Tag Archives: Liezel Labios

Spontaneous assembly of nanocubes in water lock like tiny floating checkerboards

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This is what the tiny checkerboards look like,

SEM image of a checkerboard pattern created by self-assembly of the nanocubes. Scale bar = 500 nm, inset = 100 nm. Image by Wang et al., Nature Communications [downloaded from https://today.ucsd.edu/story/nanosized-blocks-spontaneously-assemble-in-water-to-create-tiny-floating-checkerboards]

A June 13, 2024 news item on ScienceDaily announces the research that resulted in the checkerboards,

Researchers have engineered nanosized cubes that spontaneously form a two-dimensional checkerboard pattern when dropped on the surface of water. The work, published in Nature Communications, presents a simple approach to create complex nanostructures through a technique called self-assembly.

“It’s a cool way to get materials to build themselves,” said study co-senior author Andrea Tao, a professor in the Aiiso Yufeng Li Family Department of Chemical and Nano Engineering at the University of California San Diego. “You don’t have to go into a nanofabrication lab and do all these complex and precise manipulations.”

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A June 13, 2024 University of California – San Diego news release (also on EurekAlert) by Liezel Labios, which originated the news item, provides more detail about the work, Note: A link has been removed,

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Each nanocube is composed of a silver crystal with a mixture of hydrophobic (oily) and hydrophilic (water-loving) molecules attached to the surface. When a suspension of these nanocubes is introduced to a water surface, they arrange themselves such that they touch at their corner edges. This arrangement creates an alternating pattern of solid cubes and empty spaces, resulting in a checkerboard pattern.

The self-assembly process is driven by the surface chemistry of the nanocubes. A high density of hydrophobic molecules on the surface brings the cubes together to minimize their interaction with water. Meanwhile, the long chains of hydrophilic molecules cause enough repulsion to create voids between the cubes, creating the checkerboard pattern.

To fabricate the structure, researchers applied drops of the nanocube suspension onto a petri dish containing water. The resulting checkerboard can be easily transferred to a substrate by dipping the substrate into the water and slowly withdrawing it, allowing the nanostructure to coat it.

This study stems from a collaborative effort between multiple research groups that are part of the UC San Diego Materials Research Science and Engineering Center (MRSEC). The work featured a synergistic combination of computational and experimental techniques. “We’ve built a continuous feedback loop between our computations and experiments,” said Tao. “We used computer simulations to help us design the materials at the nanoscale and predict how they will behave. We also used our experimental results in the lab to validate the simulations, fine tune them and build a better model.”

In designing the material, researchers chose silver crystal nanocubes due to the Tao lab’s expertise in their synthesis. Determining the optimal surface chemistry required extensive computational experimentation, which was led by Gaurav Arya, a professor in the Department of Mechanical Engineering and Materials Science at Duke University and co-senior author of the study. The simulations identified the best molecules to attach to the nanocubes and predicted how the cubes would interact and assemble on the water surface. The simulations were iteratively refined using experimental data obtained by Tao’s lab. Electron microscopy performed by the lab of study co-author Alex Frañó, a professor in the Department of Physics at UC San Diego, confirmed the formation of the desired checkerboard structures.

Tao envisions applications for the nanocube checkerboard in optical sensing. “Such a nanostructure can manipulate light in interesting ways,” she explained. “The spaces between the cubes, particularly near the corner edges where the cubes connect, can act as tiny hotspots that focus or trap light. That could be useful for making new types of optical elements like nanoscale filters or waveguides.”

The researchers plan to explore the optical properties of the checkerboard in future studies.

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

Self-assembly of nanocrystal checkerboard patterns via non-specific interactions by Yufei Wang, Yilong Zhou, Quanpeng Yang, Rourav Basak, Yu Xie, Dong Le, Alexander D. Fuqua, Wade Shipley, Zachary Yam, Alex Frano, Gaurav Arya & Andrea R. Tao. Nature Communications volume 15, Article number: 3913 (2024) DOI: https://doi.org/10.1038/s41467-024-47572-2 Published0: 9 May 2024

This paper is open access.

