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Published on: September 30, 2025
Development of a displacement immunoassay for human heart-type fatty acid-binding protein in plasma: the basic
D van der Voort1, M M A L Pelsers, J Korf
1Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands. d.vandervoort@fys.unimaas.nl
Insights
A novel immunosensor for heart-type fatty acid-binding protein (FABP) shows promise for rapid acute myocardial infarction (AMI) diagnosis. This displacement assay allows for continuous monitoring of FABP in emergency medicine settings.
Area of Science:
- Biochemistry
- Medical Diagnostics
- Biomarker Detection
Background:
- Cardiac markers are crucial for risk-stratifying chest pain patients with inconclusive initial evaluations.
- Early detection of acute myocardial infarction (AMI) requires rapid measurement of cardiac biomarkers.
- Heart-type fatty acid-binding protein (FABP) is a recently identified early plasma marker for AMI.
Purpose of the Study:
- To investigate the principles of a displacement assay for heart-type fatty acid-binding protein (FABP).
- To assess the feasibility of using an immunosensor for continuous FABP monitoring in plasma for AMI diagnosis.
Main Methods:
- Developed a displacement assay using sepharose-bound FABP loaded with an antibody-horseradish peroxidase (HRP) conjugate.
- Mimicked continuous FABP measurement by repeated additions and washing steps in buffer and human plasma.
- Quantified dissociation of the antibody-HRP complex in the presence of free FABP.
Main Results:
- Demonstrated significant FABP displacement in both buffer and human plasma.
- Showed that the displacement assay is concentration-dependent.
- Confirmed intermittent displacement of the antibody-HRP complex for at least 9 hours in the same batch.
Conclusions:
- The displacement assay principle is feasible for developing a sensor for FABP.
- This immunosensor technology holds potential for rapid diagnosis of AMI in emergency medicine.
- Continuous monitoring of FABP could improve risk stratification for chest pain patients.
Abstract:
To risk-stratify patients with chest pain who are admitted to emergency rooms and for whom initial evaluation is not conclusive, the use of cardiac markers has become a standard procedure. A recently introduced early plasma marker for acute myocardial infarction (AMI) is the 14.5-kDa cytoplasmic heart-type fatty acid-binding protein (FABP). To fully exploit its early release from injured myocardium, a rapid method for repeated measurements or continuous monitoring of FABP in plasma is desirable. Such an on-line method could be an immunosensor based on displacement. The aim of the present study was to further investigate the principles underlying the displacement assay of FABP, both in buffer and in plasma. Batches of sepharose-bound FABP were loaded with an antibody-horseradish peroxidase (HRP) conjugate (anti-FABP). Continuous measurement of FABP was mimicked by repeated addition of FABP containing solutions followed by several washing steps. In the presence of free FABP the antibody-HRP complex dissociated and was subsequently quantified. Significant displacement in the presence of free FABP was observed in both buffer and human plasma. Anti-FABP could be intermittently displaced in the same batch, for at least 9 h, and the displacement was concentration-dependent. These results show the feasibility of a sensor based on the displacement principle to be used for the diagnosis of AMI in emergency medicine.
