Inherent Antibacterial Properties Research Articles

Investigating alginate and chitosan electrospun nanofibers as a potential wound dressing: an in vitro study

The research project focuses on conducting an in vitro comparison between sodium alginate and chitosan electrospun nanofibers for moist wound management. These fabricated nanofibers were incorporated with levofloxacin (Lev) as a model drug to investigate their release behavior. The study included a comprehensive examination of the physicochemical, thermal, antibacterial, and cytocompatibility properties of these nanofibers. Both sodium alginate (SA-L) and chitosan (CS-L) nanofibers were successfully produced with a homogeneous and defect-free structure. XRD and FTIR analyses were conducted to validate the incorporation of Lev in the nanofibers. In terms of liquid absorption capacity, it was observed that sodium alginate nanofibers outperformed chitosan nanofibers, exhibiting absorption capacities of 5.9, 5.88, and 7.1 g/g for PBS, solution A, and DI, respectively, for SA-L, compared to 5.27, 4.42, and 5.3 g/g for CS-L nanofibers. This superior absorption ability in SA-L nanofibers may be attributed to the inherent gel-forming properties of alginate in aqueous environments. Furthermore, the release kinetics indicated that SA-L nanofibers exhibited faster drug release compared to CS-L nanofibers, which could be attributed to alginate’s natural gel-forming tendency in aqueous mediums. Both SA-L and CS-L nanofibers demonstrated remarkable efficacy against Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa), with CS-L nanofibers displaying larger inhibition zones in agar diffusion tests due to chitosan’s inherent antibacterial properties. Moreover, cytocompatibility assessments using the HaCat cell line revealed that the prepared nanofibers were biocompatible and non-toxic. Interestingly, CS-L nanofibers exhibited superior cell proliferation when compared to SA-L nanofibers, potentially attributed to the inherent positively charged amine groups which enhance proliferation and migration of negatively charged keratinocytes.

Silver and Copper Nanoparticle-Loaded Self-Assembled Pseudo-Peptide Thiourea-Based Organic-Inorganic Hybrid Gel with Antibacterial and Superhydrophobic Properties for Antifouling Surfaces.

The escalating threat of antimicrobial resistance has become a global health crisis. Therefore, there is a rising momentum in developing biomaterials with self-sanitizing capabilities and inherent antibacterial properties. Despite their promising antimicrobial properties, metal nanoparticles (MNPs) have several disadvantages, including increased toxicity as the particle size decreases, leading to oxidative stress and DNA damage that need consideration. One solution is surface functionalization with biocompatible organic ligands, which can improve nanoparticle dispersibility, reduce aggregation, and enable targeted delivery to microbial cells. The existing research predominantly concentrates on the advancement of peptide-based hydrogels for coating materials to prevent bacterial infection, with limited exploration of developing surface coatings using organogels. Herein, we have synthesized organogel-based coatings doped with MNPs that can offer superior hydrophobicity, oleophobicity, and high stability that are not easily achievable with hydrogels. The self-assembled gels displayed distinct morphologies, as revealed by scanning electron microscopy and atomic force microscopy. The cross-linked matrix helps in the controlled and sustained release of MNPs at the site of bacterial infection. The synthesized self-assembled gel@MNPs exhibited excellent antibacterial properties against harmful bacteria such as Escherichia coli and Staphylococcus aureus and reduced bacterial viability up to 95% within 4 h. Cytotoxicity testing against metazoan cells demonstrated that the gels doped with MNPs were nontoxic (IC50 > 100 μM) to mammalian cells. Furthermore, in this study, we coated the organogel@MNPs on cotton fabric and tested it against Gram +ve and Gram -ve bacteria. Additionally, the developed cotton fabric exhibited superhydrophobic properties and developed a barrier that limits the interaction between bacteria and the surface, making it difficult for bacteria to adhere and colonize, which holds potential as a valuable resource for self-cleaning coatings.

