Commercially available synthetic resins are durableand inexpensive. However, it is difficult to immobilize proteins on most commercially available synthetic resin plates, such as polypropylene (PP), polyethylene, polyurethane, and polyvinyl chloride, because these plates are durable and inactive. In this study, we attempted to immobilize bovine serum albumin (BSA) and lysozyme (LZM) on commercially available synthetic resin plates using supercritical carbon dioxide (ScCO2). Immobilization was attained by incubating a solution containing synthetic resin plates and proteins under ScCO2. BSA and LZM were successfully immobilized using this method; however, the amount of immobilized protein varied depending on the kind of protein and synthetic resin plate used as well as immobilization condition. The maximum amount of BSA immobilized on PP was 102 mu g/g-resin. Although BSA conformation did not change after 24-h incubation under ScCO2 at 40 degrees C and 8 MPa, it efficiently immobilized on PP plates. The protein immobilization mechanism by ScCO2 could be speculated that synthetic resin plates were swollen and proteins were diffused into synthetic resin. Then, proteins could be entrapped when synthetic resins were deflated by decompression. Our results suggest that use of ScCO2 may lead to new and improved methods for protein immobilization and surface modification of synthetic resins. (C) 2015 Elsevier B.V. All rights reserved.