ISSUE 19 | SPRING 2017
Convergence The Magazine of Engineering and the Sciences at UC Santa Barbara
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MESSAGE FROM the DEANs
ROD ALFERNESS Dean and Richard A. Auhll Professor, College of Engineering
PIERRE WILTZIUS Susan & Bruce Worster Dean of Science, College of Letters & Science
his issue of Convergence arrives amid all the excitement and pride befitting the 50th Anniversary of the College of Engineering and a year of events celebrating its rise to national prominence — #10 among pubic-university engineering programs in the latest U.S. News rankings. Fifty is one of those important round numbers that invite us to pause, take our bearings, and appreciate the long arc of our institution. History is immensely useful for that. It honors the visionaries who boldly set out to create the original “School of Engineering.” It recalls the thousands of faculty, staff, students, and researchers whose efforts enabled the school to become a college, and then to continue achieving and evolving. And it highlights the many partners, both across campus and beyond, in industry and government, who have joined with us to accomplish great things and link campus innovations to real-world progress and benefits. In the end, though, history is always about the present, because it ends where we are right now. For the College of Engineering, and for UCSB science generally, the present is good. Our campus is charged with energy. Our faculty are leaders in their fields. Our students excel as professionals. And in a broad array of fields, our research literally changes the world. In this issue, we visit the past in an article recalling the partnership of two prominent UCSB professors emeritus: Nobel laureate Herb Kroemer and National Medal of Technology and Innovation winner Arthur Gossard. Their collaborations revolutionized the semiconductor industry. We tap into the current dynamism of UCSB science and engineering in articles about curing diseases that cause degenerative blindness, using the cloud and big data to fight hunger, developing photonics to meet the insatiable demand for big data delivered fast, building the strongest form on earth, understanding the ocean’s carbon cycle, identifying the moment when stem cells start to become brain cells, the secret to mussels’ waterproof adhesion, and much more. We invite to join us in experiencing what is an undeniably exciting time at UCSB.
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10 ISSUE19 | SPRING 2017
4 Aligned for the semiconductor age
UCSB professors Herbert Kroemer and Arthur Gossard partnered to create breakthroughs that have enabled the digital age
10 Gut Reactions
Biofuel and biochemical potential from gut fungi of herbivores
11 sport of cyber-Kings
UCSB hacker team wins $1.5 million at 2016 DARPA Grand Cyber Challenge
12 The Budding Brain
Witnessing undifferentiated stem cells on the path to becoming brain cells
14 As Strong As It Gets
The first metamaterial to reach the limits of theoretical performance
15 Feeling It
Exploring the subtle ways our hands sense the world around us
16 Ocean Carbon Sleuths
Studying the earth's carbon cycle and its potential effect on climate change
17 Mussel Power
Scientists pursue the secrets to the mollusk's powers of waterproof adhesion
18 Silicon Express
UCSB's AIM Photonics Hub seeks new ways of moving data with light
24 The Digital Farm
Preventing global hunger by linking farming to big data and cloud computing
28 future Vision
Years of collaborative research provide hope for incurable eye diseases
ALIGNED for the Semiconductor Age UCSB professors Herbert Kroemer and Arthur Gossard created breakthroughs in fabricating and aligning crystalline structures, enabling dozens of indispensable technologies
The shared elements running through all these advances are semiconductors, materials that have been coupled, layered, and otherwise engineered to move electrical current with previously unmatched efficiency, giving rise to the digital age. During their careers, two UC Santa Barbara College of Engineering professors (now emeritus) were responsible
for breakthroughs that enabled these important technologies. Electrical and computer engineering professor Herbert Kroemer, who won the 2000 Nobel Prize in Physics, and UCSB materials professor Art Gossard, who received the National Medal of Technology and Innovation in 2016, worked independently and together for years to change the world in substantive ways. “Herbert Kroemer likes to say that ‘all of the interesting physics is at the interface,’” recalled UCSB College of Engineering Dean Rod Alferness. The interface he’s referring to is the “heterojunction,” where two layers of different crystalline semiconductor materials meet, each having a different band gap. Band gap allows for the control of the flow of current carried by negatively charged electrons and positively charged holes, from
A material’s “band gap” influences its ability to move electrons — that is, conduct electricity — when energy is applied to it. The larger the band gap, the less conductive the material. On one end of the conductivity spectrum are “insulators” like glass, which have large band gaps and correspondingly low conductivity. On the other end are materials like metals, which have smaller band gaps and greater conductivity. Semiconductors are "sandwiches" of materials having a range of gaps between the two extremes, allowing electrons to be moved through them with greater efficiency and with increased control over the process.
ireless communications equipment, fiber-optics, lightemitting diodes, solar cells — we normally don’t give a second thought to these ubiquitous, oftenundercover elements of modern life, but they empower technologies behind cell phones, communication satellites, laptop computers and data centers, and are the focal point for the booming fields of optoelectronics and solid-state lighting.
Fabricator: (clockwise from above) Herbert Kroemer charts progress, writes up findings, and puts a molecular beam epitaxy machine through its paces.
Crystal Vision: Art Gossard with a molecular beam epitaxy machine he helped create.
an energy generator to a collector, or device, that uses the electricity. At the interface of correctly partnered materials, it is possible to generate or modulate light, amplify signals, communicate with other devices on a network, and carry out a range of interesting functionalities associated with such heterostructured semiconductors. HETEROSTRUCTURES AHEAD In much the same way that transistors solved the design challenges inherent to vacuum tubes — bulky, fragile, short-lived devices that required a lot of power — the idea of heterostructured semiconductors originated in response to what Kroemer identified as a problem of mid-20th-century electronic technologies: they were slow, because they relied on conventional junction transistors, a type of semiconductor.
