Daily event news
Thursday 6 February
Wednesday 5 February
Tuesday 4 February
Monday 3 February
Sunday 2 February
Translational Research: outcomes-based studies
Saturday 1 February
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Thursday 6 February
'Another great show!'
More was promised, and more was delivered at SPIE Photonics West 2014. The premier annual event for the international optics and photonics community drew 21,360 registered attendees to San Francisco this year, setting yet another all-time attendance record for the event and demonstrating that its emphasis on moving ideas to market is just what the industry wants.
The sold-out mid-week Photonics West Exhibition included 1,256 exhibiting companies, topping last year's previous record, and the weekend BiOS Expo held strong with 214.
The biggest attendance growth was in exhibit visitors. The number of people who came from Silicon Valley and other regions to walk the trade show floor was 8% higher than last year.
Exhibitors in both exhibitions were pleased with the results.
"I came from the East Coast to BiOS on the West Coast and found that my East Coast customers are here," said a first-time exhibitor at the weekend BiOS Expo. "I think that BiOS is the best show we have ever done. Both the traffic and the quality of leads are very good."
"Another great show -- companies have to come to Photonics West," said Daniel Bukaty Jr., president of PG&O. "It's the best show of the year!"
There were plenty of smiles Thursday morning at the booth of Hübner GmbH & Co. KG (above). The company won an unprecedented two Prism Awards for Photonics Innovation at the Wednesday gala awards banquet, taking honors in the categories of Defense and Security, and Scientific Lasers. (See more on the awards: Winners named for 2014 Prism Awards for Photonics Innovation.)
See more photos in the exhibition gallery.
Wednesday 5 February
Photonics executives feeling upbeat
A panel of executives offered a consistently upbeat view of photonics markets and their near-term potential in a session moderated by SPIE Industry and Market Analyst Steve Anderson on Wednesday afternoon.
Healthcare and the various markets for sensors were repeatedly cited as areas of impressive growth in the past year, and good prospects for the coming year. While sequestration did impact the defense industry in particular, some companies were less affected than anticipated. Rick Plympton of Optimax even looked at it in a positive light, saying "sequestration is going to realign defense spending." The industry will have an advantage in the new era, as government looks for cost savings that can be enabled by photonics, he said.
The sentiment was echoed by Tim Day of Daylight Solutions. A detailed analysis of lifecycle costs will be a part of any defense acquisitions, and "photonics has a distinct advantage" when that is factored in, he said.
When asked where the opportunities lie in the years ahead, almost everyone mentioned life science and healthcare. Dirk Rothweiler of Jenoptik also cited the proliferation of "ambient intelligence" -- beyond the desktop or laptop computer, he said semiconductor manufacturing is benefiting from consumer items with programmable displays. And the automotive industry, he said, continues to be an important market, including photonics in displays, ambient lighting, and potentially even self-driving cars.
An audience member asked what disruptive technology worries them as a threat to their business and markets, but most analysts had a hard time coming up with an answer. Day's response to the question was to point out that it's actually photonics that is the disruptive technology.
"There's so much opportunity; I see growth," said Jerry Jurkiewicz of IDEX. "If all of us on this stage organize our companies, our talents and our technology on those opportunities, I think the positive side of the ledger so far outweighs the negative side, that I do not lose sleep at night in this industry."
Near the end, Dennis Werth of Newport said that while there are opportunities all around the world, he would bet on the United States as the place the next big thing might come from. He cited Google, Amazon, and eBay as examples of successful innovators.
"This country just has a repeated history of creating whole new industries," he said. "You just don't see that anywhere else."
Tuesday 4 February
OPTO plenaries: They said it couldn’t be done
Tuesday morning's OPTO Symposium plenary talks showcased two technologies -- silicon photonics and thin-disk lasers -- that just a decade or two ago were considered "impossible."
"If you had asked any laser expert 20 years ago if it is possible to do what we do today, they would have said 'no,'" said Ursula Keller of ETH Zurich in her presentation on ultrafast laser advances. "But today we have picosecond laser oscillators with no additional amplifier that generates 100 microjoule pulses at megahertz pulse rep rates and femtosecond/picosecond laser oscillators with no additional amplifier that can generate 300 W average output power."
