Preparation of Gd-doped AuNBP@mSiO2 nanocomposites for the MR imaging, drug delivery and chemo-photothermal synergistic killing of breast cancer cells

Under near-infrared (NIR) light, gold nanobipyramids (AuNBPs) exhibit a high photothermal conversion rate and photothermal stability, making them ideal mediators for photothermal therapy (PTT). In this study, highly purified AuNBPs are prepared, followed by coating their surfaces with mesoporous silica (mSiO2). The obtained AuNBP@mSiO2 nanocomplex exhibits an ellipsoidal shape with a relatively large specific surface, pore diameter and pore volume. To achieve MRI guided chemo-photothermal therapy of breast cancer cells, the nanocomplex is further coupled with the MRI contrast agent Gd-DTTA and the chemotherapeutic drug doxorubicin (DOX). The results indicated that under NIR light irradiation, AuNBPs exhibited promising PTT effects, while the cumulative release rate of DOX was significantly enhanced to 81.40%. Moreover, the chemo-photothermal therapy approach effectively eradicated 4T1 breast cancer cells. This work successfully confirms that chemo-photothermal synergistic therapy is an effective tumor treatment strategy and demonstrates the potential application of AuNBP@mSiO2 as a nano-drug delivery platform. Additionally, it introduces new ideas for the integrated study of breast cancer diagnosis and treatment.