Working on transistors in the 1950s, when they were very new, Kroemer was already thinking about how to improve them — in particular, he recalled, he wanted to understand “how to make them fast.” Kroemer was in his twenties. He had just received his PhD in theoretical physics from the University of Göttingen and was employed as the “house theorist” in the telecommunications laboratory at the German Postal Service. It occurred to him that a semiconductor that had a “graded composition” — one that transitioned smoothly between one material having certain electronic properties and another material having different but complementary properties — could push the charge-carrying electrons and holes from an emitter to a collector in the way required to operate the device. He referred to
this notion in a paper published in 1954, but the idea was ahead of its time, and no technology was available to prove the concept. “Part of the power of Herb Kroemer’s idea was that he was proposing those kinds of structures even before anyone knew how you could make them,” Alferness said. “But he understood the physics.” Kroemer would return to his concept of heterojunctions in 1957, in a paper he wrote on improved transistor performance while a researcher at RCA’s David Sarnoff Research Center at Princeton University. “I simply asked what the consequences would be if you were to change this energy throughout the structure — not from the perspective of a particular transistor but just from the perspective of the physics.” That line of questioning would lead to the concept of the quasi-electric field — a characteristic of semiconductors having varying band gaps — which offers more control over the direction and movement of electrons and holes. It was a powerful concept, Kroemer said, but again, there was no way to prove it at the time. Six years later, as a scientist at Varian Associates in Palo Alto, California, Kroemer was listening to a colleague’s talk about newly invented semiconductor lasers, which, Kroemer said, were exciting but at the time, little more than a “laboratory curiosity,” because they could emit light only in pulses and at very low temperatures. The lecturer himself described a continuous-operation roomtemperature semiconductor laser as “fundamentally impossible.” Kroemer disagreed; in fact, he already had a solution mapped out for concentrating the charge carriers that needed to meet in order to produce continuous laser light. “The challenge with the laser is that you need very large numbers of electrons SPRING 2017
"I had always said we needed someone like Art Gossard. I was a great admirer of his work, and he was known to be a fabulous collaborator." and holes,” Kroemer explained. When an electron meets a hole, the electron transitions to a lower-energy state, releasing energy as light. The problem in homogenous semiconductors, he added, was that the charge carriers flow through in opposite directions as quickly as they are supplied. But with a double heterostructure consisting of two low-conductivity, large-band-gap semiconductor layers sandwiching a highly conductive, lowerband-gap material, with other elements added to keep the carriers from exiting the material on either side, enough electrons and holes could be brought together in the middle layer to emit coherent, or steady, light. This notion of a double heterostructure would later be refined to create the “quantum well.” But the success of the compound semiconductor depended enormously on the transition between the different materials — the heterojunction. The crystal lattices into which the semiconductor materials were organized had to match, or align, in a way that would allow the mobile carriers to pass easily from one material into the next. The technology to create such perfect alignments did not exist yet, but research was gaining momentum as scientists everywhere sought out ideal combinations of materials and methods for fabricating those structures. THE PERFECT MATCH: PIONEERING THE SUPER-THIN From the late 1960s into the ’70s, Bell Labs was a hotbed of research and development. Lasers and optical fibers had been developed there as the first technologies
to use light to transmit information. Both were significant developments in the field of optics, but it would not be possible to make a high-quality doubleheterostructure laser until the super-thin layers of semiconductor material itself could be fabricated with better precision and purity. At around the same time that Kroemer joined the UCSB engineering faculty in 1976, Art Gossard was a Bell Labs scientist who was becoming known for his mastery of an emerging technique for creating new materials, called molecular beam epitaxy (MBE). Developed in the late 1960s by Bell Labs scientists Alfred Y. Cho and John R. Arthur, Jr., MBE is a method of “growing” a film of one material on top of another by depositing each layer, atom by atom, in an ordered fashion. “Being able to put one crystal layer onto another gave you what you needed to make improved transistors and lasers,” said Gossard, who had come to Bell Labs just after receiving his PhD in physics from UC Berkeley in 1960. A specialist in solid-state physics, his interests led him to investigate such phenomena as nuclear magnetic resonance (NMR) in ferromagnets, and to apply NMR spectroscopy and other advanced techniques to make measurements of new materials. “I thought the materials themselves were actually more interesting and important than making measurements on them,” he said, so he began focusing on MBE, and Bell Labs responded by pairing him with “genius machinist/super-technician” Bill 7
Wiegmann to work with the earliest versions of MBE machines. “You couldn’t buy an MBE system back then,” said Gossard. The equipment had to be made in-house and required special attention. Soon, Gossard and his team were turning out new materials and measuring interesting electron behaviors. Other scientists were turning to them with their ideas for materials and benefiting from Gossard’s solid-state physics expertise and Wiegmann’s technical acumen. They could fabricate increasingly sophisticated materials with, for instance, quantum wells having graded sides to control the behavior and movement of charge carriers. That process — adding strategically placed atoms to a material to provide electrons precisely where they are needed — is referred to as “doping.” “We worked more on tailoring the structure than on the chemical composition,” Gossard explained. “You could build a quantum well of any shape, but purity and smoothness of the material were of utmost importance.”
Kroemer had his eye on the MBE expert. “I had always said we needed someone like Art Gossard,” Kroemer recalled. “I was a great admirer of his work, and he was known to be a fabulous collaborator.” The campus began to court Gossard as part of the concerted effort to build its compound-semiconductor activity. At first he resisted; he was happy at Bell, but then came the antitrust court decision in the ’80s that split the Bell system into smaller companies. Meanwhile, UCSB had managed to recruit another Bell Labs scientist, Pierre Petroff, who had been Gossard’s top collaborator at Bell. Thanks to circumstances he could not have foreseen, Gossard recalled, “UCSB was beginning to look more attractive.”
"The gamble paid off, as UCSB gained prominence in the field of compound semiconductors."
Back in California, Kroemer was realizing the potential for using MBE to fabricate semiconductors from different materials having highly crystalline qualities, provided the two materials had the same lattice constants, or dimensions of unit cells so that they could align.
“I decided that molecular beam epitaxy is something that even a theorist can understand,” Kroemer quipped. His job included helping to amplify and steer research efforts at UCSB’s solid-state laboratory, which was part of the university’s emerging College of Engineering. Instead of jumping into what had already become the highly competitive field of silicon semiconductor technology, Kroemer had convinced Ed Stear, then-chair of the Electrical and Computer Engineering Department, to focus on compound semiconductors, which were already showing promise. As part of the effort, Kroemer had managed to acquire an MBE machine, only the second one to be sent to a university. “He was able to buy one, which was amazing, because he was a theorist and not an experimentalist,” said Gossard, explaining that in the late 1970s and ’80s, MBE was still a relatively new technology. “But on the other hand, he was a very determined visionary, and he saw the opportunity.” Gossard visited and spoke at UCSB in 1979 during the second-ever MBE conference in the United States. The gathering, organized by 8
Kroemer, hosted the small but growing community of scientists and engineers interested in the technology and its applications.
By the time he joined UCSB in 1987, along with trusted development engineer John English, materials research was ramping up. The Materials Department was established that year, and a steady stream of top faculty and researchers, many from Bell Labs, had been arriving. Among them were Vincent Jaccarino, who arrived at UCSB’s Department of Physics before Kroemer came to campus, and Jim Merz, whom Kroemer brought in. In fact, the Bell breakup proved to be an opportunity for Kroemer’s efforts to bring world-class engineers and scientists to the campus. “Jim and I raided Bell Labs and brought in Larry Coldren, Evelyn Hu and John Bowers, in addition to Pierre Petroff,” Kroemer said. Not long after, Jim Allen was recruited to the Department of Physics upon Gossard’s recommendation. “UCSB has always excelled at collaboration,” said Gossard. Kroemer would agree: he recalled that the opportunity to build a community around his science was a driving factor that brought him here. A PAYOFF IN BREAKTHROUGHS What started as something of a gamble paid off, as UCSB gained prominence in the field of compound semiconductors. Electronics and photonics research on campus has grown largely around theories and discoveries related to heterojunctions and the methods by which two different materials are fused to achieve specific attributes. The materials program has consistently been ranked first in the nation among such programs at public institutions.
