Caltech Scientists Create Titanium-Based Structural Metallic-Glass Composites

The new alloys are lighter and less expensive, but are still tough and ductile enough for use in aerospace applications

PASADENA, Calif.--Scientists from the California Institute of Technology (Caltech) have created a range of structural metallic-glass composites, based in titanium, that are lighter and less expensive than any the group had previously created, while still maintaining their toughness and ductility--the ability to be deformed without breaking.

A paper describing these breakthrough metallic-glass alloys is now online in the Proceedings of the National Academy of Sciences (PNAS) Early Edition in advance of an upcoming print publication.

Earlier this year, the same Caltech group had published a paper in the journal Nature, describing new strategies for creating the liquid-metal composites. This research resulted in "alloys with unrivaled strength and toughness," notes Douglas Hofmann, visiting scientist and lead author on the PNAS paper that, along with the Nature paper, describes work he did while a graduate student at Caltech. "They are among the toughest engineering materials that currently exist."

Still, there were shortcomings to the alloys presented in Nature. Because they were created for use in the aerospace industry--among other structural applications--they needed to have very low densities. Ideally, the alloys would have had densities in or around those of crystalline titanium alloys, which fall between 4.5 and 5 grams per cubic centimeter (g/cc). The original alloys, made predominantly of zirconium, fell between 5.6 and 6.4 g/cc, putting them "in a no-man's-land of densities for aerospace structures," says Hofmann.

And so Hofmann and his colleagues--including William Johnson, Caltech's Ruben F. and Donna Mettler Professor of Engineering and Applied Science, and a pioneer in the creation of metallic glass--began tweaking the components in their composites, eventually coming up with a group of alloys with a high percentage of titanium, but which maintained the properties of the previously created zirconium alloys.

"Despite being based in titanium," Hofmann notes, "these alloys exhibit the same impressive properties as the zirconium alloys. They are still tough--in other words, they resist cracking--and they are still ductile. In fact, they are even more ductile than the alloys we'd created in the past."

This decrease in density also resulted in a reduction in cost, adds Hofmann, since zirconium is a more expensive metal than is titanium.

The work detailed in the paper, "Development of tough, low-density titanium-based bulk metallic glass matrix composites with tensile ductility," was supported by the U.S. Office of Naval Research. Hofmann was supported by the U.S. Department of Defense through the National Defense Science and Engineering Graduate Fellowship program.

The paper's coauthors included Johnson; Caltech graduate students Jin-Yoo Suh and Aaron Wiest; Mary-Laura Lind, a visitor in materials science; and Marios Demetriou, a senior research fellow in materials science.

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Lori Oliwenstein
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George W. Housner, 97

George W. Housner, often considered the father of earthquake engineering, passed away on November 10 at the age of 97. Housner died of natural causes in Pasadena, California.

Housner was Braun Professor of Engineering, Emeritus, at the California Institute of Technology (Caltech).

Born in Michigan in 1910, Housner received his bachelor's degree from the University of Michigan and his master's and PhD degrees from Caltech.

Housner's interest in earthquake engineering began after the Long Beach quake of 1933. After receiving his PhD, he worked for the Army Corps of Engineers before advising the Air Force during World War II.

Housner spent much of his time during the war in North Africa, where he devised an equation that helped increase the success of pilots navigating barrage balloons--designed to prevent attacks on oil fields--and a new tactic for Air Force bombers to attack bridges, improving their effectiveness.

In 1945 he was honored with the Distinguished Civilian Service Award given by the U.S. War Department.

After the war, Housner joined Caltech as an assistant professor of applied mechanics. He later became the Braun Professor before retiring in 1981. He was named a Caltech Distinguished Alumni in 2006, the Institute's highest honor bestowed on graduates.

Housner's interests included civil projects, such as California's statewide water system. His earthquake-engineering techniques were used to strengthen the dozens of dams and aqueducts running through California--one of the first times modern earthquake engineering was used for this purpose.

"George really has to be considered one of the most original and clearest thinkers ever within the entire engineering profession," said John Hall, professor of civil engineering and dean of students at Caltech.

His expertise in earthquakes led to his chairing a National Academy of Sciences engineering committee evaluating the damage left by the 1964 Alaska earthquake. Soon after, he became a member of the National Academy of Engineering. He was elected to the National Academy of Sciences in 1972 and to the American Academy of Arts and Sciences.

Housner was the founding member of the Earthquake Engineering Research Institute, and a medal is given by the organization each year in his name. He was also instrumental in the formation of the International Association for Earthquake Engineering and Caltech's Earthquake Research Affiliates.