They glow under stress: soft, living materials made with algae

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Caption: These soft, living materials glow in response to mechanical stress, such as compression, stretching or twisting. Credit: UC San Diego Jacobs School of Engineering

An October 20, 2023 news item on phys.org describes research into bioluminescent materials, Note: A link has been removed,

A team of researchers led by the University of California San Diego has developed soft yet durable materials that glow in response to mechanical stress, such as compression, stretching or twisting. The materials derive their luminescence from single-celled algae known as dinoflagellates.

The work, inspired by the bioluminescent waves observed during red tide events at San Diego’s beaches, was published Oct. 20 [2023] in Science Advances.

…

An October 23, 2023 University of California at San Diego news release (also on EurekAlert but published October 20, 2023) by Liezel Labios, which originated the news item, delves further into the research,

An exciting feature of these materials is their inherent simplicity—they need no electronics, no external power source,” said study senior author Shengqiang Cai, a professor of mechanical and aerospace engineering at the UC San Diego Jacobs School of Engineering. “We demonstrate how we can harness the power of nature to directly convert mechanical stimuli into light emission.”

This study was a multi-disciplinary collaboration involving engineers and materials scientists in Cai’s lab, marine biologist Michael Latz at UC San Diego’s Scripps Institution of Oceanography, and physics professor Maziyar Jalaal at University of Amsterdam.

The primary ingredients of the bioluminescent materials are dinoflagellates and a seaweed-based polymer called alginate. These elements were mixed to form a solution, which was then processed with a 3D printer to create a diverse array of shapes, such as grids, spirals, spiderwebs, balls, blocks and pyramid-like structures. The 3D-printed structures were then cured as a final step.

When the materials are subjected to compression, stretching or twisting, the dinoflagellates within them respond by emitting light. This response mimics what happens in the ocean, when dinoflagellates produce flashes of light as part of a predator defense strategy. In tests, the materials glowed when the researchers pressed on them and traced patterns on their surface. The materials were even sensitive enough to glow under the weight of a foam ball rolling on their surface.

The greater the applied stress, the brighter the glow. The researchers were able to quantify this behavior and developed a mathematical model that can predict the intensity of the glow based on the magnitude of the mechanical stress applied.

The researchers also demonstrated techniques to make these materials resilient in various experimental conditions. To reinforce the materials so that they can bear substantial mechanical loads, a second polymer, poly(ethylene glycol) diacrylate, was added to the original blend. Also, coating the materials with a stretchy rubber-like polymer called Ecoflex provided protection in acidic and basic solutions. With this protective layer, the materials could even be stored in seawater for up to five months without losing their form or bioluminescent properties.

Another beneficial feature of these materials is their minimal maintenance requirements. To keep working, the dinoflagellates within the materials need periodic cycles of light and darkness. During the light phase, they photosynthesize to produce food and energy, which are then used in the dark phase to emit light when mechanical stress is applied. This behavior mirrors the natural processes at play when the dinoflagellates cause bioluminescence in the ocean during red tide events. 

“This current work demonstrates a simple method to combine living organisms with non-living components to fabricate novel materials that are self-sustaining and are sensitive to fundamental mechanical stimuli found in nature,” said study first author Chenghai Li, a mechanical and aerospace engineering Ph.D. candidate in Cai’s lab.

The researchers envision that these materials could potentially be used as mechanical sensors to gauge pressure, strain or stress. Other potential applications include soft robotics and biomedical devices that use light signals to perform treatment or controlled drug release.

However, there is much work to be done before these applications can be realized. The researchers are working on further improving and optimizing the materials.

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

Ultrasensitive and robust mechanoluminescent living composites by Chenghai Li, Nico Schramma, Zijun Wang, Nada F. Qari, Maziyar Jalaal, Michael I. Latz, and Shengqiang Cai. Science Advances 20 Oct 2023 Vol 9, Issue 42 DOI: 10.1126/sciadv.adi8643

This paper is open access.

