A facile voltammetric method for detection of heparin in plasma based on the polyethylenimine modified electrode

Abstract

The development of a technically simple yet effective method for the quantification of heparin in plasma is of great importance because of its high biological and clinical relevance. This study demonstrates a facile and cost-effective voltammetric method for detection of heparin in plasma based on the polyethylenimine (PEI) modified electrode. Herein, PEI was immobilized onto the electrode surface via carbon nanotubes and the redox probe ferricyanide (i.e., Fe(CN)₆³⁻) was afterwards confined owing to the electrostatic interaction between Fe(CN)₆³⁻ and PEI. The presence of heparin caused Fe(CN)₆³⁻ to be removed from the electrode surface because of the higher affinity of PEI toward heparin than toward Fe(CN)₆³⁻, which validates heparin detection using the current decrease of confined Fe(CN)₆³⁻ as the signal readout. The method shows dynamic linear concentration of heparin in the ranges of 0.1–2 U mL⁻¹ and 2–20 U mL⁻¹ which cover the clinically relevant levels of heparin. With the animal experiments, the method has been demonstrated to be highly selective and quite effective for heparin level quantification in plasma. This study offers a facile voltammetric method for heparin detection with less technically demanding and simple operating procedures, which could be envisaged to find more biological and clinical applications associated with heparin.