Sensitive quantitative protein concentration method using luminescent resonance energy transfer on a layer-by-layer europium(III) chelate particle sensor

: Härmä H., Dähne L., Pihlasalo S., Suojanen J., Peltonen J., Hänninen P.

: 2008

Analytical Chemistry

: Analytical Chemistry

: 80

: 24

: 9781

: 9786

: 6

: 0003-2700

DOI: https://doi.org/10.1021/ac801960c

: http://api.elsevier.com/content/abstract/scopus_id:58149140102

A particle-based protein quantification method was developed. The method relies on adsorption of proteins on particles and time-resolved fluorescence resonance energy transfer (TR-FRET). Layer-by-layer (LbL) particles containing europium(III) chelate donor were prepared. A protein labeled with an acceptor was adsorbed onto the particles and near-infrared energy transfer signal was detected in time-gated detection mode. Sample proteins efficiently occupied the particle surface preventing binding of the acceptor-labeled protein leading to a particle sensor with a significant signal change. We detected subnanomolar protein concentration using the rapid and simple mix-and-measure method with a coefficient of variation below 10%. Compared to known protein concentration methods, the developed method required no hazardous substances or elevated temperature to reach the high-sensitivity level. © 2008 American Chemical Society.