This document discusses the use of microelectromechanical systems (MEMS) in biomedical applications. Some key points: - MEMS allow the miniaturization of devices down to subcellular scales, enabling applications in areas like biology, medicine, and biomedical engineering. - MEMS integrate electrical and mechanical components on a single chip at microscopic scales (less than a human hair). This enables small, low power, less invasive medical devices. - Examples of MEMS applications discussed include lab-on-a-pill endoscopy, ultrasonic cutting tools, microneedles for drug delivery, and smart pills with sensors and drug reservoirs. - Challenges for medical MEMS include

1. MEMS
in
biomedical applications
U.GAYATHRI,
Dept of EEE,
Surya group of institutions,
Villupuram.

2. ABSTRACT:
Micromachining and MEMS
technologies can be used to produce complex
electrical, mechanical, fluidic, thermal, optical
,
and magnetic structures, devices, and systems
on a scale ranging from organs to subcellular
organelles.This miniaturization ability has
enabled MEMS to be applied in many areas of
biology, medicine, and biomedical engineering
a field generally referred to as BioMEMS.

3. what is MEMS ?
 MEMS stands for Micro Electro Mechanical
Systems.
 It is a technique of combining Electrical and
Mechanical components together on a chip, to
produce a system of miniature dimensions …
 By miniature, we mean dimensions less than the
thickness of human hair !!!!

4. Benefits of MEMS in medical
applications
 Small volume of reagent samples (like blood), required for
analysis.
 Low power consumption, hence lasts longer on the same
battery.
 Less invasive, hence less painful.
 Integration permits a large number of systems to be built on a
single chip.
 Batch processing can lower costs significantly.
 Existing IC technology can be used to make these devices.
 Silicon, used in most MEMS devices, interferes lesser with
body tissues.

5. Can MEMS devices really
replace the existing medical
devices ?
 A lot of MEMS medical
devices have been
developed that are
much more sensitive
and robust than their
conventional
counterparts.
 Market trends for MEMS
medical devices show a
promising future ahead.
http://www.sensorsmag.com/articles/0497/medical/main.shtml
www.edmond-wheelchair.com/ bp_monitors3.htm

6. Classification of biological
MEMS devices
 Biomedical MEMS – deals “in vivo”, within the host body.
→ precision surgery
→ Biotelemetry
→ Drug delivery
→ Biosensors and other physical sensors
 Biotechnology MEMS – deals “in vitro”, with the biological
samples obtained from the host body.
→ Diagnostics
→ gene sequencing
→ Drug discover
→ pathogen detection

7. MEMS Sensors
MEMS sensors in the biomedical field maybe used
as:
 Critical sensors, used during operations.
 Long term sensors for prosthetic devices.
 Sensor arrays for rapid monitoring and
diagnosis at home.

8. MEMS and endoscopy
 What is endoscopy ?
 A diagnostic procedure which involves the introduction of a
flexible device into the lower or upper gastrointestinal tract for
diagnostic or therapeutic purposes.
 Conventional endoscopes
 Can be used to view only the first
third of the small intestine.
 Require sedation of patient
 Is an uncomfortable procedure
http://www.surgical-optics.com/new_autoclavable_rigid_endoscope.htm
http://www.mobileinstrument.com

9. MEMS redefines endoscopy with
“Lab on a Pill”
Size : 35mm
Components of lab on a pill
 Digital camera (CMOSTechnology)
 Light source
 Battery
 Radio transmitter
 Sensors (MEMSTechnology)
 Requires no sedation
 Can show a view of the
entire small intestine
 Can aid in early detection
of colon cancer
http://www.see.ed.ac.uk/~tbt/norchip2002.pdf
http://www.spie.org/web/oer/august/aug00/cover2.html

10. Ultrasonic MEMS cutting tool
 These tools make use of piezoelectric materials attached to the
cutter.
 Consist of microchannels to flush out the fluid and debris while
cutting.
 Can be used to cut tough tissues, like the hardened lenses of
patients with cataract

11. Skin Resurfacing
 Skin resurfacing is a form of cosmetic surgery that is often used to
aesthetically enhance the appearance of wrinkles, skin lesions, pigmentation
irregularities, moles, roughness, and scars.
Conventional resurfacing techniques involve the use of :
 Dermabraders – devices or tools used in plastic surgery.
 Chemical peels – chemicals such as glycolic acid.
 Though still not commercially available, MEMS tools have been found to
overcome many drawbacks present in the conventional techniques.
 They can be used to remove raised skin lesions as well as lesions up to certain
depths.
 These MEMS structures are packaged
onto rotary elements and used
over the affected areas.
 The debris can then be sucked out
using a suction pump.

12. Removal of the diseased area
 Fatty material deposited on the
arterial walls causing artery
blockage, can be physically
removed using nanoblades.
 Physically shredding tumor can
pose a great threat.The pieces
can be carried to other locations
and result in furthering of
cancerous cells.
 One effective approach to kill the
cancerous cells would be to
enclose the entire tumor in a nano
box and destroying everything in
the box. www.foresight.org/.../Gallery/ Captions/Image201.html

13. A Graphical Representation of Nano robots working in a blood vessel, to remove
a cancerous cells using MEMS.

14. MEMS microneedles
 MEMS enables hundreds of hollow
microneedles to be fabricated on a
single patch of area, say a square
centimeter.
 This patch is applied to the skin and
drug is delivered to the body using
micropumps.
 These micropumps can be
electronically controlled to allow
specific amounts of the drug and
also deliver them at specific
intervals.
 Microneedles are too small to reach
and stimulate the nerve
endings, and hence cause no pain to
the body.
gtresearchnews.gatech.edu/ newsrelease/NEEDLES.htm

15. Smart Pill
 A MEMS device that can be
implanted in the human body.
 Consists of
 biosensors
 Battery
 Control circuitry
 Drug reservoirs
 The biosensors sense the
substance to be measured, say
insulin.
 Once this quantity falls below a
certain amount required by the
body, the pill releases the drug.
http://mmadou.eng.uci.edu/

16. Challenges for MEMS medical
sensors
 Biocompatibility remains the biggest hurdle
for MEMS medical devices.
 Life of the device.
 Retrieving data out of the device.
 Resist drifting along with the body fluids.

17. REFERENCES:
 1.WCB/McGaw-Hill, 1998, ISBN
 0-07-290722-[1] Micromechanics and MEMS: Classic and
 Seminal Papers to 1990,W.Trimmer (Ed.),
 IEEE Press, NewYork, NY, 1996, ISBN
 0-7803-1085-3.
 [2]G.T.A. Kovacs, MicromachinedTransducers
 Sourcebook3.
 [3] M. Madou, Fundamentals of Microfabrication.
 Boca Raton, FL: CRC Press, Inc., 1997, ISBN
 0-8493-9451-1.
 [4] J. Bustillo, R.T. Howe, and R. S. Muller,
 “Surface micromachining for microelectromechanical
 systems”, Proceedings of the IEEE,
 vol. 86, no. 8, August 1998, pp. 1552-1574.
 [5] K. E. Petersen, “Silicon as a Mechanical
 Material”, Proceedings of the IEEE, vol. 70,
 no. 5, May 1982, pp. 420-457.