摘要:
Near-infrared (NIR) biophotonics-based smart photon-converting systems (PCSs) have made great process in recent academic research and biomedical applications, such as optical bioimaging and phototheranostics. Owing to the versatile controllability, superb spatiotemporal resolution and minimal tissue invasiveness in practical operations, these NIR-responsive platforms provide opportunities and possible solutions to investigate the physiopathological and therapeutic aspects from cells to the organism level. In principle, the design of NIR-biophotonic PCSs is primarily based on the photophysical process and physicochemical properties of the optical materials upon NIR photoirradiation, and the mechanisms include the radiative and nonradiative transitions-mediated photon emission, heat generation as well as the cascade energy transfer. So far various optical biomaterials have been explored and used, includ ing small-molecule dyes, quantum dots (QDs), semiconducting polymers nanoparticles (SPNs), upconversion nanoparticles (UCNPs) and so on. These NIR-sensitive agents have their own photophysical performances and merits in biological sensing and therapeutic interventions. In particular, UCNPs with promising anti-Stokes shift emissive features show the potentials in deep-tissue luminescent imaging and photoactivation of cellular signaling. Besides, the NIR- absorbing materials with low-emissivity like charge-transfer nanocomplexes (CTNs) exhibit the distinctive capability of photothermal conversion, serving as superb biophotonic platforms for photoacoustic imaging (PAI) and photothermal therapy (PTT) with desirable therapeutic efficacy. In this thesis, I just focus on the development of NIR photon-converting systems based on UCNPs, cyanine dyes and CTNs for multipurpose biological applications, including liver pathological bioimaging, tumor phototheranostics, bacterial infection sensing and optogenetic regulation of insulin resistance, as shown in the following sections. I