NDC) with carbon defects and Ag3PO4 can significantly enhance the photocatalytic ability of Ag3PO4. After it was exposed to visible light for 5 min, the photocatalytic degradation efficiency of oxytetracycline (OTC) by the composite photocatalyst Ag3PO4@NDC could reach 100%. In addition, the structure of NDC, Ag3PO4, and Ag3PO4@NDC was systematically characterized by SEM, TEM, XRD, Raman, and EPR. The XPS results revealed intense interface interaction between Ag3PO4 and NDC, and electrons would transfer from Ag3PO4 to the NDC surface. A possible mechanism for enhancing the photocatalytic reaction of the Ag3PO4@NDC composite catalyst was proposed. This study provides a highly efficient visible light catalytic material, which can be a valuable reference for designing and developing a new highly efficient visible light catalyst.

Synthesis of Ag@AgCl/CA and Visible-Light Photocatalytic Degradation of Oxtetracycline.

Chemical coupling, in-situ deposition of supported AgCl, and photoreduction were used to create Ag@AgCl/CA. The morphology, structure, and surface area of the prepared Ag@AgCl/CA were characterized by SEM, TEM, FT-IR, and BET. The photogenerated electron transport efficiency and visible light absorption were analyzed by photocurrent and electrochemical impedance spectroscopy (EIS), respectively. The surface electrical properties and degradation stability were evaluated by zeta potential measurement and cyclic catalytic degradation experiments, and the photocatalytic mechanism was proposed in detail based on the ESR test and trapping experiment. The results showed that the cluster of Ag@AgCl nanoparticles were distributed on the CA crosslinking structure. The prepared Ag@ AgCl/CA photocatalytic material has a high Zeta potential, stable photocurrent, and small photogenerated electron transfer resistance. It has good adsorption and photocatalytic degradation stability for OTC. The material has a relatively strong absorption in the visible light range. Temperature and initial pH had significant effects on the degradation of OTC by photocatalytic materials. The photocatalytic degradation rate was the highest at 40°C and pH6, and the photocatalytic degradation process conformed to the quasi-first-order reaction kinetics. Holes (h+) and superoxide radicals (·O2－) were the main active species for the degradation of OTC.

Biosynthesis of Silver Chloride Nanoparticles (AgCl-NPs) from Extreme Halophiles and Evaluation of Their Biological Applications.

The biosynthesis of nanoparticles (NPs) has gained an overwhelming interest due to their biological applications. However, NPs synthesis by pigmented extreme halophiles remains underexplored. The NPs synthesis using pigmented halophiles is inexpensive and less toxic than other processes. In this study, pigmented halophilic microorganisms (n = 77) were screened to synthesize silver chloride nanoparticles (AgCl-NPs) with silver nitrate as metal precursors, and their biological applications were assessed. The synthesis of AgCl-NPs was possible using the crude extract from cellular lysis (CECL) of six extreme halophiles. Two of the AgCl-NPs viz. AK2-NPs and MY6-NPs synthesized by the CECL of Haloferax alexandrinus RK_AK2 and Haloferax lucentense RK_MY6, respectively, exhibited antimicrobial, antioxidative, and anti-inflammatory activities. The surface plasmon resonance of the AgCl-NPs was determined with UV spectroscopy. XRD analysis of AK2-NPs and MY6-NPs confirmed the presence of silver in the form of chlorargyrite (silver chloride) having a cubic structure. The crystallite size of AK2-NPs and MY6-NPs, estimated with the Scherrer formula, was 115.81 nm and 137.50 nm. FTIR analysis verified the presence of diverse functional groups. Dynamic light-scattering analysis confirmed that the average size distribution of NPs was 71.02 nm and 117.36 nm for AK2-NPs and MY6-NPs, respectively, with monodisperse nature. The functional group in 1623-1641 cm-1 indicated the presence of protein ß-sheet structure and shifting of amino and hydroxyl groups from the pigmented CECL, which helps in capping and stabilizing nanoparticles. The study provides evidence that CECL of Haloferax species can rapidly synthesize NPs with unique characteristics and biological applications.

Enhanced photocatalytic treatment using plasmonic Ag@Ag3PO4/Ag@AgCl nanophotocatalyst for simultaneous degradation of multiple parabens and UV-filters in various aquatic environments under visible light irradiation.

