High Antibacterial Properties Research Articles

Synthesis of Cu/Co-hybrid MOF as a multifunctional porous compound in catalytic applications, synthesis of new nanofibers, and antimicrobial and cytotoxicity agents

Several biological properties of metal–organic frameworks (MOFs) and fiber compounds have been reported, and combinations of these structures can have unique properties. In this study, copper-containing and cobalt-containing MOF nanostructures were synthesized by the ultrasonic technique. Then, novel Cu/Co-hybrid MOF nanostructures were synthesized using the ultrasonic method. Synthesized Cu/Co-hybrid MOF nanostructures were used as a new and efficient recyclable catalyst in the synthesis of pyrano[2,3-c]pyrazole derivatives using the four-component reaction of phenylhydrazine, ethyl acetoacetate, malononitrile, and aldehyde. In the following, novel Cu/Co-hybrid MOF/PVA (poly vinyl alcohol) fiber nanostructures were synthesized by electrospinning and using Cu/Co-hybrid MOF nanostructures and PVA. The structures of the Cu/Co-hybrid MOF nanostructures and the Cu/Co-hybrid MOF/PVA fiber nanostructures were identified and confirmed using BET, TGA, FTIR, SEM, and XRD. In biological studies, the antibacterial, antifungal, and cytotoxicity activities of Cu/Co-hybrid MOF and Cu/Co-hybrid MOF/PVA fiber nanostructures were evaluated. In investigating the catalytic activity of Cu/Co-hybrid MOF, pyrano[2,3-c]pyrazole derivatives were synthesized with higher efficiency and less time than previously reported methods. High antibacterial (against gram-negative and gram-positive strains) and antifungal properties of synthesized Cu/Co-hybrid MOF nanostructures and Cu/Co-hybrid MOF/PVA fiber nanostructures were observed (MIC between 16 and 256 μg/mL), which were higher than some commercial drugs. In the investigation of cytotoxicity activity, the effectiveness on breast cancer cells was studied. The maximum cell proliferation and viability for Cu/Co-hybrid MOF and Cu/Co-hybrid MOF/PVA fiber nanostructures were 38% and 38% higher than the control in a concentration of 200 μg/mL after 48 h. The high catalytic and biological properties of the synthesized nanoparticles can be attributed to the presence of nano-sized bioactive metals and their high specific surface area. The significant physical-chemical properties obtained for synthesized nanoparticles in this study can be related to the desirable synthesis methods, the development of materials with high purity, and the incorporation of hybrid compounds into the nanostructures.

Bio-Fabrication and Efficiency Analysis of Annona Muricata Extract Coated on Bamboo Fiber for Wound Healing Application

ABSTRACT This study focusses on the bio-fabrication of leaf extracts of Annona muricata dyed bamboo woven fabric and its application in wound healing. Annona muricata was exposed to ultrasonic-assisted extraction (UAE) with acetone for fabric finishing. Bioactivity is characterized and employed in textile fabric coating to evaluate the efficacy of its antibacterial and wound healing characteristics. The treated fabric was then tested for antibacterial activity using gram-positive and gram-negative bacteria, aroma, color intensity, olfaction, and invivo wound healing. The invivo test was carried out in wistar rats for 21 days for 50%, 75%, and 100%. According to the results of the analysis, the extract is a good antibacterial agent against gram-positive bacteria (Bacillus subtilus) and gram-negative bacteria (Pseudomonas sp.), which aids in the prevention of bacteria and other germs from sticking to the injured area since the leaf extracts have high antibacterial properties. The wound healing impact of the plant extract coated with bamboo fabric on in vivo wound models in rats (Wistar albino rats) demonstrated a significant increase in wound closure, showing the efficacy of the coated fabric.

Self-Healable, Adhesive, Anti-Drying, Freezing-Tolerant, and Transparent Conductive Organohydrogel as Flexible Strain Sensor, Triboelectric Nanogenerator, and Skin Barrier.

