Engineering principles of nanomedicine in gas-mediated enhanced anti-tumor photodynamic therapy

Abstract

Photodynamic therapy (PDT), a highly selective treatment with low drug resistance and invasiveness, has brought new hope in tumor treatmen but severely compromised by distribution of photosensitizers and immunosuppressive tumor microenvironment. Inspried by the synergetic function of gas and PDT, gas therapy improves the intratumoral distribution of photosensitizers and modulates the immune response, thereby rasing a promising scope for addressing current bottlenecks of PDT. In this review, we summarize the tumor-suppressing pathways of different gases and emphasis on the cascade effects of reactive oxygen species (ROS) and gases. Furthermore, we elaborate on the design principles of spatiotemporally controlled gas delivery systems. Finally, we summarize the challenges of gas-assisted PDT and issues that require further research.