A new fluorescent test for cell vitality using calcofluor white M2R

Area of Science:

• Cell Biology
• Histology

Background:

• Distinguishing between living and dead cells is crucial for various biological studies.
• Existing viability assays may have limitations in accuracy or toxicity.

Purpose of the Study:

• To evaluate the efficacy of Calcofluor white M2R (CFW) as a fluorescent stain for assessing cell viability.
• To determine the optimal staining concentrations and assess the safety of CFW.

Main Methods:

• CFW staining was applied to various animal (mouse fibroblasts, trout red blood cells) and plant (onion, Tradescantia, broad bean) cell types.
• Cell vitality was assessed by observing staining patterns (cell wall vs. cytoplasm/nucleus) and confirmed using plasmolysis-deplasmolysis tests.
• Staining concentrations were optimized, and toxicity was evaluated.

Main Results:

• CFW did not stain living animal cells but stained cell walls of living plant cells.
• Heat-killed cells showed lightly stained cytoplasm and brightly stained nuclei.
• Optimal CFW concentrations (0.01%-0.03%) were non-toxic.
• CFW correctly predicted cell vitality in approximately 98% of tested cells, comparable to other viability dyes.

Conclusions:

• Calcofluor white M2R is a reliable and accurate fluorescent dye for differentiating viable from non-viable cells across diverse species.
• Its low, non-toxic concentrations and high accuracy make it a valuable tool for cell viability studies.