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FOx BIOSYSTEMS quantification in crude samples applications icon

The FOx technology uses fiber-optic-based surface plasmon resonance (FO-SPR) to directly measure an analyte of interest from blood, resuspended dried blood spots and other crude matrices. Providing accurate results from a range of sample inputs demonstrates the robustness and versatility of the FO-SPR technology.

  • Serum
  • Plasma
  • Whole blood
  • Dried blood spots
  • Cell supernatant
  • Cell lysate

Case study: Dry blood spot sampling

Dry blood spots are an ideal method for patients to provide blood samples from home, with minimal transportation requirements. However, blood cell bursting, and the altered structure of analytes caused by the drying process, can influence the detection efficiency.

In tests with infliximab (IFX), a monoclonal antibody used for the treatment of inflammatory bowel disease, the FO-SPR bioassay demonstrated that:

  • The blood drying process did not affect analyte extraction or interfere with the bioassay antibodies.
  • IFX was uniformly distributed across the blood spot on the paper.
  • Non-specific binding due to blood cell bursting did not interfere with the FO-SPR bioassay.

FO-SPR can accurately detect antibodies in dried blood spots. The therapeutic drug antibody, infliximab (IFX), was spiked into blood and dried, or spiked to the dried blood spot. The IFX concentration from the extract using FO-SPR correlated well with both spiking methods and with ELISA.

Case study: Detecting a tumor protein in serum using gold nanoparticle sandwich amplification

The Pharmacology Department at the University of Cambridge are investigating a potential biomarker to detect triple negative breast cancer tumors in blood serum. Traditional technologies (ELISA, mass spectroscopy and conventional SPR) had proven unsuitable for their purposes, so they looked to the WHITE FOxTM for an alternative method.

FO-SPR with gold nanoparticle signal amplification matched or improved on the detection sensitivity of existing SPR technology. This allowed the development of a test suitable to retrospectively test patient samples for the candidate biomarker.

Relevant publications

Found 12 Results
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Measuring ADAMTS-13 activity to diagnose thrombotic thrombocytopenic purpura: a novel, fast fiber-optic surface plasmon resonance immunoassay

Bonnez et al. (2023) RPTH 7,  DOI: 10.1016/j.rpth.2023.102171 Thrombotic thrombocytopenic purpura (TTP) is characterized by severe ADAMTS-13 activity deficiency (<10%). Diagnostic testing is challenging because of unavailability, high cost, and…


September 27, 2023

Detection of Breast Cancer-Specific Extracellular Vesicles with Fiber-Optic SPR Biosensor

Yildizhan et al. (2023) International Journal of Molecular Sciences DOI: 10.3390/ijms24043764 Extracellular vesicles (EVs) have attracted great attention as potential biomarkers for cancer diagnostics. Although several technologies have been developed…


February 15, 2023

Immunogenic affinity and extracellular vesicle quantification in blood with FO-SPR

June 20-22, 2022 – MOSBRI Scientific Conference Our CTO, Dr. Filip Delport, had the opportunity to present at the 1st MOSBRI Scientific Conference in June 2022. He explained how the…


December 7, 2022

Innovative FO-SPR Label-free Strategy for Detecting Anti-RBD Antibodies in COVID-19 Patient Serum and Whole Blood

Qu et al. (2022) ACS Sensors DOI: 10.1021/acssensors.1c02215 The ongoing COVID-19 pandemic has emphasized the urgent need for rapid, accurate, and large-scale diagnostic tools. Next to this, the significance of…


January 27, 2022

App note: AN5 Extracellular vesicle quantification in complex matrices

Application note 5 | Version 1 | Kris Ver Donck, Filip Delport, Kim Stevens Based on original publication: Yildizhan et al. (2021) Journal of Extracellular Vesicles. 10 (4) ABSTRACT Fiber-optic…


December 15, 2021

App note: AN3 Sensitive protein quantification in whole blood, dried blood spots, serum and plasma

Application note 3 | Version 1 | Kim Stevens, Kris Ver Donck, Filip Delport Based on original publication: Lu et al. (2017) Analytical Chemistry 89, 3664-3671. (1) ABSTRACT Fiber-optic surface…


June 29, 2021

App note: AN2 sensitive protein quantification in serum – comparison of FO-SPR and ELISA

Application note 2 | Kim Stevens, Kris Ver Donck, Filip Delport Based on original publication: Lu et al. (2016) Biosensors and Bioelectronics 79, 173–179. (1) ABSTRACT This application note demonstrates…


April 23, 2021

WHITE FOxTM technical specifications

You can find the technical specifications of the White FOxTM here: DOWNLOAD


April 8, 2021

FO-SPR biosensor calibrated with recombinant extracellular vesicles enables specific and sensitive detection directly in complex matrices

Yilidzhan et al. (2021) J. Extracell. Vesicles 10   Extracellular vesicles (EVs) have drawn huge attention for diagnosing myriad of diseases, including cancer. However, the EV detection and analyses procedures…


February 23, 2021

Immunoassay for detection of infliximab in whole blood using a fiber-optic surface plasmon resonance biosensor

Lu et al. (2017) Anal. Chem. 89, 3664−3671   Monitoring the concentration of a therapeutic drug antibody, infliximab (IFX), is recommended for enhancing its efficacy in patients with inflammatory bowel…


February 22, 2017

Competitive inhibition assay for the detection of progesterone in dairy milk using a fiber optic SPR biosensor

Daems et al. (2017) Analytica Chimica Acta 950, 1e6   Analytical methods that are often used for the quantification of progesterone in bovine milk include immunoassays and chromatographic techniques. Depending on the selected method,…


January 15, 2017

Fiber optic-SPR platform for fast and sensitive infliximab detection in serum of inflammatory bowel disease patients

Lu et al. (2016) Biosensors and Bioelectronics 79, 173–179    Infliximab (IFX) is a therapeutic monoclonal antibody used for treating patients with inflammatory bowel disease (IBD). In order to improve…


May 15, 2016

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