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

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 TiO 2 (Mn‐doped TiO 2 ) nanozymes that integrate the chemical stability and biocompatibility of TiO 2 with the redox activity and biofunctional potential of manganese oxide within a single‐phase oxide platform. The Mn‐doped TiO 2 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 TiO 2 lattice. Biological evaluations demonstrated excellent compatibility in both encapsulation models (phosphate‐functionalized nanospheres and Al 2 O 3 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 TiO 2 nanozymes as a multifunctional promising platform for cell‐surface engineering, bioencapsulation, and future applications in regenerative medicine and theranostics.