Agricultural pest control with nanoparticles derived from plant viruses

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As with many of these ‘nanoparticle solutions’ to a problem, it seems the nanoparticles are the delivery system. A September 21, 2023 news item on ScienceDaily announces the research,

A new form of agricultural pest control could one day take root — one that treats crop infestations deep under the ground in a targeted manner with less pesticide.

Engineers at the University of California San Diego have developed nanoparticles, fashioned from plant viruses, that can deliver pesticide molecules to soil depths that were previously unreachable. This advance could potentially help farmers effectively combat parasitic nematodes that plague the root zones of crops, all while minimizing costs, pesticide use and environmental toxicity.

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A September 21, 2023 University of California at San Diego news release (also on EurekAlert) by Liezel Labios, which originated the news item, provides more information about the problems along with a nod to nanomedicine as the inspiration for the proposed solution, Note: Links have been removed,

Controlling infestations caused by root-damaging nematodes has long been a challenge in agriculture. One reason is that the types of pesticides used against nematodes tend to cling to the top layers of soil, making it tough to reach the root level where nematodes wreak havoc. As a result, farmers often resort to applying excessive amounts of pesticide, as well as water to wash pesticides down to the root zone. This can lead to contamination of soil and groundwater.

To find a more sustainable and effective solution, a team led by Nicole Steinmetz, a professor of nanoengineering at the UC San Diego Jacobs School of Engineering and founding director of the Center for Nano-ImmunoEngineering, developed plant virus nanoparticles that can transport pesticide molecules deep into the soil, precisely where they are needed. The work is detailed in a paper published in Nano Letters.

Steinmetz’s team drew inspiration from nanomedicine [emphasis mine], where nanoparticles are being created for targeted drug delivery, and adapted this concept to agriculture. This idea of repurposing and redesigning biological materials for different applications is also a focus area of the UC San Diego Materials Research Science and Engineering Center (MRSEC), of which Steinmetz is a co-lead. 

“We’re developing a precision farming approach where we’re creating nanoparticles for targeted pesticide delivery,” said Steinmetz, who is the study’s senior author. “This technology holds the promise of enhancing treatment effectiveness in the field without the need to increase pesticide dosage.”

The star of this approach is the tobacco mild green mosaic virus, a plant virus that has the ability to move through soil with ease. Researchers modified these virus nanoparticles, rendering them noninfectious to crops by removing their RNA. They then mixed these nanoparticles with pesticide solutions in water and heated them, creating spherical virus-like nanoparticles packed with pesticides through a simple one-pot synthesis.

This one-pot synthesis offers several advantages. First, it is cost-effective, with just a few steps and a straightforward purification process. The result is a more scalable method, paving the way toward a more affordable product for farmers, noted Steinmetz. Second, by simply packaging the pesticide inside the nanoparticles, rather than chemically binding it to the surface, this method preserves the original chemical structure of the pesticide.

“If we had used a traditional synthetic method where we link the pesticide molecules to the nanoparticles, we would have essentially created a new compound, which will need to go through a whole new registration and regulatory approval process,” said study first author Adam Caparco, a postdoctoral researcher in Steinmetz’s lab. “But since we’re just encapsulating the pesticide within the nanoparticles, we’re not changing the active ingredient, so we won’t need to get new approval for it. That could help expedite the translation of this technology to the market.”

Moreover, the tobacco mild green mosaic virus is already approved by the Environmental Protection Agency (EPA) for use as an herbicide to control an invasive plant called the tropical soda apple. This existing approval could further streamline the path from lab to market.

The researchers conducted experiments in the lab to demonstrate the efficacy of their pesticide-packed nanoparticles. The nanoparticles were watered through columns of soil and successfully transported the pesticides to depths of at least 10 centimeters. The solutions were collected from the bottom of the soil columns and were found to contain the pesticide-packed nanoparticles. When the researchers treated nematodes with these solutions, they eliminated at least half of the population in a petri dish.

While the researchers have not yet tested the nanoparticles on nematodes lurking beneath the soil, they note that this study marks a significant step forward.

“Our technology enables pesticides meant to combat nematodes to be used in the soil,” said Caparco. “These pesticides alone cannot penetrate the soil. But with our nanoparticles, they now have soil mobility, can reach the root level, and potentially kill the nematodes.”