"George was a man of great intellect, which he used diligently to reduce the impact of earthquakes on our society," said Tom Heaton, professor of engineering seismology at Caltech. "He was one of those special people who changed our world."

In 1981, Housner was given the Harry Fielding Reid Medal from the Seismological Society of America, awarded annually for outstanding contributions in seismology and earthquake engineering.

In a 1988 White House ceremony, President Ronald Reagan awarded the National Medal of Science to Housner. The award citation honored Housner "for his profound and decisive influence on the development of earthquake engineering worldwide. His research contributions have guided the development of earthquake engineering and have had an important impact on other major disciplines."

After the 1989 Loma Prieta earthquake in Northern California, Governor George Deukmejian named Housner chair of the board investigating the collapse of freeways and bridges. He also served as chair of the Caltrans Seismic Advisory Board.

Housner never married and will be cremated and interred at Mountain View Cemetery in Altadena, California.

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$10 Million Gift Will Create New Engineering Center at Caltech

Pasadena, CA--The Gates Frontiers Fund has pledged $10 million to the California Institute of Technology (Caltech) to support the establishment of the Charles C. Gates Center for Mechanical Engineering within the soon-to-be-renovated Thomas Laboratory on the Caltech campus. This gift marks the launch of a $20 million fund-raising effort for an endowment in mechanical engineering. With this endowment, mechanical engineering at Caltech will step up its efforts in energy innovation, helping the Institute address global energy and climate problems and the country develop energy-market leadership.

The new center will be guided by Kaushik Bhattacharya, professor of mechanics and materials science at Caltech and executive officer for mechanical engineering, and will support research and academic priorities including the Energy Engineering Initiative in mechanical engineering, a program to develop new approaches and technologies to address the challenges of energy demand and supply.

The gift is being made in honor of Charles C. Gates, a Caltech trustee for 25 years and longtime champion of the Institute. Says Diane G. Wallach, Charles Gates's daughter and a co-trustee of the Gates Frontiers Fund, "My father felt that Caltech did things differently than other prominent universities; he liked the concentration of energy going into science and technology, and loved Caltech's focus on the hard sciences. He was an engineer himself, and believed that mechanical engineering should cut across all the disciplines, that we have to get people from all these areas into the same room, get them talking to each other to solve problems. This gift will help make that happen."

According to Caltech president Jean-Lou Chameau, the Gates Frontiers Fund's decision to underwrite the Gates Center "stands as a turning point in the history of mechanical engineering at Caltech and lends great strength to our efforts in building a program that will not only educate the next generation of pathbreakers in the field of energy and sustainability, but also provide critical energy solutions."

"This endowment will ensure that the mechanical engineering program continues to attract, retain, and educate the best engineers and scientists in the world," says Bhattacharya. "The societal impact of the Energy Engineering Initiative has the potential to be far-reaching, and the proposed Charles C. Gates Center for Mechanical Engineering will play an integral role in the initiative's success, while also honoring the memory and resolve of Charles Gates."

# # #

About Caltech:

The California Institute of Technology is a small, independent university that offers instruction in science and engineering for a student body of 900 undergraduate and 1,200 graduate students. With an outstanding faculty, Caltech is one of the world's major research centers, focusing on those areas in which it has the faculty and facilities to excel.

Since 1923, Caltech faculty and alumni have garnered 32 Nobel Prizes and five Crafoord Prizes. Forty-nine alumni and faculty have been awarded the National Medal of Science, and 10 faculty and alumni have received the National Medal of Technology.

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MacArthur Foundation Names Alexei Kitaev Latest Caltech "Genius"

Notes that his work brings us "closer to the realization of the full potential of quantum computing"

PASADENA, Calif.-- Alexei Kitaev, a California Institute of Technology (Caltech) faculty member, has been named a MacArthur Fellow, winning one of the five-year, $500,000 grants that are awarded annually to creative, original individuals and that are often referred to as the "genius" awards. 

With a joint appointment at Caltech as professor of theoretical physics and computer science in the Divisions of Physics, Mathematics and Astronomy and of Engineering and Applied Science, Kitaev explores the mysterious behavior of quantum systems and their implications for developing practical applications, such as quantum computers. He has made important theoretical contributions to a wide array of topics within condensed-matter physics, including quasicrystals and quantum chaos.

More recently, Kitaev has devoted considerable attention to the use of quantum physics for performing computation. Upon learning of the first algorithm for factoring numbers (an important aspect of cryptography) with quantum computers, he independently developed an alternative approach using "phase estimation," a solution that generalizes to an even wider range of calculations.