NIR-activated electrospun nanodetonator dressing enhances infected diabetic wound healing with combined photothermal and nitric oxide-based gas therapy

Diabetic wounds pose a challenge to healing due to increased bacterial susceptibility and poor vascularization. Effective healing requires simultaneous bacterial and biofilm elimination and angiogenesis stimulation. In this study, we incorporated polyaniline (PANI) and S-Nitrosoglutathione (GSNO) into a polyvinyl alcohol, chitosan, and hydroxypropyltrimethyl ammonium chloride chitosan (PVA/CS/HTCC) matrix, creating a versatile wound dressing membrane through electrospinning. The dressing combines the advantages of photothermal antibacterial therapy and nitric oxide gas therapy, exhibiting enduring and effective bactericidal activity and biofilm disruption against methicillin-sensitive Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Escherichia coli. Furthermore, the membrane’s PTT effect and NO release exhibit significant synergistic activation, enabling a nanodetonator-like burst release of NO through NIR irradiation to disintegrate biofilms. Importantly, the nanofiber sustained a uniform release of nitric oxide, thereby catalyzing angiogenesis and advancing cellular migration. Ultimately, the employment of this membrane dressing culminated in the efficacious amelioration of diabetic-infected wounds in Sprague–Dawley rats, achieving wound closure within a concise duration of 14 days. Upon applying NIR irradiation to the PVA-CS-HTCC-PANI-GSNO nanofiber membrane, it swiftly eradicates bacteria and biofilm within 5 min, enhancing its inherent antibacterial and anti-biofilm properties through the powerful synergistic action of PTT and NO therapy. It also promotes angiogenesis, exhibits excellent biocompatibility, and is easy to use, highlighting its potential in treating diabetic wounds.Graphical

Bioactive Lyocell Fibers with Inherent Antibacterial, Antiviral and Antifungal Properties.

Functional Lyocell fibers gain interest in garments and technical textiles, especially when equipped with inherently bioactive features. In this study, Lyocell fibers are modified with an ion exchange resin and subsequently loaded with copper (Cu) ions. The modified Lyocell process enables high amounts of the resin additive (>10%) through intensive dispersion and subsequently, high uptake of 2.7% Cu throughout the whole cross-section of the fiber. Fixation by Na2CO3 increases the washing and dyeing resistance considerably. Cu content after dyeing compared to the original fiber value amounts to approx. 65% for reactive, 75% for direct, and 77% for HT dyeing, respectively. Even after 50 household washes, a recovery of 43% for reactive, 47% for direct and 26% for HT dyeing is proved. XRD measurements reveal ionic bonding of Cu fixation inside the cellulose/ion exchange resin composite. A combination of the fixation process with a change in Cu valence state by glucose/NaOH leads to the formation of Cu2O crystallites, which is proved by XRD. Cu fiber shows a strong antibacterial effect against Staphylococcus aureus and Klebsiella pneumonia bacteria, even after 50 household washing cycles of both >5 log CFU. In nonwoven blends with a share of only 6% Cu fiber, a strong antimicrobial (CFU > log 5) and full antiviral effectiveness (>log 4) was received even after 50 washing cycles. Time-dependent measurements already show strong antiviral behavior after 30 s. Further, the fibers show an increased die off of the fungal isolate Candida auris with CFU log 4.4, and nonwovens made from 6% Cu fiber share a CFU log of 1.7. Findings of the study predestines the fiber for advanced textile processing and applications in areas with high germ loads.

Ultrasonic synthesis of green lipid nanocarriers loaded with Scutellaria barbata extract: a sustainable approach for enhanced anticancer and antibacterial therapy.

Ultrasonic manufacturing has emerged as a promising eco-friendly approach to synthesize lipid-based nanocarriers for targeted drug delivery. This study presents the novel ultrasonic preparation of lipid nanocarriers loaded with Scutellaria barbata extract, repurposed for anticancer and antibacterial use. High-frequency ultrasonic waves enabled the precise self-assembly of DSPE-PEG, Span 40, and cholesterol to form nanocarriers encapsulating the therapeutic extract without the use of toxic solvents, exemplifying green nanotechnology. Leveraging the inherent anticancer and antibacterial properties of Scutellaria barbata, the study demonstrates that lipid encapsulation enhances the bioavailability and controlled release of the extract, which is vital for its therapeutic efficacy. Dynamic light scattering and transmission electron microscopy analyses confirmed the increase in size and successful encapsulation post-loading, along with an augmented negative zeta potential indicating enhanced stability. A high encapsulation efficiency of 91.93% was achieved, and in vitro assays revealed the loaded nanocarriers' optimized release kinetics and improved antimicrobial potency against Pseudomonas aeruginosa, compared to the free extract. The combination of ultrasonic synthesis and Scutellaria barbata in an eco-friendly manufacturing process not only advances green nanotechnology but also contributes to sustainable practices in pharmaceutical manufacturing. The data suggest that this innovative nanocarrier system could provide a robust platform for the development of nanotechnology-based therapeutics, enhancing drug delivery efficacy while aligning with environmental sustainability.

