The present study describes the fabrication of an ovel electrochemical apta sensor for the label-free determination of adenosine.The immobilization surface is prepared by the modification of a glassy carbon (GC)electrode with a robust nanocomposite containing multiwalled carbon nanotubes, ionic liquid and chitosan(MWCNTs-IL-CHIT).Amine-terminated12-mercaptureprobe(ssDNA1)is covalently attached on to the nanocomposite using glutaraldehyde (GA)as the linking agent,a32-meradenosine- specific aptamer (ssDNA2) immobilized on to the electrode surface through hybridization with the ssDNA1 and methyleneblue (MB)used as there doxprobe. The peak current of MB decreased linearly with increasing adenosine concentration due to the formation of aptamer-adenosine complexand displacement of the aptamer from the modified electrode surface. The apta sensor showed alow detection limit of150pMandhighsensitivityof0.67 μAnM−1 at aconcentrationrangeofupto0.4 μM. Through the control experimentsperformed by using some othernucleosidessuchasguanosine,cytidineanduridine, the excellent specificity ofthissensortowardadenosinedetectionisdemonstrated.Thepotential applicability of the apta sensor is successfully applied for measuring adenosine concentration in blood serum and drug formulation samples. The here in described methodology may hold great promise for fabrication of other apta sensors and immunosensors.
