Excellent Antibacterial Properties Research Articles

Synthesis and evaluation of the anti-bacterial effect of modified silica gel supported silver nanoparticles on E. coli and S. aureus

Scientists are looking for new antibacterial agents to disinfect point-of-use water sources due to the dearth of clean drinking water in developing nations and disaster areas. Because of the growth of antibiotic and disinfectant resistance as well as the emergence of multiple unfavorable effects brought on by using current antibacterial agents like chlorine compounds, this is the case. Because of their antibacterial properties, silver nanoparticles (AgNPs) have become a useful replacement for other nanomaterials. This study aimed to evaluate the antibacterial activity of AgNPs embedded in modified silica gel (MSG). It was used to kill Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) and to test its efficacy in water purification in a batch and zone of inhibition system. Trimethyl chlorosilane (TMCS) was used to modify MSG, which was then ground into powder using a process known as the ambient dry method. Using a reagent made from Vernonia amygdalina leaf extract, AgNPs were prepared using a green technique. With the aid of FT-IR, BET, XRD, SEM/EDX, and UV–vis spectrophotometers, the MSG supported by AgNPs was studied. E. coli and S. aureus were tested for their antibacterial abilities in MSG supplements with AgNPs samples. AgNPs have excellent antibacterial properties that enable zone inhibition and batch system tests with MSG. Batch system tests showed that both gram-positive and gram-negative microorganisms decreased effectively after 10 min of exposure. Zone inhibition tests indicated that MSG with AgNPs was effective against both kinds of bacteria.

Mentha longifolia assisted nanostructures: An approach to obliterate microbial biofilms.

Microbes maneuver strategies to become incessant and biofilms perfectly play a role in scaling up virulence to cause long-lasting infections. The present study was designed to assess the use of an eco-friendly formulation of functionalized silver nanoparticles generated from Mentha longifolia leaf extract (MℓE) for the treatment of biofilm-producing microbes. Nanoparticles synthesized using MℓE as a reducing agent were optimized at different strengths of AgNO3 (1 mM, 2 mM, 3 mM, and 4 mM). Synthesis of M. longifolia silver nanoparticles (MℓAgNPs) was observed spectrophotometrically (450 nm) showing that MℓAgNPs (4 mM) had the highest absorbance. Various techniques e.g., Fourier transforms Infrared spectroscopy (FTIR), Dynamic light scattering (DLS), zeta potential (ZP), X-ray Diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) were used to characterize MℓAgNPs. In the present study, the Kirby-Bauer method revealed 4mM was the most detrimental conc. of MℓAgNPs with MIC and MBC values of 0.62 μg/mL and 1.25 μg/mL, 0.03 μg/mL and 0.078 μg/mL, and 0.07 μg/mL and 0.15 μg/mL against previously isolated and identified clinical strains of Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Staphylococcus aureus, respectively. Moreover, the MℓAgNP antibiofilm activity was examined via tissue culture plate (TCP) assay that revealed biofilm inhibition of up to 87.09%, 85.6%, 83.11%, and 75.09% against E. coli, P. aeruginosa, K. pneumonia, and S. aureus, respectively. Herbal synthesized silver nanoparticles (MℓAgNPs) tend to have excellent antibacterial and antibiofilm properties and are promising for other biomedical applications involving the extrication of irksome biofilms. For our best knowledge, it is the first study on the use of the green-synthesized silver nanoparticle MℓAgNP as an antibiofilm agent, suggesting that this material has antibiotic, therapeutic, and industrial applications.

A chitosan-coated PCL/nano-hydroxyapatite aerogel integrated with a nanofiber membrane for providing antibacterial activity and guiding bone regeneration.

