Mesoporous Silica-Coated Gold Nanorods with Designable Anchor Peptides for Chemo-Photothermal Cancer Therapy

The incorporation of bioactive peptides often creates unprecedented opportunities in design of hierarchical nanocomposites. In this contribution we employed mesoporous silica-coated gold nanorods (AuNR@SiO2) as a theranostic platform for synergistic chemo-photothermal cancer therapy. Utilizing an in situ grafting–cleavage strategy, the cell penetrating TAT peptide (YGRKKRRQRRR) could be covalently grafted onto the silica surface of AuNR@SiO2 nanocomposites and in situ activated by standard cleavage treatment to afford AuNR@SiO2-TAT drug nanocarriers directly. FT-IR spectroscopies and sharp polarity changes evidenced the effectiveness of these peptide modification procedures. As expected, TAT-modified drug nanocarriers exhibited significant enhancement in intracellular uptake and acidic endolysosome internalization, as well as passive tumor accumulation. Upon triggering of the NIR irradiation, AuNR@SiO2-TAT/DOX drug aggregates displayed photothermal-controlled drug release and synergistic efficacy on inhibiting the growth of tumors in vivo. More importantly, the in situ grafting–cleavage strategy also provided a simple and versatile pathway to tether bioactive peptides on an interface to fabricate complicated nanohybrids for multipurpose biomedical applications.