A Nanobody‐on‐Quantum Dot Displacement Assay for Rapid and Sensitive Quantification of the Epidermal Growth Factor Receptor (EGFR)

• DOI: 10.1002/anie.202207797
• Publication Date: 2022-06-27T15:29:02Z
• Authors: Ruifang Su; Yu‐Tang Wu; Sofia Doulkeridou; Xue Qiu; Thomas Just Sørensen; Kimihiro Susumu; Igor L. Medintz; Paul M. P. van Be...; Niko Hildebrandt
• Keywords: [PHYS]Physics [physics]; EGFRvIII; 0301 basic medicine; 0303 health sciences; [SDV]Life Sciences [q-bio]; General Chemistry; Single-Domain Antibodies; Catalysis; Communications; [PHYS] Physics [physics]; [SDV] Life Sciences [q-bio]; ErbB Receptors; 03 medical and health sciences; Lanthanides; [CHIM] Chemical Sciences; Quantum Dots; FRET; Fluorescence Resonance Energy Transfer; [CHIM]Chemical Sciences; Nanoparticles; Terbium; Diagnostics

Abstract Biosensing approaches that combine small, engineered antibodies (nanobodies) with nanoparticles are often complicated. Here, we show nanobodies different C‐terminal tags can be efficiently attached to a range of the most widely used biocompatible semiconductor quantum dots (QDs). Direct implementation into simplified assay formats was demonstrated by designing rapid and wash‐free mix‐and‐measure immunoassay for epidermal growth factor receptor (EGFR). Terbium complex (Tb)‐labeled hexahistidine‐tagged were specifically displaced from QD surfaces via EGFR‐nanobody binding, leading an EGFR concentration‐dependent decrease Tb‐to‐QD Förster resonance energy transfer (FRET) signal. The detection limit 80±20 pM (16±4 ng mL −1 ) 3‐fold lower than clinical cut‐off concentration soluble up 10‐fold compared conventional sandwich FRET assays required pair nanobodies.