Characterization and antibacterial of soybean protein isolate composite film with carvacrol and walnut peel extract

In order to alleviate plastic pollution and to substitute specific conventional polymer packaging, this research deployed biodegradable soy protein isolate (SPI) as a basis to create natural polymer composite films, integrating walnut peel extract (WPE) and carvacrol (CV) for their inherent antibacterial properties. The inhibition rates of the SPI/WPE5%/CV5% composite film on E.coli and S.aureus were 99.66% and 99.52%, the DPPH radical was 73.3% and ABTS radical was 95.5%. The SPI/WPE5%/CV5% composite film also exhibited excellent UV-visible barrier properties. Compared with the pure SPI film, the tensile strength of the SPI/WPE5%/CV5% composite film increased by 89.00%, the water solubility increased by 2.67%, and the water vapor permeability was reduced by 7.69%, While the water contact angle increased by 155.93%. Fourier Transform Infrared Spectroscopy studies possibly indicate that the polyphenol-proteins in the SPI/WPE/CV composite film are bound together by hydrogen bonding. X-ray Diffraction study demonstrated that the crystallinity of the SWC films increased. Scanning Electron Microscope results revealed the surface level and internal molecular structure of the SWC films. Thermal weight analysis showed that after adding WPE and CV, the thermal properties of the SWC films improved. This study explored release of the film and found that the composite film can continuously release polyphenols, which play an antibacterial and antioxidant role.

Enhanced physiochemical, antibacterial, and hemostatic performance of collagen-quaternized chitosan-graphene oxide sponges for promoting infectious wound healing

Bacteria-infected wound healing has attracted widespread attention in biomedical engineering. Wound dressing is a potential strategy for repairing infectious wounds. However, the development of wound dressing with appropriate physiochemical, antibacterial, and hemostatic properties, remains challenging. Hence, there is a motivation to develop new synthetic dressings to improve bacteria-infected wound healing. Here, we fabricate a biocompatible sponge through the covalent crosslinking of collagen (Col), quaternized chitosan (QCS), and graphene oxide (GO). The resulting Col-QCS-GO sponge shows an elastic modulus of 1.93-fold higher than Col sponge due to enhanced crosslinking degree by GO incorporation. Moreover, the fabricated Col-QCS-GO sponge shows favorable porosity (84.30 ± 3.12 %), water absorption/retention (2658.0 ± 113.4 %/1114.0 ± 65.7 %), and hemostasis capacities (blood loss <50.0 mg). Furthermore, the antibacterial property of the Col-QCS-GO sponge under near-infrared (NIR) irradiation is significantly enhanced (the inhibition rates are 99.9 % for S. aureus and 99.9 % for E. coli) due to the inherent antibacterial properties of QCS and the photothermal antibacterial capabilities of GO. Finally, the Col-QCS-GO+NIR sponge exhibits the lowest percentage of wound area (9.05 ± 1.42 %) at day 14 compared to the control group (31.61 ± 1.76 %). This study provides new insights for developing innovative sponges for bacteria-infected wound healing.

