Bovine serum albumin‑dependent charge‑transfer kinetics controls the electrochemical immunosensitive detection: Vibrio cholerae as a model bioanalyte.
Ozoemena, Okoroike C. Tobechukwu J. Ehirim, Tobechukwu J. Khawula, Tobile Makgopa, Katlego Shai, Leshweni J. Ozoemena, Kenneth I.
Ozoemena, Okoroike C.
Tobechukwu J. Ehirim, Tobechukwu J.
Khawula, Tobile
Makgopa, Katlego
Shai, Leshweni J.
Ozoemena, Kenneth I.
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Abstract
immunosensors, can impact on the sensitivity of detection when integrated with antibody (Ab) pre-encapsulated with (i) insulating polyacrylonitrile (PAN) fibre (i.e., GCE-PAN-Ab-BSA immunosensor) or (ii) conducting PAN-grafted iron (II) phthalocyanine (FePc) (i.e., GCE-PAN@FePc-Ab-BSA immunosensor), using Vibrio cholerae toxin as a case study bioanalyte.
Both immunosensors show different charge-transfer kinetics that strongly impact on their immunosensitive detection. From the electrochemical data, GCE-PAN-Ab-BSA is more insulating with the presence of BSA, while the GCE-PAN@ FePc-Ab-BSA is more conducting with BSA. The CV of the GCE-PAN-Ab-BSA is dominated by radial diffusion process, while that of the GCE-PAN@FePc-Ab-BSA is planar diffusion process. The behaviour of GCE-PAN@FePc-Ab-BSA has been associated with the facile coordination of BSA and FePc that permits co-operative charge-transport of the redox probe, while that of the GCE-PAN-Ab-BSA is related to the interaction-induced PAN-BSA insulating state that suppresses charge transport. As a consequence of these different interaction processes, GCE-PAN-Ab-BSA immunosensor provides higher electroanalytical performance for the detection of Vibrio cholerae toxin (with sensitivity of 16.12 Ω/log [VCT, g/mL] and limit of detection (LoD) of 3.20 × 10− 13 g/mL compared to those of the GCE-PAN@FePc-Ab-BSA (4.16 Ω/log (VCT, g mL− 1) and 2.00 × 10− 12 g/mL). The study confirms the need for a thorough understanding of the physico-chemistries of the electrode platforms for the construction of immunosensors. Although this work is on immunosensors for cholera infection, it may well apply to other immunosensors.
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Date
2021-06-09
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Springer
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Keywords
Vibrio cholerae detection, Bovine serum albumin (BSA), Iron (II) phthalocyanine (FePc), Polyacrylonitrile (PAN) fibre, Charge-transfer kinetics, Sensitivity