Protein鈥揅onjugated Quantum Dots Interface: Binding Kinetics and Label-Free Lipid Detection

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• 作者：Md. Azahar Ali ; S. Srivastava ; M. K. Pandey ; Ved V. Agrawal ; R. John ; B. D. Malhotra
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：February 4, 2014
• 年：2014
• 卷：86
• 期：3
• 页码：1710-1718
• 全文大小：604K
• ISSN：1520-6882

文摘

We propose a label-free biosensor platform to investigate the binding kinetics using antigen鈥揳ntibody interaction via electrochemical and surface plasmon resonance (SPR) techniques. The <span class="smallcaps">lspan>-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 k惟 渭M<sup>鈥?sup>/cm<sup>2sup>) in the detection range, 5鈥?20 mg/dL. Besides this, efforts have been made to investigate the kinetics of antigen鈥揳ntibody 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<sup>鈥?sup> s<sup>鈥?sup> indicating higher affinity toward LDL biomolecules and a dissociation constant of 0.896 ms<sup>鈥?sup>. The results of these studies prove the efficacy of the CysCdS-Au platform as a high throughput compact biosensing device for investigating biomolecular interactions.