Kroemer earned his Nobel Prize in Physics for inventing semiconductor heterostructures. The technology continues to underlie cutting-edge research on campus, including discoveries that led to UCSB professor Alan Heerger’s winning the 2000 Nobel Prize in Chemistry for his discovery of conductive polymers, and materials professor Shuji Nakamura’s winning the 2014 Nobel Prize in Physics for creating the bright blue LED.
▶ Herbert Kroemer receives the 2000 Nobel Prize in Physics at the ceremony in Stockholm, Sweden. ▶ Arthur Gossard accepts the National Medal of Technology and Innovation from President Barack Obama in 2016.
Photo courtesy of Ryan K. Morris and the National Science & Technology Medals Foundation.
Other recent breakthroughs by Gossard and his collaborators include improved thermoelectric materials that enable efficient generation of electricity directly from heat, improved broad-spectrum solar cells having record efficiencies, and quantum dot lasers. Grown directly on silicon, quantum dot lasers enable maximum communication and control within silicon integrated circuits. In 2016 Gossard received the National Medal of Technology and Innovation, the nation’s highest honor for technological achievement, given to recognize those who have made lasting contributions to America’s competitiveness and quality of life.
Photo courtesy of Nobel Media AB 2014.
Gossard would go on to co-discover the quantumconfined Stark effect — used to create fast, efficient fiberoptic light switches and quantum computation devices — and the fractional quantization of the Hall effect. The latter, which won the 2008 Nobel Prize for some who worked on it, is a new, unanticipated, ordered lowtemperature quantum state found in sheets of electrons within strong magnetic fields. The innovations that led to that discovery also enabled electron “superhighways” in semiconductors, which are now the basis for highperformance transistor circuits in a range of technology, including today’s cell phones and satellite receivers.
Kroemer and Gossard’s research has had a global footprint. Countless technologies that are part of our daily lives — from smartphones, computers, and lighting to advanced machines for telecommunications, data transmission, and sensing — are made possible by semiconductor heterostructures. At UCSB, this essential technology has inspired tech spinoff companies, numerous patents, and close partnerships with industry. The work also continues to inform research on campus, as scientists, engineers, and their students strive to increase their understanding of quantum physics so that they can develop the high-performance, energy-efficient materials that will enable future technologies and solve 21st-century challenges. SPRING 2017
GUT REACTIONS CHEMICAL ENGINEER MICHELLE O'MALLEY FINDS BIOFUEL AND BIOCHEMICAL POTENTIAL IN THE GUT FUNGI OF HERBIVORES Who knew that a possible solution to our growing energy needs could be found in a cow’s gut? Chemical engineering professor Michelle O’Malley suspected it could, and now the anaerobic gut fungi that have evolved over millennia to break down the tough lignins in plants are being eyed for their biofuel potentials. “Compared to microbes that thrive in the presence of oxygen, anaerobes are woefully understudied,” O’Malley said. Research into these primitive and little-understood anaerobic gut fungi — found primarily in the digestive systems of large herbivores — has given O’Malley and her group an insider’s look at how they work to access the cellulose trapped behind the tough lignin walls of the “non-food” parts of plants, such as stems and roots. The fungi can also secrete enzymes that convert cellulose and hemicellulose into sugars, and ferment them. In a large herbivore, the enzymes act to release much needed energy for the animal, but they can also be used to generate biochemicals and biofuels. Thanks to a collaboration with partners including the federal Joint Genome Institute and the Pacific Northwest National Laboratory, and colleagues at Harvard, MIT, and Harper Adams University in the U.K., the researchers have been able to genetically sequence representative fungal strains — which are difficult to isolate and grow — and molecularly sequence their large repertoire of novel enzymes. That knowledge could allow researchers to fine-tune the specific compounds they produce from plant cellulose. This breakthrough represents a significant step in the effort to generate fuels from alternative sources. While food crops provide the most accessible sources of cellulose, using food crops for fuel has several down sides, including the potential to drive food prices higher and divert food from human consumption just as a growing world population needs more. There is still much to learn, according to O’Malley, who has received early-career awards from both the U.S. Department of Energy and the National Science Foundation to investigate the energy potential of anaerobic gut fungi. New knowledge about gut microbes and the enzymes they secrete may also find application in bioprocessing techniques that could result in efficient production of advanced pharmaceuticals derived from sugars. 10
SPORT OF CYBER-KINGS
Shellphish teammates celebrate their success at the DARPA 2016 Cyber Grand Challenge.
The ever-evolving group of graduate students in the lab of UCSB computer science professors Giovanni Vigna and Christopher Kruegel pitted their skills against some of the best hacker teams in the country, testing their ability to simultaneously detect and fix weaknesses in their own home base of servers while seeking out and exploiting bugs in their rivals’ systems.
The theme for this year’s challenge, the Internet of Things, addressed the proliferation of internetconnected appliances, which can make our lives easier while also increasing our vulnerability to attacks. With virtually every aspect of our lives coming online, participants had to consider what will be the best strategy for catching and fixing bugs with minimal disruption to the indispensable services the appliances provide. At least some of those mysteries were explored by Mechanical Phish, Shellphish’s robotic hacker alter-ego, which netted the team its big cash prize, plus bragging rights and a well-deserved post-event rest.
rtesy of DARPA.
UC Santa Barbara’s resident hackers, Team Shellphish, earned $750,000 for their third-place finish at the Defense Advanced Research Projects Agency’s (DARPA) 2016 Cyber Grand Challenge, held August 4 in Las Vegas. The team also earned $750,000 just for qualifying and was the only academic team to emerge as a top finisher.
The competition required each team to build and program an autonomous bot, which would wage battle against other bots in a no-holdsbarred cyber-melee. Once deployed, the bots were untouchable, so team members had little to do on the day of the final competition, which was held alongside the famous DEF CON hacking conference, except watch the test of their programming and engineering skills in action.
UCSB HACKER TEAM EARNS $1.5 MILLION AT 2016 DARPA CYBER GRAND CHALLENGE
UCSB NEUROSCIENTISTS WITNESS THE MOMENT WHEN UNDIFFERENTIATED STEM CELLS TAKE THE PATH TO BECOMING BRAIN CELLS
At the earliest stages of development, a human is essentially a small mass of identical stem cells, each endowed with tremendous potential. Those undifferentiated stem cells can turn into the various cell types that become the parts of the body. But how is it, exaclty, that a stem cell goes from being indistinguishable from its neighbors to having a specific structure and specialized function? A large part of that mystery was solved at UC Santa Barbara's Neuroscience Research Institute, as scientists witnessed the pivotal moment when stem cells begin to morph into neuroectoderms, the precursor to brain cells. Kenneth S. Kosik, Harriman Professor of Neuroscience Research in the Department of Molecular, Cellular, and Developmental Biology, and postdoctoral fellow Jiwon Jang have described a series of steps along a pathway they have labeled the PAN (Primary cilium, Autophagy Nrf2) axis. The pathway, they say, appears to determine the cell’s fate. The PAN axis emerges before the cells show any hint of going down a lineage that will ultimately turn them into neurons, explained Kosik. During the Gap 1 (G1) phase of the eukaryotic cell cycle, the cells may become either neuroectoderms or mesoendoderms — both precursors to muscles and organs — or they may continue to divide into more identical undifferentiated cells.
