title: Further in-vitro characterization of an implantable biosensor for ethanol monitoring in the brain.
abstract: Ethyl alcohol may be considered one of the most widespread central nervous system (CNS) depressants in Western countries. Because of its toxicological and neurobiological implications, the detection of ethanol in brain extracellular fluid (ECF) is of great importance. In a previous study, we described the development and characterization of an implantable biosensor successfully used for the real-time detection of ethanol in the brain of freely-moving rats. The implanted biosensor, integrated in a low-cost telemetry system, was demonstrated to be a reliable device for the short-time monitoring of exogenous ethanol in brain ECF. In this paper we describe a further in-vitro characterization of the above-mentioned biosensor in terms of oxygen, pH and temperature dependence in order to complete its validation. With the aim of enhancing ethanol biosensor performance, different enzyme loadings were investigated in terms of apparent ethanol Michaelis-Menten kinetic parameters, viz. IMAX, KM and linear region slope, as well as ascorbic acid interference shielding. The responses of biosensors were studied over a period of 28 days. The overall findings of the present study confirm the original biosensor configuration to be the best of those investigated for in-vivo applications up to one week after implantation.
authors.affiliation: Department of Clinical and Experimental Medicine, Medical School, University of Sassari, Sassari 07100, Italy. osecchi@uniss.it
authors.forename: Ottavio
authors.initials: O
authors.lastname: Secchi
authors.forename: Manuel
authors.initials: M
authors.lastname: Zinellu
authors.forename: Ylenia
authors.initials: Y
authors.lastname: Spissu
authors.forename: Marco
authors.initials: M
authors.lastname: Pirisinu
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Bazzu
authors.forename: Rossana
authors.initials: R
authors.lastname: Migheli
authors.forename: Maria Speranza
authors.initials: MS
authors.lastname: Desole
authors.forename: Robert D
authors.initials: RD
authors.lastname: O'Neill
authors.forename: Pier Andrea
authors.initials: PA
authors.lastname: Serra
authors.forename: Gaia
authors.initials: G
authors.lastname: Rocchitta
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D001923:Brain Chemistry; D004798:Enzymes / Q000378:metabolism; D000431:Ethanol / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D008962:Models, Theoretical; D010100:Oxygen; D019736:Prostheses and Implants; D051381:Rats; D013696:Temperature
chemical_list: D004798:Enzymes; D000431:Ethanol; D010100:Oxygen