Visible Light-Responsive Drug Delivery Nanoparticle via Donor-Acceptor Stenhouse Adducts (DASA)

Stimuli-responsive drug release from a nanocarrier triggered by light enables the control of the amount of drug locally. Here, block copolymer micelles based on poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) as the hydrophilic block and a polymer with pendant donor-acceptor Stenhouse adducts (DASA) are used as a means to trigger the release of drugs under green light. The micelles are loaded with ellipticine to yield light-responsive nanoparticles with sizes of around 35 nm according to transmission electron microscopy (TEM) analysis. Two micelles with a drug loading content of 4.75 and 7.4 wt% are prepared, but the micelle with the higher drug loading content leads to substantial protein adsorption. The release of ellipticine from the micelle, which is monitored using the polarity-sensitive fluorescence of ellipticine, can be switched on by light and off by thermal recovery of DASA in the dark. The micelles are readily taken up by Michigan Cancer Foundation-7 breast cancer cells. Subsequent light irradiation leads to enhanced drug release inside the cell as seen by the enhanced fluorescence.