Category Archives: nanotechnology

Science diplomacy: high school age Pakistani students (terror attack survivors) attend NanoDiscovery Institute in New York State

The visiting students are from the Peshawar Army School in Pakistan, which suffered a terrorist attack in 2014. From the Peshawar School Massacre Wikipedia entry (Note: Links have been removed),

On 16 December 2014, seven gunmen affiliated with the Tehrik-i-Taliban (TTP) conducted a terrorist attack on the Army Public School in the northwestern Pakistani city of Peshawar. The militants, all of whom were foreign nationals, included one Chechen, three Arabs and two Afghans. They entered the school and opened fire on school staff and children,[8][9] killing 145 people, including 132 schoolchildren, ranging between eight and eighteen years of age.[10][11] A rescue operation was launched by the Pakistan Army’s Special Services Group (SSG) special forces, who killed all seven terrorists and rescued 960 people.[9][12][13] Chief military spokesman Major General Asim Bajwa said in a press conference that at least 130 people had been injured in the attack.[8]

As of July 29, 2015 seven of the student survivors are visiting New York State to attend a NanoDiscovery Institute program, according to a July 29, 2015 news item on Nanotechnology Now,

In support of Governor Andrew M. Cuomo’s commitment to provide high-tech educational opportunities in New York State, SUNY Polytechnic Institute’s Colleges of Nanoscale Science and Engineering (SUNY Poly CNSE), in partnership with Meridian International Center (Meridian) and with the support of the U.S. Embassy in Islamabad, today announced that SUNY Poly CNSE will host a group of students from Peshawar, Pakistan, from July 29 through August 4 [2015] at the institution’s world-class $20 billion Albany NanoTech Complex. The weeklong “NanoDiscovery Institute” will follow a custom-tailored curriculum designed to inspire the students with the limitless potential of the nanosciences. The students, who will take part in a number of nanotechnology-themed activities, presentations, and tours, survived a brutal attack on their school by terrorists last December when more than 140 students and teachers were killed in their classrooms.

A July 29, 2015 SUNY (State University of New York) Polytechnic Institute’s Colleges of Nanoscale Science and Engineering (SUNY Poly CNSE), news release, which originated the news item, describes the purpose of the visit to CNSE in more detail,

“Governor Andrew Cuomo’s innovation-based educational blueprint not only offers unprecedented opportunities for students in New York State, it also enables the exchange of scientific know-how far beyond its borders and we are thrilled to be able to host these students from Pakistan and engage and inspire them through the power of nanotechnology,” said Dr. Alain Kaloyeros, President and CEO of SUNY Poly. “It has been a pleasure to work with Meridian to create this positive educational experience for these students who have endured more in their young lives than most of us will see in a lifetime. We hope their visit will give them a greater understanding of the nanosciences, as well as an appreciation for America and New York State and our commitment to progress through education, the cornerstone of a better world.”

“We are proud to connect these science-oriented students from Pakistan with the globally recognized educational resources of SUNY Poly CNSE,” said Bonnie Glick, Senior Vice President of Meridian. “This exchange will expose these students to the nanotechnology world through a weeklong visit to SUNY Poly CNSE’s unmatched facilities. This is a perfect way to show Meridian’s mission in action as we seek to share ideas and engage people across borders and cultures to promote global leadership and to help to form future leaders. For these students in particular, this first-of-a-kind opportunity will not erase what happened, but we hope it will provide them with tools to enhance their educations and to foment global collaboration. Through the Nanotechnology Institute at SUNY Poly CNSE, these students will see, concretely, that there is more that unites us than divides us – science will be a powerful unifier.”

During their visit to SUNY Poly CNSE, the visiting Peshawar Army Public School students will create business plans as part of a Nanoeconomics course designed by SUNY Poly CNSE staff members, and they will also participate in nanotechnology career briefings. Two Pakistani high school teachers and a military liaison are accompanying the students as they attend the five-day NanoDiscovery Institute facilitated by SUNY Poly CNSE professors. Four students from the U.S. with similar academic interests will join the group, encouraging cross-cultural interactions. The group will become immersed in the nanosciences through hands on experiments and engaging presentations; they will learn how small a nanometer is and see first-hand New York State’s unique high-tech ecosystem to better understand what is underpinning technological progress and how an education focused on science, technology, engineering, and mathematics (STEM) can lead to exciting opportunities. As part of the U.S.-Pakistan Global Leadership and STEM program designed by Meridian to promote global collaboration through the sciences, the students will also engage in a global leadership skills training in Washington, D.C., and participate in cultural activities in New York City.

For a description of all of the activities planned for the students’ two week visit to the US, Shivani Gonzalez offers more detail in a July 29, 2015 article for timesunion.com,

“I am so thankful for this opportunity,” said Hammad, one of the students. (Organizers of the trip asked that the student’s last names not be used by the media.) “I know that this education will help us in the future.”

In December [2014[, the Peshawar school was attacked …

International outrage over the attack prompted the Pakistani government, which has been criticized for its lackluster pursuit of violent extremists, to strengthen its military and legal efforts.

The students are in the country for two weeks, and are being hosted by the Meridian International Center in Washington, D.C., where their packed itinerary began earlier this week. In addition to tours of the Pentagon and Capitol, the group met Secretary of State John Kerry.

After that [NanoDiscovery Institute], the students will go to the Baseball Hall of Fame in Cooperstown for a different kind of cultural exchange: The visitors will learn how to play baseball, and their U.S. counterparts will learn the fundamentals of cricket. A dual-sports tournament is planned.

The students will also visit West Point to see the similarities and differences with their military school back home.

To finish up the trip, the students will present their final nanotech projects to SUNY Poly staff, and will fly back to Washington to present the projects to U.S. military officials.

What a contrast for those students. In six months they go from surviving a terrorist attack at school to being part of a science diplomacy initiative where they are being ‘wined and dined’.

If you are interested in the Meridian International Center, there is this brief description at the end of the CNSE July 29, 2015 news release about the visit,

Meridian is a non-profit, non-partisan organization based in Washington, DC. For more than 50 years, Meridian has brought international visitors to the United States to engage with their counterparts in government, industry, academia, and civil society. Meridian promotes global leadership through the exchange of ideas, people, and culture. Meridian creates innovative education, cultural, and policy programs that strengthen U.S. engagement with the world through the power of exchange, that prepare public and private sector leaders for a complex global future, and that provide a neutral forum for international collaboration across sectors. For more information, visit meridian.org.

