Chapter 5
Materials and Methods in Chemical-Sensor Manufacturing
5.1 Introduction
Fabrication of a chemical sensor consists of integrating a transducer with the sensing element, which includes receptor sites. Often, this is largely a matter of immobilizing the receptor at the transducer surfaces. However, many sensors require additional active components. At the same time, the sensing element should be designed so as to be able to allow the access of the analyte to the receptor. In addition, implantable sensors should be compatible with living tissue. That is why, in general terms, building up the sensing part of the sensor is not simply a problem of receptor immobilization, although this is a key issue.
Commercialization of chemical sensors brings about additional requirements as far as the fabrication method is concerned. The ideal commercial sensor should be as simple as possible and suitable for mass production. The sensor characteristics should be stable for a sufficiently long period of time under operational and storage conditions. As far as stability under operation is concerned, the requirements are less stringent in the case of disposable sensors, but in this case an inexpensive fabrication technology is sought.
A broad variety of methods for assembling the sensing element has been developed [1]. For example, confinement of an enzyme solution between a perm-selective membrane and the transducer surface is a straightforward method that was widely used at the beginning ...
