Tag Archives: University of Massachusetts at Amherst

Chad Mirkin’s periodic table of modified nucleic acid nanoparticles

Chad Mirkin has been pushing his idea for a new periodic table of ‘nanoparticles’ since at least Feb. 2013 (I wrote about this and some of Mirkin’s other work in my Feb. 19, 2013 posting) when he presented it at the 2013 American Association for the Advancement of Science (AAAS) annual meeting in Boston, Massachusetts. From a Feb. 17, 2013 news item on ScienceDaily,

Northwestern University’s Chad A. Mirkin, a leader in nanotechnology research and its application, has developed a completely new set of building blocks that is based on nanoparticles and DNA. Using these tools, scientists will be able to build — from the bottom up, just as nature does — new and useful structures.

Mirkin will discuss his research in a session titled “Nucleic Acid-Modified Nanostructures as Programmable Atom Equivalents: Forging a New Periodic Table” at the American Association for the Advancement of Science (AAAS) annual meeting in Boston.

“We have a new set of building blocks,” Mirkin said. “Instead of taking what nature gives you, we can control every property of the new material we make. [emphasis mine] We’ve always had this vision of building matter and controlling architecture from the bottom up, and now we’ve shown it can be done.”

Mirkin seems a trifle grandiose; I’m hoping he doesn’t have any grand creation projects that require seven days.

Getting back to the new periodic table, the Feb. 13, 2013 Northwestern University news release by Megan Fellman, which originated the news item,  provides a few more details,

Using nanoparticles and DNA, Mirkin has built more than 200 different crystal structures with 17 different particle arrangements. Some of the lattice types can be found in nature, but he also has built new structures that have no naturally occurring mineral counterpart.
Mirkin can make new materials and arrangements of particles by controlling the size, shape, type and location of nanoparticles within a given particle lattice. He has developed a set of design rules that allow him to control almost every property of a material.

New materials developed using his method could help improve the efficiency of optics, electronics and energy storage technologies. “These same nanoparticle building blocks have already found wide-spread commercial utility in biology and medicine as diagnostic probes for markers of disease,” Mirkin added.

With this present advance, Mirkin uses nanoparticles as “atoms” and DNA as “bonds.” He starts with a nanoparticle, which could be gold, silver, platinum or a quantum dot, for example. The core material is selected depending on what physical properties the final structure should have.

He then attaches hundreds of strands of DNA (oligonucleotides) to the particle. The oligonucleotide’s DNA sequence and length determine how bonds form between nanoparticles and guide the formation of specific crystal lattices.

“This constitutes a completely new class of building blocks in materials science that gives you a type of programmability that is extraordinarily versatile and powerful,” Mirkin said. “It provides nanotechnologists for the first time the ability to tailor properties of materials in a highly programmable way from the bottom up.”

Mirkin and his colleagues have since published a paper about this new periodic table in Angewandte Chemie (May 2013). And, earlier today (July 5, 2013) Philip Ball writing (A self-assembled periodic table) for the Royal Society of Chemistry provided a critique of the idea while supporting it in principle,

Mirkin and his colleagues perceive the pairing of [DNA] strands as somewhat analogous to the covalent pairing of electrons and call their DNA-tagged nanoparticles programmable atom equivalents (PAEs). These PAEs may bind to one another according to particular combinatorial rules and Mirkin proposes a kind of periodic table of PAEs that systematises their possible interactions and permutations.
Well, it’s not hard to start enumerating ways in which PAEs are unlike atoms. Most fundamentally, perhaps, the bonding propensity of a PAE need bear no real relation to the ‘atom’ (the nanoparticle) with which it is associated: a given nanoparticle might be paired with any other, and there’s nothing periodic about those tendencies.

I recommend reading Ball’s piece for the way he analyzes the weaknesses and for why he thinks the effort to organize PAEs conceptually is worthwhile.

