Molecular engineering of tetraphenylethene/thiophene-based donor/ π-bridge units to enhance the AIE effect and boost the oxygen-independent type-I ROS generation

초록

The development of oxygen -independent type -I photosensitizers (PSs) with aggregation -induced emission (AIE) characteristics is highly in demand to treat hypoxic tumors but remains challenging. In this contribution, three anion -n + AIE-PSs (TPEMA-SI, TPEMA-SSI, and TPETPA-SSI) with strong donor -n -acceptor (D -n -A) configurations were facially synthesized by modulating donor/ pi-bridge units. The strength of D -n -A configurations as well as the AIE-effect that collectively promotes the intersystem crossing (ISC) for boosting the type -I ROS could be enhanced significantly by tuning the electronic characters of D/n-bridge units. The anion -n + AIE-PSs, with strong D -n -A configurations and heavy atom effect, produced a mixture of type -I as well as type -II ROS. Among them, TPETPA-SSI, with strong D -n -A configuration as well as greater AIE-effect, demonstrated superior type -I ROS generation efficiency. The biocompatible nanoparticles of anion -n + AIE-PSs (AIE-PSs NPs) were fabricated after being encapsulated into an amphiphilic polymer (DSPE-PEG). The TPETPA-SSI NPs with superior ROS generation efficiency, demonstrate efficient PDT effects towards MCF-7 and U87MG cancer cells in both normoxia and hypoxia environments. This study provides insights into the design and development of type -I AIE-PSs by enhancing the strength of D- pi - A configurations and the AIE effect

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