Future research will involve testing the nanoparticles on actual infested plants to assess their effectiveness in real-world agricultural scenarios. Steinmetz’s lab will perform these follow-up studies in collaboration with the U.S. Horticultural Research Laboratory. Her team has also established plans for an industry partnership aimed at advancing the nanoparticles into a commercial product.

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

Delivery of Nematicides Using TMGMV-Derived Spherical Nanoparticles by Adam A. Caparco, Ivonne González-Gamboa, Samuel S. Hays, Jonathan K. Pokorski, and Nicole F. Steinmetz. Nano Lett. 2023, 23, 12, 5785–5793 DOI: https://doi.org/10.1021/acs.nanolett.3c01684 Publication Date:June 16, 2023 Copyright © 2023 American Chemical Society

This paper is behind a paywall.

Humans can distinguish molecular differences by touch

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Yesterday, in my December 18, 2017 post about medieval textiles, I posed the question, “How did medieval artisans create nanoscale and microscale gilding when they couldn’t see it?” I realized afterwards that an answer to that question might be in this December 13, 2017 news item on ScienceDaily,

How sensitive is the human sense of touch? Sensitive enough to feel the difference between surfaces that differ by just a single layer of molecules, a team of researchers at the University of California San Diego has shown.

“This is the greatest tactile sensitivity that has ever been shown in humans,” said Darren Lipomi, a professor of nanoengineering and member of the Center for Wearable Sensors at the UC San Diego Jacobs School of Engineering, who led the interdisciplinary project with V. S. Ramachandran, director of the Center for Brain and Cognition and distinguished professor in the Department of Psychology at UC San Diego.

So perhaps those medieval artisans were able to feel the difference before it could be seen in the textiles they were producing?

Getting back to the matter at hand, a December 13, 2017 University of California at San Diego (UCSD) news release (also on EurekAlert) by Liezel Labios offers more detail about the work,

Humans can easily feel the difference between many everyday surfaces such as glass, metal, wood and plastic. That’s because these surfaces have different textures or draw heat away from the finger at different rates. But UC San Diego researchers wondered, if they kept all these large-scale effects equal and changed only the topmost layer of molecules, could humans still detect the difference using their sense of touch? And if so, how?

Researchers say this fundamental knowledge will be useful for developing electronic skin, prosthetics that can feel, advanced haptic technology for virtual and augmented reality and more.

Unsophisticated haptic technologies exist in the form of rumble packs in video game controllers or smartphones that shake, Lipomi added. “But reproducing realistic tactile sensations is difficult because we don’t yet fully understand the basic ways in which materials interact with the sense of touch.”

“Today’s technologies allow us to see and hear what’s happening, but we can’t feel it,” said Cody Carpenter, a nanoengineering Ph.D. student at UC San Diego and co-first author of the study. “We have state-of-the-art speakers, phones and high-resolution screens that are visually and aurally engaging, but what’s missing is the sense of touch. Adding that ingredient is a driving force behind this work.”

This study is the first to combine materials science and psychophysics to understand how humans perceive touch. “Receptors processing sensations from our skin are phylogenetically the most ancient, but far from being primitive they have had time to evolve extraordinarily subtle strategies for discerning surfaces—whether a lover’s caress or a tickle or the raw tactile feel of metal, wood, paper, etc. This study is one of the first to demonstrate the range of sophistication and exquisite sensitivity of tactile sensations. It paves the way, perhaps, for a whole new approach to tactile psychophysics,” Ramachandran said.

Super-Sensitive Touch

In a paper published in Materials Horizons, UC San Diego researchers tested whether human subjects could distinguish—by dragging or tapping a finger across the surface—between smooth silicon wafers that differed only in their single topmost layer of molecules. One surface was a single oxidized layer made mostly of oxygen atoms. The other was a single Teflon-like layer made of fluorine and carbon atoms. Both surfaces looked identical and felt similar enough that some subjects could not differentiate between them at all.