Though his work is focused mainly at the conceptual level, he also participates in "hands-on" efforts to develop working quantum computers.

Kitaev says he was "very surprised" when he received the call from Daniel Socolow, director of the MacArthur Fellows Program, telling him of his selection for the award. "I didn't know what the award was at first," admits Kitaev, who was born and educated in Russia. "But then I looked up the names of people who have previously received a MacArthur award, and saw that they are very good scientists. I am excited and honored to be in the same group with them."

"We are thrilled that Alexei has received this well-deserved honor," says Andrew Lange, the Marvin L. Goldberger Professor of Physics and chair of the Division of Physics, Mathematics and Astronomy at Caltech. "He is a stunningly original thinker who has made profound theoretical contributions to both quantum computing and condensed-matter physics. Alexei forged a deep connection between these two disparate subjects by proposing the 'topological quantum computer,' an idea now being aggressively pursued in laboratories around the world. Fostering such interdisciplinary insights is a central part of Caltech's mission, and we are proud to have Alexei on our faculty."

Kitaev received a diploma from the Moscow Institute of Physics and Technology in 1986, and his PhD from Russia's Landau Institute for Theoretical Physics in 1989. He served as a researcher at Microsoft Research from 1999 until 2001. He first came to Caltech as a visiting associate and a lecturer in 1998, and he was named professor of theoretical physics and computer science in 2002.

The MacArthur awards traditionally come out of the blue--most awardees have no idea that they are even being considered--and with no strings attached. MacArthur Fellows are not required to account for the ways in which they spend the money. Still, Kitaev says he feels it is important for him to use the award to do work that is "innovative and creative," and expects to take some time to figure out just what will fit the bill.

"The MacArthur Fellows Program celebrates extraordinarily creative individuals who inspire new heights in human achievement," says MacArthur president Jonathan Fanton. "With their boldness, courage, and uncommon energy, this new group of Fellows--men and women of all ages in diverse fields--exemplifies the boundless nature of the human mind and spirit."

Kitaev is one of 25 newly named 2008 Fellows--a list which includes UCLA astronomer Andrea Ghez, who received her MS in 1989 and her PhD in 1993 from Caltech, and Harvard Medical School neurobiologist Rachel Wilson, who was a postdoctoral fellow at Caltech from 2001 to 2004. Kitaev also joins the ranks of previous Caltech MacArthur Fellows, including its two 2007 awardees, Michael Elowitz and Paul W. Rothemund.

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Caltech Invention Earns R&D 100 Award

PASADENA, Calif.-Research done at the California Institute of Technology (Caltech) has been honored with R&D Magazine's R&D 100 Award. The award recognizes significant new technologies from the past year. 

Making the list this year was work conceived by Morteza Gharib (PhD '83), the Hans W. Liepmann Professor of Aeronautics and professor of bioengineering at Caltech, and by his team, including Emilio Graff (PhD '07) and postdoctoral fellow Francisco Pereira. The team designed a three-dimensional camera with a vast array of possibilities, ranging from 3-D movement tracking for rehabilitation to underwater surveillance. Their invention, the Volumetric 3-Component Velocimetry Video (V3V) System, has been licensed and marketed by TSI Inc., a Minnesota-based company that designs and manufactures precision instruments used to measure flow, particulates, and other key parameters.

"This award is a recognition that basic research can have a by-product for society," says Gharib. "My dream is for this device to become routine in robotic surgery."

The path to developing his three-dimensional camera began in 1992, when he and graduate student Christian Willert came up with the idea of "defocusing." As simple as it sounds, it's the process of making a "perfect image imperfect, and then extracting information out of that so-called imperfection," says Gharib.

The work was originally developed as underwater flow surveillance technology for the U.S. Navy. The camera includes a lens with three apertures--as opposed to one used in typical cameras. Rather than viewing a two-dimensional image, the three apertures give the image depth.

Gharib quickly recognized the camera's potential use in fields such as sports, industry, and medicine. For example, if physicians wanted to analyze the velocity of a person's gait, the camera might be used to record movements versus recording measurements by attaching multiple wires to the legs. The V3V camera converts those movements into numbers, information a computer program then analyzes.

Gharib also sees a potential for using his camera on the end of a surgical catheter, allowing a surgeon to better observe a patient's arteries during minimally invasive surgery. Using 3-D imagery from the camera, the surgeon would be able to make more precise incisions from within the artery itself.

