A1 Refereed original research article in a scientific journal

Ultrasensitive Protein Concentration Measurement Based on Particle Adsorption and Fluorescence Quenching




AuthorsPihlasalo S, Kirjavainen J, Hanninen P, Harma H

PublisherAmerican Chemical Society ACS

Publication year2009

Journal:Analytical Chemistry

Journal name in sourceANALYTICAL CHEMISTRY

Journal acronymANAL CHEM

Volume81

Issue12

First page 4995

Last page5000

Number of pages6

ISSN0003-2700

DOIhttps://doi.org/10.1021/ac9001657


Abstract
A new easy-to-use method for quantification of proteins in solution has been developed. It is based on adsorption competition of the sample protein and fluorescently labeled bovine serum albumin (BSA) onto gold particles. The protein concentration is determined by observing the magnitude of fluorescence altered by quenching the fluorescence on the gold particles in a homogeneous assay format. Under optimal low pH conditions, the assay allowed the determination of picogram quantities (7.0 mu g/L) of proteins with an average variation of 4.5% in a 10 min assay. The assay sensitivity was more than 10-fold improved from those of the commonly used most sensitive commercial methods. In addition, the particle sensor provides a simple and rapid assay format without requirements for hazardous test compounds and elevated temperature. Eleven different proteins were tested with the constructed sensor exhibiting a protein-to-protein variability less than 15% allowing protein concentration measurements without the need for recalibration of different proteins.



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