3D Printing Lab Instruments One Block At a Time

3D Printing Lab Instruments One Block At a Time

A team of researchers and students at the University of California, Riverside has created a Lego-like system of blocks that enables users to custom make chemical and biological research instruments quickly, easily and affordably. The system of 3D-printed blocks can be used in university labs, schools, hospitals, and anywhere there is a need to create scientific tools.

The blocks, which are called Multifluidic Evolutionary Components (MECs) because of their flexibility and adaptability, are described today (July 20) in the journal PLOS ONE. Each block in the system performs a basic task found in a lab instrument, like pumping fluids, making measurements or interfacing with a user. Since the blocks are designed to work together, users can build apparatus—like bioreactors for making alternative fuels or acid-base titration tools for high school chemistry classes—rapidly and efficiently.  The blocks are especially well suited for resource-limited settings, where a library of blocks could be used to create a variety of different research and diagnostic tools.

Am image showing how the MEC system can be used to build instruments.

The project is led by Douglas Hill, a graduate student working withWilliam Grover, assistant professor of bioengineering in UCR’s Bourns College of Engineering. Before joining UCR’s Ph.D. program in Bioengineering, Hill worked for 20 years in the field of electronics design, where he used electronic components that were designed to work with each other. He was surprised to see there was no similar set of components in the life sciences.

“When Doug came to UC Riverside, he was a little shocked to find out that bioengineers build new instruments from scratch,” Grover said.  “He’s used to putting together a few resistors and capacitors and making a new circuit in just a few minutes. But building new tools for life science research can take months or even years.  Doug set out to change that.”

Armed with a grant from the National Science Foundation’s Instrument Development for Biological Research program, Hill and Grover began to develop their building blocks. They enlisted help from UC Riverside undergraduates, who have designed new blocks and built instruments using them. Thus far, more than 50 students from across the UCR campus have participated, creating an extensive system of over 200 MEC blocks and a system of schematics that guide assembly of the MEC building blocks into finished instruments.

Grover said in addition to its functionality and affordability, the MEC system offers students a unique learning experience as they work together to create instruments one piece at a time.

“This is a truly interdisciplinary project—we’ve had computer science students write the code that runs the blocks, bioengineering students culture cells using instruments built from the blocks, and even art students design the graphical interface for the software that controls the blocks,” he said.

“Once the students have created these instruments, they also understand how they work, they can ‘hack’ them to make them better, and they can take them apart to create something else.”

A photo of the MEC research team.

Grover and Hill are now planning to pilot the MEC system in two California school districts, where it will support recently introduced ‘Next Generation Science Standards,’ a multi-state initiative to strengthen science education in K-12 schools.

“The Next Generation Science Standards require that science teachers provide their students with engineering experiences, but sometimes that’s hard for teachers to do, especially in biology and chemistry classes where they might not have the tools they need.  By using our blocks, the students can receive an engineering experience by designing, building, and refining their instruments, and also a science experience as they use their instruments to learn about biology and chemistry,” Grover said.

Hill said the team’s long-term goal is to make the MEC blocks available and affordable for others to use.

“As 3D printers become more mainstream, we’ll see them being used by schools and non-profits working in underserved communities, so ultimately we would like people to be able to use those printers to create their own MEC blocks and build the research and educational tools they need,” he said.

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Researchers Find New Ways to Make Clean Hydrogen, Rechargable Zinc Batteries

Researchers Find New Ways to Make Clean Hydrogen, Rechargable Zinc Batteries

A Stanford University research lab has developed new technologies to tackle two of the world’s biggest energy challenges – clean fuel for transportation and grid-scale energy storage.

The researchers described their findings in two studies published this month in the journals Science Advances and Nature Communications.

Hydrogen fuel

Hydrogen fuel has long been touted as a clean alternative to gasoline. Automakers began offering hydrogen-powered cars to American consumers last year, but only a handful have sold, mainly because hydrogen refueling stations are few and far between.

array of silicon nanocones
Stanford engineers created arrays of silicon nanocones to trap sunlight and improve the performance of solar cells made of bismuth vanadate (1µm=1,000 nanometers). (Image credit: Wei Chen and Yongcai Qiu)

Stanford engineers created arrays of silicon nanocones to trap sunlight and improve the performance of solar cells made of bismuth vanadate (1µm=1,000 nanometers).(Image credit: Wei Chen and Yongcai Qiu)

“Millions of cars could be powered by clean hydrogen fuel if it were cheap and widely available,” said Yi Cui, associate professor of materials science and engineering at Stanford.