According to the researchers, human subjects can feel these differences because of a phenomenon known as stick-slip friction, which is the jerking motion that occurs when two objects at rest start to slide against each other. This phenomenon is responsible for the musical notes played by running a wet finger along the rim of a wine glass, the sound of a squeaky door hinge or the noise of a stopping train. In this case, each surface has a different stick-slip frequency due to the identity of the molecules in the topmost layer.

In one test, 15 subjects were tasked with feeling three surfaces and identifying the one surface that differed from the other two. Subjects correctly identified the differences 71 percent of the time.

In another test, subjects were given three different strips of silicon wafer, each strip containing a different sequence of 8 patches of oxidized and Teflon-like surfaces. Each sequence represented an 8-digit string of 0s and 1s, which encoded for a particular letter in the ASCII alphabet. Subjects were asked to “read” these sequences by dragging a finger from one end of the strip to the other and noting which patches in the sequence were the oxidized surfaces and which were the Teflon-like surfaces. In this experiment, 10 out of 11 subjects decoded the bits needed to spell the word “Lab” (with the correct upper and lowercase letters) more than 50 percent of the time. Subjects spent an average of 4.5 minutes to decode each letter.

“A human may be slower than a nanobit per second in terms of reading digital information, but this experiment shows a potentially neat way to do chemical communications using our sense of touch instead of sight,” Lipomi said.

Basic Model of Touch

The researchers also found that these surfaces can be differentiated depending on how fast the finger drags and how much force it applies across the surface. The researchers modeled the touch experiments using a “mock finger,” a finger-like device made of an organic polymer that’s connected by a spring to a force sensor. The mock finger was dragged across the different surfaces using multiple combinations of force and swiping velocity. The researchers plotted the data and found that the surfaces could be distinguished given certain combinations of velocity and force. Meanwhile, other combinations made the surfaces indistinguishable from each other.

“Our results reveal a remarkable human ability to quickly home in on the right combinations of forces and swiping velocities required to feel the difference between these surfaces. They don’t need to reconstruct an entire matrix of data points one by one as we did in our experiments,” Lipomi said.

“It’s also interesting that the mock finger device, which doesn’t have anything resembling the hundreds of nerves in our skin, has just one force sensor and is still able to get the information needed to feel the difference in these surfaces. This tells us it’s not just the mechanoreceptors in the skin, but receptors in the ligaments, knuckles, wrist, elbow and shoulder that could be enabling humans to sense minute differences using touch,” he added.

This work was supported by member companies of the Center for Wearable Sensors at UC San Diego: Samsung, Dexcom, Sabic, Cubic, Qualcomm and Honda.

For those who prefer their news by video,

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

Human ability to discriminate surface chemistry by touch by Cody W. Carpenter, Charles Dhong, Nicholas B. Root, Daniel Rodriquez, Emily E. Abdo, Kyle Skelil, Mohammad A. Alkhadra, Julian Ramírez, Vilayanur S. Ramachandran and Darren J. Lipomi. Mater. Horiz., 2018, Advance Article DOI: 10.1039/C7MH00800G

This paper is open access but you do need to have opened a free account on the website.

Cleaning up carbon dioxide pollution in the oceans and elsewhere

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I have a mini roundup of items (3) concerning nanotechnology and environmental applications with a special focus on carbon materials.

Carbon-capturing motors

First up, there’s a Sept. 23, 2015 news item on ScienceDaily which describes work with tiny carbon-capturing motors,

Machines that are much smaller than the width of a human hair could one day help clean up carbon dioxide pollution in the oceans. Nanoengineers at the University of California, San Diego have designed enzyme-functionalized micromotors that rapidly zoom around in water, remove carbon dioxide and convert it into a usable solid form.

The proof of concept study represents a promising route to mitigate the buildup of carbon dioxide, a major greenhouse gas in the environment, said researchers. …

A Sept 22, 2015 University of California at San Diego (UCSD) news release by Liezel Labios, which originated the news release, provides more details about the scientists’ hopes and the technology,

“We’re excited about the possibility of using these micromotors to combat ocean acidification and global warming,” said Virendra V. Singh, a postdoctoral scientist in Wang’s [nanoengineering professor and chair Joseph Wang] research group and a co-first author of this study.