In this study, simultaneous photocatalytic degradation of different parabens (methyl-, ethyl-, propyl-, and butyl paraben) and UV filters (benzophenone-3, 4-methylbenzylidene camphor, 2-ethylhexyl 4-(dimethylamino) benzoate, ethylhexyl methoxycinnamate and octocrylene) in water matrices was performed under visible light irradiation using novel double plasmonic Ag@Ag3PO4/Ag@AgCl nanophotocatalyst, synthesized by an easy and fast photochemical conversion and photo-reduction. It was found that the nanophotocatalyst with appropriate mole ratio of Ag@Ag3PO4/Ag@AgCl (1:3) showed superior photocatalytic activity than individual plasmonic nanoparticles. This is because there are two simultaneous surface plasmon resonances (SPR) generated by the metallic Ag nanoparticles, in addition to the hetero-junction structure formed at the interface between Ag@Ag3PO4 and Ag@AgCl. The structures of the synthesized photocatalysts were characterized, and the principal reactive oxygen species in the photocatalytic process were identified via a trapping experiment, confirming superoxide radicals (∙O2-) as the key reactive species of the photocatalytic system. The process of photodegradation of the target pollutants was monitored using an optimized method that incorporated solid-phase extraction in combination with gas chromatography-mass spectrometry. The simultaneous photodegradation process was modeled and optimized using central composite design. The kinetic study revealed that the degradation process over Ag@Ag3PO4 (30%)/Ag@AgCl (70%) under visible light followed a pseudo-first-order kinetic model. The simultaneous degradation of target compounds was further investigated in sewage treatment plant effluent as well as tap water. It was found that the matrix constituents can reduce the photodegradation efficiency, especially in the case of highly contaminated samples.

SMART: Silver diamine fluoride reduces microtensile bond strength of glass ionomer cement to sound and artificial caries-affected dentin.

Silver-modified atraumatic restorative technique (SMART) is an emerging restorative technique; however, the effect of silver diamine fluoride (SDF) application on the bond strength of glass ionomer cement (GIC) is unknown. This study aimed to determine if SDF application to sound and artificial caries-affected dentin (ACAD) immediately prior to GIC restoration affected microtensile bond strength (µTBS). Caries was induced on extracted molars using a pH-cycling protocol that was validated against natural caries (similar µTBS). Dentin surfaces were treated with 38% SDF, control groups with de-ionized water and immediately restored. Beam-shaped specimens were sectioned and subjected to tensile forces for µTBS determination. Two hundred and eighty-seven specimens from 40 teeth were tested. SDF application significantly (p<0.001) reduced µTBS in sound dentin (19.00±8.20 MPa vs. 14.60±6.68 MPa), while no difference was found in ACAD. No difference was found in failure mode among groups. For SMART, SDF application on sound dentin before immediate GIC restoration may decrease bond strength.

Efficient Photoinduced Thermocatalytic Chemiluminescence System Based on the Z-Scheme Heterojunction Ag3PO4/Ag/Bi4Ti3O12 for H2S Sensing.

Cataluminescence as a highly efficient gas transduction principle has attracted wide attention among research in environmental monitoring and clinical diagnosis with increasing awareness of human safety. Nowadays, the development of innovation sensing systems and the construction of the sensing mechanism to improve the analytical performance of compounds remain a major challenge. Herein, we construct an advanced photoinduced thermocatalytic chemiluminescence (PI-TC-CL) gas-sensing system via the introduction of a Z-scheme heterojunction Ag3PO4/Ag/Bi4Ti3O12 to achieve higher efficient detection of H2S. The unique electron transport path of the Z-scheme heterojunction and the LSPR effect of Ag nanoparticles fascinate the generation of the photoinduced electron-hole pair on the surface of catalysts when stimulated by LED lamps and slow down the recombination of electron-hole pairs under thermal conditions. Thus, based on the cooperative effect of the Z-scheme heterojunction AgPO/Ag/BTO and PI-TC-CL system, we have successfully established an efficient H2S CTL detection system, which has a response three times higher than that on the traditional CTL system and even 45 times higher than that on BTO and ranges among the best of the state-of-the-art CTL performance in H2S detection with the linear range of 0.095-8.87 µg mL-1 and a limit of detection of 0.0065 µg mL-1. Besides, to explore the gas-sensing mechanism, the synergetic effects of photoinduction and thermal catalysis are investigated thoroughly via conductivity and electrochemical experiments. This research provides a new perspective of engineering highly efficient catalysts and ingenious sensor systems through designing the nanostructure of materials and synergism catalytic mechanism.