Conductive hydrogels have attracted tremendous interest in the construction of flexible strain sensors and triboelectric nanogenerators (TENGs) owing to their good stretchability and adjustable properties. Nevertheless, how to simultaneously achieve high transparency, self-healing, adhesion, antibacterial, anti-freezing, anti-drying, and biocompatibility properties through a simple method remains a challenge. Herein, a transparent, freezing-tolerant, and multifunctional organohydrogel (PAOAM-PDO) as electrode for strain sensors and TENGs was constructed through a free radical polymerization in the 1,3-propanediol (PDO)/water binary solvent system, in which oxide sodium alginate, aminated gelatin, acrylic acid, and AlCl3 were used as raw materials. The obtained PAOAM-PDO exhibited good transparency (>90%), self-healing, adhesiveness, antibacterial property, good conductivity (1.13 S/m), and long-term environmental stability. The introduction of PDO endowed PAOAM-PDO with freezing resistance with a low freezing point of -60 °C, and PAOAM-PDO could serve as a protective skin barrier to prevent frostbite at low temperature. PAOAM-PDO could be assembled as strain sensors to monitor heterogeneous human movements with high strain sensitivity (gauge factor of 7.05, strain = 233%). Meanwhile, PAOAM-PDO could be further fabricated as a TENG with a "sandwich" structure in single electrode mode. Moreover, the resulting TENG achieved electrical outputs with simple hand tapping and served as a self-powered device to light light-emitting diodes. This work displays a feasible strategy to build environment-tolerant and multifunctional organohydrogels, which possess potential applications in the wearable electronics and self-powered devices.

Enhancing anti‐biofouling property by incorporating graphene oxide‐silver nanocomposite into polycaprolactone membrane for ultrafiltration application

AbstractBACKGROUNDThe control of biofouling is crucial in the membrane separation process. In the present study, graphene oxide‐silver (GO‐Ag) nanocomposite was fabricated and incorporated into polycaprolactone (PCL) membrane for the first time to increase its antibacterial properties and reduce its biofouling. Characterization of GO‐Ag nanocomposite was done by X‐ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier‐transform infrared (FTIR) spectroscopy. The PCL/GO‐Ag membranes were also characterized by XRD, attenuated total reflectance Fourier‐transform infrared (ATR‐FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), porosity determination, water contact angle measurement, and tensile test. Furthermore, pure water flux (PWF) and bovine serum albumin (BSA) rejection of the membranes were evaluated. Finally, the antibacterial activity of membranes was investigated by diffusion inhibition zone test and plate count of colony‐forming units.RESULTSThe results demonstrated that Ag nanoparticles were formed on the GO surfaces. In addition, membranes incorporated with the GO‐Ag nanocomposite were more hydrophilic, more porous, and more permeable to pure water while showing a lower protein rejection in the filtration of a BSA solution. Adding the GO‐Ag nanocomposite to the PCL membrane increased the inhibition effect against bacteria. The colony counting method confirmed that PCL/GO‐Ag membranes had higher antibacterial properties than the pure PCL membrane, and the PCL/1.8% GO‐Ag membrane represented the maximum antibacterial efficiency of 90% and 98% against P. aeruginosa and S. aureus, respectively.CONCLUSIONOverall, by the incorporation of GO‐Ag nanocomposite into the PCL membrane, PWF and antibacterial property were augmented, while protein rejection dropped. © 2023 Society of Chemical Industry.

