pH/NIR-responsive nanocarriers based on mesoporous polydopamine encapsulated gold nanorods for drug delivery and thermo-chemotherapy

Gold nanorods (AuNRs) have potential application value in the field of cancer therapy. However, the poor stability, high dark toxicity, insufficient drug-carrying capacity and photothermal conversion efficiency have limited its practical applications. In this study, we encapsulated AuNRs in mesoporous polydopamine (mPDA) shells. The mPDA has exceptional adhesion, excellent biocompatibility, large specific surface area and favorable photothermal properties, making AuNRs@mPDA an ideal photothermal composite and drug delivery carrier. AuNRs@mPDA can generate heat under near-infrared (NIR) laser irradiation, which disrupts the intermolecular forces and hydrogen bonds between PDA shell and drug, showing a photothermal enhanced drug release. Furthermore, by using polyethyleneimine (PEI) to seal the pore channels of mPDA, the pH-/NIR-responsive nanocarrier of AuNRs@mPDA@PEI was fabricated, which shows a high drug loading capacities for DOX to 121.7 mg/g. What's more, by combination of chemotherapy and photothermal therapy, the AuNRs@mPDA-DOX@PEI nanocarrier exhibits significant anticancer effect in vitro. In a word, this carrier demonstrated high drug capacity, excellent photothermal conversion efficiency (55.7%) and pH/NIR stimulation-responsive de-livery performance, and promising to become a nanoplatform for multifunctional cancer therapy in the future.