Dependence of biomolecule detection on magnetic nanoparticle concentration

摘要: Abstract This paper investigates the influence of magnetic nanoparticle (MNP) concentration on biomolecule detection with particle spectroscopy (MPS). Streptavidin-coated MNPs, dominated by Brownian relaxation, are used to detect biotinylated Immunoglobulin G (IgG). The conjugation IgG onto surface functionalized MNPs enlarges their hydrodynamic sizes, thus increasing relaxation time and changing MPS signal. Experimental samples prepared relaxation-dominated MNP different mole concentrations from 6.67 0.67 nM 0 8.33 nM. results ac susceptibility spectra indicate that increases 0.85 1.20 ms decreasing at a given 5 nM. show ratio 3rd 1st harmonics decreases more significantly lower concentration. absolute variation in is characterize measurement sensitivity IgG. It shows 1.68 × 10−3 12.25 × 10−3 nM−1 an excitation frequency 180 Hz. study demonstrates can improve biomolecules range 180 1418 Hz. We emphasize our findings great importance reach highly sensitive approach for detection.