Related Experiment Video
Updated: Jun 1, 2026
Fully Automated Centrifugal Microfluidic Device for Ultrasensitive Protein Detection from Whole Blood
Published on: April 16, 2016
Electrochemical immunoassay platform for high sensitivity protein detection based on redox-modified carbon nanotube
Wilanee Chunglok1, Porntip Khownarumit, Patsamon Rijiravanich
1School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkhuntien Campus, Bangkok, 10150, Thailand.
Abstract:
We report a highly sensitive immunoassay protocol based on the use of redox-modified multi-walled carbon nanotubes (MWNTs) as electrochemical labels. The MWNTs were coated with methylene blue (MB) at an optically-determined loading of 3.41 × 10(-3) mol g(-1), and were then attached to secondary antibodies (Ab(2)) by adsorption. As a model analyte mouse IgG was collected by primary antibody (Ab(1))-coated magnetic beads. Following binding of the MB-MWNT-Ab(2) conjugates, IgG could be measured by MB reduction. Using differential pulse voltammetry for quantification, IgG was calibrated with a dynamic range of 0.1 pg mL(-1) to 100 pg mL(-1). Given the different possible Ab(1)-MB-MWNT-Ab(2) orientations on the magnetic beads, it was likely that not all the MB communicated with the electrode. A greater quantity of MB could be accessed by using the Fe(CN)(6)(3-/4-) redox couple as a solution phase mediator. This enabled us to lower the dynamic range down to 5 fg mL(-1) to 100 fg mL(-1).
