Acrylated polyurethane — photopolymeric membrane for amperometric glucose biosensor construction

Abstract

A new membrane for the construction of an amperometric glucose biosensor is described in this work. The membrane is based on an acrylated–polyurethane photocurable polymer to which the enzyme is immobilized by entrapment. The amperometric transducer is based on an epoxy–graphite conductive composite. The advantages of using the acrylated photo-crosslinkable for enzyme immobilization are several: this polymer permits a good adhesion of the membrane to the graphite–epoxy surface of the transducer. Besides, the membrane preparation process using this photocurable polymer is fast and simple and it can be adapted to photolitographic techniques for microsensor construction (i.e. ISFETs). After mixing all the components of the membrane a short exposure time of 30 s under 365 nm UV radiation allowed us to obtain a robust membrane with a long-term stability of around 3 months. The improvement of the sensor response was also studied introducing graphite powder in the polymeric matrix. Sensors prepared with this procedure presented a sensitivity of 1.68 A/mM in a linear range of 0.1–5 mM glucose. The response time was low, from 3 to 30 s and the lifetime was up to 1 month.