Mineral nanoparticles: synthesis and biocontrol applications

Abstract

This thesis investigates how the composition, defect structure, and interfacial chemistry of functional nanomaterials determine their performance in electrochemical, catalytic, and biological systems. Manganese-doped titanium dioxide (Mn-doped TiO2) was prepared from a single-source precursor to examine how Mn doping modifies the crystal lattice. Although high Mn integration hindered lithium intercalation, the associated surface defects created redox-active sites and enabled selective oxidase-like activity. NMR and LC-MS/MS analyses identified products consistent with oxidative deamination and Cα–Cβ bond cleavage of selected aromatic amino acids, with DFT calculations supporting the proposed reaction pathway. At biological interfaces, PEG-assisted synthesis improved the dispersion and cytocompatibility of Mn-doped TiO2 nanoparticles, and their combination with polydopamine facilitated the formation of continuous coatings on Saccharomyces cerevisiae cells. A complementary biphasic assembly strategy produced reversible luteolin-Fe3+ shells on Lactobacillus acidophilus, preserving cell viability while improving resistance to acidic conditions, lysozyme exposure, and refrigerated storage. Taken together, the work links precursor design and defect formation to efficacy in lithium storage, selective surface catalysis, and single-cell nanoencapsulation.