Photoresponsive systems for controlled drug release, extracellular matrix fabrication for tissue engineering emerged in the recent years due to their fine spatiotemporal control and non-invasiveness. Yet, most of them require phototoxic blue/UV light with poor tissue penetration. This issue will be overcome via triplet-triplet annihilation upconversion process that enables in situ blue/UV light generation upon safe red light-excitation of greater penetration depth. Thus, the process will allow to perform phototriggered drug release deeper in tissue with less phototoxicity. The similar issue in tissue engineering will be addressed by using a two-component system (containing red light-absorbing sensitizer and co-initiator) capable to create radicals upon safe red light-excitation. Hence, the red light will initiate free radical polymerization of an injectable polymer-cells suspension to form cell-laden hydrogel in situ deeper in tissue in minimally invasive and well controlled manner.

2023

2027