Soft materials are great at damping energy — that’s why rubber tires are so good at absorbing the shock of bumps and potholes. But if researchers are going to build autonomous soft systems, like soft robots, they’ll need a way to transmit energy through soft materials.
Now, researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), in collaboration with colleagues at the California Institute of Technology, have developed a way to send mechanical signals through soft materials.
The research is described in the Proceedings of the National Academy of Sciences.
“Soft autonomous systems have received a lot of attention because, just like the human body or other biological systems, they can be adaptive and perform delicate movements. However, the highly dissipative nature of soft materials limits or altogether prevents certain functions,” said Jordan Raney, postdoctoral fellow at SEAS and first author of the paper. “By storing energy in the architecture itself we can make up for the energy losses due to dissipation, allowing the propagation of mechanical signals across long distances.”
The system uses the centuries-old concept of bistable beams — structures stable in two distinct state — to store and release elastic energy along the path of a wave. The system consists of a chain of bistable elastomeric beams connected by elastomeric linear springs. When those beams are deformed, they snap and store energy in the form of elastic deformation. As the signal moves down the elastomer, it snaps the beams back into place, releasing the stored energy and sending the signal downstream like a line of dominos. The bistable system prevents the signal from dissipating downstream.
“This design solves two fundamental problems in transmitting information through materials,” said Katia Bertoldi, the John L. Loeb Associate Professor of the Natural Sciences at SEAS and senior author of the paper. “It not only overcomes dissipation, but it also eliminates dispersive effects, so that the signal propagates without distortion. As such, we maintain signal strength and clarity from start to end.”
The beam geometry requires precise fabrication techniques. If the angle or thickness of one beam is off by one degree or millimeter, the whole system fails.
The team used advanced 3D printing techniques to fabricate the system.
“We’re developing new materials and printing methods that enable the fabrication of soft materials with programmable bistable elements,” said Jennifer A. Lewis, the Hansjorg Wyss Professor of Biologically Inspired Engineering and coauthor of the paper.
The team designed and printed a soft logic gate using this system. The gate, which looks like a tuning fork, can be controlled to act as either as an AND or as an OR gate.
“It’s amazing what you can do using simple beams — a building block that’s been around hundreds of years,” said Bertoldi. “You can do new stuff with a very old, well studied and very simple component.”
Learn more: Transmitting energy in soft materials
New system surpasses efficiency of photosynthesis
The days of drilling into the ground in the search for fuel may be numbered, because if Daniel Nocera has his way, it’ll just be a matter of looking for sunny skies.
Nocera, the Patterson Rockwood Professor of Energy at Harvard University, and Pamela Silver, the Elliott T. and Onie H. Adams Professor of Biochemistry and Systems Biology at Harvard Medical School, have co-created a system that uses solar energy to split water molecules and hydrogen-eating bacteria to produce liquid fuels.
The paper, whose lead authors include postdoctoral fellow Chong Liu and graduate student Brendan Colón, is described in a June 3 paper published in Science.
“This is a true artificial photosynthesis system,” Nocera said. “Before, people were using artificial photosynthesis for water-splitting, but this is a true A-to-Z system, and we’ve gone well over the efficiency of photosynthesis in nature.”
While the study shows the system can be used to generate usable fuels, its potential doesn’t end there, said Silver, who is also a founding core member of the Wyss Institute at Harvard University.
The Wyss Institute for Biologically Inspired Engineering is a cross-disciplinary research institute at Harvard University which focuses on developing new bioinspired materials and devices for applications in healthcare, manufacturing, robotics, energy, and sustainable architecture.
The Institute has two sites: one in the Center for Life Sciences Boston building in Boston’s Longwood Medical Area, and one on Harvard’s main campus in Cambridge, Massachusetts. The Wyss Institute was launched in January 2009 with a $125 million gift to Harvard—the largest single philanthropic gift in its history—from Hansjörg Wyss.
The Institute works as an alliance among Harvard Medical School, Harvard School of Dental Medicine, Harvard School of Engineering and Applied Sciences, Harvard Faculty of Arts and Sciences, Children’s Hospital Boston, Dana-Farber Cancer Institute, Beth Israel Deaconess Medical Center, Boston University, Brigham and Women’s Hospital, Massachusetts General Hospital, Spaulding Rehabilitation Hospital, and the University of Massachusetts Medical School. Translating technological discoveries into commercial products and therapies is an important part of the organization’s mission.
