FTIR study of the effect of nTiO2 on the biochemical constituents of gill tissues of Zebrafish (Danio rerio)

In the present study, an attempt is made to assess the changes in the biochemical contents in general, and the protein structural changes in particular, in the gill tissues of Zebrafish (Danio rerio) due to titanium nanoparticles and their bulk counterpart using FTIR spectroscopy. The FTIR spectra show that the intensity differences between the control and titanium-exposed tissues are remarkable. For example, TiO₂-exposed tissues show higher intensities at amide I and amide II of proteins, but lower at 2924 cm^?1 (CH₂ asymmetric stretching of lipids), 2853 cm^?1 (CH₂ symmetric stretching of lipids) and 1744 cm^?1 (CO stretching of phospholipids) when compared with the control tissues. This suggests that there is an increase or decrease in the percentage of a certain types of biomolecules relative to the total infrared-active constituents in the gill tissues. The curve-fitting analysis suggests an increase in α-helical structure and a decrease in β-sheet structure due to TiO₂ exposure. These results confirm that the structural conformation of proteins in fish gill tissues was significantly influenced by TiO₂ exposure. Further, the changes are more due to nTiO₂ when compared to TiO₂ bulk, suggesting that nTiO₂ are affecting the biochemical constituents more than their bulk counterpart.