Azobenzene Photoswitch for Isomerization-Dependent Cancer Therapy via Azo-Combretastatin A4 and Phototrexate.

The adverse effects of chemotherapeutic drugs to healthy organs/cells greatly limit their clinical efficacy and patient compliance. The unique behavior of azobenzene photoswitch offers a remarkable tool to address the side effects of chemotherapeutic drugs. The azobenzene moiety has been integrated within some chemotherapeutic drugs to realize photo-triggered activation of drug cytotoxicity. However, the clinical translation of these agents has been facing a few barriers. In this short review, we present our viewpoints on potential solutions to address the following challenges associated with azobenzene-based photoswitchable chemotherapeutic drugs, including poor tissue penetration of light, hypoxia-induced drug degradation in solid tumor and the autonomous cis-trans relaxation.