Optical size determination of quantum dots using FRET with terbium complexes as donors

Abstract

We present the use of luminescent terbium complexes (LTCs) as FRET donors and luminescent semiconductor quantum dots (QDs) as FRET acceptors for spectroscopic ruler measurements. The LTCs were labeled to polyhistidine-appended peptides which self-assembled onto three different QDs allowing optical multiplexed measurements. Forster distances were in the range of 60-75 Å and FRET efficiencies of up to 97 % were realized. Time-resolved analysis allowed the determination of donor-acceptor separation distances. The results suggests the efficient use of our LTC-to-QD FRET systems for multiplexed optical size determination, molecular ruler measurements and multi-parameter diagnostics.