Ultrasensitive transglutaminase based nanosensor for early detection of celiac disease in human.

A GQD/PAMAM nanohybrid modified on gold nanoparticles (AuNP) embedded in multiwalled carbon nanotubes (MWCNT) based immunosensor was developed for detection of celiac disease in human. The AuNP embedded in MWCNT were linked with thiol groups of cysteine and amino groups were further coupled with carboxyl moieties of graphene quantum dots (GQDs) using EDC-NHS cross-linking chemistry. To enhance the sensitivity of the sensor, polyamidoamine (PAMAM) dendrimer was attached with GQDs through carbodiimide coupling. The tissue transglutaminase (tTG) antigen was immobilized on PAMAM to form nanoprobe for sensing specific anti-tissue transglutaminase (anti-tTG) antibodies (immunoglobin A isotype) in human serum. The electrochemical changes after specific binding of antibody with antigen was measured cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The modifications in sensor surface were characterized using FE-SEM. The sensor is highly specific to anti-tissue transglutaminase antibodies and showed negligible response to non-specific serum proteins. The sensitivity of the sensor was 1297.14μA/cm2/pg with DPV and lower limit of detection of anti-tissue transglutaminase antibody was found 0.1fg per 6μl.