A label-free amperometric immunosensor for alpha-fetoprotein determination based on highly ordered porous multi-walled carbon nanotubes/silica nanoparticles array platform

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• 作者：Ru-Ping Liang  ; [Author Vitae] ; Zhong-Xia Wang  ; [Author Vitae] ; Li Zhang  ; [Author Vitae] ; Jian-Ding Qiu ; ^{jdqiu@ncu.edu.cn}  ; [Author Vitae]
• 关键词：Silica nanoparticles array ; Multi-walled carbon nanotubes ; Galvanostatic deposition ; Alpha-fetoprotein ; Immunosensors
• 刊名：Sensors and Actuators B: Chemical
• 出版年：2012
• 出版时间：20 May, 2012
• 年：2012
• 卷：166-167
• 期：Complete
• 页码：569-575
• 全文大小：945 K

文摘

In this contribution, we develop a novel type of multi-walled carbon nanotubes/silica nanoparticles array (MWCNTs/SiO₂) composite by the galvanostatic deposition technique. In this process, MWCNTs were mixed with ammonium fluorosilicate to form a doped precursory sol solution, the electrochemically generated hydroxyl ions at negative potentials promote the hydrolysis of ammonium fluorosilicate, and the simultaneously generated hydrogen bubbles assist the formation of three-dimensional porous silica matrix, further facilitating the construction of SiO₂ NPs array with uniform distribution, as confirmed by scanning electron microscopy. The formation of SiO₂ NPs array provides a higher surface area and biocompatible microenvironment for retaining the native activity of the immobilized biomolecules. Further incorporation of MWCNTs into SiO₂ NPs array improves the electronic conductivity and enhances the electroactive surface area of the film, making the fabricated three-dimensional porous MWCNTs/SiO₂ electrode an ideal platform for further immobilization of alpha-fetoprotein (AFP), as a model protein. This method achieves ultrasensitive detection of AFP antigen with ferricyanide as a probe. The obtained results provided a linear response range from 0.1 to 30.0 ng mL^? AFP antigen with a lower detection limit of 0.018 ng mL^?. This work implies that the biocompatible and controllable three-dimensional porous SiO₂ NPs array possessed potential applications for biosensing.