Title :
Fast and Sensitive Measurement of Specific Antigen-Antibody Binding Reactions With Magnetic Nanoparticles and HTS SQUID
Author :
Öisjöen, Fredrik ; Schneiderman, Justin Fleer ; Zaborowska, Magdalena ; Shunmugavel, Karthikeyan ; Magnelind, Per ; Kalaboukhov, Alexey ; Petersson, Karolina ; Astalan, Andrea Prieto ; Johansson, Christer ; Winkler, Dag
Author_Institution :
Chalmers Univ. of Technol., Goteborg, Sweden
fDate :
6/1/2009 12:00:00 AM
Abstract :
We have developed an HTS SQUID system for both time and frequency domain measurements of magnetic signals from the Brownian relaxation of liquid-suspended magnetic nanoparticles (MNPs) coated with antibodies. A planar YBa2Cu3O7-x dc SQUID gradiometer with a baseline of 3 mm allows stable operation of the measurement system in an unshielded environment. Agglomeration of MNPs induced by prostate specific antigen-antibody binding complexes is characterized with our system and benchmarked with frequency domain measurements performed by Imego AB using an induction coil magnetometer. We estimate an upper bound for our immunoassay analyte sensitivity of 1.8 ng/radicHz.
Keywords :
Brownian motion; SQUID magnetometers; barium compounds; biomagnetism; biomedical equipment; high-temperature superconductors; magnetic particles; nanobiotechnology; nanoparticles; suspensions; yttrium compounds; Brownian relaxation; HTS SQUID system; YBa2Cu3O7-x; agglomeration; biomagnetics; frequency domain measurement; immunoassay analyte sensitivity; induction coil magnetometer; liquid-suspended magnetic nanoparticles; magnetic signals; planar dc SQUID gradiometer; prostate specific antigen-antibody binding complexes; size 3 mm; specific antigen-antibody binding reactions; time domain measurement; Benchmark; SQUIDs; biomagnetics; immunoassay; magnetic nanoparticles;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2009.2019246