Construction of Z-scheme Ag-AgBr/Bi2O2CO3/CNT heterojunctions with remarkable photocatalytic performance using carbon nanotubes as efficient electronic mediators.

It is a useful strategy to use a solid electronic mediator with good conductivity to assist the separation of semiconductor photo-induced electron-hole pairs and the redox of semiconductor materials. In order to construct a photocatalyst for more efficient photocatalytic degradation of antibiotics, a simple hydrothermal and precipitation method was used to construct the Ag-AgBr/Bi2O2CO3/CNT Z-scheme heterojunction by using carbon nanotubes (CNTs) as electronic mediators. Compared with the pristine AgBr, Bi2O2CO3, Bi2O2CO3/CNT, the 30%Ag-AgBr/Bi2O2CO3/CNT photocatalyst has better photocatalytic activity under visible light irradiation, showing the best degradation ability to tetracycline (TC). Meanwhile, the photocatalytic properties of 30%Ag-AgBr/Bi2O2CO3/CNT in different pH and inorganic ions were studied. Finally, the degradation pathway and catalytic mechanism of 30%Ag-AgBr/Bi2O2CO3/CNT photocatalytic degradation of TC were also argued. The construction of the Z-scheme electron transport pathway, in which CNTs were used as electronic mediators, and the SPR effect of Ag and Bi metal, which enable the effective separation and transfer of photo-generated electron-hole pairs, are responsible for the significant improvement in photocatalytic performance. It opens up new possibilities for designing and developing high-efficiency photocatalysts with CNTs as the electronic mediator.

Visible Light-Based Ag3PO4/g-C3N4@MoS2 for Highly Efficient Degradation of 2-Amino-4-acetylaminoanisole (AMA) from Printing and Dyeing Wastewater.

In this research, the preparation of a Ag3PO4/g-C3N4@MoS2 photocatalyst and the performance and mechanism of degradation of 2-amino-4-acetaminoanisole (AMA) were studied. The phase composition and morphology of the synthesized samples were comprehensively characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), ultraviolet-visible diffuse reflectance (UV-Vis), and photoelectron spectroscopy (XPS). The catalytic performance of the photocatalyst was evaluated by the visible-light catalytic degradation of the AMA. The experimental results show that the Ag3PO4/g-C3N4@MoS2 composite photocatalyst has stronger photocatalytic oxidation and reduction capabilities than Ag3PO4 and Ag3PO4/g-C3N4. The material only decreases by 31.3% after five cycles of use, indicating that the material has good light stability. Free radical capture experiments prove that photo-generated holes (h+) and superoxide radicals (·O2-) are the main active substances in the photocatalytic process. The fundamental studies in the present research provide a new perspective for constructing an innovative type of visible-light photocatalyst and a new way to promote the photocatalytic degradation of organic pollutants.

Transparent Anti-SARS-CoV-2 and Antibacterial Silver Oxide Coatings.

Transparent antimicrobial coatings can maintain the aesthetic appeal of surfaces and the functionality of a touch-screen while adding the benefit of reducing disease transmission. We fabricated an antimicrobial coating of silver oxide particles in a silicate matrix on glass. The matrix was grown by a modified Stöber sol-gel process with vapor-phase water and ammonia. A coating on glass with 2.4 mg of Ag2O per mm2 caused a reduction of 99.3% of SARS-CoV-2 and >99.5% of Pseudomonas aeruginosa, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus compared to the uncoated glass after 1 h. We envisage that screen protectors with transparent antimicrobial coatings will find particular application to communal touch-screens, such as in supermarkets and other check-out or check-in facilities where a number of individuals utilize the same touch-screen in a short interval.

A versatile technique based on surface-enhanced Raman spectroscopy for label-free detection of amino acids and peptide formation in body fluids.

