The FOx BIOSYSTEMS biosensor can accurately detect and quantify your target protein 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)

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 proteins 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.

Case study: Immobilizing His-tagged bioreceptors

His tags are a commonly used method of selectively extracting proteins of interest from cells or display libraries.

A FO-SPR probe with NTA surface chemistry allows the oriented binding of such proteins for use as a bioreceptor, e.g. for display library screening. This chemistry is particularly convenient for using nanobodies and recombinant proteins, and also allows probe regeneration and reuse by easy removal of the bound protein.

The His tag binding has further benefits. Sequential analysis bioreceptor and immobilization followed by signal amplification using two different gold-labelled detection antibodies has been successfully demonstrated, allowing multiplexed target detection in buffer and 100-fold diluted human blood plasma.

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