pH-responsive MTX-BSA@MnO2-Cy5.5 for NIRF/MR imaging guided chemotherapy of anaplastic thyroid carcinoma

Anaplastic thyroid carcinoma (ATC) has been confirmed as a highly aggressive and lethal endocrine malignancy. Currently, there has not been any effective diagnosis and treatment strategy in terms of ATC. Multifunctional nanotechnology is urgently required to optimize the therapeutic and diagnostic prospects of ATC. In this study, MTX-BSA@MnO2-Cy5.5 (MBMC NPs) was prepared for ATC visualization fluorescence/magnetic resonance (NIRF/MR) imaging and synergistic chemotherapy using bovine serum albumin (BSA) biomineralized manganese dioxide (MnO2) loaded with methotrexate (MTX) and Cy5.5. First, the basic characterization of MBMC NPs was examined, and the cytotoxicity, targeted uptake, and apoptosis-inducing ability exhibited by the MBMC NPs were examined through CCK8, laser confocal microscopy, and flow cytometry. Subsequently, the NIRF/MR imaging performance and anti-tumor effects of the MBMC NPs on the 8305C BALB/c nude mouse model were explored. Lastly, the hemolytic effect and systemic side effects of the MBMC NPs were assessed. The prepared MBMC NPs fell into a scope of spherical nanoparticles of nearly 105.7 ± 21.4 nm in size with high stability. The drug loading of MBMC NPs reached 30.45%, and the release of MTX in the MBMC NPs was pH-dependent. As indicated by in vitro and in vivo studies, MBMC NPs were specifically taken up and effectively aggregated to tumor regions with prominent NIRF/MR imaging properties and anti-tumor activity. Histological results suggested that the MBMC NPs exhibited low toxicity to major organs and good in vivo biocompatibility. The prepared MBMC NPs exhibited excellent targeting, NIRF/MR imaging performance, and therapeutic effects. It is expected to serve as a safe and effective theranostic method that lays a theoretical basis for the effective treatment of thyroid cancer.