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Label free thrombin detection in presence of high concentration of albumin using an aptamer-functionalized nanoporous membrane

Gosai, Agnivo, Hau Yeah, Brendan Shin, Nilsen-Hamilton, Marit, Shrotriya, Pranav
Biosensors & bioelectronics 2019 v.126 pp. 88-95
aluminum oxide, biosensors, detection limit, diagnostic techniques, electrochemistry, epitopes, human serum albumin, humans, nanopores, oligonucleotides, point-of-care systems, thrombin
Nanoporous alumina membranes have become a ubiquitous biosensing platform for a variety of applications and aptamers are being increasingly utilized as recognition elements in protein sensing devices. Combining the advantages of the two, we report label-free sensitive detection of human α-thrombin by an aptamer-functionalized nanoporous alumina membrane using a four-electrode electrochemical cell. The sensor response to α-thrombin was determined in the presence of a high concentration (500 μM) of human serum albumin (HSA) as an interfering protein in the background. The sensor sensitivity was also characterized against γ-thrombin, which is a modified α-thrombin lacking the aptamer binding epitope. The detection limit, within an appreciable signal/noise ratio, was 10 pM of α-thrombin in presence of 500 μM HSA. The proposed scheme involves the use of minimum reagents/sample preparation steps, has appreciable response in presence of high concentrations of interfering molecules and is readily amenable to miniaturization by association with existing-chip based electrical systems for application in point-of-care diagnostic devices.