Unlike gasoline-powered vehicles, which emit carbon dioxide, hydrogen cars themselves are emissions free. Making hydrogen fuel, however, is not emission free: Today, making most hydrogen fuel involves natural gas in a process that releases carbon dioxide into the atmosphere.

To address the problem, Cui and his colleagues have focused on photovoltaic water splitting. This emerging technology consists of a solar-powered electrode immersed in water. When sunlight hits the electrode, it generates an electric current that splits the water into its constituent parts, hydrogen and oxygen.

Finding an affordable way to produce clean hydrogen from water has been a challenge. Conventional solar electrodes made of silicon quickly corrode when exposed to oxygen, a key byproduct of water splitting. Several research teams have reduced corrosion by coating the silicon with iridium and other precious metals.

Writing in the June 17 edition of Sciences Advances, Cui and his colleagues presented a new approach using bismuth vanadate, an inexpensive compound that absorbs sunlight and generates modest amounts of electricity.

“Bismuth vanadate has been widely regarded as a promising material for photoelectrochemical water splitting, in part because of its low cost and high stability against corrosion,” said Cui, who is also an associate professor of photon science at SLAC National Accelerator Laboratory. “However, the performance of this material remains well below its theoretical solar-to-hydrogen conversion efficiency.”

Bismuth vanadate absorbs light but is a poor conductor of electricity. To carry a current, a solar cell made of bismuth vanadate must be sliced very thin, 200 nanometers or less, making it virtually transparent. As a result, visible light that could be used to generate electricity simply passes through the cell.

To capture sunlight before it escapes, Cui’s team turned to nanotechnology. The researchers created microscopic arrays containing thousands of silicon nanocones, each about 600 nanometers tall.

“Nanocone structures have shown a promising light-trapping capability over a broad range of wavelengths,” Cui explained. “Each cone is optimally shaped to capture sunlight that would otherwise pass through the thin solar cell.”

In the experiment, Cui and his colleagues deposited the nanocone arrays on a thin film of bismuth vanadate. Both layers were then placed on a solar cell made of perovskite, another promising photovoltaic material.

When submerged, the three-layer tandem device immediately began splitting water at a solar-to-hydrogen conversion efficiency of 6.2 percent, already matching the theoretical maximum rate for a bismuth vanadate cell.

“The tandem solar cell continued generating hydrogen for more than 10 hours, an indication of good stability,” said Cui, a principal investigator at the Stanford Institute for Materials and Energy Sciences. “Although the efficiency we demonstrated was only 6.2 percent, our tandem device has room for significant improvement in the future.”

Rechargeable zinc battery

In a second study published in the June 6 edition of Nature Communications, Cui and Shougo Higashi, a visiting scientist from Toyota Central R&D Labs Inc., proposed a new battery design that could help solve the problem of grid-scale energy storage.

“Solar and wind farms should be able to provide around-the-clock energy for the electric grid, even when there’s no sunlight or wind,” Cui said. “That will require inexpensive batteries and other low-cost technologies big enough to store surplus clean energy for use on demand.”

Illustration on left shows conventional zinc battery short circuits when dendrites growing from the zinc anode make contact with the metal cathode. On the right: Redesigned battery using plastic and carbon insulators to prevent zinc dendrites from reaching the cathode.
A conventional zinc (Zn) battery (left) short circuits when dendrites growing from the zinc anode make contact with the metal cathode. Stanford scientists redesigned the battery (right) using plastic and carbon insulators to prevent zinc dendrites from reaching the cathode. (Image credit: Shougo Higashi)

A conventional zinc (Zn) battery (left) short circuits when dendrites growing from the zinc anode make contact with the metal cathode. Stanford scientists redesigned the battery (right) using plastic and carbon insulators to prevent zinc dendrites from reaching the cathode. (Image credit: Shougo Higashi)

In the study, Cui, Higashi and their co-workers designed a novel battery with electrodes made of zinc and nickel, inexpensive metals with the potential for grid-scale storage.

A variety of zinc-metal batteries are available commercially, but few are rechargeable, because of tiny fibers called dendrites that form on the zinc electrode during charging. Theses dendrites can grow until they finally reach the nickel electrode, causing the battery to short circuit and fail.

The research team solved the dendrite problem by simply redesigning the battery. Instead of having the zinc and nickel electrodes face one another, as in a conventional battery, the researchers separated them with a plastic insulator and wrapped a carbon insulator around the edges of the zinc electrode.

