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Updated: Aug 19, 2025
Ultrasensitive Detection of Biomarkers by Using a Molecular Imprinting Based Capacitive Biosensor
Published on: February 16, 2018
Electrochemical sensor based on molecularly imprinted polymer cryogel and multiwalled carbon nanotubes for direct
Nur Indah Wardani1, Tawatchai Kangkamano2, Rodtichoti Wannapob1
1Center of Excellence for Trace Analysis and Biosensor, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand; Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand; Division of Physical Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand.
Abstract:
Insulin is the polypeptide hormone that regulates blood glucose levels. It is used as an indicator of both types of diabetes. An electrochemical insulin sensor was developed using a gold electrode modified with carboxylated multiwalled carbon nanotubes (f-MWCNTs) and molecularly imprinted polymer (MIP) cryogel. The MIP provided specific recognition sites for insulin, while the macropores of the cryogel promoted the mass transfer of insulin to the recognition sites. The f-MWCNTs increased the effective surface area and conductivity of the sensor and also reduced the potential required to oxidize insulin. Insulin oxidation was directly measured in a flow system using square wave voltammetry. This MIP cryogel/f-MWCNTs sensor provided a linear range of 0.050-1.40 pM with a very low limit of detection (LOD) of 33 fM. The sensor exhibited high selectivity and long-term stability over 10 weeks of dry storage at room temperature. The results of insulin determination in human serum using the sensor compared well with the results of the Elecsys insulin assay. The developed MIP sensor offers a promising alternative for the diagnosis and treatment of diabetes.
