Photo-responsive doxorubicin delivery: Nanogel systems based on azobenzene and host-guest interactions enhanced by squeezing action

Conventional chemotherapy methods impact both normal and cancerous cells; therefore, it is essential to design drug delivery systems to reduce undesired drug effects. Nano-scaled drug delivery systems have the advantage of high retention time in blood as well as the capability of conventional penetration into tissue barriers. In this study, light-sensitive biocompatible nanogels with a core-shell structure have been synthesized and characterized as drug delivery system loaded with doxorubicin (DOX). These smart nanogels possess a hydrophobic core, coated with hydrophilic starch polymeric chains, which are modified with β-cyclodextrin (βCD). The core-shell formation is based on host-guest interaction between azobenzene rings as photochromic agents and βCD hydrophobic cavities. The mechanism of drug release is based on the cis-trans isomerization of azobenzene molecules upon light irradiation and dissociation of crore-shell entities. Due to this isomerization, shrinkage of hydrophobic core and removal of shell occurred simultaneously, which assist the drug release. In conclusion, a nanoscale carrier was designed with sustainable drug release under light irradiation as an external and non-contact stimulus. The synthesized nanogels were characterized by FT-IR, 1H NMR, SEM, DLS, and TEM. In addition, the MTT assay proposed that the viability of the A-431 cells has plunged in the presence irradiated nanogels, also histological studies were performed to evaluate the efficacy of the prepared nanogels in cancerous tissues.