Sensors using higher integrated

Fig. 104. Comparison of the characteristic parameters of enzyme sensors and sensors using higher integrated biocatalytic systems (HIS).

Biosensors using higher integrated biocatalytic phases, i.e. cell organelles, intact cells, and tissue material, are compared with isolated enzyme sensors. The merits of the former in the determination of complex variables , such as mutagenicity and nutrient content, are outlined. 

The answer lies in microsystem design and fabrication, applied to a relatively simple arrangement of gas sensors (the higher the integration the better). Combined with microelectronics, it is perfectly suited for the mass production of EN modules. Microsystems are usually produced in batches and will meet demand at low cost. Additionally, small size, low energy consumption and long-term stability can be achieved. Of course, not only consumer applications will benefit from the microsystem approach, since the improvements are also relevant to instruments used in industrial applications, medical care or in environmental monitoring. 

An example of the DPV for thrombin DNA sensor is shown in Fig. 47.2. By integration of DPV using for example Origin 5.0 or higher version it is possible to determine total charge transfer for each record and to construct calibration curve as relative changes of charge transfer... 

With the aid of a particular class of materials (thin-film piezoelectrics), incorporation of AW devices and conventional integrated circuit components on the same silicon substrate is in fact possible. Under the proper conditions, a number of piezoelectric materials can be deposited in thin-film form, typically by RF sputtering, and retain their piezoelectric nature. For this to occur, the crystallites that grow during deposition must be predominantly oriented in a single, piezo-electrically active crystallographic direction. Two such materials are 2 0 and AIN the former has been used as an overlayer on Si wafers to fabricate all of the FPW devices studied for sensor applications to date, and also for SAW resonators. Because extremely thin piezoelectric films are readily fabricated, both ZnO and AIN have been used to make bulk resonators that operate at much higher... 

---