Navigation Links
Morphing DNA hydrogel flows like liquid but remembers its original shape

ITHACA, N.Y. A bit reminiscent of the Terminator T-1000, a new material created by Cornell researchers is so soft that it can flow like a liquid and then, strangely, return to its original shape.

Rather than liquid metal, it is a hydrogel, a mesh of organic molecules with many small empty spaces that can absorb water like a sponge. It qualifies as a "metamaterial" with properties not found in nature and may be the first organic metamaterial with mechanical meta-properties.

Hydrogels have already been considered for use in drug delivery the spaces can be filled with drugs that release slowly as the gel biodegrades and as frameworks for tissue rebuilding. The ability to form a gel into a desired shape further expands the possibilities. For example, a drug-infused gel could be formed to exactly fit the space inside a wound.

Dan Luo, professor of biological and environmental engineering, and colleagues describe their creation in the Dec. 2 issue of the journal Nature Nanotechnology.

The new hydrogel is made of synthetic DNA. In addition to being the stuff genes are made of, DNA can serve as a building block for self-assembling materials. Single strands of DNA will lock onto other single stands that have complementary coding, like tiny organic Legos. By synthesizing DNA with carefully arranged complementary sections Luo's research team previously created short stands that link into shapes such as crosses or Y's, which in turn join at the ends to form meshlike structures to form the first successful all-DNA hydrogel. Trying a new approach, they mixed synthetic DNA with enzymes that cause DNA to self-replicate and to extend itself into long chains, to make a hydrogel without DNA linkages.

"During this process they entangle, and the entanglement produces a 3-D network," Luo said. But the result was not what they expected: The hydrogel they made flows like a liquid, but when placed in water returns to the shape of the container in which it was formed.

"This was not by design," Luo said.

Examination under an electron microscope shows that the material is made up of a mass of tiny spherical "bird's nests" of tangled DNA, about 1 micron (millionth of a meter) in diameter, further entangled to one another by longer DNA chains. It behaves something like a mass of rubber bands glued together: It has an inherent shape, but can be stretched and deformed.

Exactly how this works is "still being investigated," the researchers said, but they theorize that the elastic forces holding the shape are so weak that a combination of surface tension and gravity overcomes them; the gel just sags into a loose blob. But when it is immersed in water, surface tension is nearly zero there's water inside and out and buoyancy cancels gravity.

To demonstrate the effect, the researchers created hydrogels in molds shaped like the letters D, N and A. Poured out of the molds, the gels became amorphous liquids, but in water they morphed back into the letters. As a possible application, the team created a water-actuated switch. They made a short cylindrical gel infused with metal particles placed in an insulated tube between two electrical contacts. In liquid form the gel reaches both ends of the tube and forms a circuit. When water is added, the gel reverts to its shorter form that will not reach both ends. (The experiment is done with distilled water that does not conduct electricity.)

The DNA used in this work has a random sequence, and only occasional cross-linking was observed, Luo said. By designing the DNA to link in particular ways he hopes to be able to tune the properties of the new hydrogel.

Contact: John Carberry
Cornell University

Related biology news :

1. Debris flows, landslides, fossil microatolls, paleo-seasonality, and carbonate ore deposits
2. Faster, cheaper gas and liquid separation using custom designed and built mesoscopic structures
3. Liquid glucagon formulation discovered for potential use in artificial pancreas systems
4. Microbe that can handle ionic liquids
5. High-resolution atomic imaging of specimens in liquid by TEM using graphene liquid cell
6. Odorant shape and vibration likely lead to olfaction satisfaction
7. Oh, my stars and hexagons! DNA code shapes gold nanoparticles
8. Cells to Civilizations: The Principles of Change That Shape Life
9. Simple mathematcal pattern describes shape of neuron jungle
10. Not a 1-way street: Evolution shapes environment of Connecticut lakes
11. International team uncovers new genes that shape brain size, intelligence
Post Your Comments:
(Date:10/29/2015)... Va. , Oct. 29, 2015 Daon, ... today that it has released a new version of ... customers in North America have ... IdentityX v4.0 also includes a FIDO UAF certified ... are already preparing to activate FIDO features. These customers ...
(Date:10/27/2015)... -- In the present market scenario, security is one ... verticals such as banking, healthcare, defense, electronic gadgets, and ... secure & simplified access control and growing rate of ... bank accounts, misuse of users, , and so on. ... and smartphones are expected to provide potential opportunities for ...
(Date:10/26/2015)...  Delta ID Inc., a company focused on bringing ... devices, announced its ActiveIRIS® technology powers the iris recognition ... by NTT DOCOMO, INC in Japan ... to include iris recognition technology, after a very successful ... May 2015, world,s first smartphone to have this capability. ...
Breaking Biology News(10 mins):
(Date:11/28/2015)... ... ... • Jeon Jin Bio Corp, a Korean Biotech venture company, has developed ... Bird Free, an oil-based, gel formula made from natural ... smell, taste and touch, enabling safe, effective avian control without toxic chemicals , ...
(Date:11/26/2015)... , England , November 26, 2015 /PRNewswire/ ... Medical, an innovative medical device company specializing in imaging technologies, ... from the European Commission as part of the Horizon 2020 ... company to carry out a large-scale clinical trial in breast ...      (Logo: , --> ...
(Date:11/25/2015)... Mass. , Nov. 25, 2015 Harvard ... biotechnology company developing bioengineered organ implants for life-threatening conditions, ... present at the LD Micro "Main Event" investor conference ... The presentation will be webcast live and posted for ... be available at the conference for one-on-one meetings on ...
(Date:11/25/2015)... PORTLAND, Oregon , November 25, 2015 /PRNewswire/ ... Deep Market Research Report is a professional and ... Genomics industry.      (Logo: ... basic overview of the industry including definitions, classifications, ... analysis is provided for the international markets including ...
Breaking Biology Technology: