AAWSAP DIRD, Biosensors and BioMEMS: A Survey of the Present Field, March 2010

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What is BioM EMS?
BioMEMS stands for biomedical micro-_glectro-mechanical ~ystems. It is a name applied
to biological and medical devices that are created using advanced fabrication processes
that allow the devices to be very small relative to comparable devices produced by
traditional techniques. BioMEMS devices can also exploit the microscale to provide new
functions that are not practical or possible in large-scale devices.
The name applies to an exceptionally wide variety of engineered devices that derive
from electrical, mechanical, chemical, and molecular engineering. The name
distinguishes these from nanoMEMS which are submicron in scale such as carbon
nanotube structures.
Recently BioMEMS has become something of a misnomer as many of the latest
technologies are being designed and developed based on nanoscale technologies which
are many times smaller than microscale technologies. While current devices are
manufactured mostly on the microscale, many of the functioning parts and the
materials they operate on are at the nanoscale level.
NanoMEMS for biomedical applications are mostly carbon-based materials that have
emerged as prime materials because of their favorable mechanical and electrical
properties. Carbon-based nanostructures such as graphene exhibit a high Young's
modulus (stiffness), high strength, low density, low friction and large surface area. The
low friction of a carbon nanotube allows production of practically frictionless bearings
and has thus been a huge motivation towards applications such as nanomotors. Carbon
nanostructures are much stronger than steel, which allows carbon-based materials to
meet high-stress demands in biomedical applications such as weight-bearing
prosthetics (like hip-joint or bone replacements), where other materials would fail.
The field of BioMEMS encompasses micro devices that are often but not exclusively
made by the same photolithographic techniques used to make computer chips. Their
applications include neuroprosthetics, sensors and actuators, and microchemistry
systems. A microchemistry system, often called a lab on a chip, can analyze chemical
properties of a very small quantity of material such as a tiny blood sample. Advanced
systems can perform several tests on the sample at one time.
There are also drug-delivery systems, miniature hearing aids, artificial retinas, DNA
analysis systems, cancer diagnostics, and an amazing variety of devices which support
the function of the human body. Figure 1 shows some devices that were developed by
the faculty of Biomedical Engineering at Arizona State University.
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