BIOCOMPATIBLE BIODEGRADABLE MATERIALS BASED ON CHITOSAN MODIFIED WITH NANOSTRUCTURED TITANIUM DIOXIDE

In light of current trends to reduce the ecological load, much attention is being paid to biopolymer-based materials - from the development of biomedical drugs, membranes for purification and packaging materials. Large-scale research in this direction is carried out using chitosan (CTS) due to its biocompatibility, biodegradability, and antimicrobial properties. The CTS limiting factor is its low physical-mechanical characteristics and thermal stability. The actual task is CTS modification by combining it with materials that are also biocompatible and non-toxic. One of the promising compounds is TiO₂, which has a pronounced antimicrobial and photocatalytic activity. At the same time, the strengthening of useful properties of the composite material should be expected when TiO₂ in nanostructured form is used.

The research aims to obtain CTS based materials modified with TiO₂ nanoparticles (NPs); and study their biodegradation, physical-mechanical, thermal-physical and antibacterial properties. TiO₂ NPs with average sizes ranging from 20 to 920 nm were prepared from Ti(OPrⁱ)₄ by sol-gel technology. TiO₂ NPs were incorporated into solutions of 3 wt.% CTS in acetic acid. The TiO₂ concentration was varied from 0.5 to 10 wt.% (relative to CTS mass), acetic acid - from 1.2 to 6 wt.%. Transparent homogeneous materials with high physical-mechanical properties were obtained. The highest tensile strength and deformation - up to 100 MPa and 30% - are possessed by films containing up to 2 wt.% of TiO₂ (< 50 nm). The effect decreases when the TiO₂ NPs size and concentration increase. Thermal-physical characteristics of CTS with 2 wt.% of TiO₂ NPs were studied by differential scanning calorimetry and dynamic mechanical analysis methods. It was found that the materials are degraded by Aspergillus niger by 50% within 4 weeks and exhibit antibacterial activity against Staphylococcus Aureus.

The work was financially supported by the Russian Science Foundation (project No. 23-74-10069).