Exploring the potential of graphene oxide nanocomposite as a highly efficient photocatalyst for antibiotic degradation and pathogen inactivation

The widespread use of antibiotics in human and veterinary medicine makes them an emerging contaminant in the aquatic environment. The degradation of antibiotics is essential for environmental remediation and requires low-cost, high-performance photocatalysts. In this work, water-dispersible, highly efficient Yttrium oxide/Nickel Oxide anchored Graphene Oxide (GO/Y2O3/NiO) ternary composites were fabricated via a facile hydrothermal procedure and photocatalytically active for the degradation of the antibiotics ciprofloxacin (CIP) and + amoxicillin (AMOX) under visible light illumination. The formation of GO/Y2O3/NiO was confirmed by a variety of spectroscopic and microscopic techniques. GO/Y2O3/NiO ternary composite material exhibits 94.03 % degradation efficiency for CIP and 78 % for AMOX, associated with a faster reaction rate and a longer response to visible light. In addition, the presence of GO in the ternary nanocomposite served as an electron conductor, leading to the production of superoxide and hydroxy radicals that have reduced band gap of 2.8 eV. A unique combination of GO /Y2O3/NiO nanocubes, nanorods and nanosheets enhanced the photocatalytic activity. In addition, GO/Y2O3/NiO exhibits high antibacterial and concentration-dependent cytotoxic properties. These studies demonstrated that GO/Y2O3/NiO nanocomposite photocatalysts have unique potential as both antibacterial and eco- friendly photocatalysts, which has great potential for use in photo nanotechnology.

Synthesis, Characteristation and Biological Activity of Silver Nanoparticles Generated Using the Leaf and Stembark Extract of Combretum erythrophyllum.

Medicinal plants are known to contain numerous phytometabolites with suggested pharmacological value. Literature suggests that the medicinal use of phytometabolites in its natural state has limited success due to poor absorption rates. Currently, the focus lies on synthesizing phytometabolites extracted from medicinal plants and silver ions to generate nano-scale carriers with specialized properties. Thus, the nano-synthesis of phytometabolites with silver (Ag+) ions is proposed. The use of silver is promoted due to its known antibacterial and antioxidant effectiveness, among many. Nanotechnology allows for the green generation of nano-scaled particles that are able to penetrate target areas due to its size and unique structure. Therefore, this study aimed to generate a novel protocol for the synthesis of AgNP's using the leaf and stembark extracts of C. erythrophyllum. In addition, the biological activity of the generated nanoparticles was evaluated. To synthesis silver nanoparticles (AgNP's) using the leaf and stembark extracts of Combretum erythrophyllum. The relative shape, size, distribution, and zeta potential of the synthesised particles were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Energy-dispersive X-ray (EDX), Nanoparticle tracking analysis (NTA), and UV Spectrophotometry (UV -vis). To screen the synthesised particles for its potential antibacterial, apoptotic and cytotoxic properties. A novel protocol for the synthesis of silver nanoparticles (AgNP's) using the leaf and stembark extracts of Combretum erythrophyllum was established. The generated AgNP's were characterised using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Energy-dispersive X-ray (EDX), Nanoparticle tracking analysis (NTA), and UV Spectrophotometry (UV -vis). Furthermore, the AgNP's were evaluated for their antibacterial, cytotoxic and apoptotic activity against a range of bacterial strains and cancer cells. Characterisation was based upon particle size, shape and elemental silver composition. Within the stembark extract, synthesised nanoparticles were large, spherical in shape and dense in elemental silver composition. While synthesised nanoparticles of the leaf extract were small to medium in size, varied in shape established and contained minimal quantities of silver (substantiated by the TEM and NTA results). Furthermore, it was established that the synthesized nanoparticles exhibited high antibacterial properties due to the conducted antibacterial assay. The FTIR analysis revealed the presence of numerous functional groups within active compounds found in the synthesised extracts. Functional groups found varied between the leaf and stembark extracts, each with proposed pharmacological activity. Presently, antibiotic-resistant bacteria are continuously evolving thus, posing as a threat to conventional drug delivery systems. Nanotechnology provides a platform that enables the formulation of a low-toxicity and hypersensitive drug delivery system. Further studies evaluating the biological activity of extracts of C. erythrophyllum synthesized with silver nanoparticles could enhance its proposed pharmaceutical value.

Antibacterial and biofilm-inhibiting cotton fabrics decorated with copper nanoparticles grown on graphene nanosheets.

