Analytica Chimica Acta 420 (2000) 9–17 Disposable interference-free glucose biosensor based on an electropolymerised poly(pyrrole) permselective film M. Quinto a , I. Losito a , F. Palmisano a,∗ , C.G. Zambonin b a Dipartimento di Chimica, Università degli Studi di Bari, Via E. Orabona 4, 70126 Bari, Italy b Dipartimento di Chimica, Università degli Studi della Basilicata, Via N. Sauro 85, 85100 Potenza, Italy Received 4 February 2000; received in revised form 15 May 2000; accepted 23 May 2000 Abstract Miniaturised disposable amperometric biosensors for glucose determination in serum are described. A commercially avail- able three-electrode system created on a planar corundum ceramic base was used as biosensor substrate and the working Pt electrode was modified by an electrogenerated overoxidised poly(pyrrole) film (PPYox). After the optimisation of the PPy layer synthesis, two different approaches were investigated for glucose oxidase (GOD) immobilisation: enzyme entrapment into the electropolymerised film by an ‘all-electrochemical’ procedure (PPYox/GOD) and gel-entrapment over the PPYox modified electrode by co-crosslinking with glutaraldehyde/bovine serum albumin (PPYox/ GOD-gel). A comparison of the sensitivities to glucose, performed by dropping 50 l of the sample solutions onto the relevant electrode systems, showed that both sensors have a linearity range extending up to 10 mM, though Pt/PPYox/GOD-gel sensor is more sensitive (168±15 versus 53±7nAm/M). The two sensors showed remarkable anti-interferent selectivity, moreover the PPYox/GOD-gel sensor had also a good stability and could be used for flow injection analysis of glucose, with a linearity range extending up to 25mM. © 2000 Elsevier Science B.V. All rights reserved. Keywords: Glucose oxidase; Overoxidised poly(pyrrole) film; Glutaraldehyde gel; Disposable biosensors 1. Introduction The increasing demand for rapid, inexpensive and reliable determination of clinically significant analytes has resulted in a huge effort in academic and indus- trial laboratories devoted to biosensors development [1]. Among the various clinically significant metabo- lites, blood glucose determination deserves a particu- ∗ Corresponding author. Tel.: +39-80-5442016; fax: +39-80-5442129. E-mail address: palmisano@chimica.uniba.it (F. Palmisano). lar attention since it is of fundamental importance in the treatment of diabetic patients. A successful glucose biosensor should ideally pos- sess a number of requisites such as being not too expensive, easy to use, capable of mass production [2], stable and easy to calibrate and able to operate with small sample volumes of undiluted whole blood. It should also be disposable and/or of small size, in order to be incorporated in a portable analyser, e.g. for continuous monitoring [3–6]. Several devices have been already developed to meet these requirements, in particular screen-printed biosensors based on the co-immobilisation of glu- 0003-2670/00/$ – see front matter © 2000 Elsevier Science B.V. All rights reserved. PII:S0003-2670(00)00998-3