Role of MEMS and nanotechnology in medical technologies

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Role of MEMS and nanotechnology in medical
technologies
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First of all, 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 !!!!

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The wonder called nanotechnology

• Nanotechnology is the technology of arranging
  atoms and molecules in a material.
• This allows to alter the properties of a material
  and build structures of desired features.
• A nanometer is one-billionth of a meter.
• Nanotechnology makes it possible to manufacture
  devices 80,000 times smaller than the thickness
  of human hair !!

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A simple analogy..

• The atoms in an object can be compared to the
  blocks in a building game.
• In a building game, the blocks can be arranged to
  create different looking structures.
• Similarly, atoms can be arranged differently to
  produce a multitude of devices. This forms the
  basis of nanotechnology.

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Benefits of MEMS and nanotechnology 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.

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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.

www.edmond-wheelchair.com/ bp_monitors3.htm
http//www.sensorsmag.com/articles/0497/medical/ma
in.shtml
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Projected MEMS market share in 2006
http//www.memsindustrygroup.org/industy_statistic
s.asp
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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

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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.

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MEMS and nanotechnology in precision surgery
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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.mobileinstrument.com
http//www.surgical-optics.com/new_autoclavable_ri
gid_endoscope.htm
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MEMS redefines endoscopy with Lab on a Pill

• Size 35mm
• Components of lab on a pill
• Digital camera (CMOS Technology)
• Light source
• Battery
• Radio transmitter
• Sensors (MEMS Technology)
• Requires no sedation
• Can show a view of the
• entire small intestine
• Can aid in early detection
• of colon cancer

http//www.spie.org/web/oer/august/aug00/cover2.ht
ml
http//www.see.ed.ac.uk/tbt/norchip2002.pdf
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Working of this magic pill !

• The pill is intended to be swallowed like any
  normal pill.
• Once within the body, the pill's sensors sample
  body fluids and pick up "meaningful patient data"
  such as temperature, dissolved oxygen levels and
  pH.
• The pill is expected to retrieve all data over a
  12-hour period and disposed off, once excreted.
• This data is transmitted wirelessly to a card
  attached
• to the wrist of the individual.

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Micro-surgical tools

• Present day surgeons operate within a domain
  restricted by the mobility and control of the
  surgical tools at hand.
• MEMS surgical tools provide the flexibility and
  accuracy to perform precision surgery.

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MEMS driven scalpels

• Precise control of the scalpel is an important
  requirement in any surgery.
• MEMS piezoelectric motor help to accurately
  position the scalpel.
• MEMS pressure sensors incorporated on the
  scalpel, can help to measure the force exerted on
  the area operated upon. Accordingly, the scalpel
  can he handled.

http//www.ee.ucla.edu/jjudy/publications/confere
nce/msc_2000_judy.pdf
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Ultrasonic MEMS cutting tool
http//www.ee.ucla.edu/jjudy/publications/confere
nce/msc_2000_judy.pdf

• 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

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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.
  

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Drawbacks of the conventional approaches in skin
resurfacing

• May cause excessive bleeding
• Often require time-consuming procedures
• Require multiple sessions.
• Lightened pigments at the operated site
• Furthermore, chemical peels cannot be
• used for removal of lesions with
• significant depth.

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MEMS skin resurfacing tools

• 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 upto 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.

http//www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd
RetrievedbPubMedlist_uids12787986doptAbstrac
t
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Micro/Nano Robots in medical field

• These are micro/nano scale devices capable of
  treating and eliminating medical problems.
• Such problems may arise due to the accumulation
  of unwanted organic substances, which interfere
  with the normal body functions, such as
• Tumors
• Life threatening blood clots
• Accumulation of scar tissue
• Arterial blockage
• Localized sites of infection.

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Considerations before introducing the robots into
the body.

• The robot size should be smaller than the
  diameter of the artery .
• The robot should not damage the arterial walls as
  it
• traverses through it.
• The robot can be introduced into the body through
  the circulatory system of the body.
• The femoral artery in the leg would be the most
  suited, because it is a large diameter artery and
  is traditionally used to introduce catheters in
  the body.

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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.h
tml
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A Graphical Representation of nanorobots working
in a blood vessel, to remove a cancerous cell
www.e-spaces.com/portfolio/ trans/blood/
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• MEMS and drug delivery

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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

http//www.pharmtech.com/pharmtech/data/articlesta
ndard/pharmtech/022004/80733/article.pdf
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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/
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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.

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Acknowledgements

• This effort is based upon work partially
  supported by the National Science Foundation
  under Grant No. 0239262 and The Florida Hi-Tech
  Corridor Workforce Training grant
• Any opinions, findings, and conclusions or
  recommendations expressed in this material are
  those of the author(s) and do not necessarily
  reflect the views of the National Science
  Foundation or the Florida HiTech Corridor
  Workforce Training Grant.

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