“With our design, zinc ions are reduced and deposited on the exposed back surface of the zinc electrode during charging,” said Higashi, lead author of the study. “Therefore, even if zinc dendrites form, they will grow away from the nickel electrode and will not short the battery.”

To demonstrate stability, the researchers successfully charged and discharged the battery more than 800 times without shorting.

“Our design is very simple and could be applied to a wide range of metal batteries,” Cui said.

Other co-authors of the Nature Communications study, “Avoiding short circuits from zinc metal dendrites in anode by backside-plating configuration,” are Seok Woo Lee and Jang Soo Lee of Stanford, and Kensuke Takechi of Toyota Central R&D Labs Inc.

Four lead authors contributed equally to the Science Advances study, “Efficient solar-driven water splitting by nanocone BiVO4-perovskite tandem cells”: Yongcai Qiu, Wei Liu and Wei Chen of Stanford, and Wei Chen of Huazhong University. Other authors are Guangmin Zhou, Po-Chun Hsu, Rufan Zhang and Zheng Liang of Stanford; and Shoushan Fan and Yuegang Zhang of Tsinghua University. Support was provided by the U.S. Department of Energy, Stanford’s Global Climate and Energy Project, the National Natural Science Foundation of China and the Natural Science Foundation of Jiangsu Province in China.

Researchers Identify Potential Alternative to CRISPR-Cas Genome Editing Tools

Researchers Identify Potential Alternative to CRISPR-Cas Genome Editing Tools

An international team of CRISPR-Cas researchers has identified three new naturally-occurring systems that show potential for genome editing. The discovery and characterization of these systems is expected to further expand the genome editing toolbox, opening new avenues for biomedical research.  The research, published today in the journal Molecular Cell, was supported in part by the National Institutes of Health.

“This work shows a path to discovery of novel CRISPR-Cas systems with diverse properties, which are demonstrated here in direct experiments,” said Eugene Koonin, Ph.D., senior investigator at the National Center for Biotechnology Information (NCBI), National Library of Medicine (NLM), part of the NIH. “The most remarkable aspect of the story is how evolution has achieved a broad repertoire of biological activities, a feat we can take advantage of for new genome manipulation tools.”

Enzymes from the CRISPR system are revolutionizing the field of genomics, allowing researchers to target specific regions of the genome and edit DNA at precise locations.  “CRISPR” stands for Clustered Regularly Interspaced Short Palindromic Repeats, which are key components of a system used by bacteria to defend against invading viruses. Cas9 — one of the enzymes produced by the CRISPR system — binds to the DNA in a highly sequence-specific manner and cuts it, allowing precise manipulation of a region of DNA. Enzymes such as Cas9 provide researchers with a gene editing tool that is faster, less expensive and more precise than previously developed methods.

The three newly-characterized systems share some features with Cas9 and Cpf1, a recently characterized CRISPR enzyme, but have unique properties that could potentially be exploited for novel genome editing applications. This study highlights the diversity of CRISPR systems, which can be leveraged to develop more efficient, effective, and precise ways to edit DNA.

The researchers took a novel bioinformatics approach to discover the new proteins, provisionally termed C2c1, C2c2, and C2c3, developing a series of computational approaches to search NIH genomic databases and identify new CRISPR-Cas systems. In addition to Koonin, the research team included Feng Zhang of the Broad Institute of MIT and Harvard and the McGovern Institute for Brain Research at MIT, Konstantin Severinov of Rutgers University – New Brunswick and the Skolkovo Institute of Science and Technology, Omar Abudayyeh, a graduate student at the Harvard- MIT Division of Health Sciences and Technology, and NCBI’s Kira Makarova, Sergey Shmakov (also at Skolkovo Institute of Science and Technology), and Yuri Wolf.

“There are multiple ways to modify the search algorithm, so more exciting and distinct CRISPR-Cas mechanisms should be expected soon,” said Severinov. “These new mechanisms will undoubtedly attract the attention of basic and applied scientists alike.”

Initial experimental work exploring the function of these proteins reveals that they are substantially different from the well-characterized Cas9 protein, which has been widely used for genome editing.

With the analysis of C2c1, C2c2, and C2c3, the team was able to infer the intricate evolutionary pathway of these adaptive defense systems.

“The collaborative nature of this work highlights the power of bringing together top scientists with diverse strengths to innovate at the interface of computation, molecular biology and evolutionary biology,” said Zhang.

