Nanomedicine - Bionanoelectronics: Bioinquiring and Bioinspired Devices - page 132

control
electronic circuit

biocompatible
membrane

biosensor

drug
release

drug

batteries

Fig. 4.6 The electric-controlled release of the drug

to pressure
sensor inductive antenna

Fig. 4.7 An inductive stent micromachined antenna

structure of such a capsule is displayed in Fig. 4.8 . The future prospect of this
capsule is to pass over the entire gastrointestinal tract, to send views of the organs
positioned along this tract with the help of the imaging system displayed at the
left end of the endoscope in Fig. 4.8 , to perform drug delivery, and to collect tissue
samples. The interaction with the control unit occurs via the antenna and the RF
transmitter.
There are two recent reviews about microchips and capsules used in drug delivery
systems: ( Ainslie and Desai 2008 )and( Staples 2010 ), both indicating the role
of wireless microchips in drug delivery systems. The battery contained in these
systems can be replaced by inductive coupling at radiofrequencies (RFs), solution
that provides a much larger autonomy and allows the reduction of the dimensions
to these intelligent drug delivery devices. In this case, the transfer of RF energy
through the skin is achieved by an emitter coil and a receiving coil. In this way, the
microchips could be powered by RF energy. The control of wireless drug release is
performed by tens of micromachined cavities, as displayed in Fig. 4.1 . In the device
depicted in Fig. 4.9 , it is possible to control which cavity will deliver the drug at a
prescribed moment in time to power the implant or even to slow down its movement