Epifluorescent single-molecule counting with Streptavidin-Phycoerythrin conjugates

Area of Science:

• Biophysics
• Biochemistry
• Microscopy

Background:

• Single-molecule counting offers high sensitivity in biological research.
• Traditional methods often necessitate specialized and costly equipment.
• There is a need for accessible single-molecule counting techniques.

Purpose of the Study:

• To demonstrate a simplified approach for single-molecule counting.
• To utilize readily available epifluorescence microscopy and bright SA-PE conjugates.
• To enable sensitive single-molecule analyses for broader research applications.

Main Methods:

• Utilized bright Streptavidin-Phycoerythrin (SA-PE) conjugates.
• Employed standard epifluorescence microscopy for imaging.
• Applied the method to visualize single molecules on glass surfaces, magnetic microparticles, and cell surfaces.

Main Results:

• Successfully visualized individual molecules on various surfaces.
• Demonstrated the feasibility of single-molecule diagnostic assays on magnetic microparticles.
• Confirmed the ability to image individual foci on cell surfaces using the described method.

Conclusions:

• Bright SA-PE conjugates combined with epifluorescence microscopy provide a simple and effective method for single-molecule counting.
• This approach lowers the barrier for researchers seeking to perform sensitive single-molecule analyses.
• The technique is versatile, applicable to diverse biological samples and surfaces.