As an effective analytical method, surface-enhanced Raman spectroscopy (SERS) is widely used in the detection of nucleic acids, amino acids, and other biomolecules. However, obtaining the SERS signal of nonaromatic amino acids is still a challenge. In this work, excess sodium borohydride was used as a reducing agent to prevent the surface of silver nanoparticles from being coated with AgO to enable amino acid molecules to reach the surface of silver nano-substrates. Calcium ions were used as aggregators for silver nano-substrates to successfully achieve the label-free and accurate fingerprint determination of various nonaromatic amino acids. Different types of amino acids were distinguished based on the changes in their peak intensity that were obtained using colorless and transparent organic dichloromethane (DCM) as the internal standard. A Raman signal for low-concentration amino acids in body fluids was detected, and the detection limit for tyrosine was 5 ng/mL. Moreover, the physical and chemical properties of peptides and the formation of peptide chains were further analyzed. The proposed method can potentially be applied to protein sequencing.

Study of thin layer film evolution near bacterial cellulose membrane by Ag|AgCl electrodes in chamber with lower concentration.

We used the method of measuring potential difference between two Ag|AgCl electrodes immersed directly into electrolyte solution with lower concentration and at different distances from membrane. The bacterial cellulose membrane was placed in horizontal plane in the membrane system with configurations with higher NaCl concentration and density under (A) and over the membrane (B). In both configurations at the initial moment the voltage between electrodes amounted to zero. After turning off mechanical stirring of solutions, in configuration A we observed the monotonic increase and next stabilization of voltage while in configuration B after short time dependent on the initial quotient of NaCl concentrations on the membrane we observed appearance of pulsations of measured voltage and gradual decrease of mean voltage over time. Smooth changes of voltage are connected with diffusional reconstruction of Concentration Boundary Layers (CBLs) while fast increase and subsequent pulsations of voltage are connected with the appearance of hydrodynamic instabilities (gravitational convection) near membrane imposed on diffusive reconstruction of thin layer. The time needed for the appearance of hydrodynamic instabilities in CBL depended nonlinearly on the initial ratio of electrolyte concentrations on the membrane.

Preparation and antibacterial properties of an AgBr@SiO2/GelMA composite hydrogel.

Pure gelatin hydrogels lack antibacterial function and have poor mechanical properties, which restrict their application in wound dressings. In this study, nanosized silver bromide-doped mesoporous silica (AgBr@SiO2) microspheres with hollow structures were prepared by a modified Stober method. The novel microspheres can not only release silver ions to treat bacteria but also release drugs to treat skin wound. Furthermore, AgBr@SiO2microspheres were modified with propyl methacrylate, incorporated into methacrylated gelatin (GelMA), and crosslinked by UV light to prepare AgBr@SiO2/GelMA dressings consisting of composite hydrogels. The results showed that the AgBr@SiO2microspheres could enhance the mechanical properties of the hydrogels. With the increase in the AgBr@SiO2concentration from 0.5 to 1 mg ml-1, the dressings demonstrated effective antimicrobial activity against bothStaphylococcus aureusandEscherichia coli. Furthermore, full-thickness skin woundsin vivowound healing studies with Sprague-Dawley rats were evaluated. When treated with AgBr@SiO2/GelMA containing 1 mg ml-1AgBr@SiO2, only 15% of the wound area left on day 10. Histology results also showed the epidermal and dermal layers were better organized. These results suggest that AgBr@SiO2/GelMA-based dressing materials could be promising candidates for wound dressings.

Photochromic immunoassay for tumor marker detection based on ZnO/AgI nanophotocatalyst.

A photochromic immunoassay was built for tumor marker detection based on ZnO/AgI nanophotocatalyst. Frist, ZnO/AgI nanoparticles were synthesized and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and Fourier transform infrared spectrometry (FTIR). The color development is caused by tetramethyl benzidine (TMB) solution oxidated by ZnO/AgI nanomaterials. The electron transitions in ZnO/AgI nanomaterials are driven by visible light irradiation, generating photogenerated hole and oxidizing TMB to blue solution. Appropriate band width between ZnO and AgI promotes separation of photogenerated electrons and holes and enhances oxidation efficiency. A sandwich-type immunoassay was constructed based on ZnO/AgI nanomaterial as labels. The absorbance at 650 nm of reaction solution is positively correlated with antigen concentration. The developed immunoassay showed good performance for carcinoma embryonic antigen (CEA) detection in the range 0.1-7.0 ng/mL with a detection limit of 65 pg/mL. The photochromic immunoassay also exhibited preferable selectivity, repeatability, and stability. A novel colorimetric immunoassay was constructed based on ZnO/AgI photocatalyst. ZnO/AgI nanomaterials occur electron transitions under visible light irradiation and generate photogenerated hole, which can oxidize TMB to blue solution. Carcinoembryonic antigen in sample was detected sensitively due to the high catalytic efficiency of ZnO/AgI nanomaterials.

