Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Enzymes Dig Channels

11.09.2012
Enzymatic etching used to build nano- and microscale surface topologies

In living systems, complex nano- and microscale structures perform a host of physical and biological functions. While two-dimensional patterns can be recreated fairly well with techniques like microlithography, three-dimensional structures represent a big challenge.



In the journal Angewandte Chemie, American researchers have now reported a new method for the lithography-free etching of complex surface motifs with the use of biodegradable polymers and enzymes. Starting with structured microchannels, they have built an assembly for the isolation and concentration of cells from whole blood.

A team led by Victor M. Ugaz at Texas A&M University uses proteinase K (PK), a protein-cleaving enzyme that can also break down the bioplastic polylactic acid. First, the researchers apply a mask to a small block of polylactic acid, leaving only a narrow trail. The liquid containing PK is directed through this microchannel. Wherever the enzyme comes into contact with the polylactic acid, the latter is etched away.

Within microchannels, liquids can flow past each other without appreciable mixing. The researchers use this phenomenon to make structured channels. They direct PK solution through the channels on the left and right, while allowing a protein solution flowing through the middle to inhibit the etching process. This etches neighboring channels separated by a “weir” into the polymer.

In the next step, a protein solution is directed through one of the etched channels and over the central weir, while the second channel is further etched with PK. This allows one channel to remain flat while the second is made deeper. Finally, all three “tracks” are made even deeper with PK. This causes the top of the weir to be lower than the outer edges of the double channel.

To make their device, the researchers bent one such channel into a hairpin turn and put a lid over it. They allow blood spiked with tumor cells to flow through the inner, flatter channel.

A buffer solution flows through the deeper outer channel. In the curve, centrifugal forces push blood cells into the outer track with the buffer. However, the small space between the top of the weir and the lid over the system only allows small blood cells to pass through. The larger tumor cells do not fit through and become more concentrated in the inner channel as the red blood cells become less concentrated. The different depths of the channels enhances this process. Rare cells like freely circulating tumor cells can be detected much more rapidly and easily when blood samples are tested by this method than by conventional methods like membrane filtration.

Special thermal preparation allows for the targeted formation of crystalline regions in the polylactic acid. PK does not degrade these regions well. This allows for the formation of defined small obstacles within the channels, which could be useful in filtration or chromatography systems.

About the Author
Dr. Victor M. Ugaz is an Associate Professor and Kenneth R. Hall Development Professor in the Artie McFerrin Department of Chemical Engineering at Texas A&M University. His research focuses broadly on understanding and exploiting the unique characteristics of transport and flow at the microscale. He also serves as Chair of the interdisciplinary Professional Program in Biotechnology (PPiB) at Texas A&M.
Author: Victor M. Ugaz, Texas A&M University, College Station (USA), http://www.che.tamu.edu/people/faculty/info?fid=11
Title: Enzymatic Sculpting of Nanoscale and Microscale Surface Topographies
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201204600

Victor M. Ugaz | Angewandte Chemie
Further information:
http://pressroom.angewandte.org
http://www.che.tamu.edu/people/faculty/info?fid=11

More articles from Life Sciences:

nachricht Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>