Infectious pathogens can be transmitted through textiles. Therefore, additional efforts are needed to develop functional fabrics containing antimicrobial substances to prevent the growth of antibiotic-resistant bacteria and their biofilms. Here, we developed a cotton fabric coated with reduced graphene oxide (rGO) and copper nanoparticles (Cu NPs), which possessed hydrophobic, antimicrobial, and anti-biofilm properties. Once the graphene oxide was dip-coated on a cellulose cotton fabric, Cu NPs were synthesized using a chemical reduction method to fabricate an rGO/Cu fabric, which was analyzed through FE-SEM, EDS, and ICP-MS. The results of our colony-forming unit assays indicated that the rGO/Cu fabric possessed high antibacterial and anti-biofilm properties against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, Corynebacterium xerosis, and Micrococcus luteus. Particularly, the fabric could inhibit the growth of E. coli, C. xerosis, and M. luteus with a 99% efficiency. Furthermore, our findings confirmed that the same concentrations of rGO/Cu had no cytotoxic effects against CCD-986Sk and Human Dermal Fibroblast (HDF), human skin cells, and NIH/3T3, a mouse skin cell. The developed rGO/Cu fabric thus exhibited promising applicability as a cotton material that can maintain hygienic conditions by preventing the propagation of various bacteria and sufficiently suppressing biofilm formation while also being harmless to the human body.

Development of Ag doped ZnO nanostructure and tranexamic acid infused chitosan-guargum film: A multifunctional antimicrobial dressing with haemostatic and wound closure potential

Modern wound care requires multifunctional dressings that can efficiently control bleeding and subsequent infection, facilitating faster healing which reduces the healthcare costs. Our study aimed to develop a nanocomposite biopolymeric film composed of Ag doped ZnO nanoparticle and drug tranexamic acid (TRA) loaded into chitosan guargum matrix (CGT/AgZnO) for obtaining improved antibacterial, antibiofilm and haemostatic properties, along with potential wound healing effects.The films were developed via solution casting method and characterized by various standard biophysical techniques such as X-ray diffraction, infrared spectroscopy, electron microscopy imaging etc. The polymeric nanocomposite films exhibited strong antibacterial efficacy against bacteria such as E. coli, P. aeruginosa, S. aureus and B. subtilis. The films loaded with 3 wt% of nanoparticles (CGT/AgZnO3) exhibited remarkable growth inhibition i.e. 90% and 94% against gram-negative and gram-positive bacteria, respectively. These films also demonstrated excellent antibiofilm activity, with CGT/AgZnO3 inhibiting over 80% of bacterial biofilm formation after 72 h. The nanocomposite films exhibited a strong hemostatic effect as indicated by their blood clotting index (BCI) value. The in vitro hemocompatibility and cytocompatibility study (against the mouse fibroblast cells- L929 cell line) showed the films were highly biocompatible. The wound closure potential of the films was evaluated using in vitro scratch assays, exhibiting enhanced cell migration (100%) after 24 h, as compared to the control groups (66%). These findings confirmed that the developed CGT/AgZnO films have the potential as an excellent wound dressing material with high antibacterial, hemostatic, and wound healing properties.

3D printing MOF nanozyme hydrogel with dual enzymatic activities and visualized glucose monitoring for diabetic wound healing

Promoting rapid healing of diabetic wounds caused by hyperglycemia, bacterial infection, and chronic inflammation is a global challenge. To address this issue, we design and prepare a novel cerium-based MOF nanozyme hydrogel via 3D printing technology to provide a personalized hydrogel wound dressing. The hydrogel is unique in that cerium-based MOFs are grown into the hydrogel network, simplifying the printing process of MOF hydrogel. The prepared hydrogel exhibits specific catalytic activity to various oxygen free radicals and glucose concentration-dependent color changes due to the interconversion between different valence cerium ions. This feature allows for indirect monitoring of glucose content around the wound. Additionally, the hydrogel presented high antibacterial properties and biocompatibility. In animal experiments, diabetic wounds in rats with a size of 1 cm2 fully healed within 21 days due to the synergistic effect of the anti-inflammatory and hyperglycemia capabilities of the cerium-based MOF nanozyme hydrogel. The results suggest that this novel hydrogel will revolutionize traditional treatment methods in diabetic wounds and provide an efficient, rapid, personalized treatment program.

