pH Responsive Hybrid Zwitterionomer for Protein Separation: Smart Nanostructured Adsorbent

Nanostructured zwitterionic (ZI) hybrid materials have great potential for protein separation/purification because of dual functional groups (acidic and basic) grafted on polymer matrix. Herein, we are reporting a versatile method for preparation of ZI monomer (N,N-dimethyl-N-methacryloyloxyethyl-N-(3-sulfopropyl) ammonium, DMMSA) by a simple epoxide ring opening reaction. The prepared adsorbent was highly stable and showed pH responsive protein adsorption (bovine serum albumin (BSA) and lysozyme (LYS) as the hmodel case). Adsorption kinetics revealed second order kinetics (Freundlich isotherm) and favorable adsorption of BSA and LYS. Separation of proteins was effectively achieved by isoelectric focusing, and the ZI nature of the adsorbent plays an important role. Moreover, more than 90% desorption of protein by changing the external environment with negligible loss (1-2%) in adsorption capacity indicates the practical applicability of the process.