Design and construction of a label free aptasensor for electrochemical detection of sodium diclofenac

► A label free electrochemical aptasensor for determination of sodium diclofenac is introduced. ► Sodium diclofenac was sandwiched between two aptamers on the surface of a glassy carbon electrode. ► DCF concentration in a human blood serum sample was measured successfully. ► The plasmonic band of Ag-NPs upon the modification with the aptamer and DCF have been investigated.