The synthesis and characterization of styrene-based polymers and copolymers containing pendant tetra(ethylene glycol) and phosphorylcholine groups is reported. These polymers are obtained via radical polymerization reactions using alpha,alpha'-azobis(isobutyronitrile) as the initiator, and are developed as protective biocompatible coatings for implantable biosensors. Cell morphology studies show that none of the synthesized polymers and copolymers are toxic, and that the rate of cell growth can be tuned by changing the monomer composition. The presence of tetra(ethylene glycol) groups in the coatings lowers the protein adsorption, thereby influencing the rate of cell growth. An equally profound effect is observed when a low percentage of phosphorylcholine groups is present in the polymers. (C) 2001 John Wiley & Sons, Inc.