A Dual-Layer Biomimetic Membrane with Unidirectional Liquid Transport, Intrinsic Antibacterial, and Bacteria-Blocking...

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.