Tag Archives: ORNl

Corrections: Hybrid Photonic-Nanomechanical Force Microscopy uses vibration for better chemical analysis

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*ETA  Nov. 4, 2015: I’m apologizing to anyone wishing to read this posting as it’s a bit of a mess. I deeply regret mishandling the situation. In future, I shall not be taking any corrections from individual researchers to materials such as news releases that have been issued by an institution. Whether or not the individual researchers are happy with how their contributions or how a colleague’s contributions or how their home institutions have been characterized is a matter for them and their home institutions.

The August 10, 2015 ORNL news release with all the correct details has been added to the end of this post.*

A researcher at the University of Central Florida (UCF) has developed a microscope that uses vibrations for better analysis of chemical composition. From an Aug. 10, 2015 news item on Nanowerk,

It’s a discovery that could have promising implications for fields as varied as biofuel production, solar energy, opto-electronic devices, pharmaceuticals and medical research.

“What we’re interested in is the tools that allow us to understand the world at a very small scale,” said UCF professor Laurene Tetard, formerly of the Oak Ridge National Laboratory. “Not just the shape of the object, but its mechanical properties, its composition and how it evolves in time.”

An Aug. 10, 2015 UCF news release (also on EurekAlert), which originated the news item, describes the limitations of atomic force microscopy and gives a few details about the hybrid microscope (Note: A link has been removed),

For more than two decades, scientists have used atomic force microscopy – a probe that acts like an ultra-sensitive needle on a record player – to determine the surface characteristics of samples at the microscopic scale. A “needle” that comes to an atoms-thin point traces a path over a sample, mapping the surface features at a sub-cellular level [nanoscale].

But that technology has its limits. It can determine the topographical characteristics of [a] sample, but it can’t identify its composition. And with the standard tools currently used for chemical mapping, anything smaller than roughly half a micron is going to look like a blurry blob, so researchers are out of luck if they want to study what’s happening at the molecular level.

A team led by Tetard has come up with a hybrid form of that technology that produces a much clearer chemical image. As described Aug. 10 in the journal Nature Nanotechnology, Hybrid Photonic-Nanomechanical Force Microscopy (HPFM) can discern a sample’s topographic characteristics together with the chemical properties at a much finer scale.

The HPFM method is able to identify materials based on differences in the vibration produced when they’re subjected to different wavelengths of light – essentially a material’s unique “fingerprint.”

“What we are developing is a completely new way of making that detection possible,” said Tetard, who has joint appointments to UCF’s Physics Department, Material Science and Engineering Department and the NanoScience Technology Center.

The researchers proved the effectiveness of HPFM while examining samples from an eastern cottonwood tree, a potential source of biofuel. By examining the plant samples at the nanoscale, the researchers for the first time were able to determine the molecular traits of both untreated and chemically processed cottonwood inside the plant cell walls.

The research team included Tetard; Ali Passian, R.H. Farahi and Brian Davison, all of Oak Ridge National Laboratory; and Thomas Thundat of the University of Alberta.

Long term, the results will help reveal better methods for producing the most biofuel from the cottonwood, a potential boon for industry. Likewise, the new method could be used to examine samples of myriad plants to determine whether they’re good candidates for biofuel production.

Potential uses of the technology go beyond the world of biofuel. Continued research may allow HPFM to be used as a probe so, for instance, it would be possible to study the effect of new treatments being developed to save plants such as citrus trees from bacterial diseases rapidly decimating the citrus industry, or study fundamental photonically-induced processes in complex systems such as in solar cell materials or opto-electronic devices.

Here’s a link to and a citation for the paper,

Opto-nanomechanical spectroscopic material characterization by L. Tetard, A. Passian, R. H. Farahi, T. Thundat, & B. H. Davison. Nature Nanotechnology (2015) doi:10.1038/nnano.2015.168 Published online 10 August 2015

This paper is behind a paywall.

*ETA August 27, 2015:

August 10, 2015 ORNL news release (Note: Funding information and a link to the paper [previously given] have been removed):

A microscope being developed at the Department of Energy’s Oak Ridge National Laboratory will allow scientists studying biological and synthetic materials to simultaneously observe chemical and physical properties on and beneath the surface.

The Hybrid Photonic Mode-Synthesizing Atomic Force Microscope is unique, according to principal investigator Ali Passian of ORNL’s Quantum Information System group. As a hybrid, the instrument, described in a paper published in Nature Nanotechnology, combines the disciplines of nanospectroscopy and nanomechanical microscopy.

“Our microscope offers a noninvasive rapid method to explore materials simultaneously for their chemical and physical properties,” Passian said. “It allows researchers to study the surface and subsurface of synthetic and biological samples, which is a capability that until now didn’t exist.”

ORNL’s instrument retains all of the advantages of an atomic force microscope while simultaneously offering the potential for discoveries through its high resolution and subsurface spectroscopic capabilities.

