Zwitterionic (ZI) membranes are well known for their super-low fouling behaviour during protein separation with high resolution. Zwitterionic ultrafilter membrane (ZI-UFM) with controllable acidic-alkaline charge density and pore-size was prepared by the sol gel followed by formal cross-linking. Synthesis of ZI silica precursor (SP) has been reported by epoxide ring-opening reaction by (3-glycidoxy propyl) trimethoxysilane and 1, 4 butane sultone. ZI-UFM showed 70 kD molecular cut-off and 1.3 x 10(-5) l m(-2) h(-1) bar(-1) water permeability. Furthermore, with high dynamic i.e. practical protein capture capacity, acidic-alkaline charged and dimensional stable nature, ZI-UFM was suitable for proteins separation with high through-put. High separation factor (SF) values for BSA and LYS at pH: 6.1, confirmed rapid and highly selective protein electro-separation using ZI-UFM. Because of ZI nature of membranes showed antifouling properties for proteins, and switchable behaviour at varied pH due to presence of acidic and basic functional groups. (c) 2013 Elsevier B.V. All rights reserved.