A guided bone regeneration (GBR) membrane can act as a barrier to prevent the invasion and interference from foreign soft tissues, promoting infiltration and proliferation of osteoblasts in the bone defect area. Herein, a composite scaffold with dual functions of osteogenesis and antibacterial effects was prepared for GBR. A polycaprolactone (PCL)/nano-hydroxyapatite (n-HA) aerogel produced by electrospinning and freeze-drying techniques was fabricated as the loose layer of the scaffold, while a PCL nanofiber membrane was used as the dense layer. Chitosan (CS) solution served as a middle layer to provide mechanical support and antibacterial effects between the two layers. Morphological results showed that the loose layer had a porous structure with n-HA successfully dispersed in the aerogels, while the dense layer possessed a sufficiently dense structure. In vitro antibacterial experiments illustrated that the CS solution in the middle layer stabilized the scaffold structure and endowed the scaffold with good antibacterial properties. The cytocompatibility results indicated that both fibroblasts and osteoblasts exhibited superior cell activity on the dense and loose layers, respectively. In particular, the dense layer made of nanofibers could work as a barrier layer to inhibit the infiltration of fibroblasts into the loose layer. In vitro osteogenesis analysis suggested that the PCL/n-HA aerogel could enhance the bone induction ability of bone mesenchymal stem cells, which was confirmed by the increased expression of the alkaline phosphatase activity. The loose structure facilitated the infiltration and migration of bone mesenchymal stem cells for better osteogenesis. In summary, such a composite scaffold exhibited excellent osteogenic and antibacterial properties as well as the barrier effect, thus holding promising potential for use as GBR materials.

Poly(sulfobetaine) versus poly(ethylene glycol) based copolymer modified polyurethane catheters for antifouling.

Polyurethane (PU) catheters are commonly used in clinical treatment. However, the hydrophobic nature of the PU catheter surface leads to adhesion or adsorption to platelets, proteins, bacteria, and other molecules when used in human treatment. To achieve a surface with strong hydrophilicity, high stability and excellent biocompatibility, it is necessary to functionalize the PU catheters. In this paper, a coating with antifouling function was constructed on the surface of PU catheters using plasma technology and an amide coupling reaction. A series of characterization methods, including X-ray photoelectron spectroscopy (XPS), water contact angles (WCA), and atomic force microscopy (AFM), were used to prove the successful modification of the polymer coatings. The coatings showed good stability under conditions such as PBS (pH 7.4, 720 h), 75% ethanol (6 h) and 1 wt% SDS (10 min). Additionally, the coatings exhibit excellent hemocompatibility and antibacterial properties. The PU/PEI/PCSB coating has the best anti-fouling performance among them, which means that using the PCSB copolymer has the potential to modify different clinical catheters into highly effective antifouling coatings.

Multifunctional MXene-doped photothermal microneedles for drug-resistant bacteria-infected wound healing.

Skin injuries and drug-resistant bacterial infections pose serious challenges to human health. It is essential to establish a novel multifunctional platform with good anti-infection and wound-healing abilities. In this study, a new MXene-doped composite microneedle (MN) patch with excellent mechanical strength and photothermal antibacterial and ROS removal properties has been developed for infected wound healing. When the MN tips carrying the MXene nanosheets are inserted into the cuticle of the skin, they will quickly dissolve and subsequently release the nanomaterials into the subcutaneous infection area. Under 808 nm NIR irradiation, the MXene, as a "nano-thermal knife", sterilizes and inhibits bacterial growth through synergistic effects of sharp edges and photothermal antibacterial activity. Furthermore, ROS caused by injury and infection can be cleared by MXene-doped MNs to avoid excessive inflammatory responses. Based on the synergistic antibacterial and antioxidant strategy, the MXene-doped MNs have demonstrated excellent wound-healing properties in an MRSA-infected wound model, such as promoting re-epithelialization, collagen deposition, and angiogenesis and inhibiting the expression of pro-inflammatory factors. Therefore, the multifunctional MXene-doped MN patches provide an excellent alternative for clinical drug-resistant bacteria-infected wound management.

Gallic acid: design of a pyrogallol-containing hydrogel and its biomedical applications.

Polyphenol hydrogels have garnered widespread attention due to their excellent adhesion, antioxidant, and antibacterial properties. Gallic acid (GA) is a typical derivative of pyrogallol that is used as a hydrogel crosslinker or bioactive additive and can be used to make multifunctional hydrogels with properties superior to those of widely studied catechol hydrogels. Furthermore, compared to polymeric tannic acid, gallic acid is more suitable for chemical modification, thus broadening its range of applications. This review focuses on multifunctional hydrogels containing GA, aiming to inspire researchers in future biomaterial design. We first revealed the interaction mechanisms between GA molecules and between GA and polymers, analyzed the characteristics GA imparts to hydrogels and compared GA hydrogels with hydrogels containing catechol. Subsequently, in this paper, various methods of integrating GA into hydrogels and the applications of GA in biomedicine are discussed, finally assessing the current limitations and future development potential of GA. In summary, GA, a natural small molecule polyphenol with excellent functionality and diverse interaction modes, has great potential in the field of biomedical hydrogels.