From Cameras to Computers, New Material Could Change How We Work and Play

From Cameras to Computers, New Material Could Change How We Work and Play

Serendipity has as much a place in sci­ence as in love.

That’s what North­eastern physi­cists Swastik Kar and Srinivas Sridhar found during their four-year project to modify graphene, a stronger-than-steel infin­i­tes­i­mally thin lat­tice of tightly packed carbon atoms. Pri­marily funded by the Army Research Lab­o­ra­tory and Defense Advanced Research Projects Agency, or DARPA, the researchers were charged with imbuing the decade-old mate­rial with thermal sen­si­tivity for use in infrared imaging devices such as night-vision gog­gles for the military.

What they unearthed, pub­lished Friday in the journal Sci­ence Advances, was so much more: an entirely new mate­rial spun out of boron, nitrogen, carbon, and oxygen that shows evi­dence of mag­netic, optical, and elec­trical prop­er­ties as well as DARPA’s sought-after thermal ones. Its poten­tial appli­ca­tions run the gamut: from 20-megapixel arrays for cell­phone cam­eras to photo detec­tors to atom­i­cally thin tran­sis­tors that when mul­ti­plied by the bil­lions could fuel computers.

We had to start from scratch and build every­thing,” says Kar, an assis­tant pro­fessor of physics in the Col­lege of Sci­ence. “We were on a journey, cre­ating a new path, a new direc­tion of research.”

The pair was familiar with “alloys,” con­trolled com­bi­na­tions of ele­ments that resulted in mate­rials with prop­er­ties that sur­passed graphene’s—for example, the addi­tion of boron and nitrogen to graphene’s carbon to con­note the con­duc­tivity nec­es­sary to pro­duce an elec­trical insu­lator. But no one had ever thought of choosing oxygen to add to the mix.

What led the North­eastern researchers to do so?

Well, we didn’t choose oxygen,” says Kar, smiling broadly. “Oxygen chose us.”

Oxygen, of course, is every­where. Indeed, Kar and Sridhar spent a lot of time trying to get rid of the oxygen seeping into their brew, wor­ried that it would con­t­a­m­i­nate the “pure” mate­rial they were seeking to develop.

That’s where the Aha! moment hap­pened for us,” says Kar. “We real­ized we could not ignore the role that oxygen plays in the way these ele­ments mix together.”

So instead of trying to remove oxygen, we thought: Let’s con­trol its intro­duc­tion,” adds Sridhar, the Arts and Sci­ences Dis­tin­guished Pro­fessor of Physics and director of Northeastern’s Elec­tronic Mate­rials Research Institute.

Oxygen, it turned out, was behaving in the reac­tion chamber in a way the sci­en­tists had never antic­i­pated: It was deter­mining how the other elements—the boron, carbon, and nitrogen—combined in a solid, crystal form, while also inserting itself into the lat­tice. The trace amounts of oxygen were, metaphor­i­cally, “etching away” some of the patches of carbon, explains Kar, making room for the boron and nitrogen to fill the gaps.

It was as if the oxygen was con­trol­ling the geo­metric struc­ture,” says Sridhar.

They named the new mate­rial, sen­sibly, 2D-BNCO, rep­re­senting the four ele­ments in the mix and the two-dimensionality of the super-thin light­weight mate­rial, and set about char­ac­ter­izing and man­u­fac­turing it, to ensure it was both repro­ducible and scal­able. That meant inves­ti­gating the myriad per­mu­ta­tions of the four ingre­di­ents, holding three con­stant while varying the mea­sure­ment of the remaining one, and vice versa, mul­tiple times over.

Next they will examine the new material’s mechan­ical prop­er­ties and begin to exper­i­men­tally val­i­date the mag­netic ones con­ferred, sur­pris­ingly, by the inter­min­gling of these four non­mag­netic ele­ments. “You begin to see very quickly how com­pli­cated that process is,” says Kar.After each trial, they ana­lyzed the struc­ture and the func­tional prop­er­ties of the product— elec­trical, optical—using elec­tron micro­scopes and spec­tro­scopic tools, and col­lab­o­rated with com­pu­ta­tional physi­cists, who cre­ated models of the struc­tures to see if the con­fig­u­ra­tions would be fea­sible in the real world.

Helping with that com­plexity were col­lab­o­ra­tors from around the globe. In addi­tion to   North­eastern asso­ciate research sci­en­tists, post­doc­toral fel­lows, and grad­uate stu­dents, con­trib­u­tors included researchers in gov­ern­ment, industry, and acad­emia from the United States, Mexico, and India.

