Biosensors obtained by immobilising glucose oxidase 'unentrapped' and 'entrapped in liposomes', both with a classical H(2)O(2) amperometric electrode and with screen-printed electrochemical sensor, were compared. Electrode response, linearity range and the influence of some parameters as phospholipid nature, temperature and measurement techniques were investigated. Experimental results showed that, while with the unentrapped enzyme the output current is linear only up to about 4 mM glucose concentration. the linearity range increases up to about 20 mM using enzyme-loaded liposomes, however the low permeability of the lipid bilayer decreases the electrode sensitivity to very low values (200 nA/M for palmitoylolelyl phosphatidylcholine liposomes). The approach with screen-printed sensors showed a better performance and gave biosensors with higher sensitivity (about 14 500 nA/mM). A mathematical model, useful to compare the behaviour of the different analytical systems and to design electrodes with the required properties, was also proposed. (C) 2002 Elsevier Science B.V. All rights reserved.
A comparison between different immobilised glucoseoxidase-based electrodes / Memoli, Adriana; Annesini, Maria Cristina; Marco, Mascini; Stefano, Papale; Petralito, Stefania. - In: JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS. - ISSN 0731-7085. - 29:6(2002), pp. 1045-1052. (Intervento presentato al convegno 9th International Meeting on Recent Developments in Pharmaceutical Analysis (RDPA 01) tenutosi a LIPARI, ITALY nel JUN 03-08, 2001) [10.1016/s0731-7085(02)00145-0].
A comparison between different immobilised glucoseoxidase-based electrodes
MEMOLI, Adriana;ANNESINI, Maria Cristina;PETRALITO, Stefania
2002
Abstract
Biosensors obtained by immobilising glucose oxidase 'unentrapped' and 'entrapped in liposomes', both with a classical H(2)O(2) amperometric electrode and with screen-printed electrochemical sensor, were compared. Electrode response, linearity range and the influence of some parameters as phospholipid nature, temperature and measurement techniques were investigated. Experimental results showed that, while with the unentrapped enzyme the output current is linear only up to about 4 mM glucose concentration. the linearity range increases up to about 20 mM using enzyme-loaded liposomes, however the low permeability of the lipid bilayer decreases the electrode sensitivity to very low values (200 nA/M for palmitoylolelyl phosphatidylcholine liposomes). The approach with screen-printed sensors showed a better performance and gave biosensors with higher sensitivity (about 14 500 nA/mM). A mathematical model, useful to compare the behaviour of the different analytical systems and to design electrodes with the required properties, was also proposed. (C) 2002 Elsevier Science B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
