Abstract
In the present work, we demonstrate the fabrication of laccase biosensor to detect the catechol (CC) using laccase immobilized on graphene-cellulose microfibers (GR-CMF) composite modified screen printed carbon electrode (SPCE). The direct electrochemical behavior of laccase was investigated using laccase immobilized different modified SPCEs, such as GR/SPCE, CMF/SPCE and GR-CMF/SPCE. Compared with laccase immobilized GR and CMF modified SPCEs, a well-defined redox couple of CuI/CuII for laccase was observed at laccase immobilized GR-CMF composite modified SPCE. Cyclic voltammetry results show that the as-prepared biosensor has 7 folds higher catalytic activity with lower oxidation potential towards CC than SPCE modified with GR-CMF composite. Under optimized conditions, amperometric i-t method was used for the quantification of CC, and the amperometric response of the biosensor was linear over the concertation of CC ranging from 0.2 to 209.7 μM. The sensitivity, response time and the detection limit of the biosensor for CC is 0.932 μMμA−1 cm−2, 2 s and 0.085 μM, respectively. The biosensor has high selectivity towards CC in the presence of potentially active biomolecules and phenolic compounds. The biosensor also accessed for the detection of CC in different water samples and shows good practicality with an appropriate repea.
Highlights
Time consuming when compared with electrochemical methods[10]
The scanning electron microscope (SEM) image of graphene-cellulose microfibers (GR-cellulose microfibers (CMF)) composite shows that a typical 3D morphology and the GR nanoflakes were well exploited when dispersed in CMF (B)
The surface of the GR was smother in GR-CMF when compared to pristine GR, which is due to the presence of CMF
Summary
Selvakumar Palanisamy[1], Sayee Kannan Ramaraj[2], Shen-Ming Chen[1], Thomas C. We demonstrate the fabrication of laccase biosensor to detect the catechol (CC) using laccase immobilized on graphene-cellulose microfibers (GR-CMF) composite modified screen printed carbon electrode (SPCE). Cellulose microfibers (CMF) are hydrophilic and water-insoluble carbohydrate polymer, has been served as a promising biomaterial for immobilization of redox active proteins owing to its unique chemical properties and high biocompatibility[33]. To the best of our knowledge, the GR-CMF based composites have never been demonstrated yet for any electrochemical biosensor applications including immobilization matrix for any redox active enzymes or proteins. A highly sensitive and selective CC biosensor was developed based on laccase immobilized GR-CMF composite modified screen printed carbon electrode (SPCE). The resulting biosensor was further used for the detection of CC and was quantified using an amperometric method
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