Functional hybrid bionanomaterials based on titanium dioxide and cellulose, possessing antibacterial and drug delivery properties

The present work focuses on development and investigation of new functional hybrid nanomaterials based on titania nanoparticles and cellulose, possessing an important set of practical properties. The study includes two parts: first, nanocrystalline TiO₂ hydrosols produced by low-temperature sol-gel synthesis were successfully applied for cotton fabric modification. Comprehensive characterization of the cotton/TiO₂ composite was undertaken using such techniques as SEM-EDX analysis, FT-IR spectroscopy, X-ray diffraction, low-temperature nitrogen adsorption/desorption, Nanoparticle Tracking analysis, X-ray diffraction, and TGA. The interaction of TiO₂ nanoparticles with the functional groups of cotton fibers was achieved with the help of a cross-linking agent (1,2,3,4 –butanetetracarboxylic acid) through the formation of transverse ester bonds. The obtained TiO₂/composite demonstrated high bacteriostatic effect against gram-negative Escherichia coli bacteria after exposure to UV-irradiation for 10 minutes, and reduced bacteria survival by 70%. In the second part of the thesis, the nanocomposites with potential for dermal drug delivery application were developed. They were produced using titania nanosol chemically grafted onto cellulose nanofibers as active ingredient for enhanced uptake and controlled release of model drug loads. Four different medicines, Diclofenac sodium, Penicillamine-D, Phosphomycin and Tetracycline were chosen as model drugs for the synthesis and further investigation of resulting drug release systems. Two different methods of medicine introduction were used to show that various interactions between TiO₂ and drug molecule could be used to control the kinetics of long-term drug release. The viability on the action of the released drug was examined for common and most widely tested pathogen micro-organisms: Staphylococcus aureus and Escherichia coli. The photocatalytic test showed that cellulose nanofibers–titania nanocomposites possessed high photocatalytic properties and could potentially be utilized in photovoltaic devices and photocatalysis. The influence of UV irradiation on the stability of the obtained nanocomposites loaded with drugs and their antibacterial properties was also investigated