Figure 4

PEG-PCL micelles co-loaded with PhA as the singlet oxygen generator and CAR as the singlet oxygen scavenger for targeted PDT. (A) Chemical structures of PEG-b-PCL copolymer, CAR, and PhA. (B) Co-incorporation of PhA and CAR into PEG-PCL micelle. (C) Schematic presentation of photodynamic cancer therapy using PhA/CAR micelles: i. intravenous administration of drug-loaded micelles; ii. during blood circulation, PhA/CAR micelles is expected to be safe with minimal photodamage to non-target tissues induced by CAR-mediated singlet oxygen scavenging; iii. when the micelles were internalized by cancer cells, PhA and CAR molecules are released from the micelles and then become spatially isolated, resulting in PhA-induced singlet oxygen production and photokilling activity; iv. tumor site restored to health after PDT. Reproduced with permission from: [76].