Carboxymethyl cellulose assisted immobilization of silver nanoparticles onto cellulose nanofibers for the detection of catechol

• A facile approach to produce AgNPs-CMC/cellulose composite nanofibrous mats has been developed.
• Laccase biosensor based on AgNPs-CMC/cellulose composite nanofibrous mats for catechol detection was developed in this work.
• The detection limit of the obtained biosensor to catechol is 1.64 μM.
• The composite nanofibers could provide a new platform for other redox proteins immobilization.

We report a facile approach to synthesize and immobilize silver nanoparticles (AgNPs) onto carboxymethyl cellulose (CMC)-modified electrospun cellulose nanofibers and demonstrate the potential application of as-prepared AgNPs-CMC/cellulose composite nanofibrous mats as effective biosensor substrate materials. Cellulose nanofibers were prepared by the combination of electrospinning with deacetylation. Then, CMC was adsorbed onto cellulose nanofibers to complex silver ions through the chemical binding with the free carboxyl groups of CMC for subsequent reductive formation of AgNPs. The AgNPs-CMC/cellulose nanofibers immobilized with laccase (Lac) by electrostatic interactions were used as biosensor substrate materials for catechol detection. The cyclic voltammetries revealed that the AgNPs-CMC/cellulose nanofibers was beneficial to the immobilization of Lac and facilitated the direct electron transfer between Lac and electrode. Lac/AgNPs-CMC/cellulose/glassy carbon electrode exhibited a detection limit of 1.64 μM (S/N = 3), and a wide linear range from 4.98 μM to 3.65 mM, as well as good repeatability, reproducibility, stability, and selectivity. The CMC/cellulose nanofibrous mats have great potential applications as substrate materials for different biosensors by immobilizing other different functional nanoparticles or enzyme on them.

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