Fabrication of Ag3PO4/polyaniline-activated biochar photocatalyst for efficient triclosan degradation process and toxicity assessment.

Triclosan (TCS) is a typical environmental pollutant, which seriously threatens the health of humans and organisms. A novel strategy of biochar/Ag3PO4/polyaniline (PANI) composite photocatalyst was synthesized by a facile chemical precipitation method to efficiently degrade TCS. XRD, Raman, ESR, etc. were used to reveal the effective associations among physiochemistry, photochemistry and photocatalytic properties of the composite. It was proved the synergistic effects of biochar (T-Bio) and PANI resulted in the decrease of Ag3PO4 particle size, the enhancement of adsorption, the improvement of light utilization, the increase of photogenerated carrier separation and the promotion of reactive species. The photocatalytic mechanism showed h+ was the main active species, O2- and OH played minor roles. Under the irradiation of visible light, the optimal photocatalyst (1.0% T-Bio/AP/1.0% PANI) displayed excellent photocatalytic activity with the removal rate of 85.21% for TCS within 10 min, and the apparent rate constant K' was 2.38 times of Ag3PO4. 11 main intermediates for TCS degradation were identified, and their toxicity was significantly reduced. The possible degradation pathways were proposed. This work is the first systematic study on the degradation behavior of TCS by Ag3PO4-based photocatalyst, and it provides a new approach to fabricate photocatalysts with synergistic effects and amazing photocatalytic activity by biochar.

Biogenic Synthesis, Characterization and Antibacterial Properties of Silver Nanoparticles against Human Pathogens.

Biogenic synthesis of silver nanoparticles (AgNPs) is more eco-friendly and cost-effective approach as compared to the conventional chemical synthesis. Biologically synthesized AgNPs have been proved as therapeutically effective and valuable compounds. In this study, the four bacterial strains Escherichia coli (MT448673), Pseudomonas aeruginosa (MN900691), Bacillus subtilis (MN900684) and Bacillus licheniformis (MN900686) were used for the biogenic synthesis of AgNPs. Agar well diffusion assay revealed to determine the antibacterial activity of all biogenically synthesized AGNPs showed that P. aeruginosa AgNPs possessed significantly high (p < 0.05) antibacterial potential against all tested isolates. The one-way ANOVA test showed that that P. aeruginosa AgNPs showed significantly (p < 0.05) larger zones of inhibition (ZOI: 19 to 22 mm) compared to the positive control (rifampicin: 50 µg/mL) while no ZOI was observed against negative control (Dimethyl sulfoxide: DMSO). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) concentration against four test strains also showed that among all biogenically synthesized NPs, P. aeruginosa AgNPs showed effective MIC (3.3-3.6 µg/mL) and MBC (4.3-4.6 µg/mL). Hence, P. aeruginosa AGNPs were characterized using visual UV vis-spectroscopy, X-ray diffractometer (XRD), fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The formation of peak around 430 nm indicated the formation of AgNPs while the FTIR confirmed the involvement of biological molecules in the formation of nanoparticles (NPs). SEM revealed that the NPs were of approximately 40 nm. Overall, this study suggested that the biogenically synthesized nanoparticles could be utilized as effective antimicrobial agents for effective disease control.

Parametric estimation of gyrotactic microorganism hybrid nanofluid flow between the conical gap of spinning disk-cone apparatus.