The V3V System obtained its first of a series of patents in 2000. In January of this year, it was officially put on the worldwide market by TSI. The company serves industries, governments, research institutions, and universities.

Since 1963, R&D Magazine has showcased annually the most significant new technologies commercialized during the previous year. Winning an R&D 100 Award is recognition that the product is one of the most innovative ideas of the year. Previously, the R&D 100 Awards have recognized products such as the ATM in 1973, the liquid crystal display in 1980, the Nicoderm antismoking patch in 1992, and digital television in 1998. To get a full list of the 2008 R&D 100 winners, go to http://www.rdmag.com/awards.html.

 

 

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Caltech Scientists Create DNA Tubes with Programmable Sizes for Nanoscale Manufacturing

PASADENA, Calif.--Scientists at the California Institute of Technology (Caltech) have developed a simple process for mass producing molecular tubes of identical--and precisely programmable--circumferences. The technological feat may allow the use of the molecular tubes in a number of nanotechnology applications. 

The molecular tubes are composed of wound-up strands of DNA. DNA has been considered an ideal construction material for self-assembling molecular structures and devices because two complementary DNA strands can automatically recognize and bind with each other. DNA has been used to form rigid building blocks, known as tiles, and these tiles can further assemble into extended lattice structures, including tubes. However, it has been difficult to control the diameters of such tubes.

Peng Yin, a senior postdoctoral scholar in bioengineering and computer science at Caltech's Center for Biological Circuit Design, along with his colleagues has designed a series of flexible, single-stranded DNA molecules, called single-stranded DNA tiles. Each single-stranded tile is exactly 42 bases long and contains four modular binding sites. By pairing up the complementary binding sites, these single-stranded tiles bind with each other in a particular orientation like Lego pieces snapped together, forming a tube composed of parallel DNA helices.

The circumference of the resulting tube is determined by the number of different 42-base pieces used in its construction. For example, four pieces create a tube with a circumference of 12 billionths of a meter (or 12 nanometers); five pieces, a 15-nanometer-circumference tube; and six pieces, an 18-nanometer tube.

"We are not the first to make DNA tubes with controlled circumferences. However, compared with previous approaches, our method is distinctively simple and modular," says Yin. The simplicity and modularity of their approach permits the description of the tube design using a simple graphical abstraction system developed earlier this year in the laboratory of Niles Pierce, associate professor_of applied and computational mathematics and bioengineering at Caltech.

Just as a variety of wood sizes are used in construction projects--two by four inches for framing walls, two by eight inches for roof rafters, or four by four inches for fence posts--having nanotubes of various, precisely controlled sizes provides their user with more options. In addition, nanotubes of different sizes have varying mechanical properties; for example, tubes with a smaller diameter are more flexible and tubes with a larger diameter are more rigid. The nanotubes might eventually serve as templates for manufacturing nanowires with controlled diameters; the diameters of electron-conducting nanowires would help determine the electronic properties of the devices they are used to construct.

"The simplicity of the single-stranded tile approach promises to enable us to design ever more complex self-assembling molecular systems. The work is simultaneously elegant and useful," says Erik Winfree, associate professor of computer science, computation and neural systems, and bioengineering at Caltech. Winfree's laboratory was the primary host of Yin's research at Caltech.

The paper, "Programming DNA Tube Circumferences," was published August 8 in the journal Science. Yin's coauthors are applied physics graduate student Rizal Hariadi and computer science postdoctoral scholar Sung Ha Park from Erik Winfree's group; bioengineering graduate student Harry Choi from Niles Pierce's group; and computer science graduate student Sudheer Sahu at Duke University; Thomas LaBean, associate research professor of computer science and chemistry at Duke University; and John Reif, professor of computer science at Duke University.

The work was funded by the Center for Biological Circuit Design at Caltech and the National Science Foundation. 

 

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Caltech Researcher Recognized as One of the World's Top Young Innovators

Honor comes in Technology Review's prestigious TR35 listing

Pasadena, Calif., August 20, 2008--The California Institute of Technology today announced that Julia Greer, assistant professor of materials science in the Division of Engineering and Applied Science, has been recognized by Technology Review magazine as one of the world's top innovators under the age of 35 for her work with materials on a nanoscale level. Selected from more than 300 nominees by a panel of expert judges and the editorial staff of Technology Review, the TR35 is an elite group of accomplished young innovators who exemplify the spirit of innovation.

