Electrical Characterization of a Thiol SAM on Gold as a First Step for the Fabrication of Immunosensors based on a Quartz Crystal Microbalance

• Published in: Sensors (Basel, Switzerland) Vol. 4; no. 6; pp. 105 - 114
• Main Authors: Tlili, Asma, Abdelghani, Adnane, Hleli, Salwa, Maaref, Mhamed A.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 30-08-2004; Molecular Diversity Preservation International (MDPI)
• Subjects: Antibodies; antibody; antigen; Antigens; Biosensors; cyclic voltammetry; Dielectric properties; Electrodes; Gold; impedance spectroscopy; QCM; Sensors; Spectrum analysis; Voltammetry; France
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s40670105

In order to develop a robust biosensor based on quartz crystal microbalance technique for antigen detection, a control of the steps of the surface functionalization has been performed by impedance spectroscopy. The gold electrode is functionalized with the self-assembled monolayer technique. The high insulating properties of the acidic thiol monolayer has been characterized with cyclic voltammetry and impedance spectroscopy. The modified surface is activated with N-hydroxysuccinimide(NHS) and 1-(3-(dimethylamino)propyl)-3-ethylcarbodimide hydrochloride(EDC) cross-linker for antibody coupling. The non-specific sites are blocked with bovin serum albumine molecules. Different concentrations of antigen can be detected with a good reversibility in real time with the quartz crystal microbalance.