Membrane Has Photoswitchable Surface Properties

By grafting a photoactive vinyl monomer to a synthetic ultrafiltration membrane, researchers at Rensselaer Polytechnic Institute in Troy, N.Y., have produced a material whose protein adsorbability can be controlled with exposure to visible and ultraviolet radiation. The material, which they describe in the June 19 issue of Angewandte Chemie International Edition, may make possible the development of photoresponsive switches that control the transport of biomolecules in lab-on-a-chip systems and of micropore filters that can be cleaned in situ without the use of chemicals.

The scientists employed a UV-induced graft polymerization technique that they developed to attach vinyl spiropyran, which changes polarity under irradiation with visible light and 254-nm radiation, to a commercially available 30-kDa polyethersulfone filter. Using bovine serum albumin as a model protein, they found that the material adsorbed 26 percent more protein under visible light, which reduced the permeation flux by 17 percent.