Background: A green emission up-conversion carbon-based polymer dots (CPDs) owned excellent photophysical properties and good solubility. Most photosensitizers (PS) are hydrophobic which limits their application in biomedicine. Herein we synthesized and integrated green emitting CPDs into pyropheophorbide-α (PPa) to improve the overall properties of the PS.
Material and methods: The nano-agent was incorporated through amide condensation and electrostatic interaction. The structure, size and morphology of the prepared conjugates were determined by FTIR, TEM, DLS, TGA, 1HNMR, Uv-vis, and fluorescence spectrophotometry. The dark and light toxicity, as well as cellular uptake, was also monitored on the human esophageal cancer cell line (Eca-109).
Results: Our results illustrate that the conjugation improved the PDT efficacy by increasing the ROS generation. The nano-hybrids showed pH sensitivity as well as good hemocompatibility as the hemolysis ratio was decreased when treated with nano-conjugates. PPa-CPD1 and PPa-CPD2 had the pH response and stronger ability to absorb light and produce fluorescence in an acidic environment (pH 4.0 and pH 5.0) The synthesized nano-hybrids doesnot affect the clotting time. An increase in the absorbance wavelengths was observed. The results of MTT assay showed that dark toxicity was reduced after conjugation.
Conclusion: This CPDs-based drug enhanced tumor-inhibition efficiency as well as low dark toxicity in vitro, showing significant application potential for PDT-based treatment.
Keywords: Carbon based polymer dots (CPDs); Photodynamic therapy; Photosensitizers; Up-conversion photoluminescence; pH sensitivity.
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