Ruthenium-Containing Block Copolymer Assemblies:Red-Light-Responsive Metallopolymers with Tunable Nanostructures for Enhanced Cellular Uptake and Anticancer Phototherapy

The use of self-assembled nanostructures consisting of red-light-responsive Ru(II)-containing block copolymers (BCPs) for anticancer phototherapy is demonstrated. Three Ru-containing BCPs with different molecular weights are synthesized. Each BCP contains a hydrophilic poly(ethylene glycol) block and an Ru-containing block. In the Ru-containing block, more than half of the side chains are coordinated with [Ru(2,2:6,2-terpyridine)(2,2-biquinoline)](2+), resulting in more than 40 wt% Ru complex in the BCPs. The Ru complex acts as both a red-light-cleavable moiety and a photoactivated prodrug. Depending on their molecular weights, the BCPs assemble into micelles, vesicles, and large compound micelles. All of the BCP assemblies are taken up by cancer cells. Red-light irradiation releases the Ru complex and generates singlet oxygen (O-1(2)) in cancer cells. The released Ru complex and O-1(2) inhibit the growth of cancer cells. Among the three BCP assemblies, the BCP micelle exhibits the most efficient cellular uptake and best anticancer performance.