Data sheets | SPR Sensor chips

Biotin–modified sensor chips

XanTec's biotin-modified sensor chips are coated with a bioinert (poly)carboxylate matrix (CMD or HC), pre-functionalized with a low-molecular-weight biocytin group. Owing to the exceptionally high affinity of biotin for avidin family proteins (dissociation constant ≈ 10⁻¹⁵ M for streptavidin), these chips enable highly stable immobilization with essentially negligible dissociation of bound streptavidin or streptavidin-ligand complexes.

XanTec's biotin sensor chips have gained popularity due to their compatibility with Switchavidin, an avidin derivative with a switchable affinity for biotin. This allows quantitative ligand removal from the biotin-functionalized surface, which is difficult and time-consuming when using streptavidin. In typical workflows, Switchavidin is pre-incubated with a biotinylated ligand at a controlled stoichiometry, followed by immobilization of the Switchavidin-ligand complex on the biotin sensor surface. Without this precomplex formation, Switchavidin can become buried within the hydrogel matrix, significantly reducing the effective ligand-binding capacity.

Key features:

Regenerable with Switchavidin: Enables reversible capture of biotinylated ligands via controlled binding and removal of Switchavidin.
Oriented immobilization: Precise biotinylation strategies (e.g., AviTag) support uniform ligand orientation, maximizing activity and reproducibility.
Versatile capture capacity: Available on CMD and HC base coatings, offering different capture capacities and sensor matrices to match specific experimental needs.
High chemical stability: Supports stringent regeneration conditions for the effective removal of Switchavidin, and potentially also streptavidin, from the sensor chip.

Schematic illustration of a 3D BHC sensor chip. Red and yellow/green dots represent negatively charged carboxyl groups and biotin groups distributed along the green polymer chains. The decaying red gradient represents the evanescent field. The magnified view shows immobilized Streptavidin (purple) pre-coupled with a biotinylated ligand.¹

Product code	BP	BD200M	BHC200M
Base coating	2D, ultra-short CM-dextran (high density)	3D, 200 nm bioinert CM-dextran (medium density)	3D, 200 nm bioinert polycarboxylate (medium density)
Immobilization capacity [µRIU]²	≈ 800	≈ 7,000	≈ 7,000
Recommended ligands	biotinylated proteins peptides nucleic acids		biotinylated proteins peptides nucleic acids carbohydrates
Recommended analytes	proteins peptides nucleic acids viruses and cells	proteins peptides nucleic acids small molecules	proteins peptides nucleic acids small molecules carbohydrates
Intended purpose	compatible with Switchavidin-mediated capture of biotinylated ligands kinetic analysis of medium and large analytes especially suitable for weak binders with fast association and dissociation rates	compatible with Switchavidin-mediated capture of biotinylated ligands kinetic analysis of medium and small analytes especially suitable for situations requiring higher capture densities	compatible with Switchavidin-mediated capture of biotinylated ligands kinetic analysis of medium and small analytes including carbohydrates especially suitable for situations requiring higher capture densities

¹ All illustrations are schematic representations and are not drawn to scale; dimensions, densities, and spatial relationships do not reflect actual physical or chemical proportions.

² Based on specific binding of 100 µg/mL streptavidin in phosphate-buffered saline (PBS), with 1 µRIU corresponding approximately to 1 RU.



Products | SPR Sensor chips | Data sheets

Biotin–modified sensor chips