Chitosan-coated titanium dioxide nanoparticles: Fabrication, characterisation and toxicological evaluation in Drosophila melanogaster

Titanium dioxide nanoparticle (TiO2 NP) is one the most highly sought-after nanomaterials and are prevalent in many consumer products such as personal care products, paints and coatings, and food colouring. However, their pervasive use and high demand are expected to adversely affect organisms and ecosystems. Several articles suggest that surface modification of TiO2 with appropriate materials could mitigate its negative impacts. To facilitate this, we utilised chitosan (CS), a naturally occurring biopolymer, as a coating material to fabricate a biomaterial-based nanocomposite for consumer applications. TiO2 integration into chitosan was analysed using XRD, FTIR, UV-Vis spectroscopy, and SEM. Drosophila was employed as a model organism to assess the toxicity of the coated nanoparticles, aligning with efforts to prevent animal cruelty. The toxicity was analysed in both larvae and adult flies. Variations in antioxidant enzyme activity were observed, implying activation of nanoparticle clearance pathways. Antioxidant enzyme activation is a normal response to the ingestion of xenobiotics. Nonetheless, the cumulative response did not suggest any severe toxicity despite slight changes in antioxidant mechanisms. Our objective, however, is to employ the nanocomposite for dermal uses. Hence, the nanocomposite can be recommended for consumer applications.