Scalable, high-strength, wear-resistant, antibacterial polyethylene micro-nano fiber protective materials

Polyethylene (PE) fibers, known for their exceptional mechanical and protective properties, have found valuable applications in personal protective equipment during the COVID-19 pandemic. However, traditional PE fibers lack inherent antibacterial properties, making them susceptible to microbial contamination and potentially contributing to the secondary transmission of pathogens. Therefore, the development of antibacterial PE fibers holds paramount importance. Here, we successfully develop high-strength, wear-resistant, and antibacterial PE fibers by applying a dip-coating process with polylactic acid (PLA) solutions containing ZnO-Ag nanoparticles onto the surface of PE fibers. These antibacterial PE fibers exhibit an impressive antibacterial rate exceeding 99.9% against common bacteria, a tensile strength of 33.7 MPa, along with outstanding wear resistance, wearing comfort, and washing stability. Furthermore, continuous production of antibacterial PE nonwovens is achieved by combining roll-to-roll and dip-coating processes. Therefore, the excellent properties and industrial-scale production potential of antibacterial PE fibers position them with broad application prospects in the fields of medical protection, biochemical protection, and beyond.

Tissue‐adhesive, antibacterial, naturally‐derived polymer hydrogels as wound dressings for infected and chronic wound healing

AbstractBacterial infections are common during skin wound healing, which can interrupt the healing process, delay wound healing and seriously affect the quality of life. Long‐term antibiotic treatment may lead to the development of drug resistance. Traditional bandages, sponges, films, and textiles are commonly single‐functional, and usually fail to satisfy the complicated needs of wound healing process. In recent years, antibacterial hydrogel dressings have received extensive attention for treatment of infected and chronic wounds, which can serve as biocompatible, multifunctional platforms for both promoting tissue regeneration and inhibiting bacterial infection. Cationic polymers with inherent antibacterial properties have been used as the hydrogel backbone, and metal ions and metal nanoparticles can be loaded in the hydrogels to enhance the antibacterial effects. Besides, various drugs and bioactive factors have been incorporated to provide the hydrogel with anti‐inflammatory and antioxidant activities in complicated environment of chronic wound healing. Additionally, the tissue adhesion of hydrogel dressings can have advantages in fixing the dressings at wound sites and promoting the dressing‐tissue interactions. In this review, we focus on the designing strategies for tissue‐adhesive, antibacterial, naturally‐derived polymer hydrogels for treating infected and chronic wounds. The typical tissue adhesion mechanisms and antibacterial mechanisms of the hydrogel dressings are summarized. Finally, the prospects and challenges in the further development of multi‐functional hydrogels to treat infected and chronic wounds are proposed.

The Biologically Active Biopolymer Silk: The Antibacterial Effects of Solubilized Bombyx mori Silk Fibroin with Common Wound Pathogens.

Antibacterial properties are desirable in wound dressings. Silks, among many material formats, have been investigated for use in wound care. However, the antibacterial properties of liquid silk are poorly understood. The aim of this study is to investigate the inherent antibacterial properties of a Bombyx mori silk fibroin solution. Silk fibroin solutions containing ≥ 4% w/v silk fibroin do not support the growth of two common wound pathogens, Staphylococcus aureus and Pseudomonas aeruginosa. When liquid silk is added to a wound pad and placed on inoculated culture plates mimicking wound fluid, silk is bacteriostatic. Viability tests of the bacterial cells in the presence of liquid silk show that cells remain intact within the silk but could not be cultured. Liquid silk appears to provide a hostile environment for S. aureus and P. aeruginosa and inhibits growth without disrupting the cell membrane. This effect can be beneficial for wound healing and supports future healthcare applications for silk. This observation also indicates that liquid silk stored prior to processing is unlikely to experience microbial spoilage.

Bioactivity of chitosan nanoparticles synthesized by a novel route towards Escherichia coli and Bacillus subtilis

Chitosan nanoparticles (CSNP) with an average size of 25.67 nm were synthesized via a novel wet chemical route and characterized using scanning electron microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy. Comparative antibacterial assays of Chitosan NP suspensions prepared in water (at neutral pH) and in dilute acetic acid and chitosan gel prepared in dilute acetic acid/hydrochloric acid (all at concentrations up to 1%) were performed against Escherichia coli ( E. coli) and Bacillus subtilis ( B. subtilis) bacteria using spread plate method. A parallel viability test was conducted to confirm the presence of surviving cells in the bulk test volume. Minimum bactericidal concentration (MBC) of chitosan gel was 0.5 mg/ml for the bulk chitosan dissolved in 0.05% v/v aq. acetic acid and 0.1 mg/ml for chitosan dissolved in 0.01% v/v aqueous (aq.) hydrochloric acid. In comparison, Chitosan NP were found to be growth promoter at neutral pH and exhibited cell protective efficacy in presence of aq. acetic acid. The biocidal activity of chitosan gel in acidic media was higher when prepared in strong inorganic acid, that is, aq. HCl in comparison with the gel prepared in a relatively weak organic acid that is, aq. CH3COOH at the same concentration. Antibacterial action also showed pH dependence with higher activity at lower pH. However, respective aq. acids also gave comparable bactericidal action; indicating that chitosan may not have any inherent antibacterial property and basically it acts as a growth promoter.

