Platinum(II) Drug-Loaded Gold Nanoshells for Chemo-Photothermal Therapy in Colorectal Cancer

In the present study, we utilize a poly­[2-(N,N-dimethylamino)­ethyl methacrylate]-poly­(ε-caprolactone) (PDMA-PCL) micellar template-based gold nanoshell as a nanocarrier of a platinum-based chemotherapeutic drug, dichloro­(1,2-diaminocyclohexane)­platinum­(II) (DACHPt). The gold nanoshells not only function as a drug delivery platform but also provide a remarkable photothermal effect, resulting in synergistically combined chemo-photothermal therapy. With the positively charged outstretched hydrophilic PDMA segments, chloroauric anions are attracted to the PDMA-PCL micellar surface and reduced to gold atoms in situ, forming small seeds that nucleate the subsequent growth of gold nanoshells. The DACHPt-loaded gold nanoshells possess strong absorption in the near-infrared (NIR) region and outstanding photothermal conversion effect; thus, they can promote a temperature increase that is sufficient to ablate tumor cells under NIR laser irradiation at a moderate power density (1 W/cm2). Furthermore, by exploiting the synergistic effects of platinum-based chemotherapy and photothermal therapy, the DACHPt-loaded gold nanoshells exhibited a profound inhibition of tumor growth compared to chemotherapy or photothermal therapy alone. Therefore, the platinum­(II)-loaded gold nanoshells that we proposed herein may be a potential alternative for efficient curative therapy for colorectal cancer.