Study of mineralization of lithium calcium phosphosilicate glass ceramics in vivo during bone tissue regeneration

Prospective directions for the creation of biologically active substitutes for bone tissue were analyzed. The effectiveness of the use of calcium phosphosilicate materials modified with CuO, ZnO, Ag2O, Fe2O3, TiO2, SrO and Nb2O5 to ensure high biocompatibility and antibacterial properties of bone endoprostheses has been established. The prospective use of lithium calcium phosphate silicate glass ceramics for obtaining strengthened, biologically active bone implants was substantiated. The main criteria for the development of biocompatible glass-ceramic materials regarding their composition, structure, texture, and surface properties have been established. The influence of differences in the structure and resorption of calcium phosphosilicate glass ceramics on the mechanism of formation of an apatite-like layer in vivo was analyzed. The features of mineralization of calcium phosphosilicate glass ceramics in vivo during bone tissue regeneration were determined, and the effectiveness of the use of glass ceramics based on hydroxyapatite and lithium disilicate in bone tissue replacement was established to reduce the rehabilitation period and long-term use of endoprostheses under variable loads. The developed OS-7 calcium phosphosilicate glass-ceramic material is characterized by the content of crystalline phases of 10 vol.% lithium disilicate and 55 vol.% hydroxyapatite with a ratio of CaO/P2O5=1.67, surface microrelief of 6 m, surface free energy value of 75 mJ/m2 and crack resistance of 6.0 MPam1/2. This material is biocompatible due to the formation of carbonate hydroxyapatite crystals already on the 14th day, which allows us to consider its promising use in the treatment of fractures, defects of long bones and in the replacement of short or tubular bones.

Electricity production performance enhancement of microbial fuel cells with double-layer sodium alginate hydrogel bioanodes driven by high-salinity waste leachate

The poor bacterial loading capacity and biocompatibility of the anode lead to weak electricity production performance of microbial fuel cells (MFCs). Inspired by kelp, we developed a double-layer hydrogel bioanode based on sodium alginate (SA). The inner hydrogel layer of encapsulated Fe3O4 and electroactive microorganisms (EAMs) was used as the bioelectrochemical catalytic layer. The outer hydrogel layer formed by cross-linking SA with polyvinyl alcohol (PVA) was used as the protective layer. The 3D porous structure of the inner hydrogel formed based on Fe3O4 facilitated the electroactive bacteria colonization and electron transfer, while the high structural toughness, salt-resistance and antibacterial properties of the outer highly cross-linked hydrogel served to protect the catalytic layer for stable electricity production. When high-salt waste leachate was used as the nutrient, the amazing open-circuit voltage (OCV) of 1.17 V and the operating voltage of 781 mV were brought by the double-layer hydrogel bioanode PVA@SA&Fe3O4/EAMs@SA.

Mono and bilayer coatings of alkanethiol and silane on copper: Prevents corrosion and regulate bacterial adhesion

