Single Wall Carbon Nanotube and Magnetic Bead Based Electrochemical Immunosensor for Sensitive Detection of Salivary Secretory Immunoglobulin A

Title:Single Wall Carbon Nanotube and Magnetic Bead Based Electrochemical Immunosensor for Sensitive Detection of Salivary Secretory Immunoglobulin A

Volume: 14 Issue: 4

Author(s): Syazana Abdullah Lim, David Koh and Minhaz Uddin Ahmed*

Affiliation:

• Biosensors and Biotechnology Laboratory, Chemical Science Programme, Faculty of Science, Universiti Brunei Daruusalam, Jalan Tungku Link, Gadong, BE 1410, Brunei,Brunei Darussalam

Keywords: Salivary immunoglobulin A, magnetic beads, amperometric immunosensor, indirect competitive immunoassay format, carboxylic modified MBs, antibody.

Abstract: Background: Saliva is a clear and complex biological fluid with pH value in the range of 6.0 – 7.0 that is produced from three main salivary glands. Recently, saliva has been recognized as a noninvasive diagnostic tool for surveillance of disease and in healthcare research and promotion since saliva is able to indicate a wide range of health and disease conditions with distinctive advantages over serum. In this study, we have fabricated an electrochemical immunosensor for sensitive detection of salivary immunoglobulin A (sIgA) based on indirect competitive format and using magnetic beads (MBs) as reaction carrier.

Methods: Firstly, carboxylic modified MBs were covalently attached to sIgA with N-(3- dimethylaminopropyl)- N’-ethylcarbodiimide and N-hydroxysulfosuccinimide. Then, the sIgA immobilized on MBs and free sIgA in solution was allowed to compete with each other for fixed amount of primary antibody. Upon the formation of immunocomplex, biotin-conjugated secondary antibody was incubated with the modified MBs following affinity binding with streptavidin-hydrogen peroxidase. For amperometric measurement, the resulting MBs were immobilized onto the surface of single-walled carbon nanotube working electrode with a strong external magnet and subsequently 3,3’,5,5’,- tetramethylbenzidine and hydrogen peroxide were introduced that functioned as electron transfer mediator and as enzyme substrate, respectively.

Results: The proposed MB-based immunosensor demonstrated a wide linear range of 5 pg/mL – 10 ng/mL and a low detection limit of 5 pg/mL with excellent reproducibility.

Conclusion: The developed immunosensor has great potential for clinical diagnostic application to monitor sIgA in field setting.

Cite this article as:

Lim Abdullah Syazana, Koh David and Ahmed Minhaz Uddin*, Single Wall Carbon Nanotube and Magnetic Bead Based Electrochemical Immunosensor for Sensitive Detection of Salivary Secretory Immunoglobulin A, Current Analytical Chemistry 2018; 14 (4) . https://dx.doi.org/10.2174/2211556006666170525161225