Near-infrared light-triggered theranostics for tumor-specific enhanced multimodal imaging and photothermal therapy

The major challenge in current clinic contrast agents (CAs) and chemotherapy is the poor tumor selectivity and response. Based on the self-quench property of IR820 at high concentrations, and different contrast effect ability of Gd-DOTA between inner and outer of liposome, we developed "bomb-like" light-triggered CAs (LTCAs) for enhanced CT/MRI/FI multimodal imaging, which can improve the signal-to-noise ratio of tumor tissue specifically. IR820, Iohexol and Gd-chelates were firstly encapsulated into the thermal-sensitive nanocarrier with a high concentration. This will result in protection and fluorescence quenching. Then, the release of CAs was triggered by near-infrared (NIR) light laser irradiation, which will lead to fluorescence and MRI activation and enable imaging of inflammation. In vitro and in vivo experiments demonstrated that LTCAs with 808 nm laser irradiation have shorter T1 relaxation time in MRI and stronger intensity in FI compared to those without irradiation. Additionally, due to the high photothermal conversion efficiency of IR820, the injection of LTCAs was demonstrated to completely inhibit C6 tumor growth in nude mice up to 17 days after NIR laser irradiation. The results indicate that the LTCAs can serve as a promising platform for NIR-activated multimodal imaging and photothermal therapy.

Near-Infrared Light Induced Phase Transition of Biodegradable Composites for On-Demand Healing and Drug Release

Light responsive materials play an important role in many biomedical applications. Despite the great potential, commonly available systems are limited by their toxicity and lack of biodegradability. Here, an efficient light triggered system from safe, biodegradable star-poly(ethylene glycol) (star-PEG) and poly(ε-caprolactone) (PCL) with varying melting points controlled by the length of the CL segments is described. When incorporated with gold nanoshells (GNS) and exposed to near-infrared (NIR) irradiation, matrices temporarily disengage, thus allowing efficient on-demand healing and drug release. The responsiveness of this system to light, with its tailorable physical and healing properties, biocompatibility, biodegradability, and the capability to incorporate drugs and on-demand drug release are all desirable traits for numerous clinical applications.