Preparation and antibacterial effects of Ag/AgCl-doped quaternary ammonium-modified silicate hybrid antibacterial material

Slow-sculpting graphene oxide/alginate gel loaded with platelet-rich plasma to promote wound healing in rats

Wounds, especially chronic wounds, have become an important problem that endangers human health. At present, there are many repair methods, and among them combines materials science and biology is one of the important repair methods. This study explored the preparation method, physicochemical properties, biological activity and safety of Platelet-Rich plasma (PRP)-loaded slow-sculpting graphene oxide (GO)/alginate gel, and applied it to acute full-thickness skin defect wounds in rats to observe its role in wound healing. The results show that the slow-sculpting GO/alginate gel has excellent plasticity and is suitable for a variety of irregularly shaped wounds. At the same time, its porous structure and water content can maintain the activity of platelets and their released growth factors in PRP, thereby promoting wound collagen synthesis and angiogenesis to accelerate wound healing. This indicates that the slow-sculpting GO/alginate gel is an excellent loading material for PRP, and the combination of the two may become one of the methods to promote wound repair.

Past-expiration-date liquid disinfectants to deactivate biological and chemical toxins on building material surfaces

In this study, we evaluated the deactivating efficacy of strong basicity-based (T4-102) and hydrogen peroxide-based (DF-200) disinfectants that were past their expiration date when used to deactivate biological and chemical toxins on building material surfaces. The decontamination efficacies of DF-200 and T4-102 disinfectants against dimethyl methylphosphonate (DMMP) and 2-chloroethyl ethylsulfide (2-CEES) were studied using GC-MS analysis. The bactericidal efficacies of disinfectants against Gram-negative E. coli and P. aeruginosa, and Gram-positive B. subtilis and S. aureus, were assessed in terms of the zone of inhibition, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). The results indicated that the deactivation efficacy varied significantly according to the disinfectant amount, contact time, and building material. Higher efficacy of up to 99-100% was observed for biological toxins, despite passing their expiration dates. Approximately 70-78% of deactivation efficacies were observed for disinfectants against DMMP on the tile coupon at 100 μL and 24 h contact time. Moreover, the deactivation efficacy of DF-200 was better than that of T4-102. The data presented here demonstrate that the responders may use past-expiration-date disinfectants for efficacious disinfectaion in large-scale contamination incidents.

Silver-Polymethylhydrosiloxane-Quaternary Ammonium Coating on Anodized Aluminum with Excellent Antibacterial Property

Multidrug-resistant bacteria are known to survive on high-touch surfaces for days, weeks, and months, contributing to the rise in nosocomial infections. Inducing antibacterial property in such surfaces can presumably reduce the overall microbial burden and subsequent nosocomial infections in hygiene critical environments. In the present study, a one-pot sol-gel process has been deployed to incorporate silver (Ag) and quaternary ammonium salt (QUAT) bactericides in a polymethylhydrosiloxane (PMHS) matrix. The Ag-PMHS-QUAT nanocomposite was coated on anodized aluminum (AAO/Al) by a simple ultrasound-assisted deposition process. The morphological features and chemical composition of the Ag-PMHS-QUAT nanocomposite have been characterized using SEM, XRD spectroscopy, and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) to confirm the formation of Ag-QUAT nanocomposites within the polymeric network of PMHS. The Ag-PMHS-QUAT nanocomposite coating on anodized aluminum oxide (AAO/Al) coupon exhibited superior antibacterial property with a 6-log bacterial reduction compared to the 5-log reduction for the commercially available antimicrobial copper coupon.

Fabrication of a TiO2@Cu Core-Shell Nanorod Array as Coating for Titanium Substrate with Mechanical and Chemical Dual Antibacterial Property

Titanium (Ti) is an excellent medical metal material, but the absence of good antibacterial property restricts its widespread application. To overcome this, we thus conducted a series of modifications for Ti. First, a titanium dioxide (TiO₂) nanorod array was generated on the Ti surface by hydrothermal treatment (TiO₂/Ti). With the polymer-mediated self-assembly method, a continuous copper (Cu) shell structure on the surface of the nanorod was then generated to form a TiO₂@Cu core-shell nanorod array as coating for Ti (TiO₂@Cu/Ti). Using pure Ti as the control group, the antibacterial properties of TiO₂/Ti and TiO₂@Cu/Ti were appraised. The results manifested that the mechanical and chemical dual function of the released Cu²⁺ and TiO₂ nanorod array could effectively kill bacteria on the surface of Ti. Besides, the obtained coating exhibited no cytotoxicity and favorable biocompatibility. In this work, we found an antibacterial strategy based on multiple sterilization pathways, which made Ti have good antibacterial property and further improved its biocompatibility.

2D Black Phosphorus-Based Cytomembrane Mimics with Stimuli-Responsive Antibacterial Action Inspired by Endotoxin-Associated Toxic Behavior

Biomimetic membrane materials have been widely explored and developed for drug loading and tissue engineering applications due to their excellent biocompatibility and abundant reaction sites. However, novel cytomembrane mimics have been lacking for a long time. In this study, black phosphorus (BP) was used as the foundation for a new generation of promising cytomembrane mimics due to its multiple similarities to cytomembranes. Inspired by the dual function of endotoxins on membranes, we prepared a BP-based cytomembrane mimic with controllable antibacterial ability via electrostatic interaction between BP and [1-pentyl-1-quaternary ammonium-3-vinyl-imidazole]Br ([PQVI]Br). The release of PQVI could be manipulated in different conditions by adjusting the electrostatic force, thereby achieving controllable antibacterial ability. This report confirms the possibility of using BP as a new material to mimic cytomembranes and provides a new concept of controllable antibacterial action based on endotoxins.

