Label-free Aptasensor Array for Determination of Thrombin

KeyWord:multielectrode  aptamer  thrombin  lable free  electrochemical biosensor

Abstract:

      A label-free and sensitive aptasensor array for the determination of thrombin was developed based on thrombin binding aptamer(TBA) and the integrated gold film three-electrode array.A stable integrated gold film three-electrode array,including three gold working electrodes,a gold counter electrode and a thick-film Ag/AgCl reference electrode,was fabricated on FR-4 glass fiber substrate by the method of polyethylene adhesive masking and the gold sputtering technology.The aptasensor array was fabricated by self assembling thiolated TBA onto the surfaces of three gold working electrodes.The interaction between TBA and thrombin was monitored by the cyclic voltammetry and square wave voltammetry(SWV) using K3Fe(CN)6 as probe.When thrombin interacted with TBA,the current decreased due to the interference of bound thrombin with the transfer of K3Fe(CN)6.The oxidation peak current of K3Fe(CN)6 using SWV was linear in the range of 1.52-63 nmol/L for thrombin with a detection limit(S/N=3) of 0.92 nmol/L.The fabricated aptasensor array shows a high sensitivity,good selectivity and satisfactory regeneration.