In their experiments, nanoengineers demonstrated that the micromotors rapidly decarbonated water solutions that were saturated with carbon dioxide. Within five minutes, the micromotors removed 90 percent of the carbon dioxide from a solution of deionized water. The micromotors were just as effective in a sea water solution and removed 88 percent of the carbon dioxide in the same timeframe.

“In the future, we could potentially use these micromotors as part of a water treatment system, like a water decarbonation plant,” said Kevin Kaufmann, an undergraduate researcher in Wang’s lab and a co-author of the study.

The micromotors are essentially six-micrometer-long tubes that help rapidly convert carbon dioxide into calcium carbonate, a solid mineral found in eggshells, the shells of various marine organisms, calcium supplements and cement. The micromotors have an outer polymer surface that holds the enzyme carbonic anhydrase, which speeds up the reaction between carbon dioxide and water to form bicarbonate. Calcium chloride, which is added to the water solutions, helps convert bicarbonate to calcium carbonate.

The fast and continuous motion of the micromotors in solution makes the micromotors extremely efficient at removing carbon dioxide from water, said researchers. The team explained that the micromotors’ autonomous movement induces efficient solution mixing, leading to faster carbon dioxide conversion. To fuel the micromotors in water, researchers added hydrogen peroxide, which reacts with the inner platinum surface of the micromotors to generate a stream of oxygen gas bubbles that propel the micromotors around. When released in water solutions containing as little as two to four percent hydrogen peroxide, the micromotors reached speeds of more than 100 micrometers per second.

However, the use of hydrogen peroxide as the micromotor fuel is a drawback because it is an extra additive and requires the use of expensive platinum materials to build the micromotors. As a next step, researchers are planning to make carbon-capturing micromotors that can be propelled by water.

“If the micromotors can use the environment as fuel, they will be more scalable, environmentally friendly and less expensive,” said Kaufmann.

The researchers have provided an image which illustrates the carbon-capturing motors in action,

Nanoengineers have invented tiny tube-shaped micromotors that zoom around in water and efficiently remove carbon dioxide. The surfaces of the micromotors are functionalized with the enzyme carbonic anhydrase, which enables the motors to help rapidly convert carbon dioxide to calcium carbonate. Image credit: Laboratory for Nanobioelectronics, UC San Diego Jacobs School of Engineering.

Nanoengineers have invented tiny tube-shaped micromotors that zoom around in water and efficiently remove carbon dioxide. The surfaces of the micromotors are functionalized with the enzyme carbonic anhydrase, which enables the motors to help rapidly convert carbon dioxide to calcium carbonate. Image credit: Laboratory for Nanobioelectronics, UC San Diego Jacobs School of Engineering.

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

Micromotor-Based Biomimetic Carbon Dioxide Sequestration: Towards Mobile Microscrubbers by Murat Uygun, Virendra V. Singh, Kevin Kaufmann, Deniz A. Uygun, Severina D. S. de Oliveira, and oseph Wang. Angewandte Chemie DOI: 10.1002/ange.201505155 Article first published online: 4 SEP 2015

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

This article is behind a paywall.

Carbon nanotubes for carbon dioxide capture (carbon capture)

In a Sept. 22, 2015 posting by Dexter Johnson on his Nanoclast blog (located on the IEEE [Institute for Electrical and Electronics Engineers] website) describes research where carbon nanotubes are being used for carbon capture,

Now researchers at Technische Universität Darmstadt in Germany and the Indian Institute of Technology Kanpur have found that they can tailor the gas adsorption properties of vertically aligned carbon nanotubes (VACNTs) by altering their thickness, height, and the distance between them.

“These parameters are fundamental for ‘tuning’ the hierarchical pore structure of the VACNTs,” explained Mahshid Rahimi and Deepu Babu, doctoral students at the Technische Universität Darmstadt who were the paper’s lead authors, in a press release. “This hierarchy effect is a crucial factor for getting high-adsorption capacities as well as mass transport into the nanostructure. Surprisingly, from theory and by experiment, we found that the distance between nanotubes plays a much larger role in gas adsorption than the tube diameter does.”

