DNA origami could lead to nano 'transformers' for biomedical applications

January 5, 2015 by Pam Frost Gorder
DNA origami could lead to nano 'transformers' for biomedical applications

If the new nano-machines built at The Ohio State University look familiar, it's because they were designed with full-size mechanical parts such as hinges and pistons in mind.

The project is the first to prove that the same basic design principles that apply to typical full-size machine parts can also be applied to DNA—and can produce complex, controllable components for future nano-robots.

In a paper published this week in the Proceedings of the National Academy of Sciences, Ohio State mechanical engineers describe how they used a combination of natural and synthetic DNA in a process called "DNA origami" to build machines that can perform tasks repeatedly.

"Nature has produced incredibly complex molecular machines at the nanoscale, and a major goal of bio-nanotechnology is to reproduce their function synthetically," said project leader Carlos Castro, assistant professor of mechanical and aerospace engineering. "Where most research groups approach this problem from a biomimetic standpoint—mimicking the structure of a biological system—we decided to tap into the well-established field of macroscopic machine design for inspiration."

"In essence, we are using a bio-molecular system to mimic large-scale engineering systems to achieve the same goal of developing molecular machines," he said.

Ultimately, the technology could create complex nano-robots to deliver medicine inside the body or perform nanoscale biological measurements, among many other applications. Like the fictional "Transformers," a DNA origami machine could change shape for different tasks.

The video will load shortly.
Researchers at The Ohio State University are the first to prove that the same basic design principles that apply to typical full-size machine parts can also be applied to DNA -- and can produce complex, controllable components for future nano-robots. Here, a machine made of four DNA "planks" and hinges opens and closes. Credit: The Ohio State University.

"I'm pretty excited by this idea," Castro said. "I do think we can ultimately build something like a Transformer system, though maybe not quite like in the movies. I think of it more as a nano-machine that can detect signals such as the binding of a biomolecule, process information based on those signals, and then respond accordingly—maybe by generating a force or changing shape."

The DNA origami method for making nano-structures has been widely used since 2006, and is now a standard procedure for many labs that are developing future drug delivery systems and electronics. It involves taking long strands of DNA and coaxing them to fold into different shapes, then securing certain parts together with "staples" made from shorter DNA strands. The resulting structure is stable enough to perform a basic task, such as carrying a small amount of medicine inside a container-like DNA structure and opening the container to release it.

To create more complex nano-machines that could perform such tasks repeatedly, Castro joined with Haijun Su, also an assistant professor of mechanical and aerospace engineering at Ohio State. Combined, the two research teams have expertise in nanotechnology, biomechanics, machine engineering and robotics.

Castro said there are two keys to their unique approach for designing and controlling the machines' motion. The first involves making certain parts of the structure flexible. They make flexible parts from single-stranded DNA, and stiffer parts from double-stranded DNA.

The second key involves "tuning" the DNA structures so that the machines' movements are reversible and repeatable. The researchers dot their structures with synthetic DNA strands that hang off the edges like the awning of a roof. Rather than join portions of the machine together permanently, these strands are designed to act like strips of hook and loop fasteners—they stick together or unstick depending on chemical cues from the machine's surroundings.

In the lab, doctoral students Alexander Marras and Lifeng Zhou took long strands of DNA from a bacteriophage—a virus that infects bacteria and is harmless to humans—and "stapled" them together with short strands of synthetic DNA.

The video will load shortly.
Researchers at The Ohio State University are the first to prove that the same basic design principles that apply to typical full-size machine parts can also be applied to DNA -- and can produce complex, controllable components for future nano-robots. Here, a simple DNA hinge -- made of two DNA "planks" connected at one end -- opens and closes. Credit: The Ohio State University.

First, they joined two stiff DNA "planks" with flexible staples along one edge to create a simple hinge. Castro likened the process to "connecting two wooden 2x4's with very short pieces of string along the 4-inch edge at one end."

They also built a system that moved a piston inside a cylinder. That machine used five planks, three hinges and two tubes of different diameters—all made from pieces of double-stranded and single-stranded DNA.

To test whether the machines were moving properly, they imaged them with transmission electron microscopy. They also labeled the DNA with fluorescent tags, so that they could observe the shape changes with a spectrofluorometer. Tests confirmed that the hinges opened and closed and the piston moved back and forth—and that researchers could control the motion with the addition of chemical cues to the solution, such as additional strands of DNA.