The Meridian website is strongly oriented to visual communication (lots of videos) which is a bit a disadvantage for me at the moment since my web browser, Firefox, has disabled Adobe Flash due to security concerns.

Replacing metal with nanocellulose paper

The quest to find uses for nanocellulose materials has taken a step forward with some work coming from the University of Maryland (US). From a July 24, 2015 news item on Nanowerk,

Researchers at the University of Maryland recently discovered that paper made of cellulose fibers is tougher and stronger the smaller the fibers get … . For a long time, engineers have sought a material that is both strong (resistant to non-recoverable deformation) and tough (tolerant of damage).

“Strength and toughness are often exclusive to each other,” said Teng Li, associate professor of mechanical engineering at UMD. “For example, a stronger material tends to be brittle, like cast iron or diamond.”

A July 23, 2015 University of Maryland news release, which originated the news item, provides details about the thinking which buttresses this research along with some details about the research itself,

The UMD team pursued the development of a strong and tough material by exploring the mechanical properties of cellulose, the most abundant renewable bio-resource on Earth. Researchers made papers with several sizes of cellulose fibers – all too small for the eye to see – ranging in size from about 30 micrometers to 10 nanometers. The paper made of 10-nanometer-thick fibers was 40 times tougher and 130 times stronger than regular notebook paper, which is made of cellulose fibers a thousand times larger.

“These findings could lead to a new class of high performance engineering materials that are both strong and tough, a Holy Grail in materials design,” said Li.

High performance yet lightweight cellulose-based materials might one day replace conventional structural materials (i.e. metals) in applications where weight is important. This could lead, for example, to more energy efficient and “green” vehicles. In addition, team members say, transparent cellulose nanopaper may become feasible as a functional substrate in flexible electronics, resulting in paper electronics, printable solar cells and flexible displays that could radically change many aspects of daily life.

Cellulose fibers can easily form many hydrogen bonds. Once broken, the hydrogen bonds can reform on their own—giving the material a ‘self-healing’ quality. The UMD discovered that the smaller the cellulose fibers, the more hydrogen bonds per square area. This means paper made of very small fibers can both hold together better and re-form more quickly, which is the key for cellulose nanopaper to be both strong and tough.

“It is helpful to know why cellulose nanopaper is both strong and tough, especially when the underlying reason is also applicable to many other materials,” said Liangbing Hu, assistant professor of materials science at UMD.

To confirm, the researchers tried a similar experiment using carbon nanotubes that were similar in size to the cellulose fibers. The carbon nanotubes had much weaker bonds holding them together, so under tension they did not hold together as well. Paper made of carbon nanotubes is weak, though individually nanotubes are arguably the strongest material ever made.

One possible future direction for the research is the improvement of the mechanical performance of carbon nanotube paper.

“Paper made of a network of carbon nanotubes is much weaker than expected,” said Li. “Indeed, it has been a grand challenge to translate the superb properties of carbon nanotubes at nanoscale to macroscale. Our research findings shed light on a viable approach to addressing this challenge and achieving carbon nanotube paper that is both strong and tough.”

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

Anomalous scaling law of strength and toughness of cellulose nanopaper by Hongli Zhu, Shuze Zhu, Zheng Jia, Sepideh Parvinian, Yuanyuan Li, Oeyvind Vaaland, Liangbing Hu, and Teng Li. PNAS (Proceedings of the National Academy of Sciences) July 21, 2015 vol. 112 no. 29 doi: 10.1073/pnas.1502870112

This paper is behind a paywall.

There is a lot of research on applications for nanocellulose, everywhere it seems, except Canada, which at one time was a leader in the business of producing cellulose nanocrystals (CNC).

Here’s a sampling of some of my most recent posts on nanocellulose,

Nanocellulose as a biosensor (July 28, 2015)

Microscopy, Paper and Fibre Research Institute (Norway), and nanocellulose (July 8, 2015)

Nanocellulose markets report released (June 5, 2015; US market research)

New US platform for nanocellulose and occupational health and safety research (June 1, 2015; Note: As you find new applications, you need to concern yourself with occupational health and safety.)

‘Green’, flexible electronics with nanocellulose materials (May 26, 2015; research from China)

Treating municipal wastewater and dirty industry byproducts with nanocellulose-based filters (Dec. 23, 2014; research from Sweden)

Nanocellulose and an intensity of structural colour (June 16, 2014; research about replacing toxic pigments with structural colour from the UK)

I ask again, where are the Canadians? If anybody has an answer, please let me know.

There’s more than one black gold

‘Black gold’ is a phrase I associate with oil, signifying its importance and desirability. These days, this analogic phrase can describe a material according to a July 24, 2015 news item on Nanowerk,

If colloidal gold [gold in solution] self-assembles into the form of larger vesicles, a three-dimensional state can be achieved that is called “black gold” because it absorbs almost the entire spectrum of visible light. How this novel intense plasmonic state can be established and what its characteristics and potential medical applications are is explored by Chinese scientists and reported in the journal Angewandte Chemie …

A July 24, 2015 Wiley (Angewandte Chemie) press release, which originated the news item, provides more details,

Metal nanostructures can self-assemble into superstructures that offer intriguing new spectroscopic and mechanical properties. Plasmonic coupling plays a particular role in this context. For example, it has been found that plasmonic metal nanoparticles help to scatter the incoming light across the surface of the Si substrate at resonance wavelengths, therefore enhancing the light absorbing potential and thus the effectivity of solar cells.

On the other hand, plasmonic vesicles are the promising theranostic platform for biomedical applications, a notion which inspired Yue Li and Cuncheng Li of the Chinese Academy of Science, Hefei, China, and the University of Jinan, China, as well as collaborators to prepare plasmonic colloidosomes composed of gold nanospheres.

As the method of choice, the scientists have designed an emulsion-templating approach based on monodispersed gold nanospheres as building blocks, which arranged themselves into large spherical vesicles in a reverse emulsion system.

The resulting plasmonic vesicles were of micrometer-size and had a shell composed of hexagonally close-packed colloidal nanosphere particles in bilayer or, for the very large superspheres, multilayer arrangement, which provided the enhanced stability.