Cu2-xS homojunction coatings empower titanium implants with near-infrared-triggered antibacterial and antifouling properties.

For decades, implant-associated infections (IAIs) caused by pathogenic bacteria have been associated with high failure and mortality rates in implantation surgeries, posing a serious threat to global public health. Therefore, developing a functionalized biomaterial coating with anti-fouling and anti-bacterial functions is crucial for alleviating implant infections. Herein, a near-infrared-responsive anti-bacterial and anti-adhesive coating (Ti-PEG-Cu2-xS) constructed on the surface of titanium (Ti) implants is reported. This coating is composed of nano-Cu2-xS with anti-bacterial activity and super-hydrophilic polyethylene glycol (PEG). Under near-infrared irradiation, the nano-catalyst Cu2-xS on the surface of Ti-PEG-Cu2-xS induces bacterial death by catalyzing the production of singlet oxygen (1O2). The Ti-PEG-Cu2-xS coating can effectively prevent bacterial adhesion and biofilm formation. This coating combines the antibacterial mechanisms of "active attack" and "passive defense", which can kill bacteria and inhibit biofilm formation. The results of in vitro and in vivo experiments have shown that Ti-PEG-Cu2-xS exhibits excellent anti-bacterial properties under near-infrared irradiation and can effectively prevent implant-related infections caused by Escherichia coli (E. coli) ATCC 8739 and Staphylococcus aureus (S. aureus). The antibacterial efficiency of Ti-PEG-Cu2-xS coatings against E. coli was 99.96% ± 0.058% and that of S. aureus was 99.66% ± 0.26%, respectively. In addition, the Ti-PEG-Cu2-xS coating has good blood compatibility and excellent bactericidal ability. Therefore, this multifunctional coating combines a non-adhesive surface strategy and a near-infrared phototherapy sterilization method, effectively blocking the initial attachment and proliferation of bacteria on implants via photothermal/photodynamic effects and providing a promising method for preventing bacterium-induced IAIs.

Hierarchical double-layer microneedles accomplish multicenter skin regeneration in diabetic full-thickness wounds

IntroductionManaging large chronic wounds presents significant challenges because of inadequate donor sites, infection, and lack of structural support from dermal substitutes. Hydrogels are extensively used in various forms to promote chronic wound healing and provide a three-dimensional spatial structure, through growth factors or cell transport. ObjectivesWe present a novel multicenter regenerative model that is capable of regenerating and merging simultaneously to form a complete layer of skin. This method significantly reduces wound healing time compared to the traditional centripetal healing model. We believe that our model can improve clinical outcomes and pave the way for further research into regenerative medicine. MethodsWe prepared a novel multi-island double-layer microneedle (MDMN) using gelatin-methacryloylchitosan (GelMA-CS). The MDMN was loaded with keratinocytes (KCs) and dermal fibroblasts (FBs). Our aim in this study was to explore the therapeutic potential of MDMN in a total skin excision model. ResultsThe MDMN model replicated the layered structure of full-thickness skin and facilitated tissue regeneration and healing via dual omni-bearing. Multi-island regeneration centres accomplished horizontal multicentric regeneration, while epidermal and dermal cells migrated synchronously from each location. This produced a healing area approximately 4.7 times greater than that of the conventional scratch tests. The MDMN model exhibited excellent antibacterial properties, attributed to the chitosan layer. During wound healing in diabetic mice, the MDMN achieved earlier epidermal coverage and faster wound healing through multi-island regeneration centres and the omnidirectional regeneration mode. The MDMN group displayed an accelerated wound healing rate upon arrival at the destination (0.96 % ± 0.58 % vs. 4.61 % ± 0.32 %). Additionally, the MDMN group exhibited superior vascularization and orderly collagen deposition. ConclusionThe present study presents a novel skin regeneration model using microneedles as carriers of autologous keratinocytes and dermal fibroblasts, which allows for omni-directional, multi-center, and full-thickness skin regeneration.

