Beyond its role as a marker for cellular health, neutral red also serves as a versatile pH indicator. Under acidic conditions, it exhibits a distinctive red hue, transitioning to yellow as the pH elevates from 6.8 to 8.0. This unique attribute allows for the visualization and quantification of pH variations within cellular compartments. Notably, the acidic nature of the nucleus aligns with the yellow staining observed in this organelle when exposed to neutral red. Furthermore, the lysosomal environment, characterized by its acidic pH, manifests as a red stain upon interaction with neutral red.

The comprehensive understanding of these cellular responses is imperative for the accurate interpretation of cell proliferation dynamics and cytotoxic effects. Furthermore, the molecular characterization of neutral red, with a molecular formula of C15H17IN4 and a molecular weight of 288.8 kDa, enhances the precision and depth of our analytical toolkit. In this pursuit, the Neutral Red Cell Proliferation and Cytotoxicology Assays emerge as invaluable tools, offering a holistic perspective on cellular health, function, and response to external stimuli.