“A key advantage of this system is that such self-assembly can avoid the introduction of complex stabilization processes to lock the nanoparticles together”, the authors explain.

The hollow spheres exhibited an intense plasmonic resonance in their three-dimensionally packed structure and had a dark black appearance compared to the brick red color of the original gold nanoparticles. The “black gold” was thus characterized by a strong broadband absorption in the visible light and a very regular vesicle superstructure. In medicine, gold vesicles are intensively discussed as vehicles for the drug delivery to tumor cells, and, therefore, it could be envisaged to exploit the specific light-matter interaction of such plasmonic vesicle structures for medical use, but many other applications are also feasible, as the authors propose: “The presented strategy will pave a way to achieve noble-metal superstructures for biosensors, drug delivery, photothermal therapy, optical microcavity, and microreaction platforms.” This will prove the flexibility and versatility of the noble-metal nanostructures.

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

Black Gold: Plasmonic Colloidosomes with Broadband Absorption Self-Assembled from Monodispersed Gold Nanospheres by Using a Reverse Emulsion System by Dilong Liu, Dr. Fei Zhou, Cuncheng Li, Tao Zhang, Honghua Zhang, Prof. Weiping Cai, and Prof. Yue Li. Angewandte Chemie International Edition Article first published online: 25 JUN 2015 DOI: 10.1002/anie.201503384

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This article is behind a paywall.

There is an image illustrating the work but, sadly, the gold doesn’t look black,

BlackGold

© Wiley-VCH

That’s it!

Commercializing Titan Spine’s next generation spinal interbody fusion implant

The July 22, 2015 Titan Spine news release on BusinessWire is mainly focused on the appointment of a senior nanotechnology specialist; I’m more interested in the mention of product commercialization (first mentioned in my Nov. 26, 2014 post) in the fourth quarter of 2015,

Titan Spine, a medical device surface technology company focused on developing innovative spinal interbody fusion implants, today announced the appointment of Jim Sevey as the Company’s Senior Nanotechnology Specialist. The appointment follows the Company’s receipt of 510(k) clearance from the U.S. Food and Drug Administration (FDA) to market its Endoskeleton® line of interbody fusion implants featuring its next generation nanoLOCKTM surface technology and precedes the Company’s full commercialization of the new line, planned for the fourth quarter of this year. The nanoLOCK™ surface represents the only FDA-cleared nanotechnology for spinal implant applications.

Mr. Sevey’s role will include leading the educational initiatives to further demonstrate and communicate the scientific evidence supporting the advantages of Titan Spine’s unique nanoLOCKTM surface technology. The surface features an increased amount of nano-scaled textures that result in the up-regulation of a greater amount of osteogenic and angiogenic growth factors critical for bone growth and fusion as compared to PEEK and the company’s current surface.1

Kevin Gemas, President of Titan Spine, commented, “As our body of science continues to grow, we identified the need to bring onboard someone of Jim’s caliber to educate the spinal surgeon community and our sales force on the science and associated benefits of our current and nanoLOCK™ proprietary surface technologies. With more than 22 years of experience with medical devices and biomaterials, Jim is the right person to lead these efforts. One of Jim’s initial tasks will be to clearly differentiate the science of our nanotechnology platform from those that claim to have nanotechnology but have not been cleared by the FDA to do so. We are proud to add Jim to our ever-growing scientific team.”

Barbara Boyan, Ph.D., Dean of the School of Engineering at Virginia Commonwealth University, and lead author of several studies supporting Titan Spine surfaces, added, “The spine industry is beginning to recognize ‘nanotechnology’ as more than a marketing concept and now as a design approach that has the potential to improve spinal fusion results for patients. Titan Spine has been at the forefront of this charge for nearly a decade, conducting studies to evaluate and refine the benefits of nanotechnology for interbody fusions. I look forward to working closely with Jim to further these efforts.”

Before joining Titan Spine, Mr. Sevey held several positions at Synthes/Depuy Biomaterials, including most recently, Manager, Biomaterials Technical Specialist. In this role, he generated multidivisional sales of osteobiologic product lines by providing clinical and technical consulting, training, and education for surgeons, residents, operating room personnel, and sales consultants. Prior to Synthes/Depuy Biomaterials, Mr. Sevey was part of the founding team of Skeletal Kinetics, LLC, (Cupertino, CA) as Director of Marketing. Mr. Sevey holds a Bachelor of Science in Health Science from St. Mary’s College of California (Moraga, CA).

The full line of Endoskeleton® devices features Titan Spine’s proprietary implant surface technology, consisting of a unique combination of roughened topographies at the macro, micro, and cellular levels. This unique combination of surface topographies is designed to create an optimal host-bone response and actively participate in the fusion process by promoting the up-regulation of osteogenic and angiogenic factors necessary for bone growth, encouraging natural production of bone morphogenetic proteins (BMPs), down-regulating inflammatory factors, and creating the potential for a faster and more robust fusion.2,3,4

About Titan Spine

Titan Spine, LLC is a surface technology company focused on the design and manufacture of interbody fusion devices for the spine. The company is committed to advancing the science of surface engineering to enhance the treatment of various pathologies of the spine that require fusion. Titan Spine, located in Mequon, Wisconsin and Laichingen, Germany, markets a full line of Endoskeleton® interbody devices featuring its proprietary textured surface in the U.S. and portions of Europe through its sales force and a network of independent distributors. To learn more, visit www.titanspine.com.

Titan Spine Study References:

1 Olivares-Navarrete, R., Hyzy, S. L., Berg, M. E., Schneider, J. M., Hotchkiss, K., Schwartz, Z., & Boyan, B. D. Osteoblast Lineage Cells Can Discriminate Microscale Topographic Features on Titanium–Aluminum–Vanadium Surfaces.Ann Biomed Eng. 2014; 1-11.

2 Olivares-Navarrete, R., Hyzy, S.L., Slosar, P.J., Schneider, J.M., Schwartz, Z., and Boyan, B.D. (2015). Implant materials generate different peri-implant inflammatory factors: PEEK promotes fibrosis and micro-textured titanium promotes osteogenic factors. Spine, Volume 40, Issue 6, 399–404.

