Sustainable Synthesis of Nitrogen-Embedded Cu₂S Quantum Dots for In Vitro and In Vivo Breast Cancer Management

The burgeoning field of nanomedicine is exploring quantum dots for cancer theranostics. In recent years, chemically engineered copper sulfide (Cu₂S) quantum dots (QDs) have emerged as a multifunctional platform for fluorescence-based sensors with prominent applications in imaging and chemodynamic therapy of tumor cells. The present study demonstrates the sustainable synthesis of nitrogen-embedded copper sulfide (N@Cu₂S) quantum dots for the first time and unveils their potential application in in vitro and in vivo breast cancer management. The N@Cu₂S QDs were morphologically analyzed by using TEM, revealing an average particle size of 5.4 nm. Their crystalline phase, nitrogen embedding, and luminescence properties were further investigated with XRD, XPS, and PL spectrometers, respectively. The in vitro cytotoxicity studies revealed that N@Cu₂S QDs effectively inhibited the proliferation of both human (MDA-MB-231) and mouse (4T1) breast cancer cells while not damaging normal mouse fibroblast (NIH/3T3) cells. Furthermore, the in vivo investigation showed a significant reduction in tumor volume with a tumor growth inhibition of 63.52% in QD-treated mice, which was further supported by bioluminescence and fluorescence tumor imaging. Additionally, the organ-specific histopathological analysis validated the safety profile of the N@Cu₂S QDs. The robust anticancer properties and high biocompatibility of N@Cu₂S QDs underscore their potential as a promising option for breast cancer therapy, paving the way for future clinical applications.