A Dual-Layer Biomimetic Membrane with Unidirectional Liquid Transport, Intrinsic Antibacterial, and Bacteria-Blocking Properties for Ophthalmic Drops Filtration.

Microbial contamination in multidose ophthalmic drops primarily arises from bacteria surface adhesion and liquid backflow during use and storage. Traditional solutions relying on chemical preservatives or single-dose packaging face limitations concerning biocompatibility, environmental sustainability, and high cost. Therefore, the development of a bottle cap membrane that prevents backflow and bacterial contamination is crucial and highly meaningful. In this work, a series of cotton/polyurethane Janus composite membranes with unidirectional liquid transport, antibacterial, and bacteria-blocking functions were prepared by electrospinning and hot pressing technology. Remarkably, the structure of this composite membrane shows stable and excellent unidirectional liquid transport, with its one-way transport capacity (R) reaching grade 4 and its overall moisture management capacity (OMMC) reaching grade 5 (AATCC 195-2017). In addition, even after 50 times of washing, because polylysine (PL) is firmly fixed on cotton, the antibacterial rate of this composite membrane against S. aureus and E. coli still exceeds 99.9%. Moreover, depending on its micropore structure, its bacteria-blocking rate against S. aureus reached 99.4%, and its bacteria-blocking rate against E. coli also reached 76.9%. In addition to this, the composite membrane exhibits excellent biocompatibility, with a cell compatibility exceeding 75% and hemolysis below 5%. Collectively, this work provides a reliable solution to solve the problem of microbial pollution in the packaging of drug eye drops.