Designing and development of a nano biosensor for detection of cis-p tau protein

Abstract

Cognitive disorders and memory loss in different stages and in severe cases this disease could be evolved to dementia and even death. According to the WHO reports, about 17 million people suffer from Alzheimer's disease and number of people with Alzheimer's will get more than triple by 2050. Objectives :Nowadays, studies on the pathogenesis of this disease, which mainly includes tau protein (total and phosphorylated forms (p-tau)) makes this possible to properly monitor the progression of Alzheimer's disease.Methods and materials: In this study, an electrochemical immunosensor was developed for specific detection of Alzheimer's disease using cis-p-tau antibody as biorecognition element. ZIF-Pt based nanocomposite was applied as conductiove and high surface area platform, which was coating on the glassy carbon electrode (GCE) by electrochemical method, cyclic voltammetry (CV). This nanocomposit was characterized by SEM and FTIR. Then, Antibody of cis-p-tau was covalently immobilized on the modified GCE via EDC/NHS coupling chemistry. Finally, the target protein was senstivily captured by the designed immunosensor. Different electrochemical techniques were applied for evaluation of the developed immunosensor. Also, the modification steps and the electrode morphology were characterized by SEM imaging. Result:Finally, after passing all optimization steps, the acceptable detection limit of 10-14 M and linear dynamic range of 10-9-10-14 M were obtaned, respectively. As a proof of concent, the designed immunosensor was desirably applied for evaluation of cis-p-tau in different Alzheimer's suffering patients at different stages. Consequently, the prepared biosensor is capable to use as reference test in biomedical laboratories.Discusssion:An ultra-sensitive sensor was designed to determine low concentration of Cis-p-tau in standard samples as well as human plasma samples. Considering the unique features of immunosensor such as stable immobilization of the antibody on a new type of substrate the capability towards determination low concentrations of protein in femtomolar range, this sensor can be used in clinical models.