The Latest Updated Research News:
Wyss Institute research articles from Innovation Toronto
- Bionic leaf turns sunlight into liquid fuel at 10 times the efficiency of photosynthesis – June 3, 2016
- Soft clothing-like exosuits to increase the wearer’s strength and endurance – May 23, 2016
- Using static electricity, RoboBees can land and stick to surfaces – May 20, 2016
- 3D Printing metal in midair for customized electronic and biomedical devices – May 20, 2016
- Finding Zika one paper disc at a time in 2 to 3 hours – May 7, 2016
- Scaling up tissue engineering with a new bioprinting technique – March 14, 2016
- Imagine a house that could fit in a backpack: A foldable material that can change size, volume and shape – March 12, 2016
- Pulling water from thin air – February 25, 2016
- Biosensors on demand by designer proteins – February 14, 2016
- Sensing the future of living detectors and bioproduction – January 31, 2016
- “Kill switches” shut down engineered bacteria – December 16, 2015
- Creating a new vision for multifunctional materials – November 29, 2015
- Gene drive reversibility introduces new layer of biosafety – November 18, 2015
- Microbiomes could hold keys to improving life as we know it – October 30, 2015
- Printing lightweight, flexible, and functional materials – September 22, 2015
- Robotic insect mimics Nature’s extreme moves – August 1, 2015
- A practical gel that simply “clicks” for biomedical applications – May 2, 2015
- A slippery surface that can repel almost everything – March 29, 2015
- New Material Stops Biofilm Formation – February 14, 2015
- A Breakthrough in Artificial Photosynthesis – February 11, 2015
- Injectable 3D vaccines could fight cancer and infectious diseases – December 9, 2014
- Airway muscle-on-a-chip mimics asthma – September 29, 2014
- A Wearable Robot Suit That Will Add Power To Your Step – September 11, 2014
- Cheap and compact medical testing – August 19, 2014
- A self-organizing thousand-robot swarm – August 15, 2014
- Carbon-fiber epoxy honeycombs mimic the material performance of balsa wood – June 26, 2014
- The concept of organs on a chip opens the possibility of realistically studying human organs without the use of patients or animal testing – June 25, 2014
- Researchers use light to coax stem cells to repair teeth – May 29, 2014
- ‘Heart disease-on-a-chip’ – May 12, 2014
- Bone marrow-on-a-chip unveiled – no animal testing needed – May 6, 2014
- Smart DNA nanorobots – April 23, 2014
- Wyss Institute awarded DARPA contract to further advance sepsis therapeutic device
- Electrical generators driven by changes in humidity from sun-warmed ponds and harbors
- Bio-Inspired Robotic Device Could Aid Ankle-Foot Rehabilitation
- Programming smart molecules: Could Make Chemical Reactions Intelligent
- Programmable glue made of DNA directs tiny gel bricks to self-assemble
- Cross-Disciplinary Team From Harvard and Dana-Farber Brings Novel Therapeutic Cancer Vaccine to Human Clinical Trials
- New coating turns ordinary glass into superglass
- Lifelike cooling for sunbaked windows
- Dodging antibiotic side effects
- Soft Exosuit
- High-octane bacteria could ease pain at the pump
- A shot in the arm for old antibiotics
- Printing Tiny Batteries
- Robotic insects make first controlled flight
- Cry me a river of possibility: Scientists design new adaptive material inspired by tears
- Scientists Notch a Win in War Against Antibiotic-Resistant Bacteria
- Prefabricated healing kit: Injectable sponge delivers drugs, cells, and structure
- “Lung-on-a-chip” sets stage for next wave of research to replace animal testing
- Writing the Book in DNA
- New coating evicts biofilms for good
- Smart suit improves physical endurance
- Artificial jellyfish created from rat heart tissue and silicone
- DNA robot could kill cancer cells
- In New Mass-Production Technique, Robotic Insects Spring to Life
- Cheap, biodegradable, biocompatible “Shrilk” is a potential plastic replacement
- Carnivorous Plant Inspires Coating That Resists Just About Any Liquids
- Organs-on-a-Chip for Faster Drug Development
- Researchers Create Self-Assembling Nanodevices That Move and Change Shape on Demand
- Fingernail-sized implant successfully eliminates tumors in mammals
Lightweight suit to increase the wearer’s strength and endurance
For decades engineers have built exoskeletons that use rigid links in parallel with the biological anatomy to increase the wearer’s strength and endurance, and to protect them from injury and physical stress. In recent years, a number of systems have been developed that show strong commercial potential for helping spinal-cord injury patients walk, or helping soldiers carry heavy loads. In these systems, there is an exoskeleton structure in parallel with the wearer’s skeletal structure that is typically connected at a few locations on the body using straps or belts. These devices use motors or elastic materials to assist with joint movements, thereby enhancing human power. However, exoskeletons often fail to allow the wearer to perform his or her natural joint movements, are generally heavy, and can hence cause fatigue.
