Biofunctionalized reduced (graphene quantum dots-graphene oxide) nanohybrid modified screen printed electrode for electrochemical detection of thyroid stimulating hormone.

A selective and sensitive surface modified screen printed carbon electrode (SPCE) with reduced (graphene quantum dots-graphene oxide), r(GQD/GO) nanohybrid, is reported for the electrochemical detection of thyroid stimulating hormone (TSH). TSH specific monoclonal antibody was immobilized on r(GQD/GO)/SPCE by wet method to obtain a bioelectrode. The bioelectrode was characterized with microscopic, spectroscopic and electrochemical techniques and the differential pulse voltammetry (DPV) measurement was used for the detection of TSH in phosphate buffer saline 0.1 M PBS (pH 7.4; 0.1 M KCl). The bioelectrode showed a linear DPV response at 0.16 V to TSH over the concentration range of 1 nIU mL-1-100 μIU mL-1 with a lowest detection limit of 0.18 nIU mL-1 and sensitivity of 2.15 μA per decade of TSH concentration. The biosensing response with potential interferents indicates that the sensing platform is highly specific for the detection of TSH. The wide range of DPV response with good sensitivity and specificity make this bioelectrode potentially useful for abnormal upper and lower TSH level detection pertaining to both hypo and hyperthyroidism.