avidinebased

Avidin-based refers to systems and reagents that rely on avidin, a small homotetrameric glycoprotein derived from egg white, which binds biotin with exceptionally high affinity. The avidin–biotin interaction is one of the strongest non-covalent biological interactions, enabling robust capture, detection, and assembly of biotinylated molecules across diverse laboratory applications.

Avidin consists of four identical subunits, each containing a biotin-binding site. The tetramer can simultaneously bind up to four biotin molecules, creating stable complexes that resist dissociation under many standard conditions. In practice, avidin-based tools are valued for their versatility, compatibility with a range of buffers, and strong, specific binding that enables efficient purification and signal amplification.

Variants and related reagents include NeutrAvidin, a deglycosylated form with reduced nonspecific binding, and streptavidin, a homolog from a different source with related properties. Compared with streptavidin, avidin is more glycosylated and can be more immunogenic in vivo, while streptavidin and its derivatives often offer different stability and charge characteristics.

Applications of avidin-based technologies encompass affinity purification of biotinylated targets, diagnostic assays such as ELISA and Western blotting, immunohistochemistry, biosensors, and various research tools in nanotechnology and imaging. A common strategy to achieve reversible binding involves biotin analogs like desthiobiotin, which can compete for binding and enable milder elution conditions.

Limitations include potential interference from endogenous biotin in samples, the immunogenicity of avidin in certain in vivo contexts, and the need to optimize elution and washing conditions to balance binding strength with practical release.