The Wyss Solution
Targeting a specific set of applications where a wearer needs some partial assistance from a robot, Wyss Institute researchers are pursuing a new paradigm: the use of soft clothing-like “exosuits.” An exosuit does not contain any rigid elements, so the wearer’s bone structure must sustain all the compressive forces normally encountered by the body — plus the forces generated by the exosuit. The suit, which is composed primarily of specially designed fabrics, can be significantly lighter than an exoskeleton since it does not contain a rigid structure. It also provides minimal restrictions to the wearer’s motions, avoiding problems relating to joint misalignment.
Exosuits exemplify a new class of applications for soft robotics, an emerging field that combines classical robotic design and control principles with active soft materials.
3D printing and laser annealing of conductive metallic inks without supports could lead to customized electronic and biomedical devices
“Flat” and “rigid” are terms typically used to describe electronic devices. But the increasing demand for flexible, wearable electronics, sensors, antennas and biomedical devices has led a team at Harvard’s Wyss Institute for Biologically Inspired Engineering and John A. Paulson School of Engineering and Applied Sciences (SEAS) to innovate an eye-popping new way of printing complex metallic architectures – as though they are seemingly suspended in midair.
Reported online May 16 in the Proceedings of the National Academy of Sciences, this laser-assisted direct ink writing method allows microscopic metallic, free-standing 3D structures to be printed in one step without auxiliary support material. The research was led by Wyss Core Faculty member Jennifer Lewis, Sc.D., who is also the Hansjörg Wyss Professor of Biologically Inspired Engineering at SEAS.
“I am truly excited by this latest advance from our lab, which allows one to 3D print and anneal flexible metal electrodes and complex architectures ‘on-the-fly,’ ” said Lewis.
A novel, inexpensive method for detecting the Zika virus could help slow spread of outbreak, and potentially other future pandemic diseases
An international, multi-institutional team of researchers led by synthetic biologist James Collins, Ph.D., at the Wyss Institute for Biologically Inspired Engineering at Harvard University, has developed a low-cost, rapid paper-based diagnostic system for strain-specific detection of the Zika virus, with the goal that it could soon be used in the field to screen blood, urine, or saliva samples.
“The growing global health crisis caused by the Zika virus propelled us to leverage novel technologies we have developed in the lab and use them to create a workflow that could diagnose a patient with Zika, in the field, within 2-3 hours,” said Collins, who is a Wyss Core Faculty member, and Termeer Professor of Medical Engineering & Science and Professor of Biological Engineering at the Massachusetts Institute of Technology (MIT)’s Department of Biological Engineering.
Building off previous work done at Harvard’s Wyss Institute by Collins and his team, along with collaborators from Massachusetts Institute of Technology (MIT), the Broad Institute of Harvard and MIT, Harvard Medical School (HMS), University of Toronto, Arizona State University (ASU), University of Wisconsin-Madison (UW-Madison), Boston University (BU), Cornell University, and Addgene, joined their efforts to quickly prototype the rapid diagnostic test and describe their methods in a study published online May 6 in the journal Cell, all within a matter of six weeks. Collins is the paper’s corresponding author.
Emerging innovation during the Ebola health crisis
In October 2014, Collins’ team developed a breakthrough method for embedding synthetic gene networks — which could be used as programmable diagnostics and sensors – on portable, small discs of ordinary paper.
Harvard researchers design a tunable, self actuated 3-D material
Imagine a house that could fit in a backpack or a wall that could become a window with the flick of a switch.
Harvard researchers have designed a new type of foldable material that is versatile, tunable and self actuated. It can change size, volume and shape; it can fold flat to withstand the weight of an elephant without breaking, and pop right back up to prepare for the next task.
The research was lead by Katia Bertoldi, the John L. Loeb Associate Professor of the Natural Sciences at the John A. Paulson School of Engineering and Applied Sciences (SEAS), James Weaver, Senior Research Scientist at the Wyss Institute for Biologically Inspired Engineering at Harvard University and Chuck Hoberman, of the Graduate School of Design. It is described in Nature Communications.
“We’ve designed a three-dimensional, thin-walled structure that can be used to make foldable and reprogrammable objects of arbitrary architecture, whose shape, volume and stiffness can be dramatically altered and continuously tuned and controlled,” said Johannes T. B. Overvelde, graduate student in Bertoldi’s lab and first author of the paper.
The structure is inspired by an origami technique called snapology, and is made from extruded cubes with 24 faces and 36 edges. Like origami, the cube can be folded along its edges to change shape. The team demonstrated, both theoretically and experimentally, that the cube can be deformed into many different shapes by folding certain edges, which act like hinges. The team embedded pneumatic actuators into the structure, which can be programmed to deform specific hinges, changing the cube’s shape and size, and removing the need for external input.