Enhanced bone regeneration by osteoinductive and angiogenic zein/whitlockite composite scaffolds loaded with levofloxacin.

Promoting angiogenesis following biomaterial implantation is essential to bone tissue regeneration. Herein, the composite scaffolds composed of zein, whitlockite (WH), and levofloxacin (LEVO) were fabricated to augment bone repair by facilitating osteogenesis and angiogenesis. First, three-dimensional composite scaffolds containing zein and WH were prepared using the salt-leaching method. Then, as a model antibiotic drug, the LEVO was loaded into zein/WH scaffolds. Moreover, the addition of WH enhanced the adhesion, differentiation, and mineralization of osteoblasts. The zein/WH/LEVO composite scaffolds not only had significant osteoinductivity but also showed excellent antibacterial properties. The prepared composite scaffolds were then implanted into a calvarial defect model to evaluate their osteogenic induction effects in vivo. Micro-CT observation and histological analysis indicate that the scaffolds can accelerate bone regeneration with the contribution of endogenous cytokines. Based on amounts of data in vitro and in vivo, the scaffolds present profound effects on improving bone regeneration, especially for the favorable osteogenic, intensive angiogenic, and alleviated inflammation abilities. The results showed that the synthesized scaffolds could be a potential material for bone tissue engineering.

Unleashing excellent antibacterial performance of natural rubber composites via herbal extracts

Natural rubber latex (NRL)-based products often suffer from poor antibacterial performance, which limits their applications. Here, we fabricate NRL-based materials with enhanced antibacterial properties by incorporating natural plant extracts. Chinese herbal extracts/NRL compounds are prepared by compounding the relevant antibacterial natural plant extracts with the NRL, and the resulting mechanical properties and thermal stability are investigated. Mugwort/NRL and honeysuckle/NRL show the best antimicrobial effect, destroying the cell structure of various bacteria; no complete bacterial cells were found in the antimicrobial area. The excellent antibacterial properties，good cell compatibility and well-retained mechanical performance of the fabricated materials validate the proposed method as a novel, easy approach to preparing antibacterial NRL products. When the content of Chinese herbal extracts was 7.5 wt%, the Chinese herbal extracts/NR composites exhibited the best antibacterial and comprehensive mechanical properties. These products can be used in medical applications such as condoms, medical gloves, medical catheters and broaden the application of traditional Chinese herbal medicine. More importantly, the “template method” is proposed to rapidly determine the antibacterial ability of composite latex. This method can be applied to further scientific research and facilitate industrial production, providing strong technical support for developing more antibacterial latex products.

Synergistic disinfection effects and reduction of disinfection by-products in water treatment using magnetic quaternized cyclodextrin polymer combined with chorine disinfection process

Disinfection is vital in ensuring water safety. However, the traditional chlorine disinfection process is prone to producing toxic and harmful disinfection by-products (DBPs). The combination of quaternary ammonium polymer and the chlorine disinfection process can solve this shortcoming. Currently, research on the control of DBPs through the combined process is not systematic and the control effect between reducing the dosage of disinfectants and DBPs remains to be studied. Quaternized cyclodextrin polymers have attracted increasing attention due to their excellent adsorption and antibacterial properties, but their synergistic effect with chlorine disinfection is still unclear. In this study, a magnetic quaternized cyclodextrin polymer (MQCDP) is synthesized in an ionic liquid green system, and a combined process of MQCDP treatment and chlorine disinfection is established. The disinfection performance of the combined process on the actual water body along with its reducing effect on the amount of chlorine disinfectant as well as the trihalomethanes (THMs) and haloacetic acids (HAAs) DBPs are explored. MQCDP has a porous structure with a specific surface area of 825 m2 g−1 and is easily magnetically separated. MQCDP can remove most of the natural organic matter (UV254 absorbance decreased by 97 %) in the water at the dosage of 1 g L−1 and kill bacteria with a sterilization rate of 85 %. Compared with disinfection using chlorine alone, the combined process has higher disinfection efficiency and significantly reduces the amount of disinfectant used. A concentration of 5 mg/L of NaClO was needed to meet the standard by chlorine disinfectant alone, while only 2 mg/L of NaClO can meet the standard for the combined process, indicating 60 % of the chlorine demand was reduced. More importantly, the combined process can significantly reduce the generation potential of DBPs. When 10 mg/L of NaClO is added, the THMs and HAAs generated by the combined process decreased by 65 % and 34 %, respectively, compared with the levels produced by single chlorine disinfection. The combined process can reduce the dosage of chlorine disinfectant and MQCDP can adsorb humic acid DBP precursors in raw water, thus lowering the generation of DBPs during disinfection. In summary, MQCDP has excellent separation and antibacterial ability, and its synergistic effects combined with the chlorine disinfection process are of great significance for controlling the amount of disinfectant and the formation potential of DBPs, which has potential applications in actual water treatment.

