Characterization in vitro and in vivo of the oxygen dependence of an enzyme/polymer biosensor for monitoring brain glucose

Abstract

The oxygen dependence of a first generation amperometric biosensor was investigated in vitro and in vivo by monitoring its glucose response as a function of solution pO 2 . The biosensor was a glucose oxidase (GOx) modified poly(o -phenylenediamine) coated Pt cylinder electrode (Pt/PPD/GOx) that has been designed for neurochemical analysis in vivo. Two types of oxygen probes were used: a self-calibrating commercial macroelectrode in vitro; and a carbon paste microelectrode in vivo. Calibrations in vitro showed that oxygen interference in the operation of Pt/PPD/GOx electrodes was minimal for concentrations of glucose ( Â/0.5 mM) and oxygen ( Â/50 mM) found in brain ECF. This observation was confirmed by simultaneous monitoring in vivo of brain glucose and oxygen in the awake rat. However, at levels of glucose normally found in peripheral tissues ( Â/5 mM), the oxygen dependence was severe. We conclude that the oxygen sensitivity of Pt/PPD/GOx biosensors does not preclude their reliable use in media containing low glucose levels, such as brain ECF. #

Simultaneous recording of hippocampal oxygen and glucose in real time using constant potential amperometry in the freely-moving rat

“…Using implantable sensors allows for stable, long-term recording of a number of common analytes in the extracellular fluid (ECF) of the brain including oxygen (Lowry et al, 1996Lowry and Fillenz, 2001;Bolger and Lowry, 2005), glucose (Hu and Wilson, 1997;Fillenz and Lowry, 1998a;Lowry et al, 1998a,b,c;Lowry and Fillenz, 2001;Dixon et al, 2002), nitric oxide (Brown et al, 2009) and glutamate (Kulagina et al, 1999;McMahon et al, 2006aMcMahon et al, , 2006bMcMahon et al, , 2007Qin et al, 2008;Tian et al, 2009). Unlike other methods implanted into the brain tissue (Clark et al, 1958;Krolicki and Leniger-Follert, 1980;Doppenberg et al, 1998;Gupta et al, 1999).…”

“…A number of different glucose biosensors have been developed and have been shown to be able to rapidly detect changes in cerebral glucose (Boutelle et al, 1986;Shram et al, 1997). Measuring glucose in real time with CPA can be achieved using platinum/poly(o-phenylenediamine)/glucose oxidase (Pt/PPD/GOx) biosensors Dixon et al, 2002).…”

Method of Testing and Optimization of Amperometric Transducers

“…Тому наступною стадією запропонованої методики тестування амперометричних перетворювачів є покра-щення їх селективності за рахунок нанесення додаткових мембран. Щоб покращити селек-тивність перетворювачів та запобігти окислен-ню інтерферуючих речовин на поверхні елек-трода використовують різноманітні додаткові полімерні мембрани, що обмежують дифузію інтерферуючих речовин до поверхні перетво-рювача, при цьому пропускають до електрода цільову речовину (в нашому випадку -перок-сид водню) [6][7][8].…”

Selective potentiometric determination of uric acid with uricase immobilized on ZnO nanowires

“…Recent advances in electrochemical biosensing based on a wide variety of nanostructures such as ZnO nanowires, nanotubes and nonporous materials have attracted great interest due to their remarkable properties like non-toxicity, bio-safety, excellent biological compatibility, high-electron transfer rates, enhanced analytical performance, increased sensitivity, ease of fabrication and low cost [25][26][27][28][29]. ZnO nanomaterials can be used in a variety of electrochemical biosensing schemes due to their unique advantages in combination with immobilized enzymes.…”

“…Also ZnO nanowires exhibited better performance in perspective of signal to noise ratio as compared to ZnO thin film [33] because the nanosurfaces have other chemical properties as well. These are the reasons why nanowires are more sensitive, have an extended detection limit and possess a fast response time as compared to a thin films [24][25][26][27][28][29][30][31][32][33][34][35].…”