Impedimetric immunosensor for human serum albumin detection on a direct aldehyde-functionalized silicon nitride surface

Abstract : In this work we report the fabrication and characterization of a label-free impedimetric immunosensor based on a silicon nitride (Si3N4) surface for the specific detection of human serum albumin (HSA) proteins. Silicon nitride provides several advantages compared with other materials commonly used, such as gold, and in particular in solid-state physics for electronic-based biosensors. However, few Si3N4-based biosensors have been developed; the lack of an efficient and direct protocol for the integration of biological elements with silicon-based substrates is still one of its the main drawbacks. Here, we use a direct functionalization method for the direct covalent binding of monoclonal anti-HSA antibodies on an aldehyde-functionalized Si-p/SiO2/Si3N4 structure. This methodology, in contrast with most of the protocols reported in literature, requires less chemical reagents, it is less time-consuming and it does not need any chemical activation. The detection capability of the immunosensor was tested by performing non-faradaic electrochemical impedance spectroscopy (EIS) measurements for the specific detection of HSA proteins. Protein concentrations within the linear range of 10−13-10−7 M were detected, showing a sensitivity of 0.128 Ω μM−1 and a limit of detection of 10−14 M. The specificity of the sensor was also addressed by studying the interferences with a similar protein, bovine serum albumin. The results obtained show that the antibodies were efficiently immobilized and the proteins detected specifically, thus, establishing the basis and the potential applicability of the developed silicon nitride-based immunosensor for the detection of proteins in real and more complex samples. Highlights An impedimetric label-free immunosensor was developed for the specific detection of human serum albumin proteins. Anti-HSA antibodies were covalently immobilized on silicon nitride surfaces using a direct functionalization methodology. Silicon nitride offers multiple advantages compared to other common materials. The proposed sensor has high sensitivity and good selectivity for the detection of HSA proteins.
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Analytica Chimica Acta, Elsevier Masson, 2012, 720, pp.43-48. 〈10.1016/j.aca.2012.01.031〉
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https://hal.archives-ouvertes.fr/hal-00703651
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Soumis le : lundi 4 juin 2012 - 10:21:14
Dernière modification le : jeudi 8 février 2018 - 11:10:19

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David Caballero, Elena Martinez, Joan Bausells, Abdelhamid Errachid, Josep Samitier. Impedimetric immunosensor for human serum albumin detection on a direct aldehyde-functionalized silicon nitride surface. Analytica Chimica Acta, Elsevier Masson, 2012, 720, pp.43-48. 〈10.1016/j.aca.2012.01.031〉. 〈hal-00703651〉

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