Polyvinylpyrrolidone-mediated shape-tailored CuS core with biocompatible Fe3O4 for core@shell robotic nanozymes in targeted dual-mode oncotherapy

Robotic nanozymes offer precise, efficient, and localized cancer treatment with minimal adverse effects. The study reports the polyvinylpyrrolidone (PVP)-mediated synthesis of various copper sulfide (CuS) core morphologies, which were combined with a biocompatible Fe₃O₄ shell (CuS@Fe₃O₄) via 3-aminopropyltriethoxysilane (APTES) to form two types of robotic systems (nano- and microrobots) for dual-mode cancer therapy. For this approach, PVP with varying molecular weights (10 k, 40 k, and 360 k) was utilized to modulate the CuS core morphologies during synthesis, producing hollow spherical (CuS_10k), rod-like (CuS_40k), and elongated (CuS_360k) structures. Owing to their suitable sizes, the developed folic acid (FA)-conjugated CuS_10k@Fe₃O₄ and CuS_40k@Fe₃O₄, with magnetic targeting capabilities, were employed as nanorobots (250 ± 100 nm) and microrobots (1 µm), respectively. FA-conjugation enhanced the specificity toward folate receptors, improving the uptake efficacy in MDA-MB-231 cells. Under near-infrared irradiation, the nanorobot and microrobot achieved photothermal conversion efficiencies of 38.8 % and 32.5 %, respectively, significantly reducing cell viability by 23.6 % and 47.5 %. The use of PVP as a morphology-modulating agent to create multifunctional properties (e.g., enzyme-like activity, photothermal therapy, and magnetic control) within a single robotic nanozyme system represents a significant advancement in nanomedicine. This study introduces a novel cancer therapy platform to address current treatment challenges, minimize adverse effects, and optimize therapeutic outcomes.