During G1, an individual cell extrudes a tiny structure called a primary cilium, which acts like an antenna, taking in information about the environment. In the would-be neuroectoderms, the researchers found, the G1 phase lengthens. The longer the duration of G1, they say, the more signals the cilium receives, and that longer exposure is one indication that the cell is becoming a neuroectoderm. The type of signals the cells receive during this interval may also change. The primary cilium then activates a process within the cell called autophagy — essentially a self-cleaning, trash-disposal operation in which damaged or no-longer-needed cell structures are degraded and recycled. Next, levels of a protein called Nrf2 decrease. Nrf2 is essential to the health of the undifferentiated cells, said Kosik, because it protects them from toxins and free radicals in an effort to preserve the integrity of the genome. In cells that begin to differentiate, Nrf2 levels drop, because at that point, the cell can cut back a bit on generating perfect copies of the genome. The discovery of this very early sequence in the development of the cell illuminates a once-missing piece of fundamental knowledge in the field. Future research may apply the new findings to pathological cell development, such as in tumors, or investigate even earlier events in cell development.
As Strong As it Gets UCSB SCIENTIST'S STRUCTURE IS FIRST METAMATERIAL TO REACH THE OUTER LIMITS OF THEORETICAL PERFORMANCE
UCSB materials scientist Jonathan Berger.
In a letter published in the journal Nature, UC Santa Barbara mechanical engineer and materials scientist Jonathan Berger and his co-authors, UCSB materials and mechanical engineering professor Robert McMeeking and University of Virginia materials scientist Haydn N. G. Wadley, show that a supremely light and strong three-dimensional form that Berger conceived and named Isomax™ is the first to reach the theoretical bounds of performance.
McMeeking’s calculations also proved that, in the case of the lightest foams, the team was identifying the geometries that enabled them to achieve maximum possible stiffness.
The beauty of this solid “foam” — defined here as a combination of a stiff substance and air pockets — lies in its geometry. Instead of the typical assemblage of bubbles or a honeycomb arrangement found in other foams, the ordered cells in Isomax are set apart by walls forming the shapes of tetrahedra and octahedra that transform an intersecting pattern of "cross" and diagonal walls in three dimensions. Berger explained that the combination of cells "resulted in a structure that is mostly air and is uncommonly strong for its mass."
As resources become more limited and concern for energy efficiency grows, the value of a material with this mass-to-strength ratio increases, because it would require fewer resources to produce and less fuel to transport. The simple geometry makes it versatile, and, functionally graded, it can be used to create objects such as prosthetics and replacement joints, which need to have varying levels of stiffness within them.
“The Isomax geometry is maximally stiff in all directions,” Berger said. While other geometries, such as a honeycomb, can resist forces from one direction, force from a different direction can collapse them easily. Isomax’s cell structure enables the material to resist crushing and shearing forces without the need to make it heavier or denser.
“Isomax is going to be a very interesting metamaterial,” said Wadley. “It will be excellent for thermal insulating and sound absorption, and it could find application in aerospace structures, automobiles, and robotic machines.”
Berger and his team are currently following up the study with experimental analysis while looking into manufacturing methods that may allow for efficient fabrication. More information about Isomax can be found at Nama Development, a company Berger formed with the help of John Greathouse and UCSB’s Technology Management Program.
ASSISTANT PROFESSOR YON VISELL AND HIS STUDENTS EXPLORE THE MORE-SUBTLE WAYS OUR HANDS FEEL THE WORLD AROUND US
This is especially true of our hands, according to Yon Visell, an assistant professor in the Department of Electrical and Computer Engineering, the Department of Mechanical Engineering, and UCSB’s Media Arts and Technology graduate program. Distributed throughout our hands, he explained, are specialized sensory end organs that can capture different types of mechanical vibrations. “We can liken this to the different ways that a bell will sound if it is struck by a metal hammer or a rubber mallet,” said Visell. To explore the subtler ways our hands feel the world around us, Visell and colleagues devised a study employing a specialized array of accelerometers, or vibration sensors, that subjects wore around the sides and backs of their fingers and hands while they performed certain tasks. The tasks included tapping or sliding one or more fingers on a surface, using an item such as a pencil to tap on a surface, and grasping objects. Each action yielded different signals; the intensity of the vibration depended also on how many and which digits were being used, as well as on the object being manipulated. Tapping with a single finger, for instance, produced stronger, more localized vibrations than did sliding, grasping, or gripping. Tapping with just the middle and index fingers was enough to produce vibrations that covered most of the hand. Holding a shot
glass produced different vibration signals than holding a large cup. The knowledge gained by exploring these mechanical touch patterns may have multiple applications. Besides adding to foundational understanding of touch, the data can also be used in the realm of virtual reality, for instance, where users can interact with different objects — a feather, a brick — as though they were the real thing. Robots would be better able to navigate and interact with elements in changing and uncertain environments, including those where humans are present. Sophisticated prosthetic devices able to relay the more-subtle information might enhance functionality for users. Visell and his students are currently collaborating with medical researchers at the William Sansum Diabetes Center in Santa Barbara to investigate a new method for early detection of sensory neuropathy in those affected by diabetes.
Assistant professor Yon Visell holds a vibration sensor used to undertsand nuanced hand sensitivity.
If you’ve ever sat on your foot or slept on your arm and then tried to use those appendages as the pins and needles of returning sensation washed over them, you’ve noticed that you can still stand and walk, hold a glass to your lips or type out an email, however strange and difficult it may be. That’s because despite the lack of full touch sensation at the interface of our extremities and the surfaces they come into contact with, minute vibrations can still be sensed that give us an idea of how we are interacting with our environment.
