Cucurbit[7]uril-Capped Hybrid Conjugated Oligomer-Gold Nanoparticles for Combined Photodynamic-Photothermal Therapy and Cellular Imaging

Herein, hybrid nanoparticles composed of a red-emitting conjugated oligomer (COL) and gold nanoparticles (Au-NPs) were prepared through a one-pot synthetic method in which the oligomer acts as a reducing agent as well as a matrix to wrap the newly formed Au nanoparticles. These hybrid nanoparticles (COL-Au-NPs) exhibited photodynamic and photothermal activity against both Gram-positive and Gram-negative bacterial strains. They were also proven to possess high photostability and thermal reversibility. Dark cytotoxicity of COL-Au-NPs toward pathogens and mammalian breast cancer cells (MCF-7) reduced significantly upon complexation with cucurbit[7]uril while preserving their light-induced cytotoxic activity when irradiated with a 915 nm laser for photothermal therapy and white light for photodynamic therapy, respectively. Furthermore, these nanoparticles have cellular imaging capability because of their intrinsic fluorescence characteristics and can be used in image-guided therapy.