In addition to industrial applications such as high-speed and high-precision micromachining, ultrafast laser sources with high average powers have become a promising tool for strong-field physics and other research disciplines.
"The key for high-average-power ultrafast sources is heat removal," Keller explained. "You have to optimize your surface-to-volume ratio either with the fiber or with the thin disk."
Over the last decade, her group at ETHZ has been working with thin-disk lasers and semiconductor saturable absorber mirrors (SESAMs) to push the performance of ultrafast lasers. By using the SESAMs to passively modelock the lasers, they have achieved unprecedented pulse widths, average powers and repetition rates, Keller noted.
"SESAM modelocked thin-disk lasers have demonstrated highest average powers and highest energies of any ultrafast oscillator technology," she noted. "People thought solid-state lasers could not be modelocked; we now know that is not the case."
Looking ahead, Keller sees much promise for thin-disk VECSEL and MIXEL technologies, especially in data communications.
"I really believe in VECSEL technology, optically pumped VECSELs, for big data centers," she said. "Recently we have seen 100W+ VECSELs, so these are high power semiconductor lasers. But what gets me really excited is the MIXSEL (modelocked integrated external-cavity surface emitting laser). They offer scalability in repetition rate, have no Q-switching instabilities and offer extremely low noise performance."
What is the limit in terms of energy and output power for thin-disk lasers? "I want to keep pushing it," Keller said. "A modelocked oscillator in the kilowatt -- that would be great, wouldn't it?"
The future of silicon photonics is also quite bright, according to Michal Lipson of Cornell University. "This field has made enormous advances in the last 10 years, challenges we as a community overcame," she said.
Pushing this development has been the need to alleviate power dissipation in computers and transmit huge amounts of data over computers. Optics was the natural solution because optical interconnects do not dissipate power.
"The industry knew this was coming 10 years ago and has been looking for solutions," Lipson noted. "The condition was that anything you do in optics has to be completely compatible with the billion-dollar CMOS electronics infrastructure."
Today, photonics on a chip schemes enable monolithic integration of optics and microelectronics for applications in which high data streams are required in a small footprint. Lipson and her group at Cornell have been instrumental in pushing the development of these active devices, particularly ultrahigh-frequency modulators, silicon waveguides and optical isolators on a silicon chip.
"The performance of these modulators is as good as traditional modulators based on traditional optical communications materials, and we have learned how to make the waveguides very well, with very low loss," she explained.
Multimode photonics on a chip is another area of interest for data communication and storage as a way to increase bandwidth, Lipson noted.
"The goal of silicon photonics is to enable the transmission of enormous amounts of data over very short distances," she said. "If you can do this, you are golden."
Monday 3 February
MOEMS-MEMS plenaries target novel biomed applications
Nanoscale fabrication techniques are enabling a new wave of applications in the biomedical sector, from holographic optical tweezers to wireless miniature brain probes and cameras that mimic an arthropod's eye.
"We are looking to nature for inspiration," said John Rogers of the University of Illinois at Urbana-Champaign yesterday during his MOEMS-MEMS plenary session talk, "Bio-Integrated and Bio-Inspired Optical Microsystems."
The decreasing size of transistors has had a transformative effect on technology, he noted. "We are seeing continued miniaturization, with computers coming closer and closer to your body. These devices are always built on rigid planar surfaces, which is not really a problem if you want to keep your iPhone in your pocket. But what if you want to use it in other ways? Nothing in biology looks like a silicon wafer."
The future as he and his research group envision it is "stretchy, curvy and bio-integrated." So they have been working to develop materials and methods to enable devices that leverage this new way of thinking about form and function. The goal is to create silicon nanomembranes that can serve as the foundation for flexible silicon integrated circuits and flexible micro LEDs. Such bio-inspired devices require thin sheets of silicon with a very small bending thickness (about 200 nm).
"We can build integrated optical systems that offer a natural way to scale down to very tiny geometries," he said. "By using lithographic interconnection schemes, you don't have to do wire bonding to establish the interconnects, which then also serve as heat sensors."