The team connected 64 of these individual cells to create a 4x4x4 cube that can grow, and shrink, change its shape globally, change the orientation of its microstructure and fold completely flat. As the structure changes shape, it also changes stiffness — meaning one could make a material that’s very pliable or very stiff using the same design. These actuated changes in material properties adds a fourth dimension to the material.
“We not only understand how the material deforms, but also have an actuation approach that harnesses this understanding,” said Bertoldi. “We know exactly what we need to actuate in order to get the shape we want.”
The material can be embedded with any kind of actuator, including thermal, dielectric or even water.
“The opportunities to move all of the control systems onboard combined with new actuation systems already being developed for similar origami-like structures really opens up the design space for these easily deployable transformable structures”, said Weaver.
“This structural system has fascinating implications for dynamic architecture including portable shelters, adaptive building facades and retractable roofs,” said Hoberman. “Whereas current approaches to these applications rely on standard mechanics, this technology offers unique advantages such as how it integrates surface and structure, its inherent simplicity of manufacture, and its ability to fold flat.”
“This research demonstrates a new class of foldable materials that is also completely scalable,” Overvelde said, ” It works from the nanoscale to the meter-scale and could be used to make anything from surgical stents to portable pop-up domes for disaster relief.”
INSPIRED BY A DESERT BEETLE, CACTUS AND PITCHER PLANT, RESEARCHERS DESIGN A NEW MATERIAL TO COLLECT WATER DROPLETS
Organisms such as cacti and desert beetles can survive in arid environments because they’ve evolved mechanisms to collect water from thin air. The Namib desert beetle, for example, collects water droplets on the bumps of its shell while V-shaped cactus spines guide droplets to the plant’s body.
As the planet grows drier, researchers are looking to nature for more effective ways to pull water from air. Now, a team of researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Wyss Institute for Biologically Inspired Engineering at Harvard University have drawn inspiration from these organisms to develop a better way to promote and transport condensed water droplets.
“Everybody is excited about bioinspired materials research,” said Joanna Aizenberg, the Amy Smith Berylson Professor of Materials Science at SEAS and core faculty member of the Wyss Institute. “However, so far, we tend to mimic one inspirational natural system at a time. Our research shows that a complex bio-inspired approach, in which we marry multiple biological species to come up with non-trivial designs for highly efficient materials with unprecedented properties, is a new, promising direction in biomimetics.”
The new system, described in Nature, is inspired by the bumpy shell of desert beetles, the asymmetric structure of cactus spines and slippery surfaces of pitcher plants. The material harnesses the power of these natural systems, plus Slippery Liquid-Infused Porous Surfaces technology (SLIPS) developed in Aizenberg’s lab, to collect and direct the flow of condensed water droplets.
This approach is promising not only for harvesting water but also for industrial heat exchangers.
“Thermal power plants, for example, rely on condensers to quickly convert steam to liquid water,” said Philseok Kim, co-author of the paper and co-founder and vice president of technology at SEAS spin-off SLIPS Technologies, Inc. “This design could help speed up that process and even allow for operation at a higher temperature, significantly improving the overall energy efficiency.”
The major challenges in harvesting atmospheric water are controlling the size of the droplets, speed in which they form and the direction in which they flow.
For years, researchers focused on the hybrid chemistry of the beetle’s bumps — a hydrophilic top with hydrophobic surroundings — to explain how the beetle attracted water. However, Aizenberg and her team took inspiration from a different possibility – that convex bumps themselves also might be able to harvest water.
“We experimentally found that the geometry of bumps alone could facilitate condensation,” said Kyoo-Chul Park, a postdoctoral researcher and the first author of the paper. “By optimizing that bump shape through detailed theoretical modeling and combining it with the asymmetry of cactus spines and the nearly friction-free coatings of pitcher plants, we were able to design a material that can collect and transport a greater volume of water in a short time compared to other surfaces.”
“Without one of those parameters, the whole system would not work synergistically to promote both the growth and accelerated directional transport of even small, fast condensing droplets,” said Park.
“This research is an exciting first step towards developing a passive system that can efficiently collect water and guide it to a reservoir,” said Kim.
Learn more: Pulling water from thin air
The protective shell of a sea-dwelling chiton paves the way towards new materials that combine different functions
“The investigation of Nature’s finest ‘multitasking artists’ can provide insight into functional synergies and trade-offs in multifunctional materials and guide us in other studies toward the development of revolutionary biomimetic materials. We thus are probably one step closer to construct houses made of a material that is not only mechanically robust, but also furnished with lenses capable of flexibly regulating light and temperature inside and sense environmental conditions,” said Aizenberg.