Photo-controllable molecular hydrogels for drug delivery.

A photocleavable nitrobenzyl ester group was introduced in the backbone of self-assembling peptides using standard Fmoc-peptide systhesis. The nitrobenzyl ester group could be used as a cleavable linker to connect a gelator and a hydrophilic group. Photo-irradiation would lead to the generation of the molecular gelator and the formation of a molecular hydrogel. The nitrobenzyl ester group could also be used as one part of hydrophobic capping group for short peptides to produce molecular hydrogelators. In this case, photo-irradiation would lead to the release of hydrophobic anti-imflammatory drug of Naproxen and the gel-sol phase transition. The application of photocleavable group in molecular self-assembly would lead to photo-controllable self-assembly materials for controlled drug release, tissue engineering, and regenerative medicine.