Bioinspired Zn-MOF doped radial porous chitosan-based sponge with antibacterial and antioxidant properties for rapid hemostasis and wound healing

Herein, a novel bioinspired radial porous zinc-based metal-organic framework (Zn-MOF) doped sodium alginate/chitosan derivatives/pullulan-based SA/PSCS/Pul/Zn-MOF (SPCP/Zn) composites sponge with excellent antioxidant and antibacterial properties was fabricated by the ice-templating method. Boric acid (BA) and Ca2+, which were respectively used as hydrogen- and ionic- bonding cross-linkers, provided strong mechanical properties for sponge matrix composed of SA, PSCS, and Pul. The obtained SPCP/Zn sponge exhibited uniform porous morphology, proper hydrophilicity, and admirable biocompatibility. In addition, the SPCP/Zn sponge achieved a sustained release of Zn2+ and gallic acid, which displayed powerful antibacterial and antioxidant activities. Importantly, the SPCP/Zn sponge exhibited shorter rapid hemostasis (20.4 ± 2.9 s) and lower blood loss (19.8 ± 4.3 mg). The SPCP/Zn sponge also showed faster wound closure ratio for the rat full-thickness skin defect model. It was revealed that SPCP/Zn sponge could significantly accelerate and enhance wound healing through downregulating inflammatory cytokines (TNF-α, IL-6) and increasing the expression of growth factors (VEGF). Due to its excellent properties, the SPCP/Zn sponge may have promising potential in wound healing applications.

Fabrication of robust, durable and integrated Janus coating for corrosion and fouling protection in marine environment

Janus membranes with different valuable characteristics and integrated structures have attracted a great interest of researches in order to achieve important breakthroughs in the related fields. However, the application of Janus membranes for development of anticorrosion coatings on metallic structures has been limited, which is due to weak interfacial bonding within the Janus structure and its vulnerability to damage. To address the aforementioned drawbacks, a novel strategy based on multifunction Janus membranes is presented. In this research, the steel is coated with polyurethane, followed by electrospinning a coating composed of polyurethane nanofibers with kaolin nanoparticles, and finally coated with epoxy resin containing modified ZnO to obtain the Janus membrane. The interface of the Janus membrane is accompanied by covalent bonds, leading to 10-fold enhancement in interface adhesion compared to the resin coating. The obtained Janus coating has a top surface that is superhydrophobic and a bottom surface that is hydrophilic, with excellent antiwetting and antibacterial properties. Moreover, the Janus coating shows outstanding barrier properties and the corresponding impedance modulus is maintained about 109 Ω•cm2 after 75 immersion days. Notably, the coating surface has retained superhydrophobicity after abrasion test with 600-grit sandpaper under a load of 1000 g for 60 m distance. The antibacterial tests have shown the Janus coating could decrease the bacterial coverage on the surface by 25 %. This study has revealed the potential of the Janus electrofibrous membrane as directly coatings on the metallic substrates for the first time, and in this way, multifunction coating with corrosion and fouling protection performances has been achieved.

