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Can live cells be imaged using streptavidin conjugates?
Posted September 10, 2019
Answer
Streptavidin-based amplification techniques are widely used in flow cytometry and fluorescent imaging to increase sensitivity. Fluorescent streptavidin conjugates are used to detect biotinylated biomolecules such as primary and secondary antibodies. Since antibodies are inherently cell-impermeable due to their large molecular weight the location of the primary stain will determine whether streptavidin conjugates can be used for live cell imaging.
If the intended target is expressed on the extracellular surface of the cell membrane, then streptavidin conjugates can be used for live cell imaging. For example, CD4 is a surface marker of immune cells such as T helper cells. It can be labeled using biotinylated CD4 antibodies and streptavidin conjugates, and analyzed by flow cytometry.
If the intended target is located intracellularly, then streptavidin conjugates CANNOT be used for live cell imaging. To facilitate the entry of antibodies into cells they must be lysed first.
Additional resources
iFluor™ 647-streptavidin conjugate product page