Sub-attomolar detection of cholera toxin using a label-free capacitive immunosensor
- 25 January 2010
- journal article
- research article
- Published by Elsevier BV in Biosensors and Bioelectronics
- Vol. 25 (8), 1977-1983
- https://doi.org/10.1016/j.bios.2010.01.020
Abstract
A label-free immunosensor for the direct detection of cholera toxin (CT) at sub-attomolar level has been developed based on potential-step capacitance measurements. Anti-CT antibody was adsorbed on gold nanoparticles (AuNPs) incorporated on a polytyramine-modified gold electrode. The concentration of CT was determined by detecting the change of capacitance caused by the formation of antibody–antigen complexes. By using AuNPs adsorbed to the sensing surface, the signal was dramatically increased leading to a significantly more sensitive assay. In fact, under optimum conditions the immunosensor could detect CT concentration with a limit of detection of 9 × 10−20 M or 0.09 aM, with a dynamic range between 0.1 aM and 10 pM. Good analytical reproducibility could be obtained by injecting CT up to 36 times with an RSD of 2.5%. In addition, good performance of the developed immunosensor was achieved when applied to turbid water samples collected from a local stream that were spiked with CT.Keywords
This publication has 30 references indexed in Scilit:
- Aptamers as recognition elements for label-free analytical devicesTrAC Trends in Analytical Chemistry, 2008
- Gold nanoparticle-based electrochemical biosensorsElectrochimica Acta, 2008
- A review on novel developments and applications of immunosensors in food analysisAnalytica Chimica Acta, 2007
- Nanomaterial labels in electrochemical immunosensors and immunoassaysTalanta, 2007
- Label‐Free Impedance Biosensors: Opportunities and ChallengesElectroanalysis, 2007
- Application of Nanoparticles in Electrochemical Sensors and BiosensorsElectroanalysis, 2006
- Continuous measurements of a binding reaction using a capacitive biosensorBiosensors and Bioelectronics, 2004
- Self‐Assembled Monolayers into the 21st Century: Recent Advances and ApplicationsElectroanalysis, 2003
- Capacitive monitoring of protein immobilization and antigen–antibody reactions on monomolecular alkylthiol films on gold electrodesBiosensors and Bioelectronics, 1997
- Capacitance Measurements of Antibody−Antigen Interactions in a Flow SystemAnalytical Chemistry, 1997