A new approach for bioassays based on frequency- and time-domain measurements of magnetic nanoparticles
Journal article, 2010

We demonstrate a one-step wash-free bioassay measurement system capable of tracking biochemical binding events. Our approach combines the high resolution of frequency- and high speed of time-domain measurements in a single device in combination with a fast one-step bioassay. The one-step nature of our magnetic nanoparticle (MNP) based assay reduces the time between sample extraction and quantitative results while mitigating the risks of contamination related to washing steps. Our method also enables tracking of binding events, providing the possibility of, for example, investigation of how chemical/biological environments affect the rate of a binding process or study of the action of certain drugs. We detect specific biological binding events occurring on the surfaces of fluid-suspended MNPs that modify their magnetic relaxation behavior. Herein. we extrapolate a modest sensitivity to analyte of 100 ng/ml with the present setup using our rapid one-step bioassay. More importantly, we determine the size-distributions of the MNP systems with theoretical fits to our data obtained from the two complementary measurement modalities and demonstrate quantitative agreement between them. (

magnetorelaxometry

AC-susceptibility

prostate-specific antigen

particles

cancer

Bioassay

biomolecules

Magnetic nanoparticles

biological immunoassays

Magnetorelaxometry

SQUID

assay

Author

Fredrik Öisjöen

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Justin Schneiderman

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Andrea Prieto Astalan

Imego AB - The Institute of Micro and Nanotechnology

Alexei Kalaboukhov

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

C. Johansson

Imego AB - The Institute of Micro and Nanotechnology

Dag Winkler

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Biosensors and Bioelectronics

0956-5663 (ISSN) 18734235 (eISSN)

Vol. 25 5 1008-1013

Subject Categories

Biophysics

DOI

10.1016/j.bios.2009.09.013

PubMed

19822413

More information

Created

10/8/2017