This approach of designing simple joints and connecting them together to make more complex working systems is common in macroscopic machine design, but this is the first time it's been done with DNA—and the first time anyone has tuned the DNA to produce reversible actuation of a complex mechanism.

The research team is now working to expand the design of mechanisms for tuning the machines, and they will also attempt to scale up production of the machines for further development.

Explore further: Researchers create world's largest DNA origami

More information: Programmable motion of DNA origami mechanisms, PNAS, www.pnas.org/cgi/doi/10.1073/pnas.1408869112

Related Stories

Researchers create world's largest DNA origami

September 11, 2014

Researchers from North Carolina State University, Duke University and the University of Copenhagen have created the world's largest DNA origami, which are nanoscale constructions with applications ranging from biomedical ...

Scientists use DNA origami trick to create 2D structures

June 2, 2014

(Phys.org) —Scientists at New York University and the University of Melbourne have developed a method using DNA origami to turn one-dimensional nano materials into two dimensions. Their breakthrough, published in the latest ...

Mysteries of 'molecular machines' revealed

December 22, 2014

"Inside each cell in our bodies and inside every bacterium and virus are tiny but complex protein molecules that synthesize chemicals, replicate genetic material, turn each other on and off, and transport chemicals across ...

Computer model enables design of complex DNA shapes

December 3, 2014

MIT biological engineers have created a new computer model that allows them to design the most complex three-dimensional DNA shapes ever produced, including rings, bowls, and geometric structures such as icosahedrons that ...

Baby steps towards molecular robots

December 11, 2014

A walking molecule, so small that it cannot be observed directly with a microscope, has been recorded taking its first nanometre-sized steps.

Relaxing DNA strands by using nano-channels

August 20, 2014

A simple and effective way of unravelling the often tangled mass of DNA is to 'thread' the strand into a nano-channel. A study carried out with the participation of the International School for Advanced Studies in Trieste ...

Recommended for you

Going nano in the fight against cancer

August 17, 2017

Imagine being able to see the signs of cancer decades before we can now. URI Chemical Engineering Assistant Professor Daniel Roxbury and researchers from Memorial Sloan Kettering Cancer Center have invented a technique that ...

Multicolor MRIs could aid disease detection

August 16, 2017

Researchers at Case Western Reserve University School of Medicine have developed a method that could make magnetic resonance imaging—MRI—multicolor. Current MRI techniques rely on a single contrast agent injected into ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

JVK
1 / 5 (2) Jan 06, 2015
Excerpt: "...dot their structures with synthetic DNA strands that hang off the edges like the awning of a roof. Rather than join portions of the machine together permanently, these strands are designed to act like strips of hook and loop fasteners—they stick together or unstick depending on chemical cues from the machine's surroundings."

As is typical, protein folding involves the bio-physically constrained chemistry that links conserved molecular mechanisms from the epigenetic landscape to the physical landscape of DNA in the organized genomes of species from microbes to man via RNA-directed DNA methylation and RNA-mediated amino acid substitutions. The substitutions are fixed via the epigenetic effects of pheromones on the nutrient-dependent physiology of reproduction.

This suggests these mechanical engineers have put an end to any thoughts about careers in biology, unless they can get the nano-bots to reproduce. They may also have ended the careers of evolutionists.
Captain Stumpy
5 / 5 (1) Jan 07, 2015
and jk spouts more pseudoscience with the following
This suggests these mechanical engineers have put an end to any thoughts about careers in biology, unless they can get the nano-bots to reproduce. They may also have ended the careers of evolutionists
these scientists are following the evidence, not trying to fit it to a religious belief, for starters, unlike jk

also, jk is pushing a model of mutations while trying to claim that mutations are never beneficial, regardless of the overwhelming evidence that she is wrong as DEMONSTRATED by Lenski and Extavour, et al

stop posting PSEUDOSCIENCE kohl
you still haven't answered the questions posted by RealScience or Anonymous proving you are capable of comprehending the difference between epigenetics and showing you understand biology!
http://phys.org/n...firstCmt
http://phys.org/n...firstCmt

and in other threads too!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.