Dexter provides a good and brief summary of the research.

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

Double-walled carbon nanotube array for CO2 and SO2 adsorption by Mahshid Rahimi, Deepu J. Babu, Jayant K. Singh, Yong-Biao Yang, Jörg J. Schneider, and Florian Müller-Plathe. J. Chem. Phys. 143, 124701 (2015); http://dx.doi.org/10.1063/1.4929609

This paper is open access.

The market for nanotechnology-enabled environmental applications

Coincident with stumbling across these two possible capture solutions, I found this Sept. 23, 2015 BCC Research news release,

A groundswell of global support for developing nanotechnology as a pollution remediation technique will continue for the foreseeable future. BCC Research reveals in its new report that this key driver, along with increasing worldwide concerns over removing pollutants and developing alternative energy sources, will drive growth in the nanotechnology environmental applications market.

The global nanotechnology market in environmental applications is expected to reach $25.7 billion by 2015 and $41.8 billion by 2020, conforming to a five-year (2015-2020) compound annual growth rate (CAGR) of 10.2%. Air remediation as a segment will reach $10.2 billion and $16.7 billion in 2015 and 2020, respectively, reflecting a five-year CAGR of 10.3%. Water remediation as a segment will grow at a five-year CAGR of 12.4% to reach $10.6 billion in 2020.

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As nanoparticles push the limits and capabilities of technology, new and better techniques for pollution control are emerging. Presently, nanotechnology’s greatest potential lies in air pollution remediation.

“Nano filters could be applied to automobile tailpipes and factory smokestacks to separate out contaminants and prevent them from entering the atmosphere. In addition, nano sensors have been developed to sense toxic gas leaks at extremely low concentrations,” says BCC research analyst Aneesh Kumar. “Overall, there is a multitude of promising environmental applications for nanotechnology, with the main focus area on energy and water technologies.”

You can find links to the report, TOC (table of contents), and report overview on the BCC Research Nanotechnology in Environmental Applications: The Global Market report webpage.

Synthetic microfish (nanoengineered and 3D printed) to inspire ‘smart’ microbots

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An August 26, 2015 news item on Nanowerk features some microfish (they look like sharks to me) fabricated in University of California at San Diego (UCSD) laboratories,

Nanoengineers at the University of California, San Diego used an innovative 3D printing technology they developed to manufacture multipurpose fish-shaped microrobots — called microfish — that swim around efficiently in liquids, are chemically powered by hydrogen peroxide and magnetically controlled. These proof-of-concept synthetic microfish will inspire a new generation of “smart” microrobots that have diverse capabilities such as detoxification, sensing and directed drug delivery, researchers said.

3D-printed microfish contain functional nanoparticles that enable them to be self-propelled, chemically powered and magnetically steered. The microfish are also capable of removing and sensing toxins. Image credit: J. Warner, UC San Diego Jacobs School of Engineering.

3D-printed microfish contain functional nanoparticles that enable them to be self-propelled, chemically powered and magnetically steered. The microfish are also capable of removing and sensing toxins. Image credit: J. Warner, UC San Diego Jacobs School of Engineering.

An August 25, 2015 UCSD news release (also on EurekAlert) by Liezel Labios, which originated the news item, provides more detail,

The technique used to fabricate the microfish provides numerous improvements over other methods traditionally employed to create microrobots with various locomotion mechanisms, such as microjet engines, microdrillers and microrockets. Most of these microrobots are incapable of performing more sophisticated tasks because they feature simple designs — such as spherical or cylindrical structures — and are made of homogeneous inorganic materials. In this new study, researchers demonstrated a simple way to create more complex microrobots.

…

By combining Chen’s 3D printing technology with Wang’s expertise in microrobots, the team was able to custom-build microfish that can do more than simply swim around when placed in a solution containing hydrogen peroxide. Nanoengineers were able to easily add functional nanoparticles into certain parts of the microfish bodies. They installed platinum nanoparticles in the tails, which react with hydrogen peroxide to propel the microfish forward, and magnetic iron oxide nanoparticles in the heads, which allowed them to be steered with magnets.

