Shamsuddin, SH, Gibson, TD, Tomlinson, DC orcid.org/0000-0003-4134-7484 et al. (3 more authors) (2021) Reagentless Affimer- and antibody-based impedimetric biosensors for CEA-detection using a novel non-conducting polymer. Biosensors and Bioelectronics, 178. 113013. ISSN 0956-5663
Abstract
Polyoctopamine (POct), an amine-functionalised non-conducting polymer, as the transducer layer in an electrochemical biosensor, is presented. This polymer offers versatile covalent coupling either through thiol linker conjugation, carboxyl or aldehyde functional groups without the requirement of pre- or post-surface activation. The colorectal cancer biomarker carcinoembryonic antigen (CEA) was selected as the target analyte, whilst an antibody and a synthetic binding protein, an Affimer, were used as distinct bioreceptors to demonstrate the versatility of polyoctopamine as a transducer polymer layer for oriented immobilisation of the bioreceptors. The electrodeposited polymer layer was characterised using cyclic voltammetry, electrochemical impedance spectroscopy, and on-sensor chemiluminescent blotting. The performance of optimised POct-based biosensors were tested in spiked human serum. Results showed that the electropolymerisation of octopamine on screen printed gold electrode generates a thin polymer film with low resistance. Close proximity of the immobilised bioreceptors to the transducer layer greatly enhanced the sensitivity detection. The sensitivity of the smaller monomeric bioreceptor (Affimer, 12.6 kDa) to detect CEA was comparable to the dimeric antibody (150 kDa) with limit of detection at 11.76 fM which is significantly lower than the basal clinical levels of 25 pM. However, the Affimer-based sensor had a narrower dynamic range compared to the immunosensor (1–100 fM vs. 1 fM – 100 nM, respectively). All electrochemical measurements were done in less than 5 min with small sample volumes (10 μl). Hence, polyoctopamine features a simple fabrication of impedimetric biosensors using amine-functionalisation technique, provides rapid response time with enhanced sensitivity and label-free detection.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | Crown Copyright © 2021 Published by Elsevier B.V. All rights reserved. This is an author produced version of an article published in Biosensors and Bioelectronics. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Polyoctopamine; Non-conducting polymer; Oriented immobilisation; Electrochemical immunosensor; Affimer; CEA |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Biomedical Sciences (Leeds) The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Molecular and Cellular Biology (Leeds) > Synthetic Biology (Leed) |
Depositing User: | Symplectic Publications |
Date Deposited: | 21 Apr 2021 13:39 |
Last Modified: | 21 Jan 2022 01:38 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.bios.2021.113013 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:173074 |