There is still a long way to go but there are clear indi­ca­tions that we can tune the elec­trical prop­er­ties of these mate­rials,” says Sridhar. “And if we find the right com­bi­na­tion, we will very likely get to that point where we reach the thermal sen­si­tivity that DARPA was ini­tially looking for as well as many as-yet unfore­seen applications.”

Bend Me, Shape Me, Any Way You Want Me: Scientists Curve Nanoparticle Sheets into Complex Forms

Bend Me, Shape Me, Any Way You Want Me: Scientists Curve Nanoparticle Sheets into Complex Forms

Scientists have been making nanoparticles for more than two decades in two-dimensional sheets, three-dimensional crystals and random clusters. But they have never been able to get a sheet of nanoparticles to curve or fold into a complex three-dimensional structure. Now researchers from the University of Chicago, the University of Missouri and the U.S. Department of Energy’s Argonne National Laboratory have found a simple way to do exactly that.

The findings open the way for scientists to design membranes with tunable electrical, magnetic and mechanical properties that could be used in electronics and may even have implications for understanding biological systems.

Bend me, shape me, any way you want me: Scientists curve nanoparticle sheets into complex forms
Argonne researchers are able to fold gold nanoparticle membranes in a specific direction using an electron beam because two sides of the membrane are different. Image credit: Xiao-Min Lin et. al, taken at Argonne’s Electron Microscopy Center. Credit: Argonne National Laboratory.

Working at the Center for Nanoscale Materials (CNM) and the Advanced Photon Source (APS), two DOE Office of Science User Facilities located at Argonne, the team got membranes of gold nanoparticles coated with organic molecules to curl into tubes when hit with an electron beam. Equally importantly, they have discovered how and why it happens.

The scientists coat gold nanoparticles of a few thousand atoms each with an oil-like organic molecule that holds the gold particles together. When floated on water the particles form a sheet; when the water evaporates, it leaves the sheet suspended over a hole. “It’s almost like a drumhead,” says Xiao-Min Lin, the staff scientist at the Center for Nanoscale Materials who led the project. “But it’s a very thin membrane made of a single layer of nanoparticles.”

To their surprise, when the scientists put the membrane into the beam of a scanning electron microscope, it folded. It folded every time, and always in the same direction.

“That got our curiosity up,” said Lin. “Why is it bending in one direction?”

The answer lay in the organic surface molecules. They are hydrophobic: when floated on water they try to avoid contact with it, so they end up distributing themselves in a non-uniform way across the top and bottom layers of the nanoparticle sheet. When the electron beam hits the molecules on the surface it causes them to form an additional bond with their neighbors, creating an asymmetrical stress that makes the membranes fold.

Zhang Jiang and Jin Wang, X-ray staff at the APS, came up with an ingenious way to measure the molecular asymmetry, which at only six angstroms, or about six atoms thick, is so tiny it would not normally be measurable.

Subramanian Sankaranarayanan and Sanket Deshmukh at CNM used the high-performance computing resources at DOE’s National Energy Research Scientific Computing Center and the Argonne Leadership Computing Facility (ALCF), both DOE Office of Science User Facilities, to analyze the surface of the nanoparticles. They discovered that the amount of surface covered by the organic molecules and the molecules’ mobility on the surface both have an important influence on the degree of asymmetry in the membrane.

“These are fascinating results,” said Fernando Bresme, professor of chemical physics at the Imperial College in London and a leading theorist on soft matter physics. “They advance significantly our ability to make new nano-structures with controlled shapes.”

In principle, scientists could use this method to induce folding in any nanoparticle membrane that has an asymmetrical distribution of surface molecules. Said Lin, “You use one type of molecule that hates water and rely on the water surfaces to drive the molecules to distribute non-uniformly, or you could use two different kinds of molecules. The key is that the molecules have to distribute non-uniformly.”

The next step for Lin and his colleagues is to explore how they can control the molecular distribution on the surface and therefore the folding behavior. They envision zapping only a small part of the structure with the electron beam, designing the stresses to achieve particular bending patterns.

“You can maybe fold these things into origami structures and all sorts of interesting geometries,” Lin said. “It opens the possibilities.”

Z. Jiang, J. He, S. A. Deshmukh,  P. Kanjanaboos, G. Kamath, Y. Wang, S K. R. S. Sankaranarayanan, J Wang, H. M. Jaeger and X. Lin. “Subnanometre ligand-shell asymmetry leads to Janus-like nanoparticle membranes.”Nature Materials.