Enzyme-based ultrasensitive electrochemical biosensor using poly(l-aspartic acid)/MWCNT bio-nanocomposite for xanthine detection: A meat freshness marker

Abstract

Sensitive and selective detection of xanthine (XA) in food industries is of notable importance for evaluating the meat freshness. A new and simple-to-prepare nano-biocomposite of multi-walled carbon nanotube (MWCNT) and poly(l-aspartic acid) (Poly(l-Asp)) film is prepared for the immobilization of xanthine oxidase (XO) on glassy carbon electrode (GCE). Electropolymerization of biocompatible polymer was performed by cyclic voltammetry (CV). Bio-analytical optimal experimental conditions such as percentage of MWCNT, immobilizing time of the enzyme, the response time of electrode and the value of pH were studied in detail. The fabrication process of the XO/Poly(l-Asp)/MWCNT/GCE electrode was pursued by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The developed biosensor was employed for the determination of xanthine in fish meat based on differential pulse voltammetry (DPV) method. DPV response was showed a linear range in the range of 0.001–0.004 μM and 0.005–50.0 μM, with a low detection limit of 3.5 × 10−4 μM and surprisingly high selectivity. Finally, the developed biosensor was successfully applied for xanthine determination in fish meat at different storage times.