3 Olivares-Navarrete, R., Gittens, R.A., Schneider, J.M., Hyzy, S.L., Haithcock, D.A., Ullrich, P.F., Schwartz, Z., Boyan, B.D. (2012). Osteoblasts exhibit a more differentiated phenotype and increased bone morphogenetic production on titanium alloy substrates than poly-ether-ether-ketone. The Spine Journal, 12, 265-272.

4 Olivares-Navarrete, R., Hyzy, S.L., Gittens, R.A., Schneider, J.M., Haithcock, D.A., Ullrich, P.F., Slosar, P. J., Schwartz, Z., Boyan, B.D. (2013). Rough titanium alloys regulate osteoblast production of angiogenic factors. The Spine Journal, 13, 1563-1570.

It’s unusual (and welcome) to see citations included with a business news release for a new medical device.

I didn’t think to pose the query in my last post but I wonder if Barbara Boyan has some sort of financial interest in Titan Spine? Her Virginia Commonwealth University faculty webpage suggests the answer is no,

Experience

  • Associate Dean for Research and Innovation in the College of Engineering at Georgia Institute of Technology
  • Professor and Price Gilbert, Jr. Chair in Tissue Engineering in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University
  • Deputy Director of Research at Georgia Tech and at the Emory Center for the Engineering of Living Tissues at the Georgia Institute of Technology
  • Professor and Vice Chair for Research in the Department of Orthopaedics at the University of Texas Health Science Center at San Antonio
  • Co-founder of Osteobiologics, Inc.
  • Founder and Chief Scientific Officer of SpherIngenics, Inc.
  • Member, Board of Directors, ArthroCare Corporation and Carticept Medical, Inc.

Still, I wish there was a statement that spelled out Boyan’s relationship or lack of with Titan Spine.

Smart windows from Texas (US)

I’ve been waiting for ‘smart’ windows and/or self-cleaning windows since 2008. While this research on ‘smart’ windows at the University of Texas at Austin looks promising I suspect it will be years before these things are in the marketplace. A July 22, 2015 news item on Nanotechnology Now announces the latest research,

Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.

By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for heating and cooling buildings.

In 2013, chemical engineering professor Delia Milliron and her team became the first to develop dual-band electrochromic materials that blend two materials with distinct optical properties for selective control of visible and heat-producing near-infrared light (NIR). In a 2013 issue of Nature, Milliron’s research group demonstrated how, using a small jolt of electricity, a nanocrystal material could be switched back and forth, enabling independent control of light and energy.

A July 23, 2015 University of Texas at Austin news release, which originated the news item, provides more details about the research which has spawned two recently published papers,

The team now has engineered two new advancements in electrochromic materials — a highly selective cool mode and a warm mode — not thought possible several years ago.

The cool mode material is a major step toward a commercialized product because it enables control of 90 percent of NIR and 80 percent of the visible light from the sun and takes only minutes to switch between modes. The previously reported material could require hours.

To achieve this high performance, Milliron and a team, including Cockrell School postdoctoral researcher Jongwook Kim and collaborator Brett Helms of the Lawrence Berkeley National Lab, developed a new nanostructured architecture for electrochromic materials that allows for a cool mode to block near-infrared light while allowing the visible light to shine through. This could help reduce energy costs for cooling buildings and homes during the summer. The researchers reported the new architecture in Nano Letters on July 20.

“We believe our new architected nanocomposite could be seen as a model material, establishing the ideal design for a dual-band electrochromic material,” Milliron said. “This material could be ideal for application as a smart electrochromic window for buildings.”

In the paper, the team demonstrates how the new material can strongly and selectively modulate visible light and NIR by applying a small voltage.

To optimize the performance of electrochromics for practical use, the team organized the two components of the composite material to create a porous interpenetrating network. The framework architecture provides channels for transport of electronic and ionic change. This organization enables substantially faster switching between modes.
Smart Window

The researchers are now working to produce a similarly structured nanocomposite material by simple methods, suitable for low-cost manufacturing.

In a second research paper, Milliron and her team, including Cockrell School graduate student Clayton Dahlman, have reported a proof-of-concept demonstrating how they can achieve optical control properties in windows from a well-crafted, single-component film. The concept includes a simple coating that creates a new warm mode, in which visible light can be blocked, while near-infrared light can enter. This new setting could be most useful on a sunny winter day, when an occupant would want infrared radiation to pass into a building for warmth, but the glare from sunlight to be reduced.

In this paper, published in the Journal of the American Chemical Society, Milliron proved that a coating containing a single component ­— doped titania nanocrystals — could demonstrate dynamic control over the transmittance of solar radiation. Because of two distinct charging mechanisms found at different applied voltages, this material can selectively block visible or infrared radiation.

“These two advancements show that sophisticated dynamic control of sunlight is possible,” Milliron said. “We believe our deliberately crafted nanocrystal-based materials could meet the performance and cost targets needed to progress toward commercialization of smart windows.”

Interestingly, the news release includes this statement,

The University of Texas at Austin is committed to transparency and disclosure of all potential conflicts of interest. The lead UT investigator involved with this project, Delia Milliron, is the chief scientific officer and owns an equity position in Heliotrope Technologies, an early-stage company developing new materials and manufacturing processes for electrochromic devices with an emphasis on energy-saving smart windows. Milliron is associated with patents at Lawrence Berkeley National Laboratory licensed to Heliotrope Technologies. Collaborator Brett Helms serves on the scientific advisory board of Heliotrope and owns equity in the company.

Here are links to and citations for the two papers,

Nanocomposite Architecture for Rapid, Spectrally-Selective Electrochromic Modulation of Solar Transmittance by Jongwook Kim, Gary K. Ong, Yang Wang, Gabriel LeBlanc, Teresa E. Williams, Tracy M. Mattox, Brett A. Helms, and Delia J. Milliron. Nano Lett., Article ASAP DOI: 10.1021/acs.nanolett.5b02197 Publication Date (Web): July 20, 2015

Copyright © 2015 American Chemical Society

Spectroelectrochemical Signatures of Capacitive Charging and Ion Insertion in Doped Anatase Titania Nanocrystals by Clayton J. Dahlman, Yizheng Tan, Matthew A. Marcus, and Delia J. Milliron. J. Am. Chem. Soc., 2015, 137 (28), pp 9160–9166 DOI: 10.1021/jacs.5b04933 Publication Date (Web): July 8, 2015

Copyright © 2015 American Chemical Society

These papers are behind paywalls.

