Biosensing of telomerase antigen using sandwich type immunosensor based on poly(β-Cyclodextrin) decorated by Au@Pt nanoparticles: An innovative immune-platform toward early-stage identification of cancer

Abstract

Telomeres maintain genomic integrity in normal cells and their gradual shortening during successive cell divisions causes chromosomal instability. Sensitive and reliable analysis of telomerase activity is essential for clinical diagnosis of cancer. In this study, a novel sandwich type and label-free electrochemical immunosensor was developed for the efficient monitoring of telomerase antigen based on Au@Pt nano-alloy and Poly (beta-Cyclodextrin (β-CD)) functionalized with AuNPs-DDT and toluidine blue. For the first time, KCC-1-NH-CS2 was used as an advanced substrate to encapsulation of biotinylated antibody (Ab1) of telomerase towards maintain of antibody in the stress condition of solution. By providing a wide surface to volume using dendritic fibrous Nanosilica for the effective immobilization of the biotinylated antibody, a sensitive immunosensor was designed for the probing of antigen–antibody immunocomplex. Interestingly, the P(β-CD) assured the bioactivity and stability of the immobilized 2-AG antibody. To complete the capping part of the immunosensor (reporter), an HRP-conjugated antibody of telomerase (secondary antibody (Ab2)) was coupled to the surface of a gold electrode (AuE) modified by P(β-CD), as well as a predominantly biotinylated antibody (Ab1, encapsulated into the KCC-1-NH-CS2). Engineered immune-platform demonstrated acceptable analytical properties (LLOQ = 0.078 IU.ml). In addition, the created biosensor shows excellent selectivity and acceptable ability for the detection of telomerase in human plasma samples with satisfactory stability which might hold great application potential in cancer analysis and clinical diagnosis. This research inspires scientists and researchers to generate and develop novel biosensor platforms for point-of-care (POC) diagnostics of telomerase. Based on accurate, sensitive, inexpensive, and time-saving futures of developed biosensor compared to other methods makes it a useful platform for future analytical works.