(458e) Thiol-Affinity Immobilization of Casein-Coated Silver Nanoparticles on Polymeric Membranes for Biofouling Control

Silver nanoparticles (AgNPs) have been widely studied for the control of biofouling on polymeric membranes due to their antimicrobial properties. However, nanoparticle leaching has posed a significant impediment against their widespread use. In this study, casein-coated AgNPs were chemically attached on CA membranes to minimize the leaching of particles.

Methods

AgNPs were attached through a procedure where the epoxide groups of polyGMA were open and attached with CYS, followed by the addition of thiol groups (from CYS) attached with AgNPs. The polymer complexes were then added to the membrane dope solution to minimize the number of post-synthesis steps. The membranes were cast via the non-solvent induced phase separation (NIPS) method, and then characterized and tested.

Results

The addition of polyGMA-CYS-AgNPs changed the cross-sectional structures by producing irregular structures and generating more small channels. XPS results verified the presence of sulfur and silver on the membranes cast with CYS and AgNPs, respectively. Dead-end and crossflow leaching studies showed little leaching of AgNPs. During BSA filtration studies, membranes containing AgNPs (M2 and M3) showed higher flux values as compared to the baseline CA membranes (M1), likely due to the presence of the NPs acting as pore formers. Lastly, membranes incorporated with AgNPs showed significant suppression of Serratia marcescens, as compared to membranes without AgNPs, indicated that the AgNPs membranes effectively suppressed the growth of S. marcescens.

Discussion

This study provided a one-step method to chemically incorporate AgNPs in the dope solution, and then cast CA/AgNPs membranes, which is favored to scale up. A quantitative method of testing antimicrobial performance of larger piece of membranes was proposed and proved to be effective.