For the curious, here’s a link to and a citation for the researchers’ published paper,

Nucleic Acid-Modified Nanostructures as Programmable Atom Equivalents: Forging a New “Table of Elements by Robert J. Macfarlane, Matthew N. O’Brien, Dr. Sarah Hurst Petrosko, and Prof. Chad A. Mirkin. Angewandte Chemie International Edition Volume 52, Issue 22, pages 5688–5698, May 27, 2013. Article first published online: 2 MAY 2013 DOI: 10.1002/anie.201209336

Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This article is behind a paywall.

One final comment, this is not the first ‘nanoparticle table of elements’.  Larry Bell mentioned one in his Dec. 7, 2010 NISENet (Nanoscale Informal Science Education Network) blog posting,

The focus of today’s sessions at NSF’s [US National Science Foundation] meeting of nanoscale science and engineering grantees focuses on putting the science to practical use. First up this morning is nanomanufacturing. Mark Tuonimen from the University of Massachusetts at Amherst gave a talk about the Nanoscale Manufacturing Network and one of his images caught my imagination. This image, which comes from the draft Nano2 vision document on the next decade of nanoscale research, illustrates and idea that is sometimes referred to as a periodic table of nanoparticles.

[downloaded from http://www.nisenet.org/blogs/observations_insights/periodic_table_nanoparticles]

[downloaded from http://www.nisenet.org/blogs/observations_insights/periodic_table_nanoparticles]

Bell goes on to describe one way in which a nanoparticle table of elements would have to differ from the traditional chemistry table.

Geckskin and Z-Man

Z-Man or do I mean SpiderMan? They used to make reference to SpiderMan and/or geckos when there was some research breakthrough or other concerning adhesion (specifically, bioadhesion) but these days, it’s all geckos, all the time.

I’m going to start with the first announcement from the research team at the University of Massachusetts at Amherst, from the Feb. 17, 2012 news item on Nanowerk,

For years, biologists have been amazed by the power of gecko feet, which let these 5-ounce lizards produce an adhesive force roughly equivalent to carrying nine pounds up a wall without slipping. Now, a team of polymer scientists and a biologist at the University of Massachusetts Amherst have discovered exactly how the gecko does it, leading them to invent “Geckskin,” a device that can hold 700 pounds on a smooth wall. Doctoral candidate Michael Bartlett in Alfred Crosby’s polymer science and engineering lab at UMass Amherst is the lead author of their article describing the discovery in the current online issue of Advanced Materials (“Looking Beyond Fibrillar Features to Scale Gecko-Like Adhesion”). The group includes biologist Duncan Irschick, a functional morphologist who has studied the gecko’s climbing and clinging abilities for over 20 years. Geckos are equally at home on vertical, slanted, even backward-tilting surfaces.

Here’s a picture illustrating the material’s strength,

A card-sized pad of Geckskin can firmly attach very heavy objects such as this 42-inch television weighing about 40 lbs. (18 kg) to a smooth vertical surface. The key innovation by Bartlett and colleagues was to create a soft pad woven into a stiff fabric that includes a synthetic tendon. Together these features allow the stiff yet flexible pad to “drape” over a surface to maximize contact. Photo courtesy of UMass Amherst

This image is meant as an illustration of what the product could do and not as a demonstration, i.e., the tv is not being held up by ‘geckskin’.

There are other research teams around the world working on ways to imitate the properties of gecko feet or bioadhesion (my Nov. 2, 2011 posting mentions some work on robots with ‘gecko feet’ at Simon Fraser University [Canada] and my March 19, 2012 posting mentions in passing some work being done at the University of Waterloo [Canada] are two recent examples).

The University of Massachusetts team’s innovation (from the Feb. 17, 2012 news item),

The key innovation by Bartlett and colleagues was to create an integrated adhesive with a soft pad woven into a stiff fabric, which allows the pad to “drape” over a surface to maximize contact. Further, as in natural gecko feet, the skin is woven into a synthetic “tendon,” yielding a design that plays a key role in maintaining stiffness and rotational freedom, the researchers explain.

