title: Graphene-titanium dioxide nanocomposite based hypoxanthine sensor for assessment of meat freshness.
abstract: We report on the fabrication of a graphene/titanium dioxide nanocomposite (TiO2-G) and its use as an effective electrode material in an amperometric hypoxanthine (Hx) sensor for meat freshness evaluation. The nanocomposite was characterized by TEM, XRD, FTIR, XPS, TGA, BET, and CV using the redox couples [Fe(CN)6]-3/-4and [Ru(NH3)6]+3/+2respectively. The TiO2/G nanocomposite offered a favorable microenvironment for direct electrochemistry of xanthine oxidase (XOD). The fabricated Nafion/XOD/TiO2-G/GCE sensor exhibited excellent electro catalytic activity towards Hx with linear range of 20μM to 512μM, limit of detection of 9.5μM, and sensitivity of 4.1nA/μM. In addition, the biosensor also demonstrated strong anti-interference properties in the presence of uric acid (UA), ascorbic acid (AA) and glucose. Minimal interference of xanthine (Xn) was observed at ~7%. Moreover, the biosensor showed good repeatability (4.3% RSD) and reproducibility (3.8% RSD). The reported biosensor was tested towards the detection of Hx in pork tenderloins stored at room temperature for seven days. There was a good correlation (r=0.9795) between biosensor response and measurements obtained by a standard enzymatic colorimetric method. The TiO2-G nanocomposite is therefore an effective electrode material to be used in electrochemical biosensors to assess the freshness of meat.
authors.affiliation: School of Materials Engineering, Purdue University, 701 West Stadium Avenue, West Lafayette, IN 47907, USA; Physics Department, De La Salle University, 2401 Taft Avenue, Manila 1004, Philippines.
authors.forename: Jasmine A V
authors.initials: JAV
authors.lastname: Albelda
authors.affiliation: School of Materials Engineering, Purdue University, 701 West Stadium Avenue, West Lafayette, IN 47907, USA.
authors.forename: Aytekin
authors.initials: A
authors.lastname: Uzunoglu
authors.affiliation: Physics Department, De La Salle University, 2401 Taft Avenue, Manila 1004, Philippines. Electronic address: gil.santos@dlsu.edu.ph.
authors.forename: Gil Nonato C
authors.initials: GNC
authors.lastname: Santos
authors.affiliation: School of Materials Engineering, Purdue University, 701 West Stadium Avenue, West Lafayette, IN 47907, USA. Electronic address: lstanciu@purdue.edu.
authors.forename: Lia A
authors.initials: LA
authors.lastname: Stanciu
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D002417:Cattle; D055664:Electrochemical Techniques / Q000379:methods; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D019271:Hypoxanthine / Q000032:analysis*; D057230:Limit of Detection; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D000069466:Red Meat / Q000032:analysis*; D015203:Reproducibility of Results; D013552:Swine; D014025:Titanium / Q000737:chemistry*; D014969:Xanthine Oxidase / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; C009495:titanium dioxide; D019271:Hypoxanthine; D006108:Graphite; D014025:Titanium; D014969:Xanthine Oxidase
keywords: Biosensor; Graphene/TiO(2) nanocomposite; Hypoxanthine; Meat freshness; Xanthine oxidase