Protein–Conjugated Quantum Dots Interface: Binding Kinetics and Label-Free Lipid Detection
- 24 January 2014
- journal article
- research article
- Published by American Chemical Society (ACS) in Analytical Chemistry
- Vol. 86 (3), 1710-1718
- https://doi.org/10.1021/ac403543g
Abstract
We propose a label-free biosensor platform to investigate the binding kinetics using antigen–antibody interaction via electrochemical and surface plasmon resonance (SPR) techniques. The l-cysteine in situ capped cadmium sulfide (CdS; size < 7 nm) quantum dots (QDs) self-assembled on gold (Au) coated glass electrode have been covalently functionalized with apolipoprotein B-100 antibodies (AAB). This protein conjugated QDs-based electrode (AAB/CysCdS/Au) has been used to detect lipid (low density lipoprotein, LDL) biomolecules. The electrochemical impedimetric response of the AAB/CysCdS/Au biosensor shows higher sensitivity (32.8 kΩ μM–1/cm2) in the detection range, 5–120 mg/dL. Besides this, efforts have been made to investigate the kinetics of antigen–antibody interactions at the CysCdS surface. The label-free SPR response of AAB/CysCdS/Au biosensor exhibits highly specific interaction to protein (LDL) with association constant of 33.4 kM–1 s–1 indicating higher affinity toward LDL biomolecules and a dissociation constant of 0.896 ms–1. The results of these studies prove the efficacy of the CysCdS-Au platform as a high throughput compact biosensing device for investigating biomolecular interactions.Keywords
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