Data sheets | SPR Sensor chips

RG sensor chips (regenerable DNA-mediated capture)

XanTec’s RGD200M sensor chips are coated with a bioinert carboxymethyl-dextran matrix derivatized with a 24-nt single-stranded DNA oligonucleotide. This surface enables DNA-mediated, reversible ligand immobilization via hybridization with a complementary DNA sequence. Captured ligands are stably bound under physiological conditions, while quantitative regeneration is achieved by alkaline denaturation of the double-stranded DNA, restoring the surface for subsequent capture cycles.

Two complementary immobilization strategies are available. In Variant 1 (RG-SA), streptavidin pre-conjugated with the complementary DNA oligo is first immobilized via DNA hybridization, followed by capture of biotinylated ligands. In Variant 2 (RG-Modifier), ligands are directly conjugated to the complementary DNA oligo (e.g., via DBCO Click chemistry) and immobilized without an intermediate streptavidin step. Variant 2 can reduce nonspecific binding, lower diffusion limitations, enable higher capture densities, and facilitate faster assay setup.

Key features:

Very fast assay development: No preconcentration, no surface activation, and no regeneration screening required; immobilization under physiological conditions.
Maximum flexibility: Regenerable alternative to classic streptavidin/biotin capture immobilization.
Exceptional stability: Drift-free immobilization of oligo-modified streptavidin.
Simple regeneration: Quantitative regeneration enabling >100 capture/regeneration cycles.
Oriented immobilization: Controlled biotinylation (e.g., AviTag™) supports high ligand activity and reproducibility.
Ideal for large screening campaigns: Consistent surface performance across many cycles and sensor chips.

Schematic illustration of an RGD200M sensor chip. Variant 1 (left): DNA–streptavidin conjugate (purple) immobilized via hybridization captures biotinylated ligands (yellow). Variant 2 (right): DNA–ligand conjugates are directly immobilized via DNA hybridization. The decaying red gradient represents the evanescent field.¹

Product code	RGD200M	RGD200M
Base coating	3D, 200 nm bioinert CM-dextran (medium density)
Variant	Variant 1: RG-SA	Variant 2: RG-Modifier
Capture immobilization capacity [µRIU]	≈ 3,500²	≈ 5,000³
Recommended ligands	biotinylated proteins or peptides	proteins or peptides with NHS-reactive amino groups
Recommended analytes	proteins peptides	proteins peptides small molecules
Intended purpose	kinetic and equilibrium analyses of medium analytes assay development with new or uncharacterized binding partners screening of biotinylated peptide and protein libraries time-critical SPR experiments systems that are difficult to regenerate not recommended for DNA-binding or intercalating molecules	kinetic and equilibrium analyses of small, medium, and large analytes higher ligand densities than RG-SA superior baseline stability applications with difficult regeneration not recommended for DNA-binding or intercalating molecules

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 capture of 100 µg/mL biotinylated BSA in PBS (RG-SA pre-capture), with 1 µRIU corresponding approximately to 1 RU.

³ Based on capture of 200 nM RG-SA on an RGD200M sensor chip.

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RG sensor chips (regenerable DNA-mediated capture)