Electrochemical immunosensor for anti-tissue transglutaminase antibodies based on the in situ detection of quantum dots

A miniaturized electrochemical biosensor array with in situ detection of quantum dots (QDs) was developed for the detection of anti-transglutaminase IgG antibodies (a celiac disease biomarker) in human sera. For the fabrication of the sensor, a 8-channel screen-printed carbon electrochemical arrays were used as transducers and modified with tissue-transglutaminase by adsorption. The immunologic reaction was carried out in a few simple steps: reaction with human serum, which contains the analyte of interest, followed by the immunoreaction with anti-human IgG labeled with CdSe/ZnS QDs and electrochemical detection of Cd2+ released from QDs. All steps were performed on the screen-printed arrays as the solid support, and the detection of Cd2+ was performed in situ after acid attack of the QDs without a transfer step by voltammetric stripping. The electrochemical response was correlated with the anti-transglutaminase IgG concentration. The developed electrochemical immunosensor is a trustful screening tool for celiac disease diagnosis discriminating between positive and negative sera samples with high sensitivity.