Biomaterial immobilization on polyurethane films by XeCl excimer laser processing

The surface chemical modification of polyurethane (PU) films was performed by an UV laser-induced chemical reaction in a polysaccharide solution. This process may be applicable as hydrophilic packaging of implantable medical devices and in vivo sensors. When a PU film in contact with an aqueous algi nic acid (AAC) solution was irradiated with a XeCl laser? the PU film turne d hydrophilic. Contact angles of water on the film were reduced from 110 de grees to 60 degrees. Since light absorption of the AAC solution at 308 nm w as negligibly small, reactive sites were generated solely on the PU surface . There, AAC could be immobilized by chemical bonds thus allowing for a nan ometer-scaled grafting of this biomolecule. The mechanism was investigated by surface analyses with Fourier-transform infrared spectroscopy (FT-IR), d ye staining, ultraviolet-visible (UV-VIS) spectroscopy, and scanning electr on microscopy (SEM) techniques. A one-photon photochemical process could be identified.