Chemo-photothermal therapy of cancer cells using gold nanocages covered by smart polymers for controlled release

Light-based therapies including photothermal therapy have been validated clinically for curative and palliative treatment of solid tumors. However, these monotherapies can suffer from incomplete tumor killing and have not displaced existing ablative modalities. The combination of photothermal therapy and chemotherapy, when carefully planned, has been shown to be an effective cancer treatment option clinically and preclinically [1]. Photosensitive caged compounds have enhanced our ability to address the complexity of biological systems by generating effectors with remarkable spatial/temporal resolutions. The caging effect is typically removed by photolysis with ultraviolet light to liberate the bioactive species. The ultraviolet light may cause damage to biological samples and is suitable only for in vitro studies because of its quick attenuation in tissue. Here we address these issues by developing a platform based on the photothermal effect of gold nanocages were prepared by coating timuli-responsive thiol-end capped ABC triblock copolymer. Gold nanocages represent a class of nanostructures with hollow interiors and porous walls [2]. They can have strong absorption (for the photothermal effect) in the near-infrared while maintaining a compact size. Furthermore, the anti-cancer drug doxorubicin (DOX) was conjugated onto the gold nanorod-cored micelles (GNR@polymer) by electrostatic force. When the surface of a gold nanocage is covered with a smart polymer, the pre-loaded effector can be released in a controllable fashion using a near-infrared laser.