A Mini Review on Current Challenges and Opportunities in the Management of Bovine Mastitis

Bovine subclinical mastitis stands out as a significant challenge in the dairy industry, leading to substantial milk losses. The issue becomes more alarming as lactating cows frequently face severe infections caused by Staphylococcus aureus bacteria, resulting in detrimental udder damage. The conventional approach of combating such infections involves prolonged antibiotic treatments, contributing to the emergence of Antimicrobial Resistance (AMR) in cows. Compounding the issue, S. aureus bacteria can undergo modifications, transforming into the formidable Methicillin-Resistant S. aureus (MRSA). Addressing this pressing concern requires exploring alternative solutions, and one promising avenue lies in the realm of medicinal plants. Leveraging the inherent antibacterial properties of phytochemicals found in various medicinal plants could offer a sustainable and effective approach to managing bovine mastitis. Not only do these botanical remedies provide a potential solution to the challenges posed by conventional antibiotic treatments, but they also offer a more environmentally friendly and holistic approach to safeguarding the health of dairy cows and preserving milk production in the industry.

Periodontium-Mimicking, Multifunctional Biomass-Based Hydrogel Promotes Full-Course Socket Healing.

Preserving stable tooth-periodontal tissue integration is vital for maintaining alveolar bone stability under physiological conditions. However, tooth extraction compromises this integration and impedes socket healing. Therefore, it becomes crucial to provide early stage coverage of the socket to promote optimal healing. Drawing inspiration from the periodontium, we have developed a quaternized methacryloyl chitosan/dopamine-grafted oxidized sodium alginate hydrogel, termed the quaternized methacryloyl chitosan/dopamine-grafted oxidized sodium alginate hydrogel (QDL hydrogel). Through blue-light-induced cross-linking, the QDL hydrogel serves as a comprehensive wound dressing for socket healing. The QDL hydrogel exhibits remarkable efficacy in closing irregular tooth extraction wounds. Its favorable mechanical properties, flexible formability, and strong adhesion are achieved through modifications of chitosan and sodium alginate derived from biomass sources. Moreover, the QDL hydrogel demonstrates a superior hemostatic ability, facilitating swift blood clot formation. Additionally, the inherent antibacterial properties of the QDL hydrogel effectively inhibit oral microorganisms. Furthermore, the QDL hydrogel promotes angiogenesis, which facilitates the nutrient supply for subsequent tissue regeneration. Notably, the hydrogel accelerates socket healing by upregulating the expression of genes associated with wound healing. In conclusion, the periodontium-mimicking multifunctional hydrogel exhibits significant potential as a clinical tooth extraction wound dressing.

Azadirachta indica (AI) leaf extract coated ZnO-AI nanocore–shell particles for enhanced antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA)

