Light-responsive nanomedicine for biophotonic imaging and targeted therapy.

Nanoparticles (NPs) play a key role in nanomedicine in multimodal imaging, drug delivery and targeted therapy of human diseases. Consequently, due to the attractive properties of NPs including high stability, high payload, multifunctionality, design flexibility, and efficient delivery to target tissues, nanomedicine employs various types of NPs to enhance targeting and treatment efficacy. In this review, we primarily focus on light-responsive materials, such as fluorophores, photosensitizers, semiconducting polymers, carbon structures, gold particles, quantum dots, and upconversion crystals, for their biomedical applications. Armed with these nanomaterials, NPs represent a growing potential in biophotonic imaging (luminescence, photoacoustic, surface enhanced Raman scattering, and optical coherence tomography) as well as targeted therapy (photodynamic therapy, photothermal therapy, and light-responsive drug release).