Rod in Tube: A Novel Nanoplatform for Highly Effective Chemo-Photothermal Combination Therapy toward Breast Cancer.

Gold nanorods (GNRs) and doxorubicin (DOX) were loaded into the lumen of halloysite nanotubes (HNTs) via a rapid synthesis process (2 min) and physical adsorption. The targeting molecules of folic acid (FA) are then conjugated to HNTs via reactions with bovine serum albumin (BSA). The formation of GNRs in HNTs was verified by different techniques. Au-HNT-DOX@BSA-FA shows a maximum temperature of 26.8 °C rising after 8 min of 808 nm laser irradiation under 0.8 W cm-2. The functionalized HNTs exhibited stronger chemotherapeutic effect under laser irradiation as the laser could promote the release of DOX and temperature rising. Au-HNT-DOX@BSA-FA-treated MCF-7 cells exhibited a survival rate of 7.4% after laser irradiation. Au-HNT-DOX@BSA-FA treatment does not induce obvious toxicity in blood biochemistry, liver, and kidney function in normal mice. In vivo chemo-photothermal treatment toward 4T1-bearing mice suggested that Au-HNT-DOX@BSA-FA exhibited remarkable tumor-targeted efficiency and good controlled release effect for DOX. Also, the nanoparticles exhibited a rapid photothermal performance and an ability to inhibit the growth of tumors. Because of the synergistic effect of chemical-photothermal therapy, the toxicity of DOX to normal tissues was reduced on the premise of ensuring the same curative effect with a low dosage of 0.32 mg kg-1. This novel chemo-photothermal therapy nanoplatform provided a safe, rapid, effective, and cheap choice for the treatment of breast tumors both in vitro and in vivo.