“The originality of the instrument and technique lies in its ability to provide information about a material’s chemical composition in the broad infrared spectrum of the chemical composition while showing the morphology of a material’s interior and exterior with nanoscale – a billionth of a meter – resolution,” Passian said.

Researchers will be able to study samples ranging from engineered nanoparticles and nanostructures to naturally occurring biological polymers, tissues and plant cells.

The first application as part of DOE’s BioEnergy Science Center was in the examination of plant cell walls under several treatments to provide submicron characterization. The plant cell wall is a layered nanostructure of biopolymers such as cellulose. Scientists want to convert such biopolymers to free the useful sugars and release energy.

An earlier instrument, also invented at ORNL, provided imaging of poplar cell wall structures that yielded unprecedented topological information, advancing fundamental research in sustainable biofuels.

Because of this new instrument’s impressive capabilities, the researcher team envisions broad applications.
“An urgent need exists for new platforms that can tackle the challenges of subsurface and chemical characterization at the nanometer scale,” said co-author Rubye Farahi. “Hybrid approaches such as ours bring together multiple capabilities, in this case, spectroscopy and high-resolution microscopy.”

Looking inside, the hybrid microscope consists of a photonic module that is incorporated into a mode-synthesizing atomic force microscope. The modular aspect of the system makes it possible to accommodate various radiation sources such as tunable lasers and non-coherent monochromatic or polychromatic sources.

…

ETA2 August 27, 2015: I’ve received an email from one of the paper’s authors (RH Farahi of the US Oak Ridge National Laboratory [ORNL]) who claims some inaccuracies in this piece.  The news release supplied by the University of Central Florida states that Dr. Tetard led the team and that is not so. According to Dr. Farahi, she had a postdoctoral position on the team which she left two years ago. You might also get the impression that some of the work was performed at the University of Central Florida. That is not so according to Dr. Farahi.  As a courtesy Dr. Tetard was retained as first author of the paper.

*Nov. 4, 2015: I suspect some of the misunderstanding was due to overeagerness and/or time pressures. Whoever wrote the news release may have made some assumptions. It’s very easy to make a mistake when talking to an ebullient scientist who can unintentionally lead you to believe something that’s not so. I worked in a high tech company and believed that there was some new software being developed which turned out to be a case of high hopes. Luckily, I said something that triggered a rapid rebuttal to the fantasies. Getting back to this situation, other contributing factors could include the writer not having time to get the news release reviewed the scientist or the scientist skimming the release and missing a few bits due to time pressure.*

Research into the properties of water at the nanoscale and water droplet networks

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I have two pieces of research with the only common element being water. First, there’s a May 9, 2014 news release on EurekAlert issued by the Politecnico di Torino (Italy; rough translation: Turin Polytechnic),

Swimming in a honey pool. That’s the sensation a water molecule should “feel” while approaching a solid surface within a nanometer (i.e. less than a ten-thousandth of hair diameter). The reduction in water mobility in the very close proximity of surfaces at the nanoscale is the well-known phenomenon of “nanoconfinement”, and it is due to both electrostatic and van der Waals attractive forces ruling matter interactions at that scale.

In this context, scientists from Politecnico di Torino and Houston Methodist Research Institute have taken a further step forward, by formulating a quantitative model and a physical interpretation able of predicting the nanoconfinement effect in a rather general framework. In particular, geometric and chemical characteristics as well as physical conditions of diverse nanoconfining surfaces (e.g. proteins, carbon nanotubes, silica nanopores or iron oxide nanoparticles) have been quantitatively related to mobility reduction and “supercooling” conditions of water, namely the persistence of water in a liquid state at temperatures far below 0°C, when close to a solid surface.

This result has been achieved after two years of in silico (i.e. computer-based) and in vitro (i.e. experiment-driven) activities by Eliodoro Chiavazzo, Matteo Fasano, Pietro Asinari (Multi-Scale Modelling Lab, Department of Energy at Politecnico di Torino) and Paolo Decuzzi (Center for the Rational Design of Multifunctional Nanoconstructs at Houston Methodist Research Institute).

I love the image of swimming in a ‘honey pool’ and while developing a schema for predicting a nanoconfinement effect may not seem all that exciting to an outsider the applications are varied according to the news release,

This study may soon find applications in the optimization and rational design of a broad variety of novel technologies ranging from applied physics (e.g. “nanofluids”, suspensions made out of water and nanoparticles for enhancing heat transfer) to sustainable energy (e.g. thermal storage based on nanoconfined water within sorbent materials); from detection and removal of pollutant from water (e.g. molecular sieves) to nanomedicine.