With the rise in microbial resistance to traditional antibiotics and disinfectants, there is a pressing need for the development of novel and effective antibacterial agents. Two major approaches being adopted worldwide to overcome antimicrobial resistance are the use of plant leaf extracts and metallic nanoparticles (NPs). However, there are no reports on the antibacterial potential of NPs coated with plant extracts, which may lead to novel ways of treating infections. This study presents an innovative approach to engineer antibacterial NPs by leveraging the inherent antibacterial properties of zinc oxide NPs (ZnO NPs) in combination with Azadirachta indica (AI) leaf extract, resulting in enhanced antibacterial efficacy. ZnO NPs were synthesised by the precipitation method and subsequently coated with AI leaf extract to produce ZnO-AI nanocore–shell structures. The structural and morphological characteristics of the bare and leaf extract coated ZnO NPs were analysed by x-ray diffraction and field emission scanning electron microscopy, respectively. The presence of an AI leaf extract coating on ZnO NPs and subsequent formation of ZnO-AI nanocore–shell structures was verified through Fourier transform infrared spectroscopy and photoluminescence techniques. The antibacterial efficacy of both ZnO NPs and ZnO-AI nanocore–shell particles was evaluated against methicillin-resistant Staphylococcus aureus using a zone of inhibition assay. The results showed an NP concentration-dependent increase in the diameter of the inhibition zone, with ZnO-AI nanocore–shell particles exhibiting superior antibacterial properties, owing to the combined effect of ZnO NPs and the poly phenols present in AI leaf extract. These findings suggest that ZnO-AI nanocore–shell structures hold promise for the development of novel antibacterial creams and hydrogels for various biomedical applications.

Antibacterial polylysine-containing hydrogels for hemostatic and wound healing applications: preparation methods, current advances and future perspectives.

The treatment of various types of wounds such as dermal wounds, multidrug resistant bacteria-infected wounds, and chronic diabetic wounds is one of the critical challenges facing healthcare systems. Delayed wound healing can impose a remarkable burden on patients and health care professionals. In this case, given their unique three-dimensional porous structure, biocompatibility, high hydrophilicity, capability to provide a moist environment while absorbing wound exudate, permeability to both gas and oxygen, and tunable mechanical properties, hydrogels with antibacterial function are one of the most promising candidates for wound healing applications. Polylysine is a cationic polymer with the advantages of inherent antibacterial properties, biodegradability, and biocompatibility. Therefore, its utilization to engineer antibacterial hydrogels for accelerating wound healing is of great interest. In this review, we initially discuss polylysine properties, and then focus on the most recent advances in polylysine-containing hydrogels (since 2016) prepared using various chemical and physical crosslinking methods for hemostasis and wound healing applications. Finally, the challenges and future directions in the engineering of these antibacterial hydrogels for wound healing are discussed.

Modulating the photodynamic modality of Au22 nanoclusters through surface conjugation of arginine for promoted healing of bacteria-infected wounds.

Developing novel antibacterial agents without drug resistance is highly desired but challenging. In this study, an Au nanocluster (NC)-based photodynamic antibacterial agent with aggregation-induced emission (AIE) has been designed to promote the healing of bacteria-infected wounds by conjugating arginine (Arg) on the surface of Au22 NCs. The conjugation of Arg not only endows the NCs with enhanced visible light absorption, increased photoluminescence (PL) intensity, and prolonged PL lifetime, but it also enables switching the photodynamic production mode of reactive oxygen species (ROS) and extra production of reactive nitrogen species (RNS). These enhancements allow the Arg-Au22 NCs to combine ROS/RNS-mediated antibacterial action with the enhanced inherent antibacterial properties of Au NCs, resulting in outstanding antibacterial efficacy against both Gram-negative and Gram-positive bacteria. In vivo experiments demonstrate the effective treatment of bacteria-infected wounds by the Arg-Au22 NCs, leading to the photodynamic eradication of bacterial infections and reduced inflammation in the wound area without causing systemic harm or impairing blood and liver functions. This study introduces a novel approach to designing metal NC-based photodynamic antibacterials with multiple antibacterial actions, contributing to deeper understanding of ROS/RNS-mediated antibacterial mechanisms, and future utilization of metal NCs in antibacterial therapies.

Double Cross-Linked Hydrogel Dressings Based on Triblock Copolymers Bearing Antifreezing, Antidrying, and Inherent Antibacterial Properties.

Bacterial infections typically invade the living tissue of wounds, thereby aggravating the inflammatory response, delaying wound healing, or causing further complications. In this paper, the antibacterial hydrogel (PNVBA) with antifreezing and antidrying properties was prepared by a two-step method using N-isopropylacrylamide (NIPAM), 1-butyl-3-vinylimidazolium bromide (VBIMBr), and 3-acrylamidophenylboronic acid (AAPBA). PNVBA hydrogels exhibited a high adsorption capacity of 280 mg·g-1 for bovine serum albumin (BSA) and can adhere to the surface of different materials through ion-dipole or hydrogen-bonding interactions. Meanwhile, the PNVBA hydrogels exhibited high viscoelasticity and good adhesion after freezing at -20 °C or heating at 70 °C for 24 h with a sterilizing rate of up to 98% against multidrug-resistant (MDR) Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA). Moreover, a survival rate of up to 90% after incubation with L929 cells over 24 h was observed. Therefore, this inherent antibacterial hydrogel can be used as an excellent alternative material for wound dressings.

