Size-based protein separations in poly(ethylene glycol)-derivatized gold nanotubule membranes

An electroless plating method was used to deposit Au nanotubules within the pores of track-etched polycarbonate template membranes. The effect of nanotubule inside diameter on rate and selectivity of protein transport was investigated for three proteins: lysozyme (Lys), bovine serum albumin (BSA), and beta-lactoglobulin A. Transport selectivity increased as the inside diameter of the nanotubules within the membrane decreased, and selectivity coefficients in excess of 20 were observed for the separation of Lys from BSA. Protein adsorption, and hence membrane fouling, was eliminated by chemisorbing a poly(ethylene glycol) thiol to the Au nanotubule membranes.