A simple,sensitiveandlabel-freeaptamer-based biosensor for the detection of human immunoglobulin E (IgE) is developed using the electrochemical transduction method. A special immobilizati on inter face consisting of multi walled carbon nanotubes/ionic liquid/chitosan nanocomposite (MWCNTs/IL/Chit) is utilized to improve the conductivity and performance characteristics of the biosensor as wellas to increase the loading amount of aptamerDNA sequence.A5’-amino-terminate daptameris covalently attached onto MWCNTs/IL/Chit modified glassycarbon(GC)electrode via a linker of glutaraldehyde (GA). Methyleneblue (MB)is use dasan electrochemical indicator which is intercalated in to the aptamer through the specificinte raction with it sguanine bases. In the absence of Ig E,MB bound to the aptamer produces as trong differential pulse voltammetric (DPV) signal. But when Ig Eexists, the intercalated MB releases from the aptamer resulting an obviously decreased DPV signal. This phenomenon can be applied for human IgE detection. The peak current of MB linearly decreases with the concentration of IgE over a range of 0.5–30 nM with a detection limit of 37pM. By using Bovine serum albumin (BSA) and lysozyme, the excellent specificity of this sensing system for the detection of IgE is also demonstrated. Finally, the proposed a pta sensor is successfully used to IgE analysis in human serum sample. The obtained result is well agreed with the value obtained by the standard ELISA method. The here in described approach is expected to promote the exploitation of aptamer-based biosensors for protein as says in biochemical and biomedical studies.