Here’s an illustration of the platinum and iron oxide microfish,

Schematic illustration of the process of functionalizing the microfish. Platinum nanoparticles are first loaded into the tail of the fish for propulsion via reaction with hydrogen peroxide. Next, iron oxide nanoparticles are loaded into the head of the fish for magnetic control. Image credit: W. Zhu and J. Li, UC San Diego Jacobs School of Engineering.

Schematic illustration of the process of functionalizing the microfish. Platinum nanoparticles are first loaded into the tail of the fish for propulsion via reaction with hydrogen peroxide. Next, iron oxide nanoparticles are loaded into the head of the fish for magnetic control. Image credit: W. Zhu and J. Li, UC San Diego Jacobs School of Engineering.

Back to the news release,

“We have developed an entirely new method to engineer nature-inspired microscopic swimmers that have complex geometric structures and are smaller than the width of a human hair. With this method, we can easily integrate different functions inside these tiny robotic swimmers for a broad spectrum of applications,” said the co-first author Wei Zhu, a nanoengineering Ph.D. student in Chen’s research group at the Jacobs School of Engineering at UC San Diego.

As a proof-of-concept demonstration, the researchers incorporated toxin-neutralizing nanoparticles throughout the bodies of the microfish. Specifically, the researchers mixed in polydiacetylene (PDA) nanoparticles, which capture harmful pore-forming toxins such as the ones found in bee venom. The researchers noted that the powerful swimming of the microfish in solution greatly enhanced their ability to clean up toxins. When the PDA nanoparticles bind with toxin molecules, they become fluorescent and emit red-colored light. The team was able to monitor the detoxification ability of the microfish by the intensity of their red glow.

“The neat thing about this experiment is that it shows how the microfish can doubly serve as detoxification systems and as toxin sensors,” said Zhu.

“Another exciting possibility we could explore is to encapsulate medicines inside the microfish and use them for directed drug delivery,” said Jinxing Li, the other co-first author of the study and a nanoengineering Ph.D. student in Wang’s research group.

For anyone curious about the new 3D printing technique, the news release provides more information about that too,

The new microfish fabrication method is based on a rapid, high-resolution 3D printing technology called microscale continuous optical printing (μCOP), which was developed in Chen’s lab. Some of the benefits of the μCOP technology are speed, scalability, precision and flexibility. Within seconds, the researchers can print an array containing hundreds of microfish, each measuring 120 microns long and 30 microns thick. This process also does not require the use of harsh chemicals. Because the μCOP technology is digitized, the researchers could easily experiment with different designs for their microfish, including shark and manta ray shapes. [emphasis mine] “With our 3D printing technology, we are not limited to just fish shapes. We can rapidly build microrobots inspired by other biological organisms such as birds,” said Zhu.

The key component of the μCOP technology is a digital micromirror array device (DMD) chip, which contains approximately two million micromirrors. Each micromirror is individually controlled to project UV light in the desired pattern (in this case, a fish shape) onto a photosensitive material, which solidifies upon exposure to UV light. The microfish are built using a photosensitive material and are constructed one layer at a time, allowing each set of functional nanoparticles to be “printed” into specific parts of the fish bodies.

“This method has made it easier for us to test different designs for these microrobots and to test different nanoparticles to insert new functional elements into these tiny structures. It’s my personal hope to further this research to eventually develop surgical microrobots that operate safer and with more precision,” said Li.

Nice to see I can recognize a shark shape when I see one. Getting back to the research, yet again, here’s a link to and a citation for the paper.

3D-Printed Artificial Microfish by Wei Zhu, Jinxing Li, Yew J. Leong, Isaac Rozen, Xin Qu, Renfeng Dong, Zhiguang Wu, Wei Gao, Peter H. Chung, Joseph Wang, and Shaochen Chen. Advanced Materials Volume 27, Issue 30, pages 4411–4417, August 12, 2015 DOI: 10.1002/adma.201501372 Article first published online: 29 JUN 2015

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

This paper is behind a paywall.