Enumeration of enterovirus particles by scanning electron microscopy

Area of Science:

• Virology
• Microscopy
• Biophysics

Background:

• Accurate enumeration of virus particles is crucial for virological studies.
• Traditional methods like negative staining and transmission electron microscopy face challenges in achieving uniform virus dispersion and concentration.
• This limits precise particle counting and analysis.

Purpose of the Study:

• To develop and validate a novel electrophoretic method for concentrating enteroviruses.
• To enable high-resolution scanning electron microscopy (SEM) examination of concentrated virus preparations.
• To improve the accuracy and efficiency of virus particle enumeration.

Main Methods:

• An electrophoretic apparatus with three chambers was designed to concentrate viruses onto a polycarbonate membrane.
• Enteroviruses were concentrated by applying a constant current, with migration direction influenced by buffer pH and viral isoelectric points.
• Concentrated virus particles were examined using high-resolution scanning electron microscopy (SEM) and quantified via plaque assays.

Main Results:

• The electrophoretic method successfully concentrated enteroviruses onto a polycarbonate membrane.
• High-resolution SEM allowed for detailed examination of the concentrated virus particles.
• Particle counts derived from SEM correlated with viral titers measured by plaque assay, demonstrating method efficacy.

Conclusions:

• Electrophoresis offers an effective approach for concentrating virus particles for SEM analysis.
• This method overcomes limitations of conventional techniques for virus enumeration.
• The developed technique facilitates more accurate and reliable quantification of virus particles.