Data sheets | SPR Sensor chips

UV (Diazirine)–modified sensor chips

XanTec’s UV sensor chips are available as a 2D coating (UVHCP) or as 3D hydrogel matrices (UVHC200M, UVD200M) pre-functionalized with low-molecular-weight diazirine groups grafted onto a hydrophilic adhesion promoter on a gold support. Diazirines are stable in the dark but, upon irradiation at 365 nm, undergo photolysis, releasing N₂ and generating a highly reactive carbene. This carbene inserts into thiol, amino, hydroxy, and even C–H bonds, enabling stable covalent attachment to virtually any biomolecule.

When combined with electrostatic preconcentration, UV coupling provides a robust and efficient immobilization strategy. Efficient immobilization requires direct UV light access to the sensor surface, which may necessitate a quartz flow cell window. In combination with microarray spotters, UV-activated coupling can also be used to generate highly defined microarray sensor chips or slides.

Key features:

Robust covalent ligand coupling: Low chemical selectivity allows covalent attachment of nearly any biomolecule without additional reagents.
Compatible with spot immobilization: Particularly suitable for microarray spotting and imaging-SPR applications; high coupling yields achievable after drying prior to UV activation.
Requires special equipment: UV-permeable (quartz) flow cells are required for in-flow activation.

Schematic illustration of a 3D UV sensor chip. Blue triangles and red dots represent UV-reactive diazirine groups and negatively charged carboxyl groups along the polymer chains. Upon 365 nm irradiation, diazirine photolysis releases N₂ and generates a reactive carbene for covalent coupling.¹

Product code	UVHCP	UVHC200M	UVD200M
Base coating	2D, ultra-short bioinert polycarboxylate (high density)	3D, 1000 nm bioinert polycarboxylate (medium density)	3D, 200 nm bioinert CM-dextran (medium density)
Covalent immobilization capacity [µRIU]²	≈ 1,500	≈ 11,000	≈ 10,000
Recommended ligands	proteins peptides nucleic acids (spot immobilization) carbohydrates	proteins peptides nucleic acids (spot immobilization) carbohydrates	proteins peptides nucleic acids (spot immobilization)
Recommended analytes	proteins peptides nucleic acids carbohydrates	small peptides small nucleic acids small molecules small carbohydrates	small peptides small nucleic acids small molecules
Intended purpose	UV coupling of ligands otherwise difficult to immobilize interaction analysis with large biomolecules well suited for spot immobilization	UV coupling of ligands otherwise difficult to immobilize interaction analysis with small molecules well suited for spot immobilization	UV coupling of ligands otherwise difficult to immobilize interaction analysis with small molecules including carbohydrates well suited for spot immobilization

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 Covalent immobilization capacity determined by injecting 100 µg/mL BSA in 5 mM sodium acetate buffer (pH 5.0) and irradiating for 10 min with a 3 W, 365 nm UV LED using a quartz window flow cell.

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UV (Diazirine)–modified sensor chips