In fact this work is finding an immediate application in the field of medicine as pertaining to magnetic resonance imaging (MRI), from the news release,

The latter is the field where the research has indeed found a first important application. Every year, almost sixty millions of Magnetic Resonance Imaging (MRI) scans are performed, with diagnostic purposes. In the past decade, MRI technology benefitted from various significant scientific advances, which allowed more precise and sharper images of pathological tissues. Among other, contrast agents (i.e. substances used for improving contrast of structures or fluids within the body) importantly contributed in enhancing MRI performances.

This research activity has been able to explain and predict the increase in MRI performances due to nanoconfined contrast agents, which are currently under development at the Houston Methodist Research Institute. Hence, the discovery paves the way to further increase in the quality of MRI images, in order to possibly improve chances of earlier and more accurate detection of diseases in millions of patients, every year.

Here’s a link to and a citation for the research paper,

Scaling behaviour for the water transport in nanoconfined geometries by Eliodoro Chiavazzo, Matteo Fasano, Pietro Asinari & Paolo Decuzzi. Nature Communications 5 Article number: 4565 doi:10.1038/ncomms4565 Published 03 April 2014

This is an open access paper and, unusually, I am excerpting the Abstract as I find it helps to further explain this work (although the more technical aspects are lost on me),

The transport of water in nanoconfined geometries is different from bulk phase and has tremendous implications in nanotechnology and biotechnology. Here molecular dynamics is used to compute the self-diffusion coefficient D of water within nanopores, around nanoparticles, carbon nanotubes and proteins. For almost 60 different cases, D is found to scale linearly with the sole parameter θ as D(θ)=DB[1+(DC/DB−1)θ], with DB and DC the bulk and totally confined diffusion of water, respectively. The parameter θ is primarily influenced by geometry and represents the ratio between the confined and total water volumes. The D(θ) relationship is interpreted within the thermodynamics of supercooled water. As an example, such relationship is shown to accurately predict the relaxometric response of contrast agents for magnetic resonance imaging. The D(θ) relationship can help in interpreting the transport of water molecules under nanoconfined conditions and tailoring nanostructures with precise modulation of water mobility.

The second piece of ‘water’ research was featured in a May 13, 2014 news item on Nanowerk,

A simple new technique to form interlocking beads of water in ambient conditions could prove valuable for applications in biological sensing, membrane research and harvesting water from fog.

Researchers at the Department of Energy’s Oak Ridge National Laboratory have developed a method to create air-stable water droplet networks known as droplet interface bilayers. These interconnected water droplets have many roles in biological research because their interfaces simulate cell membranes. Cumbersome fabrication methods, however, have limited their use.

A May 13, 2014 Oak Ridge National Laboratory (ORNL) news release, which originated the news item, provides more details,

“The way they’ve been made since their inception is that two water droplets are formed in an oil bath then brought together while they’re submerged in oil,” said ORNL’s Pat Collier, who led the team’s study published in the Proceedings of the National Academy of Sciences. “Otherwise they would just pop like soap bubbles.”

Instead of injecting water droplets into an oil bath, the ORNL research team experimented with placing the droplets on a superhydrophobic surface infused with a coating of oil. The droplets aligned side by side without merging.

To the researchers’ surprise, they were also able to form non-coalescing water droplet networks without including lipids in the water solution. Scientists typically incorporate phospholipids into the water mixture, which leads to the formation of an interlocking lipid bilayer between the water droplets.

“When you have those lipids at the interfaces of the water drops, it’s well known that they won’t coalesce because the interfaces join together and form a stable bilayer,” ORNL coauthor Jonathan Boreyko said. “So our surprise was that even without lipids in the system, the pure water droplets on an oil-infused surface in air still don’t coalesce together.”

The team’s research revealed how the unexpected effect is caused by a thin oil film that is squeezed between the pure water droplets as they come together, preventing the droplets from merging into one. Watch a video of the process on ORNL’s YouTube channel.

With or without the addition of lipids, the team’s technique offers new insight for a host of applications. Controlling the behavior of pure water droplets on oil-infused surfaces is key to developing dew- or fog-harvesting technology as well as more efficient condensers, for instance.

“Our finding of this non-coalescence phenomenon will shed light on these droplet-droplet interactions that can occur on oil-infused systems,” Boreyko said.

The ability to create membrane-like water droplet networks by adding lipids leads to a different set of functional applications, Collier noted.

“These bilayers can be used in anything from synthetic biology to creating circuits to bio-sensing applications,” he said. “For example, we could make a bio-battery or a signaling network by stringing some of these droplets together. Or, we could use it to sense the presence of airborne molecules.”

The team’s study also demonstrated ways to control the performance and lifetime of the water droplets by manipulating oil viscosity and temperature and humidity levels.

Here’s another link to the paper and a citation,

Air-stable droplet interface bilayers on oil-infused surfaces by Jonathan B. Boreyko, Georgios Polizos, Panos G. Datskos, Stephen A. Sarles, and C. Patrick Collier.  PNAS 2014 ; published ahead of print May 12, 2014, doi: 10.1073/pnas.1400381111

This paper is behind a paywall.