Bacteriorhodopsin (bR) is a photochromic protein in the two-dimensional crystalline membrane—purple membrane, which is astonishingly stable towards chemical and thermal degradation.However, the lifetime of the M state in wild-type bR was considered to be too short for optical applications.The lifetime of the M state could be prolonged obviously when a crown ether complex was used as the chemical additive.With this chemically modified bR-PVA film as recording medium, micro images were stored on the film with higher contrast ratio and longer decay time in our self-made optical storage system.To our knowledge, it is the first time domestically to use the chemically modified bR film in the field of optical information storage based on the ground state and the M state.

Key words: bacteriorhodopsin, chemical modification, M state, optical information storage