Application of NMR for quantification of magnetic nanoparticles and development of paper-based assay

A S Minin,M B Rayev,I V Byzov,I V Zubarev,A A Mysik,A Ye Yermakov,S V Zhakov,P V Khramtsov,M A Uymin,A V Volegov

doi:10.1088/1742-6596/1389/1/012069

Abstract

H1 NMR relaxometry is a method that is extremely sensitive to the presence of magnetic nanoparticles, which significantly affect the transverse relaxation time of the water proton. Accordingly, the use of magnetic nanoparticles as labels allows detection of even extremely small amounts of the test substance. This paper analyzes the prospects for applying the method of solid-phase NMR-relaxometric determination of biologically active molecules. The nitrocellulose membranes are chosen as a solid phase and nanoparticles based on iron core with a carbon shell are used as magnetic labels. The possibility of detecting small concentrations of magnetic particles in porous medium is demonstrated. Finally, the ability to detect extremely low concentrations of an analyte, in this case, streptavidin protein (0.5 ng/ml to 100 ng/ml), which is actively used in various fields of biology and medicine, is demonstrated.

Highlights

IntroductionPaper-based assays utilizing porous membranes (usually cellulose or nitrocellulose) as solid support allow simple and rapid detection of various analytes: protein markers, DNA, cells, etc [1]
Paper-based assays utilizing porous membranes as solid support allow simple and rapid detection of various analytes: protein markers, DNA, cells, etc [1]
The value of T2 depends on the local magnetic field gradient, which in both cases is created by the Magnetic nanoparticles (MNPs) [22]

Summary

Introduction

Paper-based assays utilizing porous membranes (usually cellulose or nitrocellulose) as solid support allow simple and rapid detection of various analytes: protein markers, DNA, cells, etc [1]. There are various formats of paper-based assays: lateral flow assays (LFIA), microfluidic paper-based analytical devices (μPADs), flow through assays and immuno-dot blot [2, 3, 4, 5]. Most of such test-system can be used at the point-of-care, many of them are non-instrumental, application of portable and simple measuring devices can greatly increase the versatility of their applications and enhance performance [6, 4].

Methods

Results

Conclusion