Nanocellulose as a biosensor

While nanocellulose always makes my antennae quiver (for anyone unfamiliar with the phrase, it means something along the lines of ‘attracts my attention’), it’s the collaboration which intrigues me most about this research. From a July 23, 2015 news item on Azonano (Note: A link has been removed),

An international team led by the ICREA Prof Arben Merkoçi has just developed new sensing platforms based on bacterial cellulose nanopaper. These novel platforms are simple, low cost and easy to produce and present outstanding properties that make them ideal for optical (bio)sensing applications. …

ICN2 [Catalan Institute of Nanoscience and Nanotechnology; Spain] researchers are going a step further in the development of simple, low cost and easy to produce biosensors. In an article published in ACS Nano they recently reported various innovative nanopaper-based optical sensing platforms. To achieve this endeavour the corresponding author ICREA Prof Arben Merkoçi, Group Leader at ICN2 and the first author, Dr Eden Morales-Narváez (from ICN2) and Hamed Golmohammadi (visiting researcher at ICN2), established an international collaboration with the Shahid Chamran University (Iran), the Gorgan University of Agricultural Sciences and Natural Resources (Iran) and the Academy of Sciences of the Czech Republic. [emphases mine]

Spain, Iran, and the Czech Republic. That’s an interesting combination of countries.

A July 23, 2015 ICN2 press release, which originated the news item, provides more explanations and detail,

Cellulose is simple, naturally abundant and low cost. However, cellulose fibres ranging at the nanoscale exhibit extraordinary properties such as flexibility, high crystallinity, biodegradability and optical transparency, among others. The nanomaterial can be extracted from plant cellulose pulp or synthetized by non-pathogenic bacteria. Currently, nanocellulose is under active research to develop a myriad of applications including filtration, wound dressing, pollution removal approaches or flexible and transparent electronics, whereas it has been scarcely explored for optical (bio)sensing applications.

The research team led by ICREA Prof Arben Merkoçi seeks to design, fabricate, and test simple, disposable and versatile sensing platforms based on this material. They designed different bacterial cellulose nanopaper based optical sensing platforms. In the article, the authors describe how the material can be tuned to exhibit plasmonic or photoluminescent properties that can be exploited for sensing applications. Specifically, they have prepared two types of plasmonic nanopaper and two types of photoluminescent nanopaper using different optically active nanomaterials.

The researchers took advantage of the optical transparency, porosity, hydrophilicity, and amenability to chemical modification of the material. The bacterial cellulose employed throughout this research was obtained using a bottom-up approach and it is shown that it can be easily turned into useful devices for sensing applications using wax printing or simple punch tools. The scientific team also demonstrates how these novel sensing platforms can be modulated to detect biologically relevant analytes such as cyanide and pathogens among others.

According to the authors, this class of platforms will prove valuable for displaying analytical information in diverse fields such as diagnostics, environmental monitoring and food safety. Moreover, since bacterial cellulose is flexible, lightweight, biocompatible and biodegradable, the proposed composites could be used as wearable optical sensors and could even be integrated into novel theranostic devices. In general, paper-based sensors are known to be simple, portable, disposable, low power-consuming and inexpensive devices that might be exploited in medicine, detection of explosives or hazardous compounds and environmental studies.

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

Nanopaper as an Optical Sensing Platform by Eden Morales-Narváez, Hamed Golmohammadi, Tina Naghdi, Hossein Yousefi, Uliana Kostiv, Daniel Horák, Nahid Pourreza, and Arben Merkoçi.ACS Nano, Article ASAP DOI: 10.1021/acsnano.5b03097 Publication Date (Web): July 2, 2015
Copyright © 2015 American Chemical Society

This paper is behind a paywall.

Sea sapphires: now you see them, now you don’t and more about structural colour/color

The structural colour of the sea sapphire

 Scientists are studying the disappearing act of this ocean-dwelling copepod. Credit: Kaj Maney, www.liquidguru.com Courtesy: American Chemical Society


Scientists are studying the disappearing act of this ocean-dwelling copepod.
Credit: Kaj Maney, www.liquidguru.com Courtesy: American Chemical Society

Now, you’ve seen a sea sapphire. Here’s more about them and the interest they hold for experts in photonics, from a July 15, 2015 news item on ScienceDaily,

Sapphirina, or sea sapphire, has been called “the most beautiful animal you’ve never seen,” and it could be one of the most magical. Some of the tiny, little-known copepods appear to flash in and out of brilliantly colored blue, violet or red existence. Now scientists are figuring out the trick to their hues and their invisibility. The findings appear in the Journal of the American Chemical Society and could inspire the next generation of optical technologies.

A July 15, 2015 American Chemical Society (ACS) news release, which originated the news item, provides more detail,

Copepods are tiny aquatic crustaceans that live in both fresh and salt water. Some males of the ocean-dwelling Sapphirina genus display striking, iridescent colors that scientists think play a role in communication and mate recognition. The shimmering animals’ colors result when light bounces off of the thin, hexagonal crystal plates that cover their backs. These plates also help them vanish, if only fleetingly. Scientists didn’t know specifically what factors contributed to creating different shades. Scientists at the Weizmann Institute [Israel] and the Interuniversity Institute for Marine Sciences in Eilat [Israel] wanted to investigate the matter.

The researchers measured the light reflectance — which determines color — of live Sapphirina males and the spacing between crystal layers. They found that changes of reflectance depended on the thickness of the spacing. And for at least one particular species, when light hits an animal at a 45-degree angle, reflectance shifts out of the visible light range and into the ultraviolet, and it practically disappears. Their results could help inform the design of artificial photonic crystal structures, which have many potential uses in reflective coatings, optical mirrors and optical displays.

To sum this up, the colour and the invisibility properties are due to thin, hexagonal crystal plates and the spacing of these plates, in other words, structural colour, which is usually achieved at the nanoscale.

