Bioassays on FO probe surface. The surface of the gold-coated fiber-optic probe has a carboxyl monolayer to which capture antibodies are covalently bound. Target antibodies bind the capture antibodies in a label-free configuration (left). Alternatively, the signal can be enhanced by using gold nanoparticles functionalized with detection antibodies in a sandwich assay configuration (right) extending detection to the pM and fM range.

The FOx BIOSYSTEMS biosensor can accurately detect, quantify and measure the potency of your antibody of interest in a variety of sample matrices. Label-free pM to µM sensitivities in 10 minutes make our fiber-optic surface plasmon resonance (FO-SPR) biosensor a versatile development tool.

  • Fast assay time (10 min)
  • Clinically relevant sensitivity (0.97 – 80 ng/mL in 100x diluted sample)
  • Results better than ELISA, in much less time
  • Minimum sample preparation (serum, plasma and whole blood)

Case study:
Therapeutic drug monitoring

Infliximab (IFX) is a monoclonal antibody used for the treatment of inflammatory bowel disease. Optimizing the therapeutic outcome requires concentration measurements which are currently obtained using the slow ELISA or less sensitive lateral flow-based immunotherapy techniques.

Immediate dose adaptation is a challenge using these techniques because they require well-trained staff, a long time to result, and sample prep on serum samples.

FOx BIOSYSTEMS offers an accurate, fast and convenient alternative to currently used techniques. This study showed that the FO-SPR biosensor provided excellent agreement with ELISA, even for serum and plasma samples.

Antibody concentrations obtained with FO-SPR correlate with those obtained with ELISA

Antibody potency screening via surface plasmon resonance infographic

Label-free potency screening of antibody–antigen interaction: FO-SPR can reproducibly measure and rank potency across a library.

Case study:
Potency screening

Quick, label-free quantification of antibodies reveals no information about their functionality, since they could be denatured but still detected. By adding a second step to bind the target of the antibody, the signal relative to the amount of antibody present is a strong indication of its performance. This allows fast and sensitive measurement and ranking of the antigen-binding potency of a set of antibodies.

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