Luminescence stability improvement in liposome-based homogeneous luminescence resonance energy transfer

Abstract

A stable liposome-based time-resolved luminescence resonance energy transfer (TR-LRET) assay was developed based on the interaction of biotinylated lipids and streptavidin. Eu ion chelated to 4,4,4-trifluoro-1-(2- naphthalenyl)-1,3-butanedione and trioctylphosphine oxide was incorporated into liposomes. Acceptor-labeled streptavidin bound to biotinylated lipids of the liposomes enables TR-LRET. A stable assay performance was achieved by optimization. High Eu signal and stability, low variation, and sensitivity below 100 pM for free biotin was achieved by incorporating the chelate into liposomes containing cholesterol in a carbonate buffer. Potentially, the stable assay compared with the assay without cholesterol offers an improved platform to liposome-based detection systems. © 2013 Elsevier Inc.