Ocean carbon sleuths BY STUDYING THE OCEAN’S CARBON CYCLE IN DEPTH, UCSB EARTH SCIENTISTS SEEK TO UNDERSTAND HOW IT MIGHT CHANGE IN THE FUTURE AND AFFECT CLIMATE CHANGE Scientists at UC Santa Barbara’s Earth Research Institute, led by oceanographer David Siegel, have taken on the challenge of quantifying present conditions in the ocean’s carbon cycle and developing tools to predict its future states. Knowledge obtained as a result of the project will provide a deeper understanding of how the ocean’s carbon-transport processes may affect climate change around the world. “Predicting how the ocean’s carbon cycle changes in the future remains one of the greatest challenges in oceanography,” Siegel said. To gain the knowledge and understanding they seek, the researchers have developed a plan that involves using a wide range of data-collection methods to inform a comprehensive understanding of how the world’s oceans process carbon. Called the EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) Science Plan, the blueprint, which was written for NASA, will employ such methods as modeling, sampling, and remote sensing to get a deep understanding of how the ocean — the Earth’s most effective carbon sink — absorbs and stores carbon. While the total amount of carbon found on Earth and in its atmosphere remains constant, the levels of carbon held
in the air and the ocean, in rock, and in living organisms shifts continuously. Because of its depth and vastness, the ocean plays a major role in that constant, complex carbon flux. Some mechanisms dissolve carbon in surface waters, while others cause it to be absorbed in the process of photosynthesis. Organisms take up carbon as part of the shells or exoskeletons they form, and when they die, much of that material sinks to the sea bed, forming sediments and, eventually, rocks. A fraction of ocean carbon is also released back into the air when deep waters circulate upward and meet the warmer temperatures of the surface, causing evaporation. Understanding this biological pump is critical, according to Siegel. Rising temperatures and changes in nutrient concentrations could, for instance, affect the ocean’s surface ecosystem and, hence, its ability to absorb and sequester carbon effectively, which would, in turn, influence carbon levels in the atmosphere. The researchers are pursuing several types of data sets detailing the ecosystem characteristics of the ocean’s surface, such as water temperature, salinity, oxygen levels, and phytoplankton types, sizes, and productivity. That information can be used to create snapshots of the ocean’s biological pump, which can be used to understand how it functions as a complete global system. Further analysis will help scientists understand where carbon moves and how much of it gets converted into organic matter. According to Siegel, this would provide a better idea of how airsea exchanges of carbon dioxide are affected and what happens to combusted fossil fuels. Given increasing levels of CO2 in the atmosphere and the oceans and the continuing increase in global carbon emissions, detailed knowledge of how the planet's largest carbon sink functions and interacts with other planetary systems cannot come too soon.
Mussel Power INSPIRED BY THE MOLLUSK'S ADHESIVE ABILITY, SCIENTISTS COLLABORATE TO CREATE A MATERIAL THAT CAN STICK TO WET AND SUBMERGED SURFACES Scientists have long sought to develop an underwater adhesive that could bind surfaces together strongly despite the barrier created by water and its impurities. Some researchers have come close, but for the most part, have fallen short of delivering a substance that performed well enough to be practical or did not require complex functionalization and processing. Underwater adhesives are hardly a new concept. Nature provides many examples of wet adhesion, as demonstrated by barnacles and mussels, marine animals that have perfected the art of sticking to a variety of surfaces despite experiencing extremes of temperature and the constant pounding of salt water. Taking their cue from mussels, a group of UC Santa Barbara scientists and engineers have made important progress in duplicating the
mollusks’ method of generating strong adhesion. Led by research faculty member Kollbe Ahn, of UCSB’s Marine Science Institute, the researchers have successfully synthesized a material that combines the key functional molecular groups of several residues found in mussels’ biological adhesion proteins. In particular, the amino acid L-Dopa, which contains hydrogen-bonding chemical groups called catechols, shows promise. Catechols are found in large quantities at the interface between the plaques at the ends of the byssus threads mussels secrete, and the often wet and submerged surfaces to which they adhere. By mimicking the characteristics of mussel foot proteins that are especially rich in this amino acid, Ahn and colleagues designed a molecule that can prime and fuse two surfaces underwater. The material, according to Ahn, is not only simple to use, but also up to ten times as effective as similar adhesives that have been demonstrated previously.
Using the same proteins, the scientists have also created a nontoxic primer of sub-nanometer thinness that self-assembles into a defect-free monolayer at room temperature — a potentially important development in the manufacture of polymer electronics. Ahn credits much of this progress to the decades of research conducted by UCSB professor J. Herbert Waite, whose work investigating the adhesion strategies of mussels in the rocky intertidal zone provided the foundational knowledge of the biological adhesion mechanism at the molecular level. Further collaboration with researchers in other UCSB departments, including chemistry professor Bruce Lipshutz and colleagues in the lab of chemical engineering professor Jacob Israelachvili, was also important in making this development possible.
A wet adhesive could have multiple and diverse applications. In addition to the obvious — building or repairing objects that are submerged or continuously exposed to wet conditions — a wet adhesive or primer could also be added to materials so that they would self-heal in wet conditions. The material would have many uses in biomedical and dental contexts. ▶ Concept illustration of a molecular-level view of the chemical reaction at the interface where a mussel's foot meets wet rock.
A silicon-circuit testing station in the laboratory of John Bowers, Director of UCSB's West Coast Hub for AIM Photonics.
AT UCSB'S AIM PHOTONICS HUB, THE GOAL IS NOTHING SHORT OF A NEW TECH INDUSTRY
very year, the demand for Internet bandwidth and performance grows by leaps and bounds, as more gadgets — particularly mobile devices — come online, more dataintensive applications appear, and all the devices networked in the emerging Internet of Things flood telecommunication highways with endless streams of information. In 2015 alone, demand for mobile bandwidth jumped by 74 percent, and the deluge of data shows no signs of stopping. The infrastructure that makes our digital lives possible is straining to keep up with demand. Adding capacity to data centers and improving storage networks are two stop-gap approaches to coping with the growing river of data, but adding more machines requires more energy, both to operate the equipment and to keep servers cool so that data is protected. UC Santa Barbara professor of electrical and computer engineering John Bowers has had this critical digital-age challenge on his radar for a long time. A world-renowned authority on photonics and optoelectronics, both of which
involve using light to move data with extreme speed and efficiency, he is working with fellow UCSB faculty and researchers to provide a scalable solution to the problem of data overload. It involves integrating silicon photonics more deeply into communications and data processing. In 2013, the federal government put its weight behind an effort to increase energy efficiency and achieve high-performance data transmission while creating and retaining high-tech manufacturing jobs in the U.S. and accelerating research to address such challenges as rising energy needs, aging energy infrastructure, and the need for better materials. Following a competitive process, the American Institute for Manufacturing Integrated Photonics (AIM Photonics) was established in 2015 as a $500 million publicprivate initiative. UCSB was selected as the West Coast Hub, and Bowers, who is director of UCSB’s Institute for Energy Efficiency, was named West Coast director. He is now working with colleagues across the United States to develop silicon photonics — now in its infancy — into one of the nation’s leading tech industries. 19
Chasing Light: John Bowers (right) and graduate student Alan Liu beside a Lightwave Compenent Analyzer, a measurement system for quantum dot lasers.
