Analysis and optimization of a hydrogel matrix for the development of a sandwich-type glucose biosensor

LUCAS COLOMBO; ANA MARÍA BARUZZI; FERNANDO SEBASTIÁN GARAY

SENSORS AND ACTUATORS B-CHEMICAL

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2015 vol. 211 p. 125 - 130

0925-4005

The development of a sandwich-type biosensor for glucose quantification is presented. This work is focused on the optimization of the enzymatic matrix of the biosensor. The best performance was found for an enzymatic matrix composed by 30 % w/w mucin, 70 % w/w albumin, 1.35 U GOX per sensor, and glutaraldehyde diluted to 3%. The crosslinking with glutaraldehyde transforms this mixture into a hydrogel that is entrapped between two membranes of polycarbonate. The selected sandwich-type biosensor showed very good response time, sensitivity, stability, and sensor-to-sensor reproducibility. According to the results presented in this manuscript, a biosensor prepared with higher amount of enzyme would not significantly increase the analytical signal and might reduce the linear range of the sensor. In this regard, we believe that the diffusion of oxygen, the natural mediator of the sensor, could be limiting the linear response of the sensor. Simulated curves are compared with experimental data to explain the dependence of sensitivity on the concentration of enzyme. In addition, this kind of comparison represents a quite simple way to estimate the value of vmax ≈ 0.13 M.s-1 from the amperometric response of a sensor prepared with 1.34 U of GOX.Considering that sandwich-type biosensors are commonly assembled as part of devices where the sample is diluted with buffer, the more than 3 orders of magnitude of linear behavior of this sensor would ensure the possibility for assessing any sample. The accuracy of this biosensor might be compromised by the effect of electroactive interferents that are commonly present in samples such as blood or serum. The response of the biosensor when exposed to real samples will be discussed in a future work.