Synthesis of Silver-Based Plasmas by Plant Extracts for In Vitro PTT/PDT/CT Synergistic Antitumor Therapy

In this study, biosynthetic Ag@AgCl plasma is used as a photosensitizer for the first time to construct a photothermal/photodynamic/chemotherapy and pH-responsive synergistic antitumor nanomedicine delivery system CS-Ag@AgCl/C. The Ag@AgCl and AgNPs synthesized by the extracts of alpine banana, Citrus reticulata, and Citrus sinensis are characterized. The Ag@AgCl NPs synthesized with banana extract have a regular crystal shape and a granular size of 12 nm, and they are more stable than AgNPs synthesized with the other two extracts. In addition, Ag@AgCl plasma used as a photosensitizer can reduce the dependence of CS-Ag@AgCl/C on oxygen in the photodynamic process. After coating with chitosan, though the photothermal conversion efficiency of CS-Ag@AgCl/C decreases from 44.06% to 29.51%, the pH response character of it increases, and the pH response plays an important role in drug release experiments. Under an acidic environment of pH = 5.0 phosphate-buffered saline buffer, the drug release rate of the samples increases significantly. In the synergistic antitumor experiment, the cell survival rate increases from 36.83% to 78.69% after chitosan-coated Ag@AgCl/C NPs. When CS-Ag@AgCl/C-DOX+808 nm is co-cultured with HeLa cells, the cell survival rate is only 14.89%, which indicates that the constructed plasma drug delivery system has excellent photothermal/photodynamic/chemotherapy combined treatment capability.