Objective To establish a lateral flow immunoassay (LFIA) system for rapid, economic and quantitative detection of N terminal pro brain natriuretic peptide (NT-proBNP).
Method In this study, superparamagnetic nanoparticles (MNPs) were used as labels, the immuno-nanoparticles were prepared by coupling monoclone antibody specific to NT-proBNP onto MNPs, then the immunonanoparticles were used to prepare the conjugate pad of the magnetic LFIA of NT-proBNP. Another monoclone antibody specific to NT-proBNP (capture antibody) and secondary antispecies antibodies were immobilised at test line and control line, respectively. Then the magnetic LFIA for detection of NT-proBNP were established and applied to test standard samples of different NT-proBNP concentrations. The magnetic field produced by MNPs in the test line are measured by a high sensitive magnetic assay reader. From the linear relation between magnetic signal intensities and NT-proBNP concentrations, we can achieve quantitative detection of NT-proBNP. Some factors which may influence the detection sensitivity of this system were also studied, such as the amount of antibody immobilised in the Test line and the amount of antibody per MNP.
Results The sensitivity of this magnetic LFIA of NT-proBNP was 0.01 ng/ml, the detection range was reached five orders of magnitude, and the detection time was within 15 min.
Conclusion It was showed that this magnetic LFIA of NT-proBNP has a high sensitivity, wide detection range and short detection time. It is a simple, rapid, accurate, quantitative and point-of-care testing which deserve to be spread and industrialised.
- superparamagnetic nanoparticle
- point-of-care testing
- lateral flow immunoassay