Transcript Role of mems in medical technologies - Bio

Role of MEMS and nanotechnology
in medical technologies
Shekhar Bhansali
[email protected]
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 !!!!
Shekhar Bhansali
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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 !!
Shekhar Bhansali
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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.
Shekhar Bhansali
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Benefits of MEMS and nanotechnology
in medical applications
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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.
Shekhar Bhansali
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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/main.shtml
Shekhar Bhansali
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Projected MEMS market share in 2006
Consumer 3%
Medical 11%
Industrial 22%
Automotive 17%
Communictions
21%
Computer 26%
http://www.memsindustrygroup.org/industy_statistics.asp
Shekhar Bhansali
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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
Shekhar Bhansali
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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.
Shekhar Bhansali
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MEMS and nanotechnology in
precision surgery
Shekhar Bhansali
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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_rigid_endoscope.htm
Shekhar Bhansali
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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)
http://www.spie.org/web/oer/august/aug00/cover2.html
 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
Shekhar Bhansali
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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.
Shekhar Bhansali
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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.
Shekhar Bhansali
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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/conference/msc_2000_judy.pdf
Shekhar Bhansali
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Ultrasonic MEMS cutting tool
http://www.ee.ucla.edu/~jjudy/publications/conference/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
Shekhar Bhansali
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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.
Shekhar Bhansali
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Drawbacks of the conventional approaches
in skin resurfacing
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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.
Shekhar Bhansali
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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=Retrieve&db=PubMed&list_uids=12787986&dopt=Abstract
Shekhar Bhansali
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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.
Shekhar Bhansali
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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.
Shekhar Bhansali
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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.html
Shekhar Bhansali
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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/
Shekhar Bhansali
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MEMS and drug
delivery
Shekhar Bhansali
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MEMS microneedles
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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/articlestandard/pharmtech/022004/80733/article.pdf
Shekhar Bhansali
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Smart Pill
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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/
Shekhar Bhansali
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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.
Shekhar Bhansali
[email protected]
Acknowledgements
This effort is based upon work partially supported by the National
Science Foundation under Grant No. 0239262 and The Florida HiTech 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.
Shekhar Bhansali
[email protected]
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