Self-assembling molecules (SAMs) provide a flexible system for surface modification of materials by forming films of molecular thickness. SAMs protect materials from corrosion and modify surface properties such as adhesion, adsorption and wetting due to their molecular composition and orientation. In this investigation, polished copper specimens were dip coated to form SAMs of alkanethiol and silane to study bacterial adhesion as well as for corrosion prevention. The SAM coated specimens were exposed to the log phase cultures of Pseudomonas aeruginosa (aerobic bacteria) and Desulfovibrio vulgaris (anaerobic bacteria) for 12, 24 and 48 hrs, to monitor cell adhesion and biofilm thickness by microscopy. The results showed that alkanethiols SAM promoted adhesion and biofilm formation. The biofilm thickness ranged from 10 to 38 µm for Pseudomonas and 9 – 25 µm for Desulfovibrio sp. Among the SAM coatings tested, octadecyl-trichlorosilane (ODTCS), alkane-thiol and ODTCS (bilayer SAM) showed no bacterial adhesion, however, solitary alkane-thiol SAM showed significant bacterial adhesion. The high hydrophobicity (contact angle ∼140°), antibacterial and anti-biofilm property of the ODTCS coating could have regulated bacterial adhesion. The constant climate test results showed that silane SAM prevented copper corrosion up to ∼160 days (3480 hrs), while the alkanethiol coating could protect up to 10 days (240 hrs). Confocal laser scanning microscopic images of the silane coated copper specimens showed initiation of the corrosion after 160 days of exposure, while at the end of 200 days significant copper corrosion was observed. Surface modification leads to specific biochemical interactions that regulate bacterial adhesion and prevent biofilm formation and corrosion of copper.

Microencapsulated propolis in chewing gum production

Propolis is a resin with high antibacterial and antioxidant properties that honey bees (Apis mellifera L.) gather and then harmonize through their metabolic secretions. Propolis is beneficial to dental health because it contains antibacterial activity against the Streptococcus mutans, which causes tooth decay. The aim of this study is to use microencapculated propolis extract (MPE) in chewing gum formulation for the first time, in order to protect propolis from environmental effects during production and to ensure controlled release in mouth. Spray drying method was applied where maltodextrin acted as coating material. The particle structure of MPE was investigated by scanning electron microscope. The encapsulation efficiency was determined as 62.19%. The hygroscopicity and moisture content of the MPE particles was found as 31.50% and 7.98% respectively. The DPPH scavenging ability, total flavonoid and total phenolic content of the MPE appeared lower than propolis extract. The total flavonoid content of MPE was calculated as 29.06 mg/kg and total phenolic content as 89.17 mg/kg. In vitro antimicrobial activity against Streptococcus mutans of 9% MPE containing gum samples was measured highest with 4.20 mm zone diameter. Hunter b* value increased with increasing MPE concentration. The final MPE incorporated chewing gum appear to be highly functional.
 Keywords: Propolis; Spray drying; Chewing gum; Functional food

Facile photosynthesis of novel porphyrin-derived nanocomposites containing Ag, Ag/Au, and Ag/Cu for photobactericidal study

In this research, the one-step synthesis of novel porphyrin-based nanocomposites was performed easily using a photochemical under visible light illumination strategy. As a result, the focus of this research is on synthesizing and using decorated ZnTPP (zinc(II)tetrakis(4-phenyl)porphyrin) nanoparticles with Ag, Ag/AgCl/Cu, and Au/Ag/AgCl nanostructures as antibacterial agents. Initially, ZnTPP NPs were synthesized as a result of the self-assembly of ZnTPP. In the next step, in a visible-light irradiation photochemically process, the self-assembled ZnTPP nanoparticles were used to make ZnTPP/Ag NCs, ZnTPP/Ag/AgCl/Cu NCs, and ZnTPP/Au/Ag/AgCl NCs. A study on the antibacterial activity of nanocomposites was carried out for Escherichia coli, and Staphylococcus aureus as pathogen microorganisms by the plate count method, well diffusion tests, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) values determination. Thereafter, the reactive oxygen species (ROS) were determined by the flow cytometry method. All the antibacterial tests and the flow cytometry ROS measurements were carried out under LED light and in dark. The (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was applied to investigate the cytotoxicity of the ZnTPP/Ag/AgCl/Cu NCs, against Human foreskin fibroblast (HFF-1) normal cells. Due to the specific properties such as admissible photosensitizing properties of porphyrin, mild reaction conditions, high antibacterial properties in the presence of LED light, crystal structure, and green synthesis, these nanocomposites were recognized as kinds of antibacterial materials that are activated in visible light, got the potential for use in a broad range of medical applications, photodynamic therapy, and water treatment.

