03:18 PM Abstract No. 308 MnO2-coated biodegradable stent as pH/H2O2 responsive scaffold to modulate hypoxia for effective photodynamic therapy

Abstract

Construction a kind of MnO2-coated Ce6 PCL fiber with the ability of inhibiting tumor, further, the capability of this biodegradable stent in terms of technical feasibility and treatment effect was investigated through subcutaneous tumor model of the nude mice in situ In the present study, small molecule chlorine e6 (Ce6) was embedded in PCL fibers by Electrospinning method with (Ce6 stents) or without MnO2 (CM stents) coating on the surface of the fiber 1. The release of Ce6 from the stent was explored both in quantitative and qualitative assay. MTT assay was carried out to explore cell killing efficacy on ECA-109 cell line after incubated with the stents and confocal imaging was used to reveal the ROS generation. In nude mice tumor model, both Ce6 stent or CM stents was implanted below the tumor side and both tumor volume and weight of nude mice were recorded for up to two weeks. In order to further investigate the hypoxia ameliorating ability of MnO2-coated Ce6 stent, hypoxyprobe immunofluorescence assay was employed on tumor slices From the quantitative and qualitative results, we observed that the CM stents have a prolonged release of Ce6. MTT assay and confocal imaging exhibited that CM stents is superior to other groups both in cell killing efficacy and ROS generation. In vivo results revealed that the tumor growth was significantly inhibited after CM stents implantation and 660 nm2 laser irradiation, indicating remarkably improved therapeutic efficacy compared to various control groups. From the Hypoxyprobe immunofluorescence assay, we found obviously reduced green fluorescence (pimonidazolestained hypoxia) in the tumor slices of mice treated with CM stents in comparison with that of the control groups, which indicates the tumor hypoxia was successfully relieved. The CM stents were feasible for treatment of esophageal cancer because of its ability to prolong Ce6 releasing and relieve hypoxia environment of tumor for enhanced photodynamic therapy.