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

Structural Basis for the Brilliant Colors of the Sapphirinid Copepods by Dvir Gur, Ben Leshem, Maria Pierantoni, Viviana Farstey, Dan Oron, Steve Weiner, and Lia Addadi. J. Am. Chem. Soc., 2015, 137 (26), pp 8408–8411 DOI: 10.1021/jacs.5b05289 Publication Date (Web): June 22, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

For anyone who’s interested, Lynn Kimlicka has a nice explanation of structural colour in a July 22, 2015 posting on the Something About Science blog where she discusses some recent research iridescence in bird feathers and synthetic melanin. She also shares a picture of her budgie and its iridescent feathers. The ‘melanin’ research was mentioned here in a May 19, 2015 posting where I also provide a link to a great 2013 piece on structural throughout the animal and plant kingdoms by Cristina Luiggi for The Scientist.

Understanding how nanostructures can affect optical properties could be leading to new ways of managing light. A July 23, 2015 news item on ScienceDaily describes a project at the University of Delaware dedicated to “changing the color of light,”

Researchers at the University of Delaware have received a $1 million grant from the W.M. Keck Foundation to explore a new idea that could improve solar cells, medical imaging and even cancer treatments. Simply put, they want to change the color of light.

A July 23, 2015 University of Delaware (UD) news release, which originated the news item, provides more information about the proposed research,

“A ray of light contains millions and millions of individual units of light called photons,” says project leader Matthew Doty. “The energy of each photon is directly related to the color of the light — a photon of red light has less energy than a photon of blue light. You can’t simply turn a red photon into a blue one, but you can combine the energy from two or more red photons to make one blue photon.”

This process, called “photon upconversion,” isn’t new, Doty says. However, the UD team’s approach to it is.

They want to design a new kind of semiconductor nanostructure that will act like a ratchet. It will absorb two red photons, one after the other, to push an electron into an excited state when it can emit a single high-energy (blue) photon.

These nanostructures will be so teeny they can only be viewed when magnified a million times under a high-powered electron microscope.

“Think of the electrons in this structure as if they were at a water park,” Doty says. “The first red photon has only enough energy to push an electron half-way up the ladder of the water slide. The second red photon pushes it the rest of the way up. Then the electron goes down the slide, releasing all of that energy in a single process, with the emission of the blue photon. The trick is to make sure the electron doesn’t slip down the ladder before the second photon arrives. The semiconductor ratchet structure is how we trap the electron in the middle of the ladder until the second photon arrives to push it the rest of the way up.”

The UD team will develop new semiconductor structures containing multiple layers of different materials, such as aluminum arsenide and gallium bismuth arsenide, each only a few nanometers thick. This “tailored landscape” will control the flow of electrons into states with varying potential energy, turning once-wasted photons into useful energy.

The UD team has shown theoretically that their semiconductors could reach an upconversion efficiency of 86 percent, which would be a vast improvement over the 36 percent efficiency demonstrated by today’s best materials. What’s more, Doty says, the amount of light absorbed and energy emitted by the structures could be customized for a variety of applications, from lightbulbs to laser-guided surgery.

How do you even begin to make structures so tiny they can only be seen with an electron microscope? In one technique the UD team will use, called molecular beam epitaxy, nanostructures will be built by depositing layers of atoms one at a time. Each structure will be tested to see how well it absorbs and emits light, and the results will be used to tailor the structure to improve performance.

The researchers also will develop a milk-like solution filled with millions of identical individual nanoparticles, each one containing multiple layers of different materials. The multiple layers of this structure, like multiple candy shells in an M&M, will implement the photon ratchet idea. Through such work, the team envisions a future upconversion “paint” that could be easily applied to solar cells, windows and other commercial products.

Improving medical tests and treatments

While the initial focus of the three-year project will be on improving solar energy harvesting, the team also will explore biomedical applications.

A number of diagnostic tests and medical treatments, ranging from CT [computed tomography] and PET [positron emission tomography] scans to chemotherapy, rely on the release of fluorescent dyes and pharmaceutical drugs. Ideally, such payloads are delivered both at specific disease sites and at specific times, but this is hard to control in practice.

The UD team aims to develop an upconversion nanoparticle that can be triggered by light to release its payload. The goal is to achieve the controlled release of drug therapies even deep within diseased human tissue while reducing the peripheral damage to normal tissue by minimizing the laser power required.

“This is high-risk, high-reward research,” Doty says. “High-risk because we don’t yet have proof-of-concept data. High-reward because it has such a huge potential impact in renewable energy to medicine. It’s amazing to think that this same technology could be used to harvest more solar energy and to treat cancer. We’re excited to get started!”

That’s it for structural colour/color today.

Quantum and classical physics may be closer than we thought

It seems that a key theory about the boundary between the quantum world and our own macro world has been disproved and I think the July 21, 2015 news item on Nanotechnology Now says it better,

Quantum theory is one of the great achievements of 20th century science, yet physicists have struggled to find a clear boundary between our everyday world and what Albert Einstein called the “spooky” features of the quantum world, including cats that could be both alive and dead, and photons that can communicate with each other across space instantaneously.

For the past 60 years, the best guide to that boundary has been a theorem called Bell’s Inequality, but now a new paper shows that Bell’s Inequality is not the guidepost it was believed to be, which means that as the world of quantum computing brings quantum strangeness closer to our daily lives, we understand the frontiers of that world less well than scientists have thought.

In the new paper, published in the July 20 [2015] edition of Optica, University of Rochester [New York state, US] researchers show that a classical beam of light that would be expected to obey Bell’s Inequality can fail this test in the lab, if the beam is properly prepared to have a particular feature: entanglement.

A July 21, 2015 University of Rochester news release, which originated the news item, reveals more about the boundary and the research,

Not only does Bell’s test not serve to define the boundary, the new findings don’t push the boundary deeper into the quantum realm but do just the opposite. They show that some features of the real world must share a key ingredient of the quantum domain. This key ingredient is called entanglement, exactly the feature of quantum physics that Einstein labeled as spooky. According to Joseph Eberly, professor of physics and one of the paper’s authors, it now appears that Bell’s test only distinguishes those systems that are entangled from those that are not. It does not distinguish whether they are “classical” or quantum. In the forthcoming paper the Rochester researchers explain how entanglement can be found in something as ordinary as a beam of light.