Robust Ionic Cyclic Olefin Polymers with Excellent Transparency, Barrier Properties, and Antibacterial Properties

The development of materials with intrinsic antimicrobial activities has attracted great interest. In this contribution, cyclic olefin polymers (COPs) with excellent mechanical strength and high glass-transition temperature were prepared via ring-opening metathesis polymerization of both a bulky cyclic monomer and a cyclic monomer bearing ionic groups. The ionic COP membranes we obtained showed high antibacterial properties against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus); especially, the sterilization rate of H-Qa on both bacteria was higher than 99%, and it still showed a high bacteriostatic rate after repeated supplementation of new bacteria for 7 days. In addition, high light transmittance (80–90% in vis), excellent thermal stability (Td,95 > 210 °C), and low water vapor/oxygen transmittance also make the COPs promising as a bacteriostatic material with promising application potential in packaging, medical, and other fields.

Solar-powered and antibacterial water purification via Cu-BTC-embedded reduced graphene oxide nanocomposite aerogels

Advancements in the design of porous active materials for interfacial solar evaporation have shown promise in the development of next-generation solar evaporation active materials that can present a wide range of water-purification properties. In this study, a new class of metal–organic nanoparticles-embedded reduced graphene oxide (rGO) nanocomposite aerogels is developed, with both solar steam generation behavior and antibacterial properties. The self-assembly process is used to introduce Cu-BTC nanoparticles (Cu-BTC NPs) into the structure of rGO aerogels to fabricate Cu-BTC/rGO nanocomposite aerogels. By varying the content of Cu-BTC NPs in the self-assembly precursor solution, the surface area, pore texture, and evaporation rate of samples are altered to reach both high energy conversion efficiency and antibacterial properties. An evaporation rate of 1.13 kg/m2h and an efficiency of 81.8% are achieved when the highest content of Cu-BTC NPs (1 mg/ml) is introduced to the precursor solution. This evaporation efficiency is 32% and 59% higher than that of the rGO aerogel and pure water, respectively. This behavior is related to the surface area and pore size of the nanocomposite aerogels, which increase and decrease with the content of Cu-BTC NPs, respectively. Additionally, the Cu-BTC/rGO aerogel presents antibacterial activity against S. aureus and E. coli. As a result, Cu-BTC/rGO nanocomposite aerogels have great potential as active materials for the design of next-generation solar steam generation systems for the treatment of wastewater contaminated with pathogenic bacteria.

Multifunctional chitosan/carbon dots/sodium alginate/zinc oxide double-layer sponge hydrogel with high antibacterial, mechanical and hemostatic properties

Due to the fact that bacterial contamination of wounds is the cause of increased morbidity and mortality today, various antimicrobial wound dressings are developing to prevent wound contamination. In addition, an ideal wound dressing should have proper mechanical and hemostatic properties to maintain wound healing conditions. Here, a double-layer sponge hydrogel nanocomposite wound dressing was designed and manufactured by combining zinc oxide nanoparticles (ZnONPs) with different concentrations in the hydrogel layer and green carbon dots in the sponge layer. The surface morphology of two layers was investigated using a scanning electron microscope. X-ray diffraction proved the presence of ZnONPs. Physical tests showed a decrease in water absorption and water vapor transmission rate and an increase in blood absorption in the presence of ZnO. The sponge layer showed suitable absorption support in the presence of carbon dots. By combining nanoparticles in both layers, the mechanical properties were greatly enhanced. The sponge hydrogel with the highest concentration of ZnO showed excellent inhibition of 41 mm against Pseudomonas aeruginosa bacteria and 25 mm of inhibition against Staphylococcus aureus. Finally, in vitro blood clotting and animal tests confirmed the increase in the hemostatic power of the sponge hydrogel with the maximum concentration of ZnO.

