A bioelectrochemical polypyrrole-containing Fe(CN)6(3-) interface for the design of a NAD-dependent reagentless biosensor.
Ferricyanide ions were immobilized on a platinum electrode surface by means of an electrochemically grown polypyrrole film. The entrapped Fe(CN)6(3-)/Fe(CN)6(4-) redox system displayed a high heterogeneous electron transfer rate. The resulting modified electrode was efficient for the ferricyanide-mediated NADH oxidation catalyzed by a diaphorase. The bioelectrochemical interface was applied to the design of a reagentless amperometric D-lactate biosensor. A weakly polarized two polypyrrole-containing Fe(CN)6(3-) modified electrode system was involved without any reference. An enzymatic solution containing D-lactate dehydrogenase, diaphorase and NAD-dextran was further confined on the sensing electrode using a semi-permeable membrane. The sensitivity and the response time of the reagentless biosensor were similar to those of the analogous sensor working with soluble mediator and cofactor, i.e. 25 microA mM(-1) cm(-2) and 120 s, respectively. The other analytical performances were less satisfactorily: the detection limit was 5 x 10 mmol L(-1) and the linearity range was comprised between 0.1 and 0.5 mmol L(-1).
Gros
Pierre
P
Laboratoire de Génie Chimique UMR CNRS 5503, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex, France. gros@chimie.ups-tlse.fr
Comtat
Maurice
M
D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005292:Ferricyanides / Q000737:chemistry*; D007202:Indicators and Reagents / Q000737:chemistry; D045022:Lactate Dehydrogenases / Q000737:chemistry*; D019344:Lactic Acid / Q000032:analysis* / Q000737:chemistry*; D009243:NAD / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D020099:Coated Materials, Biocompatible; D005292:Ferricyanides; D007202:Indicators and Reagents; D011108:Polymers; D011758:Pyrroles; D009243:NAD; C007931:hexacyanoferrate III; C067635:polypyrrole; D019344:Lactic Acid; D045022:Lactate Dehydrogenases; C071195:D-lactate dehydrogenase