Photoswitchable Nanofiber-Nanoparticle Transformation in a Cosolvent Gel-Sol System

Photoresponsive gel-solution (gel-sol) transi-tions endow supramolecular peptide gels with a powerful ability to release on-demand cargos in a controllable manner. Photophysical peptide gelators were reported for this purpose, but their gel-sol transitions were not sufficient. An anthracene-peptide conjugate gelator, which enables photo-chemically regulated gel-sol switches, has not been reported. In this work, we report an anthracene-peptide gelator Nap-Phe-Phe-Lys(anthracene)-OH (Mo-Nap-An) which, under 365 nm laser irradiation, is efficiently converted to its dimer Di-Nap-An, accompanied by a gel-sol transition (or nanofiber- nanoparticle transformation from the microperspective) in a tetrahydrofuran/water cosolvent (THF/H2O = 40/60, v/v). Reversely, upon 254 nm light irradiation, Di-Nap-An is converted to Mo-Nap-An, switching the solution to gel. This work provides a facile bottom-up strategy of smart photogelator design for efficient and photochemical control of gel properties.

Automated summary

In this work, an anthracene-peptide gelator with photochemically regulated gel-sol switches is reported. The gel-sol transition can be achieved through laser irradiation at different wavelengths, providing a controllable method to manipulate the gel properties.