Greer came to Caltech from Stanford after receiving her undergraduate degree from MIT. Her work looks at the behavior of materials on a nanoscale level. As materials shrink in size, her research group looks at various phenomena associated with the shrinking process, including structural and mechanical integrity.

"Caltech is really an exciting place to be," says Greer. "It provides a rich environment for collaboration and discussion. It's been a great experience building my research group to study this phenomena."

The award also recognizes Greer's achievement in designing and manufacturing an instrument--dubbed the "SEMentor"--which allows her to obtain mechanical properties of materials with nanoscale dimensions.

"The TR35 honors young innovators for accomplishments that are poised to have a dramatic impact on the world as we know it," says Jason Pontin, editor in chief and publisher of Technology Review magazine. "We celebrate their success and look forward to their continued advancement of technology in their respective fields."

Greer and the other TR35 winners for 2008 will be featured in the September issue of Technology Review magazine and honored at the EmTech08 conference to be held at MIT in Cambridge, Massachusetts, September 23 to25.

"I'm especially excited about this award because MIT is my alma mater," says Greer. "I've been fortunate to go through college surrounded by innovative people and expected that in the real world I would come across it again! It's amazing to be part of a group of people moving society towards progress."

Additional information about past and present TR35 winners and judges is available at www.technologyreview.com/tr35/. For more information about the EmTech08 conference, visit www.technologyreview.com/emtech/08/index.aspx.

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Philip Geoffrey Saffman, 77

Philip Geoffrey Saffman, an influential teacher and noted researcher in fluid mechanics, died peacefully after a long illness on Sunday, August 17, in Pasadena. He was 77 years old. 

Saffman, the Theodore von Kármán Professor of Applied Mathematics and Aeronautics, Emeritus, at the California Institute of Technology, studied vortex instability and the dynamics of arrays of vortices. In particular, he looked into the phenomenon of viscous fingering, which became known as the "Saffman-Taylor Instability." This occurs when a low-viscosity fluid is injected into a higher-viscosity fluid.

His work with vortices also led him to a new mathematical analysis of the wake turbulence caused by jets as they take off, resulting in a theory describing the conditions behind several aircraft accidents.

Saffman was born in Leeds, England, and received his BA, MA, and PhD from the University of Cambridge. In 1964 he accepted Caltech's appointment as a full professor in fluid mechanics within the Division of Engineering and Applied Science. He was named von Kármán Professor in 1995.

He was a Fellow of the American Academy of Arts and Sciences and in 1988 was elected a Fellow to the Royal Society, England's premiere scientific organization. He also received the Otto Laporte Award from the American Physical Society.

Saffman served as associate editor for both the Journal of Fluid Mechanics and Physical Review Letters and was most recently an editorial board member for the journal Studies in Applied Mathematics.

Saffman is survived by his wife, Ruth; children Louise, Mark, and Emma; and grandchildren Timothy, Gregory, Rae (née Sarah), Jenny, Nadine, Aaron, Miriam, and Alexandra.

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Caltech Researchers Awarded $10 Million for Molecular Programming Project: Collaborative project may lead to revolutionary changes

PASADENA, Calif.-- The National Science Foundation's Expeditions in Computing program has awarded $10 million to the Molecular Programming Project, a collaborative effort by researchers at the California Institute of Technology and the University of Washington to establish a fundamental approach to the design of complex molecular and chemical systems based on the principles of computer science. 

The focus of their study, molecular programs, are collections of molecules that may perform a computation, fabricate an object, or control a system of molecular sensors and actuators. The project aims to develop tools and theories for molecular programming--such as programming languages and compilers--that will enable systematic design and implementation in the laboratory.

Eventually, molecular programs could be used to manufacture nanoscale objects, to create biochemical circuitry to probe the inner workings of cells, and as "programmable therapies" placed within living cells to diagnose and directly respond to diseases.

"Our project is a response to the fact that the molecular systems people are building today are now so complex, and their behavior so intricate, that future progress hinges on developing the intellectual and practical tools for mastering that complexity, the kinds of tools that computer science has already developed for silicon computers," says Erik Winfree, associate professor of computer science, computation and neural systems, and bioengineering at Caltech, and principal investigator on the project.

"The Molecular Programming Project is one of the 'outputs' from our investment in the Information Science and Technology (IST) initiative over the years," says co-investigator Richard M. Murray, the Thomas E. and Doris Everhart Professor of Control and Dynamical Systems and director of the IST program at Caltech. "The Expeditions program is intended to identify future directions in computing that have the potential to lead to 'revolutionary' changes. The collaborations between the various investigators, many of which were funded by IST, were instrumental in bringing together the team of researchers who are embarking on this project," he says. Examples include research projects and workshops funded by Caltech's Center for Biological Circuit Design, an IST initiative.

