An impedimetric aptasensor based on water soluble cadmium telluride (CdTe) quantum dots (QDs) for detection of ibuprofen

An impedimetric aptasensor is reported here for the ultrasensitive detection of ibuprofen (IBP) using water soluble cadmium telluride (CdTe) quantum dots (QDs) as the efficient electrochemical platform. The CdTe QD layer was used as a quite suitable interface for the subsequent conjugation of the aptamer (Apt). CdTe QDs owing to their large surface area, caused the increase in the amount of Apt absorbed on the modified electrode which resulted in enhanced signal response. Also, their ion centers may have had a major role on amplifying the signal. In this method, the IBP specific Apt is immobilized onto the glassy carbon electrode (GCE) and through the specific binding of the IBP and its Apt, the IBP/Apt complex is formed. More importantly, the developed strategy shows highly sensitive responses to IBP, responses more sensitive than those of previously reported methods. Under optimal conditions, IBP was detected by electrochemical impedance spectroscopy (EIS) quantitatively. Calibration curve for IBP concentration was linear up to 20 mu M and the detection limit was as low as 16 pM. The developed aptasensor was successfully used to detect IBP in real samples such as spiked human serum and pharmaceutical formulations. The use of CdTe QDs as a unique platform and the elimination of antibodies or enzymes for the amplified detection of the IBP, are the advantages of the developed aptasensor. Our work will shed light on new diagnostic applications of aptasensors and is quite promising as an alternative approach for various target assays. (C) 2015 Elsevier B.V. All rights reserved.