Reversible bacteria-killing and bacteria-releasing cotton fabric with anti-bacteria adhesion ability for potential sustainable protective clothing applications

Polydopamine bridging encapsulated laccase on MOF-based mixed-matrix membrane for selective dye/salt separation

Mixed-matrix membranes (MMMs) exhibit significant potential for dye/salt separation. However, overcoming the "trade-off" between permeability and selectivity, as well as membrane fouling, remains a formidable task. In this work, a biocatalytic membrane was prepared using polydopamine (PDA) as a "bridge" connecting the metal-organic framework (MOF)-based MMM and immobilized laccase. The MOF-based MMM featured an interconnected MOF anchoring on the polyvinylidene fluoride (PVDF) skeleton structure, effectively mitigating the "trade-off" phenomenon and enabling efficient separation of dyes and salts. Enzyme-MOF was in situ grown on the MOF-based MMM via coordination reactions between PDA and metal ion, effectively degrading the adhesion of organic pollutants and fouling, ensuring the long-term stable operation of the membrane. The Lac-MOF@PDA MMM exhibited excellent water permeability of 142.4 L·m-2·h-1, 100 % rejection for dye, and less than 10 % rejection for NaCl. Furthermore, the separation mechanism of Lac-MOF@PDA MMM was systematically investigated, and the results suggested a synergistic combination of rejection, adsorption and catalysis processes. This biocatalytic membrane with multiple sieving and biological catalysis is expected to pave a promising way for efficient wastewater treatment applications.

Fabrication of reversible bacteria-killing and bacteria-releasing cotton fabrics with anti-bacteria adhesion capacity for potential application in reusable medical materials

Nowadays, more and more smart antibacterial materials have been prepared to meet some specific application area, and most of these materials have complex fabrication processes or incompatible biocompatibility. In this paper, a smart monomer that can switch between the form of quaternary ammonium salt and zwitterionic betaine was prepared and grafted onto cotton fabric. This finished cotton was smart too, it had nice antibacterial performance (99.89 % for E. coli and 99.97 % for S. aureus) in the form of quaternary ammonium salt, and it could release most of the attached bacteria when transferred to the form of zwitterionic betaine in PBS, and the form of zwitterionic betaine could converse back to the state of quaternary ammonium salt in HAC. Simultaneously, it was biocompatible in the form of zwitterionic betaine form. Furthermore, this smart material had nice function reproducibility after repeated transformations. In general, the smart antibacterial cotton could switch between bacteria-killing and bacteria-releasing reversibly, and had good biocompatibility and nice reproducibility, showing a potential application in reusable medical protective materials.