Double Bionic Deformable DNA Hydrogel Microneedles Loaded with Extracellular Vesicles to Guide Tissue Regeneration of Diabetes Ulcer Wound

AbstractDue to the high blood glucose and low oxygen environment in diabetes wounds, complex pathological problems arise, such as failure to upregulate healing factors, biological barriers generation, microvascular lesions, and skin neuropathy. Inspired by nature and traditional Chinese paper‐cutting technology, polypeptide deoxyribonucleic acid (DNA) hydrogel microneedles (MNs) (P‐DNA gel MNs) are prepared. The obtained P‐DNA gel MNs possess optimized structure and large deformability, providing excellent clamping, stability, skin penetration, large deformation, tissue adhesion, and antibacterial properties. By incorporating extracellular vesicles (EVs) extracted under hypoxia (H‐EVs‐hypoxia), P‐DNA gel MNs can regulate tissue microenvironment, scavenge free radicals, and reduce inflammation. Notably, P‐DNA gel MNs integration system activates immune regulation and beneficial pathways, promoting neurogenesis and angiogenesis, reducing pathological pain, and achieving high‐quality healing. Overall, P‐DNA gel MNs system presents a fundamental mechanism for clinical transformation in treating diabetes wounds.

Preparation of poly (vinyl alcohol)/polydopamine/tannin acid composite hydrogels with dual adhesive, antioxidant and antibacterial properties

Sometimes traditional hydrogel dressings for wound repair were difficult to meet the needs of use due to insufficient adhesive, antibacterial and antioxidant properties, so a high-performance and multifunctional poly(vinyl alcohol)-based hydrogel dressing was prepared using poly (vinyl alcohol) (PVA), polydopamine (PDA), and tannic acid (TA) for dual adhesive, antibacterial, and antioxidant properties in this study. The structure and morphology of the hydrogel were analyzed by FTIR and SEM. The effects of the concentrations of PVA, PDA and TA on the swelling, antioxidation and adhesion of the hydrogel were investigated. The results showed that the maximum equilibrium swelling of the hydrogels were all below 6 %, and they had good anti-swelling effects in different solution environments. The maximum skin adhesive strength of the hydrogels was 75.7 kPa, and the scavenging efficiencies against free radicals were above 90 %. Due to the inherent bacteriostatic ability of TA and the good photothermal conversion efficiency of PDA, the hydrogels could inhibit E. coli and S. aureus up to 99 %. The hydrogels possessed excellent dual antioxidant, antibacterial and adhesive properties, which greatly broadened the applications of PVA composite hydrogels.

Durable Multifunctional Modification of Nylon Fabric with Excellent Flame Retardancy, Antibacterial and UV-Resistant Properties

Durable Multifunctional Modification of Nylon Fabric with Excellent Flame Retardancy, Antibacterial and UV-Resistant Properties

A H2 S-Generated Supramolecular Photosensitizer for Enhanced Photodynamic Antibacterial Infection and Relieving Inflammation.

Photodynamic therapy (PDT) is a promising treatment against bacteria-caused infections. By producing large amounts of reactive oxygen species (ROS), PDT can effectively eliminate pathogenic bacteria, without causing drug resistance. However, excessive ROS may also impose an oxidative stress on surrounding tissues, resulting in local inflammation. To avoid this major drawback and limit pro-inflammation during PDT, this work prepared a supramolecular photosensitizer (TPP-CN/CP5) based on host-guest interactions between a cysteine-responsive cyano-tetraphenylporphyrin (TPP-CN) and a water-soluble carboxylatopillar[5]arene (CP5). TPP-CN/CP5 not only possesses excellent photodynamic antibacterial properties, but also shows good anti-inflammatory and cell protection capabilities. Under 660nm light irradiation, TPP-CN/CP5 could rapidly produce abundant ROS for sterilization. After the PDT process, the addition of cysteine (Cys) triggers the release of H2 S from TPP-CN. H2 S then stops the induced inflammation by inhibiting the production of related inflammatory factors. Both in vitro and in vivo experiments show the excellent antibacterial effects and anti-inflammatory abilities of TPP-CN/CP5. These results will certainly promote the clinical application of PDT in the treatment of bacterial infectious diseases.