Eberly explained that “it takes two to tangle.” For example, think about two hands clapping regularly. What you can be sure of is that when the right hand is moving to the right, the left hand is moving to the left, and vice versa. But if you were asked to guess without listening or looking whether at some moment the right hand was moving to the right, or maybe to the left, you wouldn’t know. But you would still know that whatever the right hand was doing at that time, the left hand would be doing the opposite. The ability to know for sure about a common property without knowing anything for sure about an individual property is the essence of perfect entanglement.

Eberly added that many think of entanglement as a quantum feature because “Schrodinger coined the term ‘entanglement’ to refer to his famous cat scenario.” But their experiment shows that some features of the “real” world must share a key ingredient of Schrodinger’s Cat domain: entanglement.

The existence of classical entanglement was pointed out in 1980, but Eberly explained that it didn’t seem a very interesting concept, so it wasn’t fully explored. As opposed to quantum entanglement, classical entanglement happens within one system. The effect is all local: there is no action at a distance, none of the “spookiness.”

With this result, Eberly and his colleagues have shown experimentally “that the border is not where it’s usually thought to be, and moreover that Bell’s Inequalities should no longer be used to define the boundary.”

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

Shifting the quantum-classical boundary: theory and experiment for statistically classical optical fields by Xiao-Feng Qian, Bethany Little, John C. Howell, and J. H. Eberly. Optica Vol. 2, Issue 7, pp. 611-615 (2015) •doi: 10.1364/OPTICA.2.000611

This paper is open access.

Nanomaterials and UV (ultraviolet) light for environmental cleanups

I think this is the first time I’ve seen anything about a technology that removes toxic materials from both water and soil; it’s usually one or the other. A July 22, 2015 news item on Nanowerk makes the announcement (Note: A link has been removed),

Many human-made pollutants in the environment resist degradation through natural processes, and disrupt hormonal and other systems in mammals and other animals. Removing these toxic materials — which include pesticides and endocrine disruptors such as bisphenol A (BPA) — with existing methods is often expensive and time-consuming.

In a new paper published this week in Nature Communications (“Nanoparticles with photoinduced precipitation for the extraction of pollutants from water and soil”), researchers from MIT [Massachusetts Institute of Technology] and the Federal University of Goiás in Brazil demonstrate a novel method for using nanoparticles and ultraviolet (UV) light to quickly isolate and extract a variety of contaminants from soil and water.

A July 21, 2015 MIT news release by Jonathan Mingle, which originated the news item, describes the inspiration and the research in more detail,

Ferdinand Brandl and Nicolas Bertrand, the two lead authors, are former postdocs in the laboratory of Robert Langer, the David H. Koch Institute Professor at MIT’s Koch Institute for Integrative Cancer Research. (Eliana Martins Lima, of the Federal University of Goiás, is the other co-author.) Both Brandl and Bertrand are trained as pharmacists, and describe their discovery as a happy accident: They initially sought to develop nanoparticles that could be used to deliver drugs to cancer cells.

Brandl had previously synthesized polymers that could be cleaved apart by exposure to UV light. But he and Bertrand came to question their suitability for drug delivery, since UV light can be damaging to tissue and cells, and doesn’t penetrate through the skin. When they learned that UV light was used to disinfect water in certain treatment plants, they began to ask a different question.

“We thought if they are already using UV light, maybe they could use our particles as well,” Brandl says. “Then we came up with the idea to use our particles to remove toxic chemicals, pollutants, or hormones from water, because we saw that the particles aggregate once you irradiate them with UV light.”

A trap for ‘water-fearing’ pollution

The researchers synthesized polymers from polyethylene glycol, a widely used compound found in laxatives, toothpaste, and eye drops and approved by the Food and Drug Administration as a food additive, and polylactic acid, a biodegradable plastic used in compostable cups and glassware.

Nanoparticles made from these polymers have a hydrophobic core and a hydrophilic shell. Due to molecular-scale forces, in a solution hydrophobic pollutant molecules move toward the hydrophobic nanoparticles, and adsorb onto their surface, where they effectively become “trapped.” This same phenomenon is at work when spaghetti sauce stains the surface of plastic containers, turning them red: In that case, both the plastic and the oil-based sauce are hydrophobic and interact together.

If left alone, these nanomaterials would remain suspended and dispersed evenly in water. But when exposed to UV light, the stabilizing outer shell of the particles is shed, and — now “enriched” by the pollutants — they form larger aggregates that can then be removed through filtration, sedimentation, or other methods.

The researchers used the method to extract phthalates, hormone-disrupting chemicals used to soften plastics, from wastewater; BPA, another endocrine-disrupting synthetic compound widely used in plastic bottles and other resinous consumer goods, from thermal printing paper samples; and polycyclic aromatic hydrocarbons, carcinogenic compounds formed from incomplete combustion of fuels, from contaminated soil.

The process is irreversible and the polymers are biodegradable, minimizing the risks of leaving toxic secondary products to persist in, say, a body of water. “Once they switch to this macro situation where they’re big clumps,” Bertrand says, “you won’t be able to bring them back to the nano state again.”

The fundamental breakthrough, according to the researchers, was confirming that small molecules do indeed adsorb passively onto the surface of nanoparticles.

“To the best of our knowledge, it is the first time that the interactions of small molecules with pre-formed nanoparticles can be directly measured,” they write in Nature Communications.

Nano cleansing

Even more exciting, they say, is the wide range of potential uses, from environmental remediation to medical analysis.

The polymers are synthesized at room temperature, and don’t need to be specially prepared to target specific compounds; they are broadly applicable to all kinds of hydrophobic chemicals and molecules.

“The interactions we exploit to remove the pollutants are non-specific,” Brandl says. “We can remove hormones, BPA, and pesticides that are all present in the same sample, and we can do this in one step.”

And the nanoparticles’ high surface-area-to-volume ratio means that only a small amount is needed to remove a relatively large quantity of pollutants. The technique could thus offer potential for the cost-effective cleanup of contaminated water and soil on a wider scale.

“From the applied perspective, we showed in a system that the adsorption of small molecules on the surface of the nanoparticles can be used for extraction of any kind,” Bertrand says. “It opens the door for many other applications down the line.”

