Dual-acceptor engineering of donor-acceptor type molecules for all-round boosting anti-tumor phototherapy

The integration of robust photon-absorption capacity, high reactive oxygen species yields and photothermal conversion efficiency (PCE) into a single phototheranostic nano-agents is ideal but rarely reported. This study employed a dual-acceptor engineering strategy utilizing isoindigo and selenium-substituted [1,2,5]thiadiazolo[3,4-c]pyridine to augment the molar extinction coefficient and spin-orbit coupling effect, respectively, resulting in a substantial enhancement of photon-absorption ability and non-radiative decay energy-release process of donor-acceptor type phototherapy molecules. As the optimal phototherapy agent, IID-PSe exhibited a high molar extinction coefficient two times that of photosensitizer, excellent ¹O₂ yield (15%) and PCE (34%), exhibiting great potential for phototherapy. After encapsulating with DSPE-PEG2000, IID-PSe NPs showed excellent anti-tumor phototherapy ability both in vitro and in vivo. This work provides an effective idea for designing high-performance photosensitive dyes with high efficiency phototherapy output.