Preparation Of Bacteria-mediated Photosensitizers And Their Photodynamic Targeted Anti-tumor Effects

The nontoxic photosensitizers(PS)generate highly cytotoxic reactive oxygen species to eliminate tumor cells when exposed to light.However,PS molecules have almost no obvious targeting to tumor lead to lose efficient of anticancer activity and greatly reduces the PS in the value of clinical application.Therefore,loading photosensitizer onto tumor-targeting vectors can greatly improve the efficacy of photodynamic therapy.In our study,we used a novel drug delivery vehicle.According to the previous reports,many types of bacteria could invade and colonize solid tumors,and they could suppress and eliminate tumors.On this basis,we chose a highly biocompatibility of facultative anaerobic bacteria Escherichia coli(E.coli DH5?)used as a carrier of the PS.In vivo experiment proved that Mice had an excellent tolerance to E.coli DH5?,when the dosage of intravenous up to 108 CFU/mouse,all mice still healthy growth in the next one month.Some types of PSs can attach to bacteria.In this study,the anti-tumor therapeutic efficacy of ZnPc-type(Pc5)PSs were synthesized,and E.coli DH5? was used as a carrier to study the ability of Pcs to treat cancer.We observed each single E.coli cell could carry Pc5 up to 13.05×105 molecules?leading to high cytotoxicity to cancer cells,such as MCF-7 and 4T1,both in vitro and in vivo.Moreover,this combination(E.coli@Pc5)had great biocompatibility and had no obvious toxicity to normal organs of mice.This photodynamic therapy mediated by tumor-targeting could be a promising approach to treat cancer.