Borax methylene blue: a spectroscopic and staining study

Area of Science:

• Biochemistry
• Histology
• Parasitology

Background:

• Borax methylene blue is a staining solution used in microscopy.
• Its stability at different temperatures and pH levels is critical for reliable results.
• Previous studies have shown varying outcomes, necessitating further investigation.

Purpose of the Study:

• To investigate the stability of borax methylene blue at various temperatures and pH levels.
• To determine the optimal conditions for its use as a blood stain.
• To explain historical discrepancies in its application.

Main Methods:

• Borax methylene blue solutions were incubated at temperatures ranging from 30°C to 60°C.
• Absorption peaks were measured over time to assess polychroming.
• pH was adjusted to 6.5 using a borax-acid phosphate buffer.
• A modified staining protocol was developed and tested on malaria parasites (Plasmodium falciparum, P. vivax, P. berghei).

Main Results:

• Borax methylene blue is stable at room temperature (22-25°C).
• Polychroming occurs slowly at 30°C and rapidly at 60°C, altering the absorption peak.
• Adjusting the pH to 6.5 maintains the absorption peak at 665 nm even at 60°C.
• The optimized staining protocol yielded excellent Nocht-Giemsa type staining of malaria parasites with distinct morphological features.

Conclusions:

• pH 6.5 is critical for the stability of borax methylene blue, preventing degradation at elevated temperatures.
• The study validates historical findings and clarifies reasons for previous experimental failures.
• The optimized staining method provides a reliable tool for visualizing malaria parasites.