Ultra-sensitive magnetoreduction measurement system and ultra-sensitive, wash-free assay using the same

摘要

An ultra-sensitive, wash-free method for quantitatively determining the concentration of biomolecules in a sample solution is provided. The sensitivity of the method is 1 ppt or below. The method includes providing a reagent containing magnetic nanoparticles and measuring the ac magnetic susceptibility of the reagent. Then, a sample solution containing either multiple-active epitope biomolecules or single-active-epitope biomolecules is mixed with the reagent. The ac magnetic susceptibility of the reagent after the association with the biomolecules is measured. Thereafter, the difference in the ac magnetic susceptibility of the reagent before and after the association with the biomolecules is measured and the concentration of biomolecules in the sample solution is determined.