These devices can be integrated with biological processes that can probe much deeper into the human body than current devices and thus better explore the form and function of complex organs such as the brain, he explained.
For example, Rogers and his group have been working to develop brain-injectable micro-LEDs that can enhance the use of optogenetics to study behavioral responses to light. In research published last year in Science, they demonstrated how a multifunctional, cellular-scale, wireless optoelectronic device could be injected safely into a mouse brain and used to manipulate the animal's behavior.
"Thermal management is incredibly important because you are basically inserting a lightbulb into the brain, can only tolerate about a one degree increase in temperature," he said. "But the devices are so tiny, and they are down in a living tissue that has vasculature, which functions like a heat sink. Also, for optogenetics stimulation you don't need to operate the LEDs in continuous mode," which further decreases the thermal effect.
Optical manipulation -- aka "optical tweezers" -- has also benefitted from the increasing miniaturization of technology, noted Cornelia Denz of Westfälische Wilhelms Universität Münster, in her talk on tailoring light for optically guided nano- and microassembly.
"Increasingly microlabs want to tweeze particles in fluids or gases or cells in organisms, which requires novel tweezer tools," she said. "So how do we manipulate, move and arrange matter at the nanoscale by light? Complex light landscapes are needed."
For example, she and her colleagues have developed a holographic optical tweezer (HOT) workstation that can create up to 100 traps at a time. They are using HOT to study biological self-propelled micromixers and self-propelled biohybrid microrobots that can identify pathological situations in cells, including metastasis, inflammation and infection, and observe how the cells change over time.
Finally, in his talk on nanoelectro-mechanical (NEM) switch technologies, Roger Howe of Stanford University emphasized that NEMS switches offer several advantages over nanoscale CMOS switches, including zero leakage, infinite subthreshold slope, high temperature operation, radiation-hard operation and compatibility with other substrates, including glass and plastics. But some key issues need to be addressed before NEMS is ready for broadscale commercial production.
"NEM switch technology is a work in progress, and surface physics and chemistry at the contact are key factors," he said. Microshell encapsulation is absolutely essential for reliability and reproducible behavior, he added.
Fellows recognized; peer into the future
Nearly half of the society's 76 new Fellows named in 2014 were recognized during a luncheon Monday, and heard a forward-thinking talk on data centers of the future.
That future is near -- 2-10 years -- and will require extremely high-efficient processors, memory, and interconnects, and silicon photonics will be key to revolutionizing those communication systems, said Ashok Krishnamoorthy, chief technologist for photonics at Oracle.
The world's growing demand for mobile electronics coupled with technology companies' need to scale infrastructure and systems to meet that demand is driving database software giant Oracle to make major investments in silicon photonics.
After all, said Krishnamoorthy, we now possess more smartphones and tablets than PCs. Borrowing from philosopher René Descartes, he said, the new reality is, " I think, I text, I tweet, I blog, I post ... therefore I am."
He said Oracle Labs is working closely with industry, government and academic partners to break through today's technology limits with manufacturable and low-cost solutions to support a world that is becoming increasingly dependent on information technologies, especially with all those tablets and smartphones.
|Kumar Patel, inventor of the CO2 laser, was among Fellows honored at the luncheon;
above, from left, SPIE Past President Eustace Dereniak, Patel, and SPIE CEO Eugene Arthurs.
In the conference rooms ... Craig Robin presented the results from work on a novel acoustic and gain-tailored photonic crystal fiber (PCF) amplifier scheme in a presentation on "Single-frequency Yb-doped photonic crystal fiber amplifier with 800 W output power" (8961-2). For this work, conducted at the Air Force Research Laboratory, the researchers made use of the stack-and-draw technique utilized in PCF fabrication to construct a seven-segment core with three distinct acoustic regions.Selectively doping sections of the core with Yb and Al allowed the team to significantly reduce intrinsic Brillouin gain reducing stimulated Brillouin scattering effects.
