Eco-friendly cellulose/TiO₂-hydroxyapatite films for biomedical applications

In this work cellulose/TiO₂ flexible films coated with hydroxyapatite, aiming the development of electro-active orthopaedic scaffolds, were produced, applying sustainable procedures. The TiO₂ nanoparticles were incorporated into the cellulose, extracted from potato peel, and the films were fabricated by the casting method. The hydroxyapatite, synthesized by the sol-gel technique, was electrodeposited onto the cellulose/TiO₂ films, at room temperature. The resulting samples underwent comprehensive characterization using various techniques, including XRD, Raman Spectroscopy, SEM, EDS, TGA, DSC, and Impedance Spectroscopy (performed in a frequency range from 2 kHz to 40 MHz). The XRD and Raman Spectroscopy analyses of the extracted cellulose are consistent with the cellulose I polymorph and the SEM/EDS study of the cellulose/TiO₂ films showed that the TiO₂ nanoparticles are well dispersed within the biopolymer matrix, despite some aggregation that minimally affected film morphology. The successful electrodeposition of hydroxyapatite is suggested by SEM/EDS and confirmed by Raman Spectroscopy. The impedance spectra indicate that the uncoated samples' electrical response is associated with grain boundary effects, while for the coated ones the bulk resistance is the main contributor, with the bulk resistance and capacitance values suggesting potential for biomedical applications, particularly as electro-active orthopaedic scaffolds.