In situ deposition of Prussian blue on mesoporous carbon nanosphere for sensitive electrochemical immunoassay.
A Prussian blue (PB) functionalized mesoporous carbon nanosphere (MCN) composite was prepared for loading signal antibody and high-content glucose oxidase (GOD) to obtain a new nanoprobe for sensitive electrochemical immunoassay. The MCN nanocarrier with an average diameter of 180 nm was synthesized by using mesoporous silica nanosphere as a hard template in combination with a hydrothermal carbonization method. This hydrophilic carbon nanomaterial provided an ideal platform for in situ deposition of high-content PB to form the MCN-PB nanocomposite. Based on the step-wise assembly of polyelectrolyte and gold nanoparticles (Au NPs) on the negative-charged nanocomposite, signal antibody and high-content GOD were loaded on this nanocarrier to obtain the nanoprobe. After a sandwich immunoreaction at an Au NPs-modified screen-printed carbon electrode based immunosensor, the nanoprobes were quantitatively captured on the electrode surface to produce sensitive electrochemical response with a PB-mediated GOD catalytic reaction for immunoassay. The high loading of PB and GOD on the nanoprobe greatly amplified the electrochemical signal, leading to the development of a new immunoassay method with high sensitivity. Using human immunoglobulin G as a model analyte, excellent analytical performance including a wide linear range from 0.01 to 100 ng/mL and a low detection limit down to 7.8 pg/mL was obtained. Additionally, the immunosensor showed high specificity, satisfactory stability and repeatability as well as acceptable reliability. The PB-mediated GOD electrochemical system well excluded the conventional interference from the dissolved oxygen. Thus this immunoassay method provides great potentials for practical applications.
['Lai|Guosong|G|', 'Zhang|Haili|H|', 'Yu|Aimin|A|', 'Ju|Huangxian|H|']
D015374:Biosensing Techniques D002244:Carbon D020099:Coated Materials, Biocompatible D003217:Conductometry D004566:Electrodes D004800:Enzymes, Immobilized D004867:Equipment Design D019544:Equipment Failure Analysis D005295:Ferrocyanides D005947:Glucose D005949:Glucose Oxidase D007118:Immunoassay D058608:Nanopores D054118:Nanospheres D016062:Porosity D015203:Reproducibility of Results D012680:Sensitivity and Specificity
Prussian blue Carbon nanosphere Electrochemical immunoassay Biosensor Signal amplification