When integrated into a laser architecture, the result was an output power of 811W at 1064nm with a near diffraction limited beam quality with an M2 of 1.25. Prior state-of-the-art results were 300W for a monolithic architecture and approximately 600W for a free space laser so these results represent a significant advance in the field and demonstrate the potential of this novel core design scheme to provide a pathway to higher powers.
Commercializing microfluidic devices and systems
The Prospects and Future of Microfluidics were explored Monday evening by a panel that included Emmanuel Delamarache from IBM, Giacomo Vacca of Kinetic River, Albert van den Berg from the Universiteit Twente, and Peter Hesketh from the Georgia Institute of Technology. Moderator was Bonnie Gray, Simon Fraser University.
Discussion ranged from the make-up of the personnel in startups (should the technologist lead the company or should it be an outsider?) to a 5- to 10-year outlook of what the future might hold for micro-fluidics as commercialized products.
The panel agreed that the successes have been few as of yet, but those that found the right need in the marketplace have been very successful. They also agreed that the technology idea is not the right place to start a company; time should be spent in the field understanding the needs of potential customers. For example, the lab on a chip idea sounds appealing and there have been many technological examples of how to do it, but in the real world the product needs to be cost-effective, robust and probably disposable. The chip you design to throw away shouldn't be the expensive element.
Each panel member presented examples from their experience that echoed the same theme. While the idea needs to meet a need, it also has to be forward-looking. If it is too immediate there are likely more competing products or ideas that can address that need. A company needs to be looking more like five years out from the current state of the industry.
Another discussion focused on the cost of development and the fact that often the development platform is not in the correct material base for the final product. The use of 3D printing to make devices seems convenient, however the materials used in the process are usually not stable in water (they swell) or do not have sufficient lifetime before they begin to degrade. One prediction for the future is a consolidation of the current multiple platforms for the development of microfluidic devices.
Women in Optics answer: 'Why Industry'?
Sonia Garcia-Blanco, from the University of Twente, moderated this year's Women in Optics Panel. SPIE's female membership has doubled since 2001 and interest in these members' views and experiences was clear at Monday's session, focused on the transition from academic graduation to industry.
All panel members joined the event from careers in industry, which led to a natural first question: Why Industry?
Michelle Xu (Intel) aspired to be a professor in college, but later changed her mind. "I [didn't] want to be a professor anymore, I want[ed] to do something that's more tangible," she said, after realizing what Christina Willis (Vision Engineering Solutions) also surmised: "If you're a good professor, you don't spend much time in lab." Diana Warren (Newport Corp.) lightheartedly said she was tired of trying to find signal and eager to get into the job market.
Interest turned to the demands of a woman building her industry career and the impacts for those wanting a family. Anna-Britt Mahler (Aerospace Corp.) said, "There are a lot of women with families and [my] company is sympathetic to that... and then there are some who work a lot of hours."
Because hours spent at work correlate with job position, Mahler and others recognized the importance of careful goal prioritization. Garam Young (Synopsys, Inc.) recommended careful thought before a job interview as well. She said, "If you have questions very important to your life, ask them."
Jessica Nelson (Optimax Systems) encouraged those with doubts and said, "It is very possible, please don't let the thought of having children dissuade you from pursuing your career."
The panel members all agreed, whatever a woman's goals, having a good source of support is key.
Welcome: 'A Night at the Movies'
"... and you were there, and you were there, and ..." yes, Dorothy was there, too, to greet attendees at the Photonics West welcome reception, along with Darth Vader, King Kong, Groucho Marx, Charlie Chaplin, and (ooh la la!) Marilyn Monroe. A delighted crowd packed the Yerba Buena ballroom in the Marriott Hotel Monday evening to enjoy movie candy, fun food, and excellent company.
Sunday 2 February
BiOS Expo: 'crazy busy!'
The photonics business is off to a good start this year, according to reports from the BiOS Expo show floor.
"The first day of BiOS has been crazy busy," reported Cindy Gong-Harris of Wasatch Photonics on Saturday afternoon.
"The beginning of the 2014 business year is much better than the beginning of 2013 -- we are writing many more orders this year," said Ever Mata of Newport Thin Film Lab. The company's reps reported seeing "a lot more R&D folks at BiOS than at other shows."
