Fig. 3. Toxicity of DOPAL and the protective effect of Lys C-dots in the neuronal SH-SY5Y cells were studied by XTT assay. The left side shows the viability of the cells in the medium (grey histogram), in the presence of 100 μM DOPAL (black histogram), and in the presence of 1 mg mL⁻¹ Lys C-dots (blue histogram); the right section shows the effect of increasing concentrations of Lys-C-dots on cell viability in the presence of 100 μM DOPAL (purple histograms).