The silver, magnesium oxide and gyrotactic microorganism-based hybrid nanofluid flow inside the conical space between disc and cone is addressed in the perspective of thermal energy stabilization. Different cases have been discussed between the spinning of cone and disc in the same or counter wise directions. The hybrid nanofluid has been synthesized in the presence of silver Ag and magnesium oxide MgO nanoparticulate. The viscous dissipation and the magnetic field factors are introduced to the modeled equations. The parametric continuation method (PCM) is utilized to numerically handle the modeled problem. Magnesium oxide is chemically made up of Mg2+ and O2- ions that are bound by a strong ionic connection and can be made by pyrolyzing Mg(OH)2 (magnesium hydroxide) and MgCO3 (magnesium carbonate) at high temperature (700-1500 °C). For metallurgical, biomedical and electrical implementations, it is more efficient. Similarly, silver nanoparticle's antibacterial properties could be employed to control bacterial growth. It has been observed that a circulating disc with a stationary cone can achieve the optimum cooling of the cone-disk apparatus while the outer edge temperature remains fixed. The thermal energy profile remarkably upgraded with the magnetic effect, the addition of nanoparticulate in base fluid and Eckert number.

Sustainable phyto-fabrication of silver nanoparticles using Gmelina arborea exhibit antimicrobial and biofilm inhibition activity.

Increase in bacterial resistance to commonly used antibiotics is a major public health concern generating interest in novel antibacterial treatments. Aim of this scientific endeavor was to find an alternative efficient antibacterial agent from non-conventional plant source for human health applications. We used an eco-friendly approach for phyto-fabrication of silver nanoparticles (AgNPs) by utilizing logging residue from timber trees Gmelina arborea (GA). GC-MS analysis of leaves, barks, flowers, fruits, and roots was conducted to determine the bioactive compounds. Biosynthesis, morphological and structural characterization of GA-AgNPs were undertaken by UV-Vis spectroscopy, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometer (XRD). GA-AgNPs were evaluated for antibacterial, antibiofilm, antioxidant, wound healing properties and their toxicity studies were carried out. Results identified the presence of terpenoids, sterols, aliphatic alcohols, aldehydes, and flavonoids in leaves, making leaf extract the ideal choice for phyto-fabrication of silver nanoparticles. The synthesis of GA-AgNPs was confirmed by dark brown colored colloidal solution and spectral absorption peak at 420 nm. Spherical, uniformly dispersed, crystalline GA-AgNPs were 34-40 nm in diameter and stable in solutions at room temperature. Functional groups attributed to the presence of flavonoids, terpenoids, and phenols that acted as reducing and capping agents. Antibacterial potency was confirmed against pathogenic bacteria Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus by disc diffusion assay, MIC and MBC assay, biofilm inhibition assay, electron-microscopy, cell staining and colony counting techniques. The results from zone of inhibition, number of ruptured cells and dead-cell-count analysis confirmed that GA-AgNPs were more effective than GA-extract and their bacteria inhibition activity level increased further when loaded on hydrogel as GA-AgNPs-PF127, making it a novel distinguishing feature. Antioxidant activity was confirmed by the free radical scavenging assays (DPPH and ABTS). Wound healing potential was confirmed by cell scratch assay in human dermal fibroblast cell lines. Cell-proliferation study in human chang liver cell lines and optical microscopic observations confirmed non-toxicity of GA-AgNPs at low doses. Our study concluded that biosynthesized GA-AgNPs had enhanced antibacterial, antibiofilm, antioxidant, and wound healing properties.

Fructus Xanthii-Inspired Low Dynamic Noise Dry Bioelectrodes for Surface Monitoring of ECG.

The microstructured surfaces of bioelectrical dry electrodes are important aspects of dry electrode design. However, traditional surfaces for microstructured bioelectrical dry electrodes are costly to produce and require complex fabrication methods. In this study, a novel stacked-template method is proposed for the first time, rapidly producing microstructured dry electrodes at a low cost and with a large surface area. Three types of microstructured Ag/AgCl thermoplastic polyurethane (TPU) electrodes with a Fructus xanthii-inspired barb structure (FXbs) are prepared using this method; then, the dynamic friction, hair interference resistance, electrochemical, and electrocardiogram (ECG) signal acquisition performance of the electrodes are tested, and the dynamic noise characteristics of the electrodes are comprehensively evaluated with simulated instruments. Compared to the plate structure, the dynamic friction coefficient of the FXbs electrode improved by about 38.8%, exhibiting strong hair interference resistance. In addition, the FXbs electrode exhibits low dynamic noise and comparable performance to the wet electrode, in terms of signal acquisition, when it is tested using simulated instruments. Therefore, the prepared FXbs electrode increases the friction coefficient between the electrode and the skin, which effectively resolves issues related to dynamic noise in bioelectrical signals, making it suitable for dynamic measurements.