Dual signal amplification coupling dual inhibition effect for fabricating photoelectrochemical chlorpyrifos biosensor

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• 作者：Hanping Mao^a ; ^{maohp@ujs.edu.cn" class="auth_mail" title="E-mail the corresponding author}Author Vitae ; Yuting Yan^aAuthor Vitae ; Nan Hao^bAuthor Vitae ; Qian Liu^aAuthor Vitae ; Jing Qian^bAuthor Vitae ; Saibo Chen^bAuthor Vitae ; Kun Wang^a ; ^b ; ^{wangkun@ujs.edu.cn" class="auth_mail" title="E-mail the corresponding author}Author Vitae
• 关键词：Chlorpyrifos ; CuFe2O4 ; Graphene quantum dot ; Dual signal amplification ; Dual inhibition ; Photoelectrochemical biosensor
• 刊名：Sensors & Actuators: B. Chemical
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：238
• 期：Complete
• 页码：239-248
• 全文大小：2184 K

文摘

Photoelectrochemical (PEC) detection is an attractive analytical tool as it allows for an elegant and sensitive assay. However, designing a novel detection strategy to achieve an excellent PEC analytical performance is still highly challenging. Herein we design a novel photoelectrochemical (PEC) chlorpyrifos biosensor based on dual signal amplification strategy coupling dual inhibition effect. Dual signal amplification strategy was achieved by coupling the graphene quantum dots sensitized CuFe₂O₄ magnetic nanocrystal clusters (GQDs–CuFe₂O₄ MNCs) with the amplification of enzymolysis products. In this biosensing architecture, the GQDs–CuFe₂O₄ MNCs prepared by electrostatic adsorption showed nearly 4-fold and 30-fold enhancement photocurrent compared with the pure CuFe₂O₄ MNCs and GQDs, respectively. And the contact angle measurement demonstrated that the GQDs–CuFe₂O₄ MNCs exhibited good biocompatibility. Based on all these above advantages, the GQDs–CuFe₂O₄ MNCs were immobilized on the magnetic electrode surface by a fast and simple magnetism-assisted assembly, and the acetylcholinesterase (AChE) was further coated on the surface of the as-prepared multifunctional electrode. Due to thiocholine (enzymolysis products) acts as a sacrificial electron donor to scavenge the holes, compared with the GQDs–CuFe₂O₄ MNCs modified electrode in the acetylthiocholine chloride solution, the photocurrent of the resulting AChE-based biosensor was further significantly enhanced. Based on the dual inhibition of AChE activity by chlorpyrifos and the formation of Cu-chlorpyrifos complex hindered the electron transfer of CuFe₂O₄ MNCs toward the electrode surface, the proposed AChE-based biosensor can be applied to the quantification of chlorpyrifos with a linear range from 0.001 μg mL⁻¹ to 1 μg mL⁻¹ and a detection limit of 0.3 ng mL⁻¹ (S/N = 3). This novel dual signal amplification strategy opens up a new avenue for achieving high sensitivity in the field of PEC biosensing.