The Expeditions in Computing award, sponsored by the NSF's Directorate for Computer and Information Science and Engineering, is designed to provide investigators with the opportunity to pursue "ambitious, fundamental research agendas that promise to define the future of computing and information."

The other members of the collaboration are Jehoshua (Shuki) Bruck, the Gordon and Betty Moore Professor of Computation and Neural Systems and Electrical Engineering at Caltech; Niles A. Pierce, associate professor of applied and computational mathematics and bioengineering at Caltech; Paul W. Rothemund, senior research associate in bioengineering, computer science, and computation and neural systems at Caltech; and Eric Klavins, assistant professor of electrical engineering at the University of Washington in Seattle.

 

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Caltech Bioengineers Develop "Microscope on a Chip"

PASADENA, Calif.--Researchers at the California Institute of Technology have turned science fiction into reality with their development of a super-compact high-resolution microscope, small enough to fit on a finger tip. This "microscopic microscope" operates without lenses but has the magnifying power of a top-quality optical microscope, can be used in the field to analyze blood samples for malaria or check water supplies for giardia and other pathogens, and can be mass-produced for around $10.

"The whole thing is truly compact--it could be put in a cell phone--and it can use just sunlight for illumination, which makes it very appealing for Third-World applications," says Changhuei Yang, assistant professor of electrical engineering and bioengineering at Caltech, who developed the device, dubbed an optofluidic microscope, along with his colleagues at Caltech.

The new instrument combines traditional computer-chip technology with microfluidics--the channeling of fluid flow at incredibly small scales. An entire optofluidic microscope chip is about the size of a quarter, although the part of the device that images objects is only the size of Washington's nose on that quarter.

"Our research is motivated by the fact that microscopes have been around since the 16th century, and yet their basic design has undergone very little change and has proven prohibitively expensive to miniaturize. Our new design operates on a different principle and allows us to do away with lenses and bulky optical elements," says Yang.

The fabrication of the microscopic chip is disarmingly simple. A layer of metal is coated onto a grid of charge-coupled device (CCD) sensor (the same sensors that are used in digital cameras). Then, a line of tiny holes, less than one-millionth of a meter in diameter, is punched into the metal, spaced five micrometers apart. Each hole corresponds to one pixel on the sensor array. A microfluidic channel, through which the liquid containing the sample to be analyzed will flow, is added on top of the metal and sensor array. The entire chip is illuminated from above; sunlight is sufficient.

When the sample is added, it flows--either by the simple force of gravity or drawn by an electric charge--horizontally across the line of holes in the metal. As cells or small organisms cross over the holes, one hole after another, the objects block the passage of light from above onto the sensor below. This produces a series of images, consisting of light and shadow, akin to the output of a pinhole camera.

Because the holes are slightly skewed, so that they create a diagonal line with respect to the direction of flow, the images overlap slightly. All of the images are then pieced together to create a surprisingly precise two-dimensional picture of the object.

Yang is now in discussion with biotech companies to mass-produce the chip. The platform into which the chip is integrated can vary depending upon the needs of the user. For example, health workers in rural areas could carry cheap, compact models to test individuals for malaria, and disposable versions could be carried into the battlefield. "We could build hundreds or thousands of optofluidic microscopes onto a single chip, which would allow many organisms to be imaged and analyzed at once," says Xiquan Cui, the lead graduate student on the project.

In the future, the microscope chips could be incorporated into devices that are implanted into the human body. "An implantable microscope analysis system can autonomously screen for and isolate rogue cancer cells in blood circulation, thus, providing important diagnostic information and helping arrest the spread of cancer," says Yang.

The paper, "Lensless high-resolution on-chip optofluidic microscopes for Caenorhabditis elegans and cell imaging," was published July 28 in the early online edition of the Proceedings of the National Academy of Sciences. Yang's coauthors are graduate students Xiquan Cui and Lap Man Lee; postdoctoral research associates Xin Heng and Weiwei Zhong; Paul W. Sternberg, the Thomas Hunt Morgan Professor of Biology and an Investigator with the Howard Hughes Medical Institute; and Demetri Psaltis, the Thomas G. Myers Professor of Electrical Engineering at Caltech.

The work was funded by DARPA's Center for Optofluidic Integration at Caltech, the Wallace Coulter Foundation, the National Science Foundation, and the National Institutes of Health.

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