Our Android Future? Biomaterials Mimic Biology

AndroidLike a pair of droids out of Blade Runner, DARPA is creating a soft robot and Virginia Tech has engineered artificial proteins can now mimic the elastic properties of muscles in living organisms.

“Our goal is to use these biomaterials in tissue engineering as a type of scaffold for muscle regeneration,” said Dan Dudek, an assistant professor of engineering science and mechanics.

The work was conducted when Dudek was a postdoctoral fellow at the University of British Columbia’s Department of Zoology where he worked with the lead author Hongbin Li of the University of British Columbia’s Department of Chemistry. According to the Nature press release on the article, “This work represents a step forward in the design at the single-molecule level of potentially useful biomaterials.”

The team engineered a synthetic protein to reproduce the molecular structure of titin, the muscle protein “that largely governs the elastic properties of muscle,” according to the Nature article. The researchers tested the nanomechanical properties of the new proteins at the single-molecule level and then cross-linked them into a solid rubber-like material.

The authors wrote that synthetic biomaterials display the unique multifunctional characteristics of titin, acting like a spring with high resilience at low strain and as a shock-absorb at high strains. Dudek added that this is “a nice feat when the material at a high strain releases stress instead of tearing apart. The material’s spring-like properties are fully recoverable.”

Under normal biological circumstances, injuries causing tissue tears larger than a centimeter will not reconnect on their own, Dudek said. The newly designed biomaterial could help in the healing process by acting as a tough yet extensible scaffold, allowing new tissue to grow across the gap.

The new biomaterial is biodegradable. “You only want the scaffold to exist as long as necessary, and then dissolve itself, leaving no side effects,” Dudek said.

Producing the synthetic protein is as easy as growing bacteria, but then it must be purified. The expense comes when generating large quantities, Dudek said. “Our next step will be to see if, on the engineering side, we can make use of this in the scaffold matrix.”

 

Meanwhile at DARPA,  researchers are developing techniques for warfare of the future to create materials that self-assemble or alter their shape, perform a function and then disassemble themselves. These capabilities offer the possibility for morphing aircraft and ground vehicles, uniforms that can alter themselves in any climate, and “soft” robots that flow like mercury through small openings to enter caves and bunker complexes.

 

Several university teams, including Harvard, Cornell, and MIT,  are working on different approaches to create “programmable matter”—made of individual pieces that can self-assemble into tools or spare parts. One of the approaches being examined uses sheets of self-folding material that can form three-dimensional shapes on command.

A revolutionary new technology in being developed by DARPA that may allow future war leaders to command their equipment to physically change itself to meet new operational needs or to form spare parts or tools.

“You’re blurring the distinction between materials and machines. Materials act like computers and communications systems, and communications systems and computers act like materials,” program manager Dr. Mitchell R. Zakin says.

The Programmable Matter program is now approximately five months into its second phase, which is scheduled to last about 15 months. The first phase of the effort involved five teams, two from Harvard University, two from the Massachusetts Institute of Technology (MIT) and one from Cornell University made up of experts from a range of disciplines such as computer scientists, roboticists, biologists, chemical engineers, mechanical engineers, physicists and artists

Among the fascinating research projects is a wrench that can it disassembles itself back into its components and re-forms into a hammer

The teams methods range from developing two-dimensional objects that fold into three-dimensional shapes to particles that build up to larger structures. One group is building what Zakin describes as “self-folding origami” machines that use specialized sheets of material with built-in actuators and data. These machines use cutting-edge mathematical theorems to fold themselves into virtually any three-dimensional object.

One Harvard team has developed a programming language to manipulate the DNA. Researchers can command the binding interactions between long synthesized strands of DNA, something that has never been done before.

Another team has developed a way to both program and coat objects with DNA. The DNA strands act as a “molecular Velcro” to hold small objects together to assemble into a tool. After it is used, the DNA can be commanded to release and disassemble the object.

Another team’s approach mimics biological functions on a millimeter scale to copy how proteins are built in living organisms. Scientists created a programming language that allows each component of the material to process information. “When we put the whole thing together, it’s a computer,” he says.

Posted by Casey Kazan and Jason McManus via Virginia Tech

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DARPA Programmable Matter program: www.darpa.mil/dso/thrusts/physci/newphys/program_matter/index.htm

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