This approach could possibly be further developed, he speculates, to replace the widespread use of organic solvents for everything from decaffeinating coffee to making paint thinners. Bertrand cites DDT, banned for use as a pesticide in the U.S. since 1972 but still widely used in other parts of the world, as another example of a persistent pollutant that could potentially be remediated using these nanomaterials. “And for analytical applications where you don’t need as much volume to purify or concentrate, this might be interesting,” Bertrand says, offering the example of a cheap testing kit for urine analysis of medical patients.

The study also suggests the broader potential for adapting nanoscale drug-delivery techniques developed for use in environmental remediation.

“That we can apply some of the highly sophisticated, high-precision tools developed for the pharmaceutical industry, and now look at the use of these technologies in broader terms, is phenomenal,” says Frank Gu, an assistant professor of chemical engineering at the University of Waterloo in Canada, and an expert in nanoengineering for health care and medical applications.

“When you think about field deployment, that’s far down the road, but this paper offers a really exciting opportunity to crack a problem that is persistently present,” says Gu, who was not involved in the research. “If you take the normal conventional civil engineering or chemical engineering approach to treating it, it just won’t touch it. That’s where the most exciting part is.”

The researchers have made this illustration of their work available,

Nanoparticles that lose their stability upon irradiation with light have been designed to extract endocrine disruptors, pesticides, and other contaminants from water and soils. The system exploits the large surface-to-volume ratio of nanoparticles, while the photoinduced precipitation ensures nanomaterials are not released in the environment. Image: Nicolas Bertrand Courtesy: MIT

Nanoparticles that lose their stability upon irradiation with light have been designed to extract endocrine disruptors, pesticides, and other contaminants from water and soils. The system exploits the large surface-to-volume ratio of nanoparticles, while the photoinduced precipitation ensures nanomaterials are not released in the environment.
Image: Nicolas Bertrand Courtesy: MIT

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

Nanoparticles with photoinduced precipitation for the extraction of pollutants from water and soil by Ferdinand Brandl, Nicolas Bertrand, Eliana Martins Lima & Robert Langer. Nature Communications 6, Article number: 7765 doi:10.1038/ncomms8765 Published 21 July 2015

This paper is open access.

US Navy invests in graphene

More usually, I feature research from DARPA (Defense Advanced Research Progects Agency) which I think belongs to the US Army and the US Air Force Research Office. The US Navy has featured here only once before (a Nov. 1, 2011 posting) and even then it was tangentially. I think it’s long past time that the US Navy gets some attention.

A July 22, 2015 news item on Nanowerk explains the Navy’s interest in electricity and graphene,

The U.S. Navy distributes electricity aboard most of its ships like a power company. It relies on conductors, transformers and other bulky infrastructure.

The setup works, but with powerful next generation weapons on the horizon and the omnipresent goal of energy efficiency, the Navy is seeking alternatives to conventional power control systems.

One option involves using graphene, which, since its discovery in 2004, has become the material of choice for researchers working to improve everything from solar cells to smartphone batteries.

Accordingly, the Office of Naval Research has awarded University at Buffalo engineers an $800,000 grant to develop narrow strips of graphene called nanoribbons that may someday revolutionize how power is controlled in ships, smartphones and other electronic devices.

A July 20, 2015 University of Buffalo news release by Cory Nealon, which originated the news item, expands on the theme,

“We need to develop new nanomaterials capable of handling greater amounts of energy densities in much smaller devices. Graphene nanoribbons show remarkable promise in this endeavor,” says Cemal Basaran, PhD, a professor in UB’s Department of Civil, Structural and Environmental Engineering, School of Engineering and Applied Sciences, and the grant’s principal investigator.

Graphene is a single layer of carbon atoms packed together like a honeycomb. It is extremely thin, light and strong. It’s also the best known conductor of heat and electricity.

“The beauty of graphene is that it can be grown like biological organisms as opposed to manufacturing materials with traditional techniques,” says Basaran, director of UB’s Electronic Packaging Laboratory and a researcher in UB’s New York State Center of Excellence in Materials Informatics. “These bio-inspired materials allow us to control their atomic organizations like controlling genetic DNA makeup of a lab-grown cell.”

While promising, researchers are just beginning to understand graphene and its potential uses. One area of interest is power control systems.

Like overhead power lines, most ships rely on copper or other metals to move electricity. Unfortunately, this process is relatively inefficient; electrons bash into each other and create heat in a process called Joule heating.

“You lose a great deal of energy that way,” Basaran says. “With graphene, you avoid those collisions because it conducts electricity in a different process, known as semi-ballistic conduction. It’s like a high-speed bullet train versus bumper cars.”

Another limitation of metal-based power distribution is the bulky infrastructure – transistors, copper wires, transformers, etc. – needed to move electricity. Whether in a ship or tablet computer, the components take up space and add weight.

Graphene nanoribbons offer a potential solution because they can act as both a conductor (instead of copper) and semiconductor (instead of silicon). Moreover, their ability to withstand failure under extreme energy loads is roughly 1,000 times greater than copper.

That bodes well for the Navy, which, like segments of the automotive industry, is pivoting toward electric vehicles.

It recently launched an all-electric destroyer; the ship’s propellers and drive shafts are turned by electric motors, as opposed to being connected to combustion engines. The integrated power-generation and distribution system may also be used to fire next generation weapons, such as railguns and powerful lasers. And the automation has allowed the Navy to reduce the ship’s crew, which places fewer sailors in potentially dangerous situations.

Graphene nanoribbons could improve these systems by making them more robust and energy-efficient, Basaran said. He and a team of researchers will:

·         Design complex simulations that examine how graphene nanoribbons can be used as a power switch.

·         Explore how adding hydrogen and other elements, a process known as “doping,” to graphene nanoribbons could improve their performance.

·         Investigate graphene nanoribbons’ failure limit under high power loads and try to find ways to improve it.

The research will be performed over the next four years.

I was particularly intrigued by the caption for this image included with the news release,

The technology may lead to more powerful weapons, energy savings and reduced crew numbers [Downloaded from http://www.buffalo.edu/news/releases/2015/07/021.html]

The technology may lead to more powerful weapons, energy savings and reduced crew numbers [Downloaded from http://www.buffalo.edu/news/releases/2015/07/021.html]

Presumably “reduced crew numbers’ means fewer jobs. I wonder if they’ll figure out that people without jobs are without money to pay taxes to fund these projects.