Navigation Links
'Smart' materials get smarter with ability to better control shape and size
Date:7/3/2008

AUSTIN, TexasA dynamic way to alter the shape and size of microscopic three-dimensional structures built out of proteins has been developed by biological chemist Jason Shear and his former graduate student Bryan Kaehr at The University of Texas at Austin.

Shear and Kaehr fabricated a variety of detailed three-dimensional microstructures, known as hydrogels, and have shown that they can expand and bend the hydrogels by altering the chemistry of the environment in which they were built.

Hydrogels have been in development over the last couple of decades and are being used as parts in biology-based microdevices and medical diagnostic technologies, for drug delivery, and in tissue engineering. But the future utility of these "smart materials" relies on finding better ways to control their conformation.

Shear and Kaehr's work lays the foundation for more precise control of hydrogels. Among many applications, Shear says they will have the ability to better grow bacteria with the aim of understanding disease.

"This provides a significant new way of interacting with cultured cells," says Shear, an associate professor of chemistry and biochemistry. "The microstructures can be used to capture individual cells, and once isolated, clonal colonies of those cells can be grown and studied."

Their research appears in a paper published July 1 in Proceedings of the National Academy of Sciences.

As a proof of concept, the researchers built a rectangular house-like structure with a roof in which they trapped and then released E. coli bacteria. The bacteria blundered into the house through a funnel shaped door, where they found themselves trapped in a ring-shaped chamber. The funnel made it difficult to get out of the house.

Once inside, "they moved around the space like they were running around a racetrack," says Shear.

When the researchers increased the pH of the cell culture, the chamber changed volume, causing the house to pop off its foundation and release the bacteria.

By increasing or decreasing the volume of microstructures dynamically, Shear hopes to be able to better understand a phenomenon known as quorum sensing, where bacteria coordinate their gene expression according to the density of their population. Quorum sensing is important in the pathology of some disease-causing bacteria, such as Pseudomonas aeruginosa.

The hydrogels created by Shear and Kaehr are made of protein molecules that have been chemically bound together using a focused laser beam, a process known as photofabrication.

The laser causes amino acid side chains to link en masse and this builds a solid protein matrix. The protein scaffold is built layer by layer, much like a raster scanner.

"It's a little bit like a three-dimensional Etch-a-Sketch," says Shear.

Other high resolution structures the researchers developed include tethers that connect microspheres to surfaces, flower- and fern-like structures, and micro-hands that are less than a quarter the diameter of a hair, pinky to thumb.

Experimenting with various chemical changes, Shear and Kaehr show that changing pH caused hydrogel bands to bow out at specific points along their length and caused other shapes, like the micro-hands and bacterial chamber, to expand.

Altering ion concentrations caused the fern-like structures to coil and unfurl like fiddleheads emerging from the ground in spring. Adding ions caused contraction of the tether holding the microsphere.

Structures such as these could be used to create better micro- and nano-valves, motors and optics.

Shear says a great advantage of the hydrogels is that they are well suited for controlling and growing cells dynamically and in the environments in which they live.

Waste from the cells can move out of the structures and nutrients and other chemicals, including those added by the researchers to manipulate the cells' biology, can move in. Other microfabrication materials, such as glass, do not have such permeability.


'/>"/>
Contact: Jason Shear
jshear@mail.utexas.edu
512-232-1454
University of Texas at Austin
Source:Eurekalert

Related biology news :

1. Get smart about what you eat and you might actually improve your intelligence
2. BIO-key(R) Showcasing Public Safety Solutions for BlackBerry Smartphones at 2008 LEIM Conference
3. QUT researchers develop smart instrument for tissue damage assessment
4. Smart greenhouse research partnership unveiled
5. IDsmart Admits in Court Document That e-Smarts Technology was Used to Develop IDsmarts Smart Card
6. Nutrition research unveiled this week shows pistachios are smart for the heart
7. bioMETRX Incorporates OKIs Fingerprint Engine in its smartTOUCH Product Line
8. e-SMART Technologies Continues Delivery of Its New Super SMART Card in South Korea
9. Corporate Safe Specialists Smart Safes Capture Evidence in Robbery and Theft
10. e-Smart(R) Technologies Delivers Its New Super Smart Card(TM) in South Korea.
11. Smart holograms help patients help themselves
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/12/2016)... , May 12, 2016 WearablesResearch.com , ... published the overview results from the Q1 wave of ... recent wave was consumers, receptivity to a program where ... with a health insurance company. "We were ... share," says Michael LaColla , CEO of Troubadour ...
(Date:4/28/2016)... BANGALORE, India , April 28, 2016 ... subsidiary of Infosys (NYSE: INFY ), and Samsung ... global partnership that will provide end customers with a ... and payment services.      (Logo: http://photos.prnewswire.com/prnh/20130122/589162 ... for financial services, but it also plays a fundamental part ...
(Date:4/26/2016)... -- Research and Markets has announced the ...  report to their offering.  , ,     (Logo: ... forecast the global multimodal biometrics market to grow ... 2016-2020.  Multimodal biometrics is being implemented ... healthcare, BFSI, transportation, automotive, and government for controlling ...
Breaking Biology News(10 mins):
(Date:5/26/2016)... READING, England , May 26, 2016 ... a leading global provider of clinical, commercial and ... organisations and TranScrip ( http://www.transcrip-partners.com ), a renowned ... product lifecycle, today announced the extension of their ...      (Logo: http://photos.prnewswire.com/prnh/20141208/720248 ) , ...
(Date:5/26/2016)... ... May 26, 2016 , ... After several promising treatments in ... the City of Knowledge in Panama, a 6 year-old Duchenne’s muscular dystrophy patient ... this year following FDA approval of a second application for a single patient, ...
(Date:5/25/2016)... ... May 25, 2016 , ... Lajollacooks4u has become a ... consistently been rated one of its top attractions. Fortune 500 companies, such as ... in a unique and intimate team-building experience. , Each event kicks off with an ...
(Date:5/25/2016)... ... 25, 2016 , ... Founder of the Fitzmaurice Hand Institute ... surgery of the hand by the National Board of Physicians and Surgeons, as ... beyond in his pursuit of providing the most comprehensive, effective treatment for his ...
Breaking Biology Technology: