title: Quantum-dot-basedFörster resonance energy transfer immunoassay for sensitive clinical diagnostics of low-volume serum samples.
abstract: A myriad of quantum dot (QD) biosensor examples have emerged from the literature over the past decade, but despite their photophysical advantages, QDs have yet to find acceptance as standard fluorescent reagents in clinical diagnostics. Lack of reproducible, stable, and robust immunoassays using easily prepared QD-antibody conjugates has historically plagued this field, preventing researchers from advancing the deeper issues concerning assay sensitivity and clinically relevant detection limits on low-volume serum samples. Here we demonstrate a ratiometric multiplexable FRET immunoassay using Tb donors and QD acceptors, which overcomes all the aforementioned limitations toward application in clinical diagnostics. We demonstrate the determination of prostate specific antigen (PSA) in 50 μL serum samples with subnanomolar (1.6 ng/mL) detection limits using time-gated detection and two different QD colors. This concentration is well below the clinical cutoff value of PSA, which demonstrates the possibility of direct integration into real-life in vitro diagnostics. The application of IgG, F(ab')2, and F(ab) antibodies makes our homogeneous immunoassay highly flexible and ready-to-use for the sensitive and specific homogeneous detection of many different biomarkers.
authors.affiliation: Institut d'Electronique Fondamentale, Université Paris-Sud, 91405 Orsay Cedex, France.
authors.forename: K David
authors.initials: KD
authors.lastname: Wegner
authors.forename: Zongwen
authors.initials: Z
authors.lastname: Jin
authors.forename: Stina
authors.initials: S
authors.lastname: Lindén
authors.forename: Travis L
authors.initials: TL
authors.lastname: Jennings
authors.forename: Niko
authors.initials: N
authors.lastname: Hildebrandt
mesh_terms: D000042:Absorption; D015374:Biosensing Techniques / Q000379:methods*; D001774:Blood Chemical Analysis / Q000379:methods; D004735:Energy Transfer; D031541:Fluorescence Resonance Energy Transfer / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007128:Immunoglobulin Fragments / Q000276:immunology; D007074:Immunoglobulin G / Q000737:chemistry / Q000276:immunology; D057230:Limit of Detection; D008297:Male; D055095:Optics and Photonics; D017430:Prostate-Specific Antigen / Q000276:immunology; D045663:Quantum Dots; D044967:Serum / Q000737:chemistry*; D013696:Temperature
chemical_list: D007128:Immunoglobulin Fragments; D007074:Immunoglobulin G; D017430:Prostate-Specific Antigen