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