Photomodulation of Supramolecular Systems Containing Bioactive Small Molecules and Biopolymers

By Johannes Karcher

Molecular photoswitches can change their conformation upon irradiation with light and convert this molecular movement into macroscopic changes of sophisticated materials. By combining state-of-the-art azobenzenes with supramolecular low-molecular-weight gelators, based on cyclic dipeptides, photomodulation of hydrogels was achieved. Photochromic amino acids with structures related to the natural L-phenylalanine were an essential element. The supramolecular hydrogels are multi-responsive towards pH, ions, temperature, and, in particular, light. Hereby the gelator F2-PAP-DKP-Lys can be turned into a sol upon irradiation with green light and within this transition a drug, for example an antibiotic, was released. The further improved supergelator Cl4-PAP-DKP-Lys2 is reversibly switchable with red and violet light in the range of 0.2-0.5 % in an isotonic Ringer's solution. At a concentration of 1 %, the hydrogel consisting of Cl4-PAP-DKP-Lys2 remains stable in a boiling water bath. Thus, we envision that the enhanced stability of the supramolecular assembly of Cl4-PAP-DKP-Lys2 and orthogonal biocompatibility of F2-PAP-DKP-Lys, could enable further applications, spanning from regenerative medicine to electronic devices, besides our future vision towards photopharmacology.

• Format: Paperback
• Language: English
• ISBN: 3832550992
• ISBN13: 9783832550998
• Release Date: April 2020
• Publisher: Logos Verlag Berlin
• Length: 322 Pages