Development of a disposable immunosensor for the detection of human heart fatty-acid binding protein in human whole blood using screen-printed carbon electrodes

An amperometric immunosensor for the rapid detection of human heart fatty-acid binding protein (H-FABP) in whole blood was developed. Due to its rapid kinetics in plasma, H-FABP is a useful biochemical marker for the early assessment of acute myocardial infarction (AMI). A one-step direct sandwich assay in which analyte and alkaline phosphatase (AP) labelled antibody were simultaneously added to the immobilised primary antibody, was employed using two distinct monoclonal mouse anti-human H-FABP antibodies. p-Aminophenyl phosphate was converted to p-aminophenol by AP and the current generated by its subsequent oxidation at +300 mV vs. Ag/AgCl was measured. Total assay time was 50 min and the standard curve was linear between 4 and 250 ng ml−1. The intra- and inter-assay coefficients of variation were below 9%. No cross-reactivity of the antibodies was found with other early cardiac markers and endogenous substances in whole blood did not have an interfering effect. The overall performance of the sensor, wide working range, good precision and specificity demonstrate its potential usefulness for early assessment of AMI.