Electrical and visible light dual-responsive ZnO nanocomposite with multiple wound healing capability

The healing process of open wounds is a competition between cells and bacteria. Therefore, a strategy that can quickly remove bacteria and promote cell proliferation to accelerate wound healing is urgently needed. Inspired by photoelectric synergy tactics, we improved both the optical and electrical response of zinc oxide (ZnO) through the modification of polydopamine (PDA) and reduced graphene oxide (rGO), thus obtaining a ZnO composite named PDA-rGO-ZnO (PrZ). Combined with the photoelectric double stimulation, the sterilization target could be completed from multiple physical levels simultaneously. More importantly, the band gap of ZnO was considerably narrowed by PDA encapsulation. The encapsulated ZnO thus could be effectively excited by pure yellow light (YL) with a moderate long wavelength, which fundamentally improved its safety in exerting photocatalytic antibacterial properties. In addition, we found that electrical stimulation (ES) could not only help to clear bacteria, but also facilitate the formation of new blood vessels. Animal experiments further showed that PrZ efficaciously regulated the immune response around the wound surface, promoted cell proliferation and the formation of collagen fibers, thereby accelerating wound healing.

Heat Conduction and Antibacterial Hexagonal Boron Nitride/Polypropylene Nanocomposite Fibrous Membranes for Face Masks with Long-Time Wearing Performance

Wearing surgical masks is one of the best protective measures to protect humans from viral invasion during the 2019 coronavirus (COVID-19) outbreak. However, wearing surgical masks for extended periods will cause uncomfortable sweltering sense to users and are easy to breed bacteria. Here, we reported a novel fibrous membrane with outstanding comfortability and antibacterial activity prepared by PP ultrafine fiber nonwovens and antibacterial functionalized h-BN nanoparticles (QAC/h-BN). The thermal conductivity of commercial PP nonwovens was only 0.13 W m^-1 K^-1, but that of the QAC/h-BN/PP nanocomposite fibrous membranes can reach 0.88 W m^-1 K^-1, an enhancement of 706.5% than commercial PP nonwovens. The surface temperature of commercial PP surgical masks was 31.8 °C when the wearing time was 60 min. In contrast, QAC/h-BN/PP surgical masks can reach 33.6 °C at the same tested time, exhibiting stronger heat dissipation than commercial PP surgical masks. Besides, the antibacterial rates of QAC/h-BN/PP nanocomposite fibrous membranes were 99.3% for E. coli and 96.1% for S. aureus, and their antibacterial mechanism was based on "contact killing" without the release of unfavorable biocides. We think that the QAC/h-BN/PP nanocomposite fibrous membranes could provide better protection to people.

Tunable Superhydrophobic Aluminum Surfaces with Anti-Biofouling and Antibacterial Properties

Surfaces in a hygiene critical environment can become potential reservoirs for transmission of pathogenic infections. Engineering surfaces with the tunable anti-biofouling and antibacterial properties could reduce infections particularly in hospitals and public transport hubs. In the present work, a facile two-step process has been deployed to fabricate a superhydrophobic and antibacterial aluminum surface by chemical etching, followed by passivation with low surface energy octyltriethoxysilane (OTES) molecules. The wettability and antibacterial properties of the OTES passivated aluminum was monotonically tuned by adding quaternary ammonium (QUATs) molecules. An anti-biofouling property of 99.9% against Staphylococcus aureus, 99% against Pseudomonas aeruginosa and 99% against E. coli bacteria, was achieved.

Silicate bioceramics: from soft tissue regeneration to tumor therapy

Great efforts have been devoted to exploiting silicate bioceramics for various applications in soft tissue regeneration, owing to their excellent bioactivity. Based on the inherent ability of silicate bioceramics to repair tissue, bioactive ions are easily incorporated into silicate bioceramics to endow them with extra biological properties, such as enhanced angiogenesis, antibiosis, enhanced osteogenesis, and antitumor effect, which significantly expands the application of multifunctional silicate bioceramics. Furthermore, silicate nanobioceramics with unique structures have been widely employed for tumor therapy. In recent years, the novel applications of silicate bioceramics for both tissue regeneration and tumor therapy have substantially grown. Eliminating the skin tumors first and then repairing the skin wounds has been widely investigated by our groups, which might shed some light on treating other soft tissue tumor or tumor-induced defects. This review first describes the recent advances made in the development of silicate bioceramics as therapeutic platforms for soft tissue regeneration. We then highlight the major silicate nanobioceramics used for tumor therapy. Silicate bioceramics for both soft tissue regeneration and tumor therapy are further emphasized. Finally, challenges and future directions of silicate bioceramics stepping into the clinics are discussed. This review will inspire researchers to create the efficient and functional silicate bioceramics needed for regeneration and tumor therapy of other tissues.

Chitosan Derivatives and Their Application in Biomedicine

Chitosan is a product of the deacetylation of chitin, which is widely found in nature. Chitosan is insoluble in water and most organic solvents, which seriously limits both its application scope and applicable fields. However, chitosan contains active functional groups that are liable to chemical reactions; thus, chitosan derivatives can be obtained through the chemical modification of chitosan. The modification of chitosan has been an important aspect of chitosan research, showing a better solubility, pH-sensitive targeting, an increased number of delivery systems, etc. This review summarizes the modification of chitosan by acylation, carboxylation, alkylation, and quaternization in order to improve the water solubility, pH sensitivity, and the targeting of chitosan derivatives. The applications of chitosan derivatives in the antibacterial, sustained slowly release, targeting, and delivery system fields are also described. Chitosan derivatives will have a large impact and show potential in biomedicine for the development of drugs in future.