NIR-Triggered SrSnO3 -photosynthesized nanocatalyst: A potent anticancer agent against triple negative breast cancer cells

The major systemic therapeutic option for Triple Negative Breast Cancer (TNBC) is chemotherapy. TNBC often responds well to chemo, however, chemotherapy carries toxic adverse effects and content-limited interventional efficiency. Thereby, a drug-free treatment paradigm is imperative, in which synthetic polymers spontaneously display efficient anticancer efficacy without the use of conventional chemotherapeutic agents. Aiming at the goal to treat TNBC, SrSnO3 nanoparticles were devised as a nanocatalyst to accomplish near infrared (NIR) photocatalytic production of oxidative holes for achieving hole therapy. An inexpensive sol-gel method was employed in this study to synthesize SrSnO3 nanoparticle using strontium chloride hexahydrate and stannous chloride dihydrate. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS) analyses were used to characterize the synthesized SrSnO3 nanoparticles while Density Functional Theory (DFT) was used to study the nanoparticle at atomistic level and the band gap was calculated to be 1.84 eV using Perdew−Burke−Ernzerhof (PBE) functionals. The anticancer effect of SrSnO3 nanoparticle was tested against TNBC cell line MDA-MB-231 at different concentration (10–50 μg/mL) with near infrared (NIR) irradiation while cells without any treatment or treatment with only SrSnO3 or NIR served as controls. Under NIR irradiation, the IC50 value was found to be 40 μg/mL achieving 50% cell death with augmented release of reactive oxygen species (ROS) over time. Reduced and oxidized glutathione (GSH and GSSG, respectively) serve as cellular redox buffers and protect cells from ROS mediated damage. Nearly 18.6% reduced glutathione (GSH) was found to be consumed with 5 min of NIR irradiation that was augmented to 66.5% of GSH when exposure time was increased to 10 min suggesting a prooxidant mediated death of cancer cell line. The results suggested SrSnO3 nanoparticle is a potent photocatalyst when triggered by NIR and can enable highly effective and biosafe hole-mediated treatment for TNBC.