Phyto-fabrication of CuO–Co3O4 nanocomposites for antibacterial, photocatalytic and antioxidant evaluations: An in-vitro investigation

In this current investigation, we elucidated the microwave-assisted green synthesis of 90:10, 80:20, and 70:30 CuO–Co3O4 nanocomposites (NCs) from Ipomoea carnea leaf extract, manifesting their remarkable antibacterial, photocatalytic, and antioxidant capabilities. The spectroscopic techniques of XRD, SEM, EDX, TEM, FTIR, and UV–visible spectroscopy were employed to validate the formation of the synthesized NCs. SEM and TEM images revealed distinctive snowball-rod and distorted spherical structures in the synthesized nanocomposites, with average particle sizes of 33.36, 26.17, and 29.10 nm. The estimated energy band gap values were 1.20, 1.40, and 1.50 eV for the respective nanocomposites. The well diffusion method was utilized to explore the zone of inhibition (ZOI) against bacteria, namely Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. The nanocomposites, specifically the 90:10 and 80:20 CuO–Co3O4 blends, exhibited a noteworthy Zone of Inhibition (ZOI) during testing against B. subtilis, with approximate values of 34.76 ± 0.23 and 33.33 ± 0.32 mm, respectively. Furthermore, the photocatalytic potential has been investigated against the dyes Malachite green (MG) and Congo red (CR). Notably, the 90:10 NCs displayed an exceptional photodegradation rate of 97.69 % for MG and 95 % for CR within a mere 45 min. Moreover, the 70:30 NCs exhibited a commendable radical scavenging activity of approximately 97.53 % at a concentration of 800 μg/mL, while ascorbic acid, used as a standard, displayed a scavenging activity of 98.63 %. These investigations unveil the environmentally friendly, innovative, and cost-effective attributes of CuO–Co3O4 NCs derived from Ipomoea carnea leaf extract, which demonstrated excellent antibacterial, photocatalytic, and antioxidant properties.

Next-generation self-adhesive dressings: Highly stretchable, antibacterial, and UV-shielding properties enabled by tannic acid-coated cellulose nanocrystals

Hydrogels with excellent high-water uptake and flexibility have great potential for wound dressing. However, pure hydrogels without fiber skeleton faced poor water retention, weak fatigue resistance, and mechanical strength to hinder the development of the dressing as next-generation functional dressings. We prepared an ultrafast gelation (6 s) Fe3+/TA-CNC hydrogel (CTFG hydrogel) based on a self-catalytic system and bilayer self-assembled composites. The CTFG hydrogel has excellent flexibility (800% of strain), fatigue resistance (support 60% compression cycles), antibacterial, and self-adhesive properties (no residue or allergy after peeling off the skin). CTFG@S bilayer composites were formed after electrospun silk fibroin (SF) membranes were prepared and adhesive with CTFG hydrogels. The CTFG@S bilayer composites had significant UV-shielding (99.95%), tensile strain (210.9 KPa), and sensitive humidity-sensing properties. Moreover, the integrated structure improved the mechanical properties of electrospun SF membranes. This study would provide a promising strategy for rapidly preparing multifunctional hydrogels for wound dressing.

Preparation and characterization of quaternary bacterial cellulose composites for antimicrobial oil‐absorbing materials

AbstractThe treatment of various types of oily wastewater is paramount for environmental protection. Bacterial cellulose (BC) stands out as a highly promising material for oil/water separation, owing to its exceptional mechanical properties and three‐dimensional porous structures. However, excessive hydroxyl groups on BC make it highly hydrophilic, reducing oil absorption and promoting bacterial growth, affecting its stability. To address these challenges, we developed a straightforward in situ polymerization method for the preparation of BC‐DMC composites. The innovation lies in the concurrent enhancement of BC's hydrophobicity and antimicrobial properties only through the addition of 2‐(Methacryloyloxy)ethyltrimethylammonium chloride (DMC), considerably simplifying the synthesis of materials possessing oil‐absorbing and antimicrobial properties. Morphological and structural characterization results confirmed the successful combination of DMC onto BC while maintaining its porous structure. After process parameter optimization, the BC‐DMC composites exhibited a remarkable increase in contact angle (117.7° compared with pure BC's 19.5°). It also demonstrated excellent oil absorption performance, with maximum capacities exceeding 30 g/g for different oils, maintaining values above 20 g/g even after eight cycles. In addition, the BC‐DMC composites exhibited strong antibacterial activity, with rates of 82.4% against Escherichia coli and 97.5% against Staphylococcus aureus. The antibacterial mechanism of the BC‐DMC composites was also discussed. Our novel BC‐DMC composites provides excellent oil absorption and antibacterial properties, making it highly applicable in the field of oily wastewater treatment and serving as a valuable reference for other researchers.