Chitosan-based nanofibrous membranes for antibacterial filter applications.

Nanofibrous membranes have drawn considerable interest for filtration applications due to their ability to withstand high fluid flux while removing micro- and nano-sized particulates from solution. The desire to introduce an antibacterial function into water filter applications presents a challenge to widespread application of fibrous membranes because the addition of chemicals or biocides may produce harmful byproducts downstream. Here, we report the development of chitosan-polycaprolactone (PCL) nanofibrous membranes to utilize the natural antibacterial property of chitosan for antibacterial water filtration. Chitosan-PCL fibers with diameters of 200-400 nm and chitosan contents of 25, 50 and 75 wt% were prepared by electrospinning. In a series of bacterial challenge tests, chitosan-PCL fibrous membranes significantly reduced Staphylococcus aureus adhesion compared to PCL fibrous membranes. In water permeability and particulate size removal tests, fibrous membranes with 25% chitosan supported the greatest water flux (∼7000 L/h/m(2)) with 100% removal of 300-nm particulates, while maintaining the membrane integrity. This study demonstrates the potential of chitosan-PCL nanofibrous membranes as pre-filters for water filtration systems that demonstrate combinatorial filtration and intrinsic antibacterial advantages.