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.

The FOx BIOSYSTEMS biosensor can accurately detect, quantify and measure the potency of your target of interest in a variety of sample matrices. Label-free pM to µM sensitivities in just 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:
Label-free quantification in bioproduction samples

Monitoring the production of antibodies is crucial for understanding and optimizing the process. In this study, production of the therapeutic monoclonal antibody, Trastuzumab (TRA), was used to investigate a new method to monitor production in real time.

ELISA is the most commonly used protein detection method, but this is a slow technique and is typically run in batches of samples collected over time, greatly increasing the time to result.

The White FOx from FOx BIOSYSTEMS offers a fast and convenient alternative to ELISA, giving comparable results within 10 minutes when using pre-functionalized probes. The dip-in protocol means that even individual samples can be analyzed straight after collection, directly in the sample medium, allowing for a rapid turnaround that facilitates near-real-time process optimization.

Label-free quantification in bioproduction samples. Concentrations determined with FO-SPR are highly comparable to those obtained using ELISA, in a fraction of the time. (Pearson correlation coefficients: 0.992 at 50-fold dilution, 0.928 at 100-fold dilution)

Excellent repeatability. Calibration curves obtained from plotting the SPR shift against a function of the concentration gave almost identical results when performed five weeks apart.

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