Detection of low-concentration superparamagnetic nanoparticles using an integrated radio frequency magnetic biosensor

作者：Devkota J; Wang C; Ruiz A; Mohapatra S; Mukherjee P; Srikanth H; Phan M H^*

来源：Journal of Applied Physics, 2013, 113(10): 104701.

DOI：10.1063/1.4795134

Improving the sensitivity of existing biosensors for highly sensitive detection of magnetic nanoparticles as biomarkers in biological systems is an important and challenging task. Here, we propose a method of combining the magneto-resistance (MR), magneto-reactance (MX), and magneto-impedance (MI) effects to develop an integrated magnetic biosensor with tunable and enhanced sensitivity. A systematic study of the 7 nm Fe3O4 nanoparticle concentration dependence of MR, MX, and MI ratios of a soft ferromagnetic amorphous ribbon shows that these ratios first increase sharply with increase in particle concentration (0-124 nM) and then remain almost unchanged for higher concentrations (124nM-1240 nM). The MX-based biosensor shows the highest sensitivity. With this biosensor, similar to 2.1 x 101(17) nm Fe3O4 nanoparticles can be detected over a detection area of 2.0 x 10(5) mu m 2, which is comparable to a superconducting quantum interference device biosensor that detects the presence of similar to 1 x 10(8) 11 nm Fe3O4 nanoparticles over a detection area of 6.8 x 10(4)l mu m(2). The proposed biosensor can detect low and various concentrations of superparamagnetic nanoparticles (below 10 nm in size), which is of practical importance in biosensing applications.

• 出版日期2013-3-14