“UCSB’s selection as the West Coast Hub for AIM Photonics provides a strong, direct indication of the high value and recognition of the scientific and engineering research breakthroughs that have resulted from our many faculty-student collaborations in this field,” said College of Engineering Dean Rod Alferness, “Silicon photonics has the potential to revolutionize photonics and electronics by enabling lowcost, high-volume manufacturing of optical interconnects, with a path toward embedding high-capacity fiber optics on circuit boards and, eventually, on electronic chips,” said Bowers. Photonics in communications is already present in the form of fiber-optic cables, which came into use in the late 1970s, when phone companies began to build and upgrade their infrastructure using the high-speed, low-loss technology. The national grid of fiber-optic cables proved invaluable during the rise of the internet. “The internet would not be possible without this whole infrastructure of fiber cable carrying huge amounts of information, which it does extremely well,” said Alferness, who, in his previous career as chief scientist at Bell Labs, witnessed first-hand the enormous potential photonics had in terms of revolutionizing communications. 20
Silicon photonics has the potential to revolutionize photonics and electronics Currently, connecting electronics and photonics is costly and inefficient. Computing is done electronically, and to get on the fiber-optic highway, the electronic bits have to become optical — photonics and electronics must be brought together. “Right now, that’s being done discretely,” Alferness said. “Separate modules do the optics and the electronics.” It works, he added, but the equalization takes a lot of energy and generates heat, which can drastically reduce the performance of the silicon chips. “We know that if we can get that electrical signal converted to an optical signal on the silicon chip, it can be not only cheaper, but also much more energy efficient. We win twice, because we will need less power to get the electronic signals off and less power to do the air-conditioning.” Developing the technology is only the beginning. For photonic integrated circuit (PIC) and switch technology to flourish and have the imagined far-reaching impacts, an entire photonics manufacturing ecosystem, from lab to market, must be established. That means amplifying research, broadening the market, developing and implementing manufacturing logistics, and training a workforce. Creating that ecosystem is the responsibility of the nationwide network of AIM Photonics partners in industry, academia, and government.
Academic participants include the SUNY Polytechnic Institute — lead university in the endeavor — as well as MIT, the University of Rochester, the University of Arizona, Rochester Institute of Technology, Columbia University, UC Berkeley, UC Davis, and UCSB. Industry partners include Infinera, Cadence, Boeing, and Raytheon, while the U.S. Department of Defense, NASA, the Department of Energy, the National Science Foundation, and the states of New York, California, and Massachusetts are also involved. Beyond Bowers, UCSB has tremendous prowess in research related to silicon photonics materials, including electrical and computer engineering, mechanical engineering, and energy efficiency. Three of the six UCSB Nobel Laureates were recognized for innovations related to optics: Herb Kroemer, inventor of the double heterostructure laser (see page 4); Alan Heeger, inventor of conductive polymers; and Shuji Nakamura, inventor of the blue LED. The interdisciplinary environment at UCSB enables collaborations among some of the best researchers in the field. A growing number of graduate students and postdoctoral researchers, encouraged by their mentors and supported by peers in UCSB’s top-notch engineering programs, play important roles in this research. These brilliant, highly motivated young people routinely join forces on collaborations that result in important innovations on the path to integrating photonics and electronics.
Opportunities to collaborate with and work in the photonics industry are never far from students and researchers at UCSB. The campus’s Center for Science and Engineering Partnerships, led by Ofi Aguirre, is responsible for developing, managing, and executing the education and workforce-development components for the AIM Photonics West Coast Hub. The UCSB Materials Research Lab has also played a role in recommending students whose interests lean toward photonics research, and providing resources for that research. Many professors in the College of Engineering have strong backgrounds in industry and have licensed their inventions to existing companies, have created and run their own startups, and have relationships with companies that support their work. All that multi-layered collaboration and partnership adds up to an environment in which academia and industry can easily network, trade ideas, share facilities, and innovate — all with the goal of designing and manufacturing PIC technology that increases data and telecom performance and energy efficiency for small and large enterprises alike.
Photonics researchers at work in the the Nanofabrication Facility Cleanroom, located in the Engineering Sciences building at UCSB.
Undergraduates, too, are attracted by the combination of teamwork, the track record of success, and the desire to improve life through technology that infuses the UCSB College of Engineering. AIM Photonics’ educational outreach efforts include a research undergraduate apprenticeship at UCSB. First- and second-year engineering students, plus students from local community colleges, are invited to participate in an eight-week program, which provides them with technical and professional training in photonics. The apprentices participate in relevant research, receive guidance from the more senior members of research teams, and gain opportunities to meet and network while learning about the practical aspects of a career in photonics.
them the opportunity to learn research skills, interact with professors and graduate students, and advance state-of-theart research,” Bowers said. “It is a great chance to see if a life of research, or at least graduate school, is of interest to them.”
“The AIM apprentice program exposes students to leading research and gives SPRING 2017
Albert G. Conrad, originally head of the Department of Electrical Engineering at Yale University, was appointed the first dean and professor of the School of Engineering at UC Santa Barbara in September 1961. Dean Conrad is pictured here with an Edison Dynamo from 1888, which he was able to restore to full use almost a century after the machine was invented.
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The Digital Farm TWO UCSB COMPUTER SCIENTISTS SEEK TO PREVENT GLOBAL HUNGER. THE KEY: LINK FARMING, BIG DATA, AND CLOUD COMPUTING TO ENHANCE EFFICIENCY, PRODUCTIVITY, AND SUSTAINABILITY
UCSB's Sedgwick Reserve has been the testing site for a number of SmartFarm components.
y 2050 Earth’s population will reach 9 billion, according to United Nations estimates. The figure is currently 7 billion, and food security is already an issue. “We’re barely feeding the population we have now,” said UCSB professor of computer science Chandra Krintz. More food is needed, but as the human population grows and more land is used for biofuel production, less space is available to grow food crops without depleting critical water supplies or clearing forests, which produce our oxygen and provide a vast array of other ecosystem services. Climate change further complicates the scenario. Krintz and her collaborator, UCSB professor of computer science Rich Wolski, believe that big data and cloud computing can play a significant role in addressing the food challenge ahead. To that end, in a collaboration involving UCSB, other California universities, technology entrepreneurs, and farmers, they are developing SmartFarm, an open-source software platform enabled by big data and cloud computing to provide farmers with data and analytical tools to help them become more efficient, more productive, and more sustainable. Some farmers already pay agribusiness entities like Monsanto to provide them with data that is collected by field sensors, sent to the web, integrated into software, and presented visually to provide a real-time view of the state of their fields. But the cost of that service is prohibitive to millions of small farmers, and especially those in developing counties. That’s why Krintz and Wolski are designing SmartFarm as an inexpensive open-source system available to anyone. “Our vision is to have a huge influence in addressing the food crisis,” Krintz said. “We’re architecting new systems to bring technology that Amazon.com and other retailers have leveraged globally, and applying it to the hard problems of food production.” Krintz specializes in cloud computing, resource-constrained devices (such as cell phones and other items that rely on battery power) and distributed systems (i.e. linked computers). She spent a year creating a mirror image of Google’s cloud that was simple enough so that ordinary users could take advantage of the versatility and economies of scale that cloud computing offers without facing such a steep learning curve. Meanwhile, by studying the architecture of the Amazon.com cloud, Wolski, an expert in large-scale high-performance computing and distributed systems, realized just how powerful the consumer-oriented software technology is in terms of linking customers and sellers around the world, predicting what consumers might want, and supporting their decision making.
Wolski and Krintz joined forces at UCSB to create a similarly robust data-driven approach to support farmers around the world. Farming operations occupy nearly half of all the land on Earth. But for a variety of reasons — tradition and varying levels of access to science and technology among them — farming practices are often based on “tried-and-true” methods and educated guesswork, rather than science.
from these devices would be crunched in the cloud (which SmartFarm uniquely makes possible on or off the farm) and then appear via applications on smartphones or tablets as visualizations that would make the results easy to understand.
