As a series of plasma-assisted immobilization of bio-molecule for bio application, 12-mer oligo-DNA was immobilized on the surface of LDPE-VEMAC sheet, which was prepared by plasma-assisted method and possessed a lot of carboxyl groups on the surface. A larger amount of oligo-DNA could be immobilized by the present technique compared with other methods reported. The sheet immobilizing oligo-DNA detected the complementary oligo-DNA and was reusable for several times at least under present experimental condition. This method would be useful for the fabrication of the analytical instrument such as DNA chip, protein chip and affinity chromatography. (c) 2006 Elsevier B.V All rights reserved.