A tandem giant magnetoresistance assay for one-shot quantification of clinically relevant concentrations of N-terminal pro-B-type natriuretic peptide in human blood

We report a microfluidic sandwich immunoassay constructed around a dual-giant magnetoresistance (GMR) sensor array to quantify the heart failure biomarker NT-proBNP in human plasma at the clinically relevant concentration levels between 15 pg/mL and 40 ng/mL. The broad dynamic range was achieved by differential coating of two identical GMR sensors operated in tandem, and combining two standard curves. The detection limit was determined as 5 pg/mL. The assay, involving 53 plasma samples from patients with different cardiovascular diseases, was validated against the Roche Cobas e411 analyzer. The salient features of this system are its wide concentration range, low detection limit, small sample volume requirement (50 mu L), and the need for a short measurement time of 15 min, making it a prospective candidate for practical use in point of care analysis.

Automated summary

A microfluidic sandwich immunoassay utilizing a dual-GMR sensor array was reported for quantifying heart failure biomarker NT-proBNP in human plasma, with a broad dynamic range and low detection limit. The system demonstrated the ability to accurately analyze samples from patients with different cardiovascular diseases, showing potential for practical use in point-of-care analysis due to its wide concentration range and short measurement time.