Abstract
Abstract Polymeric-based composites can contribute to enhancing the detection, stability, and performance of enzymatic biosensors, due to their high structural stability, conductivity, and biocompatibility. This work presents the fabrication of a nanocomposite of polyaniline (PAni)/gold nanoparticles (AuNP)/carboxylated multiwalled carbon nanotubes (cMWCNT) as functional support for covalently linked catalase (CAT) enzyme. PAni was electropolymerized on a screen-printed carbon electrode (SPCE) and decorated with AuNP to improve charge transfer properties. CAT was bonded through amide formation using the carboxylic groups of cMWCNT, resulting in PAni/AuNP/cMWCNT/CAT biosensor. The structural and electroactive characteristics of the nanocomposite were studied by SEM, FT-IR, and cyclic voltammetry. The optimal performance was achieved after CAT immobilization over PAni/AuNP/cMWCNT/nanocomposite, showing improved analytical features such as a fast amperometric response of 1.28 s, a wide detection range from 0.01 to 6.8 mM, a correlation coefficient (R 2) of 0.9921, a low detection limit of 2.34 µM, and an average recovery rate of 99.6% when evaluated in milk samples. Additionally, the bioelectrode showed excellent selectivity and retained bioactivity after 30 days of storage. Such remarkable performance proved the synergistic effects of both the high surface area of the cMWCNT and AuNP and the inherent PAni electroactivity, yielding direct electron transfer from CAT.
Highlights
Enzyme-based electrochemical biosensors have been the subject of extensive research due to their promising applications in food safety, clinical diagnosis, healthcare, and environmental monitoring [1]
Enzymatic biosensors rely on carbon electrodes modified with high-performance nanomaterials like metal nanoparticles, graphene, or conductive polymers that allow enzyme linking and facilitates electron transfer between the enzyme redox center and the electrode
The particles are embedded in the surface of the PAni fibers, showing good dispersion and spherical morphology of around 50 nm
Summary
Enzyme-based electrochemical biosensors have been the subject of extensive research due to their promising applications in food safety, clinical diagnosis, healthcare, and environmental monitoring [1]. The design of polymeric-based composites as enzymatic supports contributes to enhancing the detection, stability, and performance of biosensors because of their unique properties at the nanoscale such as high structural stability, conductivity, and biocompatibility [5]. In this sense, polyaniline (PAni) has been incorporated in enzymatic biosensors due to its attractive features such as low cost, facile synthesis, conductivity, environmental stability, and biocompatibility, functioning as the transducer, mediator for electron transfer, or immobilization matrix [6]. PAni, is an effective electroactive platform for enzymatic biosensor design due to its tunable redox properties, which facilitate the charge
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