The DNA adsorption properties of poly-L-lysine-immobilized poly(2-hydroxyethyl methacrylate) (pHEMA) membrane were investigated. The pHEMA membrane was prepared by UV-initiated photopolymerization and activated with epichlorohydrin. Poly-L-lysine was then immobilized on the activated pHEMA membrane by covalent bonding, via a direct chemical reaction between the amino group of poly-L-lysine and the epoxy group of pHEMA. The poly-L-lysine content of the membrane was determined as 1537 mg m(-2). The poly-L-lysine-immobilized membrane was utilized as an adsorbent in DNA adsorption experiments. The maximum adsorption of DNA on the poly-L-lysine-immobilized pHEMA membrane was observed at 4 degreesC from phosphate-buffered salt solution (pH 7.4, 0.1 M; NaCl 0.5 M) containing different amounts of DNA. The non-specific adsorption of DNA on the plain pHEMA membrane was low (about 263 mg m(-2)). Higher DNA adsorption values (up to 5849 mg m(-2)) were obtained in which the poly-L-lysine-immobilized pHEMA membrane was used. (C) 2003 Society of Chemical Industry.