Figure 7.

IQ mapping of IR spectral region 2830–2945 cm⁻¹ of astrocytes and neurons exposed to SiO₂-NPs. The spectral region of 2830–2945 cm⁻¹ that includes specific spectral bands of symmetric and asymmetric vibrations of -CH₂ of lipids is presented for astrocytes (a–f) and neurons (g–l). A sample of cells treated with SiO₂-NPs for 24 h was dispersed on a gold-coated slide. The three-dimensional image is presented in the x, y, and z axes, and the area presented as a gradient of color indicates a decrease (from blue) or increase (red) in the spectral signal. In astrocytes (a–f), a decrease in the signal (blue area) occurred at 1 (b), 10 (c), 50 (e), and 100 (f) µg/mL of SiO₂-NPs when compared to control (a). No changes were observed at 25 µg/mL (d). In neurons (g–l), spectral signal increased (red area) from 1–50 µg/mL (h–k) when compared to control (g). The higher increase in signal was detected at 25 µg/mL (j). On the contrary, at the concentration of 100 µg/mL (l), the lowest spectral signal was detected. The image is representative of four independent experiments with three technical replicates.