Importantly, the Geckskin’s adhesive pad uses simple everyday materials such as polydimethylsiloxane (PDMS), which holds promise for developing an inexpensive, strong and durable dry adhesive.

The UMass Amherst researchers are continuing to improve their Geckskin design by drawing on lessons from the evolution of gecko feet, which show remarkable variation in anatomy. “Our design for Geckskin shows the true integrative power of evolution for inspiring synthetic design that can ultimately aid humans in many ways,” says Irschick.

The research at the University of Massachusetts is being funded, in part, by DARPA (US Defense Advanced Research Projects Agency) through its Z-man program. From the March 2, 2012 news item on Nanowerk,

“Geckskin” is one output of the Z-Man program. It is a synthetically-fabricated reversible adhesive inspired by the gecko’s ability to climb surfaces of various materials and roughness, including smooth surfaces like glass. Performers on Z-Man designed adhesive pads to mimic the gecko foot over multiple length scales, from the macroscopic foot tendons to the microscopic setae and spatulae, to maximize reversible van der Waals interactions with the surface.

Here’s the reasoning for the Z-Man program, from the March 2, 2012 news item,

The Defense Advanced Research Projects Agency (DARPA)’s “Z-Man program” aims to develop biologically inspired climbing aids to enable soldiers to scale vertical walls constructed from typical building materials, while carrying a full combat load, and without the use of ropes or ladders.

Soldiers operate in all manner of environments, including tight urban terrain. Their safety and effectiveness demand maximum flexibility for maneuvering and responding to circumstances. To overcome obstacles and secure entrance and egress routes, soldiers frequently rely on ropes, ladders and related climbing tools. Such climbing tools cost valuable time to use, have limited application and add to the load warfighters are forced to carry during missions.

The Z-Man program provides more information, as well as, images here, where you will find this image, which is not as pretty as the one with the tv screen but this one is a demonstration,

A proof-of-concept demonstration of a 16-square-inch sheet of Geckskin adhering to a vertical glass wall while supporting a static load of up to 660 pounds. (from the Z-Man Program website)

In the very latest news, the University of Massachusetts team has won international funding for its (and Cambridge University’s) work on bioadhesion. From the University of Massachusetts at Amherst March 28, 2012 [news release],

Duncan Irschick, Biology, and Al Crosby, Polymer Science and Engineering, with Walter Federle of Cambridge University, have been awarded a three-year, $900,000 grant from the Human Frontiers Science Program (HFSP) in Strasbourg, France, to study bioadhesion in geckos and insects.

Theirs was one of only 25 teams from among approximately 800 to apply worldwide. HFSP is a global organization that funds research at the frontiers of the life sciences.

Crosby, Irschick and colleagues received international scientific and media attention over the past several weeks for their discovery reported in the journal Advanced Materials, of how gecko feet and skin produce an adhesive force roughly equivalent to the 5-ounce animal carrying nine pounds up a wall without slipping. This led them to invent “Geckskin,” a device that can hold 700 pounds on a smooth wall. Irschick, a functional morphologist who has studied the gecko’s climbing and clinging abilities for over 20 years, says the lizards are equally at home on vertical, slanted and even backward-tilting surfaces.

Not having heard of the Human Science Frontier Program (HSFP) previously, I was moved to investigate further. From the About Us page,

The Human Frontier Science Program is a program of funding for frontier research in the life sciences. It is implemented by the International Human Frontier Science Program Organization (HFSPO) with its office in Strasbourg.

The members of the HFSPO, the so-called Management Supporting Parties (MSPs) are the contributing countries and the European Union, which contributes on behalf of the non-G7 EU members.

The current MSPs are Australia, Canada, France, Germany, India, Italy, Japan, Republic of Korea, Norway, New Zealand, Switzerland the United Kingdom, the United States of America and the European Union.

I wonder how much impact all the publicity had on the funding decision. In any event, it’s good to find out about a new funding program and I wish anyone who applies the best of luck!