Label-free detection of fibrinogen based on the fibrinogen-enhanced peroxidase activity of a fibrinogen–hemin composite

Abstract

A simple, label-free colorimetric method for the determination of fibrinogen (Fib) in plasma is presented. In this work, it was observed that Fib interacted with hemin to form a hemin–Fib composite. Because Fib prevented hemin from the formation of m-oxo-dimers, the hemin–Fib composite possesses excellent peroxidase-like activity. Importantly, the peroxidase-like activity of Fib–hemin increased with the increase in the Fib. This allows us to utilize the H₂O₂–ABTS colorimetric system for the quantitative analysis of Fib. This optimized method provided a linear determination range of 2.0–100 pM with a correlation of 0.9975. The limit of detection for Fib was experimentally determined to be 0.7 pM based on a signal-to-noise ratio (S/N) of 3. This novel approach provides a rapid, sensitive, cost efficient and robust bioassay for detection of Fib in pathology and clinical applications.