Optically controlled ligand delivery, 1. Synthesis of water-soluble copolymers containing photocleavable bonds

To verify the possibility of developing a ligand delivery system which is controlled by light pulses, we synthesized copolymers of N-(2-hydroxypropyl)methacrylamide ( 1 ) containing sidechains terminated in ligands (Boc-Gly, fluorescein, tetramethylrhodamine) bound via photocleavable 2-nitrobenzyl groups. Copolymers in solution were exposed to light of wavelength ≈? 360 nm which resulted in release of the bound ligands. Depending on the experimental conditions (type of solvent, presence of oxygen) changes in the structure of released fluorochromes were observed (photofading effect). These effects were quantified by determining the binding constants of released modified fluorochromes with monoclonal antifluorescyl anti-bodies.