6. Current Technology and Future Works

The capacitive measurements of deposable sensing electrodes are conventionally performed using Electrochemical Impedance Spectroscopy (EIS) [331, 332]. As shown in Fig. 6.1a, such a measurement device is connected to an array of electrodes which are exposed to analyte. Recently handheld EIS systems have received much attention as opposed to conventional EIS systems. A handheld system featuring an array of sensing sites (Fig. 6.1b) can be used for several point-of-care applications such as blood analysis (e.g. minilab, Abaxis Inc. [333]) or environmental monitoring such as bacteria detection [334]. However, researchers involved in circuit and system design and relevant biotechnological studies are willing to embed such portable systems in a single chip in the near future. In this direction, a CMOS based capacitive sensing LoC can be implemented in a syringe style package as shown in Fig. 6.1c. The biological or chemical analyte is directed by syringe towards the sensing sites through the nozzle. After each measurement, the nozzle and sensing site will be cleaned using the appropriate solutions which are directed into the channel and sensing sites in the same manner.