Reagentless Amperometric Glucose Biosensors: Ferrocene-Tethering and Copolymerization

Abstract

Ferrocene-substituted 2,5-di(thienyl)pyrrole (SNS-Fc) was electrochemically polymerized in the presence and absence of 3,4-ethylenedioxythiophene (EDOT) and utilized for biosensing upon immobilization of glucose oxidase (GOD) through crosslinking. The two biosensors, homopolymer P(SNS-Fc) and copolymer-based P(SNS-Fc-co-EDOT) were evaluated by comparison in terms of analytical performance. Due to the conducting-redox active nature of the films, the study was able to consider the developed sensors both as "first generation," monitoring H 2 O 2 oxidation and as "second generation," using the optimum potential for ferrocene oxidation. The difference in performance at these two working potentials served as assessment of the influence of ferrocene moiety within the conducting film. In the scope of further improvement, carbon nanotubes (MWCNTs) were incorporated in both type systems. This improved the detection efficiency leading to extension of linear range up to 1.5 mM with sensitivity up to 23.12 μA mM −1 cm −2 and detection limits as low as 0.43 μM. The proposed biosensors showed little to no interference to other saccharides and accurate recovery in real sample analysis, especially when glucose detection was based on mediated electron transfer. Thus, the association of ferrocene, poly 2,5-di(thienyl)pyrroles and CNTs is highly efficient in the development of sensitive "reagentless" biosensor systems.

Recent Advances of Conducting Polymers and Their Composites for Electrochemical Biosensing Applications

“…Anziphos methyl is a broad spectrum organophosphate insecticide and the measurement is based on the inhibition of the activity of tyrosinase. Ferrocene-substituted 2,5-di(thienyl)pyrrole (SNS-Fc) can be electrochemically polymerized with 3,4-ethylenedioxythiophene (EDOT) to serve as an immobilization matrix of GOX by cross-linking in the presence of MWCNTs [110]. AChE/HCS@PANI malathion 1.0 ng/mL to 10 µg/mL 0.16 ng/mL [142] GO/AAM/MAA/MMA/NVP Zika virus 10 −3 to 10 2 PFU/mL 2 × 10 −2 PFU/mL As illustrated in Table 2, conducting polymer-based composites are formed by blending or mixing CPs with other materials to achieve multifunctionality [144].…”

“…Anziphos methyl is a broad spectrum organophosphate insecticide and the measurement is based on the inhibition of the activity of tyrosinase. Ferrocene-substituted 2,5-di(thienyl)pyrrole (SNS-Fc) can be electrochemically polymerized with 3,4-ethylenedioxythiophene (EDOT) to serve as an immobilization matrix of GOX by cross-linking in the presence of MWCNTs [ 110 ].…”

“…Ferrocene and its derivatives are very popular redox mediators used in biosensor construction. They are very stable in both oxidized and reduced form, have excellent redox reversibility, and their redox capacity is not affected by the pH of the solution [ 110 , 140 ]. A highly sensitive reagentless glucose detection electrode is designed with copolymerization of ferrocene and functionalized PPY.…”

“…A highly sensitive reagentless glucose detection electrode is designed with copolymerization of ferrocene and functionalized PPY. The sensor has a detection limit of 0.43 μM with a sensitivity of 23.12 μA mM −1 cm −2 and can detect trace analytes [ 110 ]. The functionalization with the mediator shifts the working potential from 0.6 V to 0.4 V and prevents mediator leaching, thus increasing stability and limiting the interference in real samples.…”

Functional Biosensing Platform for Urea Detection: Copolymer of Fc-Substituted 2,5-di(thienyl)pyrrole and 3,4-ethylenedioxythiophene

“…As a result, a conducting material with intrinsic redox activity is rendered leading to the development of a so-called "reagentless" system. 43,44 The electrochemical properties of SNS structures can be further enhanced through copolymerization with other conducting materials, such as 3,4-ethylenedioxythiphene (EDOT); this approach has proved successful in electrochromic studies 45 by improving the electrochemical properties of the polymers (due to increased conjugation length and decreased band gap). 46,47 Albeit in incipient stages of research for biosensing devices, there is potential for enhanced electron kinetics leading to efficient transduction mechanism and, thus, fast and accurate analyte detection.…”