Nanomedicine - Bionanoelectronics: Bioinquiring and Bioinspired Devices - page 140

Fig. 4.17 The schematic
configuration of a neural
probe

recording
places

interconnection
conductors

signal
processing
chip

output leads

Fig. 4.18 The DRIE
electrodes for neural stimulus
and recording

DRIE

photoresist
mask

electrodes

electronic circuits that allow the control of drug release or, as in the example above,
the stimulation and recording of neural responses.
A very important role in controlled drug delivery is played by microfluidic/
nanofluidic devices (see Chap. 1 ). A comprehensive review about the hard and
soft micromachining applied in microfluidics and drug delivery could be found in
Ziaie et al. ( 2004 ). In general, a biochip for controlled release of drugs contains
the elements described schematically in Fig. 4.19 . In the microfluidic biochips in
Fig. 4.19 , the micropumps are the core of the entire device because they disperse
the drug in a prescribed order, i.e., with a certain flow rate and dose. There are
a multitude of pumps, which are mechanical (peristaltic, reciprocating, or rotary
pumps based on MEMS technology) and nonmechanical (electrical, magnetic,
chemical, surface-tension-driven, etc.) ( Tsai and Sue 2007 ).
An electrostatic micropump is formed from a Si membrane with two passive
check valves, and it is able to attain the following performances: a maximum back