Synthesis and Characterization of Biocompatible Manganese-Doped Titania Nanoparticles and Its Application to Single-Cell Nanoencapsulation

Abstract

Biocompatible metal oxide nanoparticles (NPs) are promising materials for biointerfaces, wound healing, and theranostic applications owing to their multifunctional properties. Here, we report manganese-doped TiO₂ (Mn-doped TiO₂) nanozymes that integrate the chemical stability and biocompatibility of TiO₂ with the redox activity and biofunctional potential of manganese oxide within a single-phase oxide platform. The Mn-doped TiO₂ nanoparticles synthesized via hydrothermal and PEG-assisted solvothermal routes exhibit uniform size (10–15 nm), high hydrophilicity, and excellent colloidal stability as confirmed by dynamic light scattering (DLS), along with suppressed photocatalytic activity to minimize ROS-mediated cytotoxicity. Structural analyses via X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed uniform manganese doping into the TiO₂ lattice. Biological evaluations demonstrated excellent compatibility in both encapsulation models (phosphate-functionalized nanospheres and Al₂O₃ plates) and living systems including immortalized human T lymphocytes (Jurkat T cells), neuronal cells, and yeast, with consistently high cell viability. Importantly, Mn redox centers confer nanozyme activity, catalyzing dopamine polymerization at cell surfaces and enabling single-cell nanoencapsulation (SCNE). These findings establish Mn-doped TiO₂ nanozymes as a multifunctional promising platform for cell-surface engineering, bioencapsulation, and future applications in regenerative medicine and theranostics.