Carbon nanotube–polyaniline (PANI@CNTs) composite electrode-based enzymatic sensor for β-glucan detection

In this work, a novel carbon nanotube-polyaniline (PANI@CNTs) composite electrode-based sensor for the detection of β-glucans, an edible polysaccharide found in mushrooms, is introduced. The sensor offers excellent sensitivity, selectivity, and quick reaction times by utilizing the special qualities of electrochemical sensing in conjunction with nanostructures. The collaborative enhancement mechanism of the sensor is achieved through the distinct and synergistic roles of each component: β-glucanase (βg) selectively hydrolyzes β-glucan into glucose, glucose oxidase (GOx) catalyzes the oxidation of glucose to gluconic acid and H 2 O 2 to amplify the electrochemical signal, while carbon nanotubes (CNTs) provide a high surface area and fast electron transfer pathways, and polyaniline (PANI) offers a conductive and biocompatible matrix for stable enzyme immobilization. An electropolymerization process yields a nanocomposite of PANI and CNTs for the modified electrode, immobilizing the enzymes βg and GO x . The effective production of the composite and the immobilization of the enzyme are confirmed by structural analysis. The βg/GOx/PANI@CNTs/GCE sensor shows a strong cathodic peak for β-glucan reduction and quasi-reversible redox peaks, with a linear increase in peak current matching to β-glucan concentration, according to electrochemical tests. The limit of detection (LOD) of the sensor is set at 9 ng/mL, its sensitivity is 0.616 µA/µg. mL −1 , and the linear concentration range is 0.5–52 µg/mL. It has exceptional durability, repeatability, and selectivity. Real sample testing shows recovery rates ranging from 97.00 % to 99.00 %, indicating the sensor's accuracy and reliability. After 27 days, the sensor maintained 96.95 % of its initial catalytic activity, demonstrating exceptional stability. The results indicate that the β g /GO x /PANI@CNTs/GCE sensor has great potential for quality control in the pharmaceutical and food sectors.