Bimetallic Biogenic Pt-Ag Nanoparticle and Their Application for Electrochemical Dopamine Sensor

In this study, Silver-Platinum (Pt-Ag) bimetallic nanoparticles were synthesized by the biogenic reduction method using plant extracts. This reduction method offers a highly innovative model for obtaining nanostructures using fewer chemicals. According to this method, a structure with an ideal size of 2.31 nm was obtained according to the Transmission Electron Microscopy (TEM) result. The Pt-Ag bimetallic nanoparticles were characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffractometry (XRD), and Ultraviolet-Visible (UV-VIS) spectroscopy. For the electrochemical activity of the obtained nanoparticles in the dopamine sensor, electrochemical measurements were made with the Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV) methods. According to the results of the CV measurements taken, the limit of detection (LOD) was 0.03 µM and the limit of quantification (LOQ) was 0.11 µM. To investigate the antibacterial properties of the obtained Pt-Ag NPs, their antibacterial effects on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria were investigated. In this study, it was observed that Pt-Ag NPs, which were successfully synthesized by biogenic synthesis using plant extract, exhibited high electrocatalytic performance and good antibacterial properties in the determination of dopamine (DA).

Antimicrobial air filter made of chitosan-ZnO nanoparticles immobilized on white silica gel beads

Airborne disease transmitted by biological air pollution threatens public space, therefore developing antimicrobial air filters is a crucial study. This study investigated the environmentally friendly preparation of synthetic zinc oxide nanoparticles (ZnOnano-synth) at ambient temperature and the ZnO immobilization technique on silica gel beads coated with chitosan. The immobilized ZnO was used as an air filter in the simulated air chamber. Methanol swelled the 4.59 ± 0.5 wt% of the chitosan layer causing ZnO particles to stick to it, being stabilized, and dispersed. The dispersed ZnO particles of 5.18 ± 1.70 nm, thereby the efficacy preparation procedure is confirmed. The ZnOnano-synth exhibited high antibacterial properties against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria in agar media with inhibition diameters up to (33.50 ± 0.10 mm). Air filters containing the ZnOnano-synth-chi-SiG exhibited high and prolonged antibacterial activity against Bacillus subtilis in the air with 92% efficacy. These synthetic ZnO nanoparticles show better characteristics than commercial ZnO nanoparticles in terms of the particle size and the antibacterial properties of Staphylococcus aureus and Escherichia coli.

Comparison of antibacterial properties between chitosan stabilized silver and zinc oxide nanoparticles immobilized on white silica beads

Most preparation of both silver (Ag) and zinc oxide (ZnO) nanoparticles (NPs) was relatively complicated. We proved a more straightforward method not only in the nanoparticle synthesis but also in their immobilization on the solid support. Since both the metal nanoparticles have antibacterial activities, comparing the efficacy and the preparation cost is still interesting to explore. TEM images show both colloidal chitosan stabilized-Ag NPs and ZnO NPs have dispersed and nano-size particles. The immobilized Ag NPs and ZnO NPs on white silica beads (SiG chi-Ag NPs and SiG chi-ZnO NPs) were successfully fabricated with appropriate techniques and suitable characteristics for antibacterial air filter materials. The colloidal and the immobilized metal NPs have high antibacterial properties against Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria. The inhibition zone diameter of SiG chi-ZnO NPs and SiG chi-Ag NPs against S. aureus and E. coli were relatively similar but needed about ten times more weight zinc than silver to kill the bacteria at a similar inhibition zone size. Silver is ten times more expensive than zinc, but it is relatively simpler to prepare SiG chi-Ag NPs than to formulate SiG chi-ZnO NPs. The cytotoxicity of silver is more than ten times higher compared to zinc cytotoxicity. Therefore, it was reasonable to substitute silver with zinc nanoparticles for antibacterial air filter material.