“Cloud computing has dramatically expanded our ability to make predictions about very small things,” Wolski said. “We want to take data and use it to make specific, localized predictions that enable more-productive and environmentally “We believe that we need to dial in big data and sensitive agriculture.” Just as Google and Amazon cloud computing to support agriculture,” Krintz can identify an individual customer’s tastes and said. “We’re trying to enable growers to use preferences, he said, SmartFarm could analyze data computing to analyze their land, their crops, and and predict on an almost per-plant basis what the their production and productivity processes to make grower might be able to do to maximize yield and them more efficient.” minimize error and associated cost. SmartFarm is intended to build on and supplement existing expertise by using real-time data to support farmers’ decisions. “Instead of having all the information in their heads, as they do today, it will all be in the computer. They can easily look at a number of different options that might be harder for a single person or even a group of people to identify,” Krintz explained.
“We want to use the same infrastructure, the same technology, the same mathematics and statistics, and the same cloud-computing software that’s being used to follow you around and figure out what you want for lunch, but we will use it to follow farmers around and figure out when they should water, and when and where they should apply fertilizer and pesticide and how much,” he said.
To see how it would work, imagine you are a farmer during a drought. With water scarcity impacting your ability to produce as you would normally, you might consider bringing in water from a well, an aquifer, or an aqueduct. But that uses energy and costs money. Should you do it or invest instead in another, less-water-intensive crop? Or could there be a way to reduce water consumption without risking your yield? Big data can inform that decision-making landscape.
The SmartFarm prototype is currently being tested on several farms, while the collaborators develop the sensor technology and software that will be the backbone of the project. One goal is, within five years, to have sensors that cost so little that they will be thought of as nearly disposable.
Or, say your main crop isn’t doing well. Could it be the soil? The micro-climate? Sneaky pests? With sensors to monitor moisture levels, water and nutrient movement, soil conditions and composition, plus mini-weather stations to document temperature and humidity, and imaging technology to detect leaks and other anomalous conditions, you could get answers. Data taken 26
“From our computer-science perspective, we want to discover the architecture of the systems that are necessary to make these kinds of breakthroughs possible,” said Wolski, “and we are also interested in the analytics and the reasoning software.” The researchers see massive potential for this kind of data gathering and processing to benefit other fields. “We want to see the various ancillary sciences move forward,” Wolski said. In 2015 the California Energy Commission and the National Science Foundation both awarded
research grants to the SmartFarm project. The NSF grant, in particular, is unusual, Krintz, said, because the US Department of Agriculture is the body that typically awards agriculture-related research, but the enormous tech component was enough to convince the NSF to take up the cause. “We’re experts in computer science and engineering at UCSB, and we’re taking perspectives on some of these problems that we may not have taken if we were enveloped by a traditional agricultural school,” she said. While the emphasis of this project will remain highly focused on the optimization of farming, agriculture, and food production, the rest of the complex food supply chain offers abundant possibilities for similar approaches. Better monitoring of farm animals’ and of food in transit could drastically reduce disease, spoilage during shipping, and outbreaks of microbe-related illness that can result — all important elements in reducing the roughly one-third of food produced globally that is lost or wasted. The researchers also plan to expand the project by involving more participants and attracting more students and researchers who have wide-ranging skillsets from other fields. The community is important, said Krintz, not just for the research but also to take a modern, technologyy-based approach to hunger, one of humanity’s oldest and most difficult problems.
Field Intelligence: Chandra Krintz (right) and Jacob Morent of Iroometer, a partner of Smart Farm that makes soil-moisture sensors, check out a newly installed device at the UCSB Sedwick Reserve test site.
“We need to meet people from all over the world who are interested in solving this problem, and time is short,” said Krintz. “This is a difficult challange, and we need to get a lot of people excited about it; 2050 seems like it’s far away, but it’s going to come quickly.”
Future Vision A prognosis of blindness comes as a hard blow. It signals a future of extreme challenges and presupposes extraordinary effort required to maintain one's independence by adapting to dramatically changed circumstances. For those diagnosed with diseases such as agerelated macular degeneration (AMD) or retinitis pigmentosa (RP), both of which affect the retina, the light-sensitive layer of tissue at the back of the eye, that prognosis is all too common. AMD is prevalent in people over 50, and RP can strike at virtually any stage in life. At UC Santa Barbara, decades of research into the cell biology of the eye have led to potential therapies that are currently undergoing clinical trials to determine whether they are safe and effective enough to be used to treat patients. If they meet stringent FDA standards, the proposed therapies — developed under the leadership of UCSB researchers in the Center for Stem Cell Biology and Engineering at the Neuroscience Research Institute (NRI), working in collaboration with scientists from USC, City of Hope, and UC Irvine — could be used to treat blindness in those afflicted with AMD and RP. AMD: BLURS AND BLANK SPOTS Those suffering from AMD may see the world as if they were looking through a camera that has
YEARS OF COLLABORATIVE RESEARCH PROVIDE HOPE FOR THOSE AFFECTED BY INCURABLE EYE DISEASES
a large, nearly opaque smudge on the lens or the viewfinder. The center is obscured, while the periphery remains sharp. Text may be blurry or illegible, straight lines may appear to be wavy, and colors may lose vibrancy. “It devastates your ability to carry out everyday tasks,” says Dennis Clegg, a neurobiologist and Wilcox Family Chair in BioMedicine at UCSB. If the disease is left untreated, the dim haze in the center of the patient’s visual field eventually becomes a large blind spot, making tasks like reading, writing, getting an object from a cupboard, recognizing faces, and even walking in a familiar space nearly impossible. Clegg explained that AMD begins with the death of a layer of cells in the back of the eye called the retinal pigmented epithelium (RPE). “The retinal pigmented epithelium is crucial to the support of photoreceptors — the light-sensitive cells that are responsible for our ability to detect light and form a visual image,” he explained. “Eventually, the photoreceptors also die.” The disease also severely affects the photoreceptors within the macula, a region of cells less than one millimeter in diameter located near the center of the retina and responsible for high-acuity vision.
by UCSB emeritus research professors Lincoln Johnson and Don Anderson, recast AMD as an inflammatory disease that affects the complement system — a component of the body’s immune system — likely leading to dysfunction and degeneration of RPE cells. Further research has identified variants in complement-system genes that are specifically linked to increased risk for AMD. Whatever the key factor, AMD has become one of the leading causes of progressive, irreversible loss of vision in millions of elderly Americans. The National Eye Institute projects that by 2030, nearly four million Americans over the age of fifty will have AMD. SEEKING THE CAUSE — TESTING A CURE
The quest for a cause of, and a potential cure for, AMD began in earnest at UCSB about twenty years ago, when the Center for the Study of Macular Degeneration (CSMD) was established within NRI. In a joint research effort, Johnson, Anderson, and collaborator Gregory Hageman — now a professor of ophthalmology and visual sciences at the University of Utah — laid out the potential role of immune reaction and inflammation The cause of AMD is not entirely clear, Clegg says. But recent research, including that conducted as causes of the RPE cell death.
