Effect of IR780-loaded silica-coated gold nanorods for photodynamic therapy of cancer

Photodynamic therapy (PDT) is a new approach to cancer treatment that activates a photosensitizer (PS), a light-sensitive chemical, with a specific wavelength of light. PDT is a promising new method, however, the efficacy of PDT is still limited because of a low accumulation of PS in the target cell and limited penetration of light to the deeper tissue which prevents the killing of all cancer cells. As a result, cancer recurrence is inevitable. Gold nanostructures are good biocompatible carriers of PS. Increasing PS accumulation on the target site leads to the effective destruction of cancer cells, but different cancer cells require different approaches. One of the resistant colon cancer types is HCT116 and it needs a better approach to treatment. Gold nanorods (GNRs) have a high absorption spectrum at near-infrared (NIR) as compared with other types of Gold nanoparticles (GNPs). However, GNRs are limited for the loading amount of PS and they tend to aggregate within cells. To overcome these limitations, we will develop mesoporous silica-coated GNRs (GNRs@SiO2) for effective PS loading in this study. To test this hypothesis, we aim to test the PDT efficacy of IR780, as a PS, loaded GNRs@SiO2, (GNRs@SiO2@IR780) and GNRs@SiO2@PEG (GNRs@SiO2@IR780@PEG). This investigation of PDT with GNRs@SiO2@IR780 and GNRs@SiO2@IR780@PEG will cause a dramatic decrease in colon cancer volume as compared with GNRs@SiO2 alone and GNRs@SiO2@PEG alone. Keywords: Photodynamic Therapy, Colon Cancer Cells, Gold Nanorods, Silica Coating, IR780.