Combined Photothermal Chemotherapy for Effective Treatment Against Breast Cancer in Mice Model

Introduction: Breast cancer ranks among the most prevalent cancers in women, characterized by significant morbidity, disability, and mortality. Presently, chemotherapy is the principal clinical approach for treating breast cancer; however, it is constrained by limited targeting capability and an inadequate therapeutic index. Photothermal therapy, as a non-invasive approach, offers the potential to be combined with chemotherapy to improve tumor cellular uptake and tissue penetration. In this research, a mesoporous polydopamine-coated gold nanorod nanoplatform, encapsulating doxorubicin (Au@mPDA@DOX), was developed. Methods: This nanoplatform was constructed by surface coating mesoporous polydopamine (mPDA) onto gold nanorods, and doxorubicin (DOX) was encapsulated in Au@mPDA owing to π-π stacking between mPDA and DOX. The dynamic diameter, zeta potential, absorbance, photothermal conversion ability, and drug release behavior were determined. The cellular uptake, cytotoxicity, deep penetration, and anti-tumor effects were subsequently investigated in 4T1 cells. After that, fluorescence imaging, photothermal imaging and pharmacodynamics studies were utilized to evaluate the anti-tumor effects in tumor-bearing mice model. Results: This nanoplatform exhibited high drug loading capacity, excellent photothermal conversion and, importantly, pH/photothermal dual-responsive drug release behavior. The in vitro results revealed enhanced photothermal-facilitated cellular uptake, drug release and tumor penetration of Au@mPDA@DOX under near-infrared irradiation. In vivo studies confirmed that, compared with monotherapy with either chemotherapy or photothermal therapy, the anti-tumor effects of Au@mPDA@DOX are synergistically improved. Conclusion: Together with good biosafety and biocompatibility, the Au@mPDA@DOX nanoplatform provides an alternative method for safe and synergistic treatment of breast cancer.