Confined assembly of 2D biofilms at the air-water interface for versatile surface biofunctionalization of osteogenic implants

The increasing aging population has created a huge demand for osteogenic implants. In this study, we report a biogenic, scalable, and osteogenic biofilm for in vivo osseointegration. Experimental and simulation studies showed vertical migration and horizontal juxtaposition of lactoferrin (LF) nanoaggregates at the air-water interface, forming 2D biofilms with highly controllable thickness, roughness, and adhesiveness. The inherent biocompatible, antibacterial, and osteogenic properties of LF clearly translated the biofilms into facile coatings for versatile surface biofunctionalization of various implants such as polylactic acid. Specifically, the defective tibiae in rat models receiving such implants featured a 149% increase in bone volume/tissue volume and a 57% increase in the number of bone trabeculae after an 8-week recovery, making the LF-based biofilms the best among the biomolecular osteo-regenerative coatings reported so far. This study provided a compelling example of how the inherent biofunctions of natural proteins can be combined with surface biofunctionalization towards advanced biomedical applications.

Long-lasting anti-bacterial face masks enabled by combining anti-bacterial materials and superhydrophobic coating

Face masks are widely used for protecting against the COVID-19 pandemic and other diseases. However, the lack of virucidal properties in conventional face masks increases the risk of cross-infection and potential contamination. Here, we report preparation of a superhydrophobic and anti-bacterial polypropylene fabric by in turn incorporation of ZnO nanoparticles and perfluorodecyl polysiloxane modified SiO2 nanoparticles. The fabric exhibits high superhydrophobicity with a water shedding angle of ~6° and excellent moisture resistance, which enable maintenance of functionality effectiveness of the face masks in cold weather conditions. When utilized as a middle layer in face masks, the fabric demonstrates remarkable anti-bacterial activity against E. coli in both laboratory and outdoor environments. This anti-bacterial performance is attributed to the synergistic effect of superhydrophobicity and the ZnO nanoparticles. The excellent superhydrophobicity significantly reduces adhesion of E. coli on the fabric. Meanwhile, the embedded ZnO nanoparticles can eliminate the small number of adhered bacteria through their inherent anti-bacterial property. The combination of superhydrophobicity and anti-bacterial property in the fabric presents a promising solution for enhancing the performance of face masks. The superhydrophobic anti-bacterial fabric holds great potential for various practical applications in the field of personal protective equipment, healthcare, and disease prevention.

Hierarchical Cu dendrites@ CuO multifunctional nanowire mesh for solar-thermal clean water production

Solar-driven interfacial evaporation is recognized as an energy-efficient and sustainable approach to combat the global freshwater crisis, particularly in rural areas where continuous energy inputs are limited. Additionally, these regions often lack effective sterilization methods for their water sources. By incorporating photothermal materials with inherent antibacterial properties, water purification can be enhanced without relying on external sterilization steps. Herein, we designed a multi-functional photothermal (MFP) evaporator based on a Cu dendrite@ CuO with abundant nanowires via a template-free method for solar-thermal clean water production. Compared to flat-type structures, the MPF evaporator with its dendritic architecture not only exhibits efficient photon absorption but also expands the evaporation area by over sevenfold, facilitating enhanced water evaporation with an efficient pathway for water transfer. Under 1 kW m−2, the MFP evaporator achieves an impressive evaporation rate of 1.40 kg m−2 h−1 and an efficiency of 87.8 %. Furthermore, the MFP evaporator demonstrates remarkable antibacterial capabilities, effectively inhibiting bacterial growth in raw water by damaging bacterial cell walls. Hence, the as-prepared MFP evaporator exhibits tremendous potential as an innovative system for solar-driven interfacial water evaporation and purification.