title: Highly sensitive amperometric biosensor based on a biocompatible calcium phosphate cement.
abstract: Brushite is a biocompatible calcium phosphate mineral with properties of solid electrolyte. In this study we take advantage of this characteristic to develop an enzymatic amperometric biosensor based on brushite cement. The biosensor was prepared by immobilizing tyrosinase (PPO) on a brushite cement layer which was subsequently cross-linked with glutaraldehyde (GA) on the surface of a glassy carbon electrode. The system was optimized for the detection of phenolic compounds in both aqueous and non-aqueous solutions. Several variables involved in the enzyme immobilization method such as glutaraldehyde cross-linking time, PPO/brushite ratio and thickness of the brushite film were investigated. Furthermore, the effects of the pH, temperature and applied potential on the biosensor performance were also optimized. On the other hand, the biosensor analytical properties were studied in presence of different organic solvents: dioxane, acetonitrile and ethanol. In both, phosphate buffer solution (PBS) and acetonitrile/PBS solution, the biosensor exhibits a rapid response (12 s); a wide linear range (0.001-3 microM and 0.007-2 microM respectively); low detection limit (1 and 2 nM respectively); and high sensitivity (46.6 and 28.6 A M(-1) cm(-2) respectively). The performance of the biosensor in the analysis of phenols in real samples was successful.
authors.affiliation: Sección Departamental de Química Analítica, Facultad de Farmacia, Universidad Complutense de Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Sánchez-Paniagua López
authors.forename: F
authors.initials: F
authors.lastname: Tamimi
authors.forename: E
authors.initials: E
authors.lastname: López-Cabarcos
authors.forename: B
authors.initials: B
authors.lastname: López-Ruiz
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D001843:Bone Cements / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D004563:Electrochemistry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D010636:Phenols / Q000032:analysis* / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D001672:Biocompatible Materials; D001843:Bone Cements; D002130:Calcium Phosphates; D010636:Phenols; C020243:calcium phosphate