Microorganism pollution induced by pathogens has become a serious concern in recent years. In response, research on antibacterial N-halamines has made impressive progress in developing ways to combat this pollution. While synthetic polymer-based N-halamines have been widely developed and in some cases even commercialized, N-halamines based on naturally occurring polymers remain underexplored. In this contribution, we report for the first time on a strategy for developing sesbania gum (SG)-based polymeric N-halamines by a four-step approach Using SG as the initial polymer, we obtained SG-based polymeric N-halamines (abbreviated as cSG-PAN nanofibers) via a step-by-step controllable synthesis process. With the assistance of advanced techniques, the as-synthesized cSG-PAN nanofibers were systematically characterized in terms of their chemical composition and morphology. In a series of antibacterial and cytotoxicity evaluations, the as-obtained cSG-PAN nanofibers displayed good antibacterial activity against Escherichia coli and Staphylococcus aureus, as well as low cytotoxicity towards A549 cells. We believe this study offers a guide for developing naturally occurring polymer-based antibacterial N-halamines that have great potential for antibacterial applications.
Pesticides are of great significance in ensuring food yield. However, the extensive use of pesticides has led to severe environmental pollution and significant economic losses. Chitosan-based pesticide delivery systems potentially present a favorable approach to enhance pesticide using efficiency. Herein, we disclose a facile strategy to construct chitosan-based supramolecular hydrogels (LP@CTAB-QCS) from eco-friendly quaternary ammonium chitosan, cost-effective quaternary ammonium surfactant cetyltrimethylammonium bromide (CTAB), and laponite (LP) clay via synergistic electrostatic and multiple hydrogen bond interactions. These hydrogels could efficiently encapsulate pesticides like naphthalene acetic acid and gibberellin, achieving a loading efficiency of 4.77% and a sustained release rate of over 80% within 28 h, thereby promoting the growth of Chinese cabbage (a nutritious common vegetable) and alfalfa (a high-quality forage grass in China’s Inner Mongolia Autonomous Region). More importantly, the gelation of CTAB not only preserves its antifungal activity but also enhances its biocompatibility. The hydrogels exhibited excellent fungicidal efficacy against Dioscorea batatas (a major threat to Dioscoreaceae crops), Setosphaeria turcica (a key pathogen of maize), and Botrytis cinerea (a key pathogen of gray mold disease), both severely impacting agricultural development, particularly staple crop production. The inhibition rates reach over 97%, 86%, and 91%, respectively, while causing no damage to the tested cell lines (Vero, 293T, and L929). This work might provide a promising and feasible route for sustainable agriculture.
The emergence of antibiotic-resistant “superbugs” in recent decades has led to widespread illness and death and is a major ongoing public health issue. Since traditional antimicrobials and antibiotics are in many cases showing limited or no effectiveness in fighting some emerging pathogens, there is an urgent need to develop and explore novel antibacterial agents that are both powerful and reliable. Combining two or more antibiotics or antimicrobials has become a hot topic in antibacterial research. In this contribution, we report on using a simple electrospinning technique to create an N-halamine/graphene oxide-modified polymer membrane with excellent antibacterial activity. With the assistance of advanced techniques, the as-obtained membrane was characterized in terms of its chemical composition, morphology, size, and the presence of active chlorine. Its antibacterial properties were tested with Escherichia coli (E. coli) as the model bacteria, using the colony-counting method. Interestingly, the final N-halamine/graphene oxide-based antibacterial fibrous membrane inactivated E. coli both on contact and by releasing active chlorine. We believe that the synergistic antimicrobial action of our as-fabricated fibrous membrane should have great potential for utilization in water disinfection, air purification, medical and healthcare products, textile products, and other antibacterial-associated fields.
Zeolitic imidazolate framework-8 (ZIF-8) was evenly loaded on the surface of TiO2 doped with KI, using a solvent synthesis method, in order to produce a ZIF-8@TiO2 (KI) adsorption photocatalyst with good adsorption and photocatalytic properties. The samples were characterized by XRD, SEM, EDX, XPS, BET and UV-Vis. The photocatalytic efficiency of the material was obtained by photocatalytic tests. The results indicate that the doping with I inhibited the grain growth and reduced the crystallite size of TiO2, reduced the band gap width and improved the utilization rate for light. TiO2 (KI) was a single crystal of anatase titanium dioxide. The combination of ZIF-8 and TiO2 (KI) improved the specific surface area and increased the reaction site. The ZIF-8@TiO2 (KI) for Congo red was investigated to validate its photocatalytic performance. The optimal concentration of Congo red solution was 30 mg/L, and the amount of catalyst was proportional to the degradation efficiency. The degradation efficiency of ZIF-8@TiO2 (5%KI) was 76.42%, after being recycled four times.