At around the same time, interest in stem cell research had taken hold. Scientists realized the vast potential of the cells, including their ability to repair damaged organs, especially those in the nervous system, which has a limited capacity for self-repair. Clegg was also interested in the neural aspect of AMD. “For me, the whole reason for conducting basic research to study neural development on a molecular and cellular basis was that it might someday be relevant in treating a disease,” he said. In 2004, California voters approved an initiative that led to the creation of the California Institute for Regenerative Medicine (CIRM), an agency to fund stem cell research. That year, Clegg said, research also showed that stem cells could be prompted to make RPE cells, the very ones destroyed by AMD.
“It’s a beautiful structure,” Lewis said, who, like Fisher, has been studying the retina for more than thirty years. “It’s somewhat simplified compared to the brain in that it has only two synaptic layers and three cell-body layers, but it’s also an accessible part of the central nervous system that allows for easier manipulation compared to the brain or the spinal cord.”
What's most interesting about the retina is that when you look at it, you're actually seeing a part of the brain.
With funding from CIRM, Clegg and Johnson initiated a collaboration with USC researchers Mark Humayun and David Hinton, Jane Lebkowski at Geron Corporation in Menlo Park, City of Hope scientists, and Caltech engineers. The team, named the California Project to Cure Blindness, developed a patch consisting of stem cell-derived RPE arrayed on a scaffold, and devised a way to insert it into the eye of an AMD patient.
The retina can also degenerate as a result of a host of genetic conditions that fall under the umbrella of retinitis pigmentosa (RP). Fisher explained RP as a family of diseases that involve over a hundred different mutations and a variety of molecules, all of which give rise to similar symptoms. While the timing, effects, and severity may vary, he said, the sequence of photoreceptor degeneration is the same. With RP, the rod photoreceptors — responsible for vision in low-light conditions and the detection of motion — die first, causing night blindness and tunnel vision. The
The surgical procedure, which has been performed on two patients in the clinical trial, involves using a specially designed instrument to insert the patch behind the retina. The RPE cells, arranged like a layer of tiny Legos, fits right onto the photoreceptors, providing them with much-needed nutritional and physiological support. The polymer scaffold used to support the RPE cell layer is made of parylene, which is also used in pacemakers and other implants. “The first patient, an 83-year-old woman, really wanted to be the first,” Clegg said, adding, “Those who volunteer for a clinical trial are my heroes.” The group hopes to perform the procedure a few more times before reporting their progress. Once the procedure has been proven safe, the next phase will be to test it on patients who are in earlier stages of the disease. RP: NIGHT BLINDNESS AND TUNNEL VISION
Postdoctoral researcher Britney Pennington prepares cell culture medium to differentiate stem cells into RPE.
To Steven Fisher and Geoff Lewis — scientists studying retinal cell biology in UCSB’s Neuroscience Research Institute — what’s most interesting about the retina is that when you look at it, you’re actually seeing a part of the brain.
“If you can slow or prevent the degeneration of the rod photoreceptors that form peripheral vision, then you can perhaps maintain central vision,” said Lewis, who focused his past research on retinal detachment and re-attachment. At around the same time, and from the same effort that resulted in the CIRM funding for AMD research, Lewis and Fisher encountered like-minded UC Irvine neurobiologist and ophthalmologist Henry Klassen, who had spent decades conducting studies and experiments on retinal diseases. With funding from CIRM, the three began collaborative experiments to pursue Klassen’s main idea, which was to inject retinal progenitor cells into the affected eye to determine whether they could rescue the failing photoreceptors. Progenitor cells, Fisher explained, are stem cells that have partially differentiated so that they lose their “pluripotent” potential, but have not yet assumed the final differentiated state of adult cells. “They are stem cells that are taken along the lineage, essentially becoming cells that will give rise to the cells, in, say, the eye. So they’re taken further along the differentiation line,” he noted. “But we don’t necessarily want them to differentiate,” Lewis added. “Ideally we want them to remain undifferentiated so that they continue to secrete biochemicals that may rescue the photoreceptors.” The progenitor cells, according to the procedure developed by Klassen, are injected into the vitreous — the clear gel between the retina and the lens of the eyeball — where they secrete molecules that protect the ailing photoreceptors and prevent further degeneration. Fisher and Lewis’s task was to assess the safety and efficacy of the procedure in animal models of RP as it made its way to clinical trials, which began in late 2015. Aside from confirming that the small cluster of about 100,000 cells would actually do its job, they also wanted to rule out potential problems, such as the formation of tumors and other undesirable effects. 30
Now, after a year of trials, and having treated one eye in each member of the first cohort of RP patients, all considered legally blind, the researchers have seen great progress. “It’s so heartwarming to hear these patients talk about how they went from darkness essentially to now seeing almost too much light compared to what they were used to,” said Lewis. “Some are even wearing sunglasses now and saying that they are starting to see color again.” Patients are reporting not only that progression toward total blindness has slowed or stopped, but also that they are seeing signs of reversal of the disease, which may represent a revival of the nonfunctional photoreceptors. Questions remain regarding the new treatment, such as how long the progenitor cells will continue to be effective and whether patients would require additional injections to maintain their vision.
Professor Dennis Clegg retrieves frozen stem cells from a liquidnitrogen storage tank in UCSB's Center for Stem Cell Biology and Engineering.
disease eventually causes the color-sensitive cones to die as well. According to the National Eye Institute, RP, which is both genetically inherited and incurable affects an estimated 1 in 4,000 people worldwide. Fisher and Lewis want to help them by finding ways to rescue those dying cells.
“We don’t know the answer to that,” Lewis said. “It’s possible that after a year or two you’ll have to re-inject additional cells, but injections into the eye are not uncommon, so we don’t anticipate any problems.” As they embark on the next phase of clinical trials, Fisher and Lewis are also looking at whether this type of technology might apply to other diseases of the retina that result in cell death, such as glaucoma or diabetic retinopathy.“There are so many diseases that cause the cells in the eye to die and lead to blindness,” Fisher explained. Should this therapy prove successful in treating what is a family of diseases that have genetic origins, he added, it may prove a “universal fit” for other diseases that aren’t the result of a malfunctioning gene. “The possibility is that this will carry over,” Fisher said. “That’s the big hope.”
◀ Concept illustration depicts rod and cone photoreceptors in the human retina, embedded in a stem cell matrix designed by Professor Clegg and his colleagues.
Concept illustration depicting the ability to add a variety of functional molecule groups to block polymers with precision, based on research by UCSB Materials professor Chris Bates. For more coverage of research breakthroughs at UCSB Engineering, visit engineering.ucsb.edu.
Convergence The Magazine of Engineering and the Sciences at UC Santa Barbara Issue Nineteen, Spring 2017 engineering.ucsb.edu/convergence Credits Writer: Sonia Fernandez Editor: James Badham Creative Director: Peter Allen Design & Layout: Michelle Mak Artwork & Photography: Peter Allen, Scott Condon, Brian Long, Matt Perko
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