Shekhar Bhansali [email protected] Role of MEMS and nanotechnology in medical technologies

Shekhar Bhansali [email protected]

Role of MEMS and nanotechnology in medical technologies


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 !!!!


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 !!


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.


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.


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


Projected MEMS market share in 2006

Medical 11%

Automotive 17%

Computer 26%

Communictions 21%

Industrial 22%

Consumer 3%

http://www.memsindustrygroup.org/industy_statistics.asp


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


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.


MEMS and nanotechnology in precision surgery


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


MEMS redefines endoscopy with “Lab on a Pill”

Size : 35mmComponents 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.see.ed.ac.uk/~tbt/norchip2002.pdf

http://www.spie.org/web/oer/august/aug00/cover2.html


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.


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.


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


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

http://www.ee.ucla.edu/~jjudy/publications/conference/msc_2000_judy.pdf


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.


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.


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


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.


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.


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


A Graphical Representation of nanorobots working in a blood vessel, to remove a cancerous cell

www.e-spaces.com/portfolio/ trans/blood/


MEMS and drug delivery


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/articlestandard/pharmtech/022004/80733/article.pdf


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/


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.


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.


We would really appreciate if you could fill in our

online feedback form and give us your opinion.

Documents

Shekhar Bhansali [email protected] Role of MEMS and nanotechnology in medical technologies