Biosensor based on cellobiose dehydrogenase for detection of catecholamines.
A cellobiose dehydrogenase (CDH)-modified graphite electrode was designed for amperometric detection of catecholamines in the flow injection mode, by their recycling between the graphite electrode (+300 mV vs Ag|AgCl) and the reduced FAD cofactor of adsorbed CDH, resulting in an amplified response signal. The high efficiency of the enzyme-catecholamine reaction leads to a detection limit below 1 nM and a sensitivity of 15.8 A.M(-1) x cm(-2) (approximately 1150 nA/microM) for noradrenaline, with a coverage of less than 2.5 microg of CDH adsorbed on the electrode surface (0.073 cm(2)). Working parameters such as pH, cellobiose concentration, carrier buffer, and applied potential were optimized, using hydroquinone as a model analyte. The sensitivity, linear range, and amplification factor can be modulated by the steady-state concentration of cellobiose in the flow buffer. The response of the sensor decreases only 2% when run continuously for 4 h in the flow injection mode. The response peak maximum is obtained within 6 s at a flow rate of 0.5 mL/min, representing the time of the entire sample segment to pass the electrode. CDH enzymes from Phanerochaete chrysosporium and Sclerotium rolfsii were investigated, providing different characteristics of the sensor, with sensors made with CDH from P. chrysosporium being the better ones.
Stoica
Leonard
L
Department of Analytical Chemistry, Lund University, P.O. Box 124, SE-22100 Lund, Sweden.
Lindgren-Sjölander
Annika
A
Ruzgas
Tautgirdas
T
Gorton
Lo
L
D015374:Biosensing Techniques; D002237:Carbohydrate Dehydrogenases / Q000378:metabolism*; D002395:Catecholamines / Q000032:analysis*; D005182:Flavin-Adenine Dinucleotide; D007202:Indicators and Reagents; D012680:Sensitivity and Specificity
D002395:Catecholamines; D007202:Indicators and Reagents; D005182:Flavin-Adenine Dinucleotide; D002237:Carbohydrate Dehydrogenases; C019859:cellobiose-quinone oxidoreductase