Another exhibitor reported getting the equivalent of several days' worth of leads on Saturday alone -- and activity continued strong throughout Sunday, despite a bit of anticipated attrition here and there as avid football fans headed off to Super Bowl parties in the late afternoon.
See more photos in the exhibition photo gallery.
The Photonics West exhibition opens Tuesday at 10 a.m., with more than 1,250 exhibiting companies -- plan to arrive early and stay late to see it all!
Translational Research: outcomes-based studies
The body of medical research may be seen as a pyramid, supported at the bottom by large efforts in fundamental investigations and converging at the top in clinical impact for patients, noted Translational Research symposium chair Bruce Tromberg (Beckman Laser Institute and Clinic, University of California, Irvine). In this imagery, translational research provides the path to the top, paved by outcome-based studies.
Examples of outcomes-based optical and light-based advancements were featured in a special lunchtime forum Sunday afternoon, in presentations by the four Translational Research Best Paper Award winners (see a photo in the awards gallery).
Michalina Gora (Harvard Medical School) and collaborators reported in “Tethered capsule OCT endomicroscopy” (8934-8) on the development of a small (25mm) tethered capsule patients can swallow unaided for real-time imaging and reconstructive mapping of the upper GI tract. This inexpensive OCT-based device could replace current invasive video-endoscopy and biopsy methods in diagnosing diseases such as Barrett’s Esophagus,. The 40 procedures already performed each took a matter of minutes.
In “Non-damaging laser therapy of the macula” (8930-39), Daniel Palanker (Stanford University) reported on success in noninvasive techniques allowing the treatment of macular retinal diseases. Current photocoagulation treatments “cook” this area causing photoreceptor damage and retinal scarring. Palanker’s method uses real time microscopy measurements to feed an algorithm that titrates laser pulse power and duration of the treatment. Although under the damage threshold, pulses still stimulate the therapeutic expression of heat shock proteins, restoring 20/20 vision in many patients with no scarring or damage.
The-Quyen Nguyen (Vanderbilt University), in “3D, real-time, and intraoperative evaluation of surgical margin status” (8935-25), noted that damage is also a major concern for the ~30% of breast cancer patients requiring second surgeries after post-op test results reveal cancerous cells within the removed tumor’s margin. Nguyen’s device scans tumors immediately after removal using Raman microscopy. Taking only ~10 minutes, this allows surgeons to re-operate if necessary while the patient is still sedated.
Ji-Xin Cheng (Purdue University) reported “Spectroscopic imaging of cholesterol accumulation essential in cancer proliferation” (8948-23). Also Raman-based, Cheng’s studies used CARS microscopy to identify cholesterol ester (CE) accumulation as a marker for aggressive cancers. Additionally, depleting CE allowed Cheng’s group to inhibit the growth of the prostate cancer. With further clinical outcome studies, these results could lead to accurate predictions of cancer aggression.
Charting a career path
The BiOS Student Lunch with the Experts hosted over 130 students and established scientists willing to share their experience and wisdom on career paths in biomedical optics.
A drawing was held among the student attendees with the winner granted open access publication for a paper of his or her choice in the Journal of Biomedical Optics. The journal's Editor-in-Chief, Lihong Wang (Washington University in St. Louis), was on-hand to announce the winner. See additional photos in the event photo gallery.
In the conference rooms
Talks drew large audiences to hear the latest work, including developments in imaging and healing skin.
Repairing skin, changing lives
In a Sunday morning keynote talk on optical treatments of skin disorders (8926A-20), Rox Anderson (Wellman Center for Photomedicine, Massachusetts General Hospital) began by outlining altruistic aspirations ranging from tissue repair to cancer cures and more, stressing the applicability of optical techniques in fulfilling these dreams.
As the most prevalent cancer type, skin cancer is still predominantly treated with either traditional surgical removal or topical medicine, while optical approaches, even in research, are far behind. Tattoo removal is already synonymous with laser treatments, and it is hoped the same will become true for skin cancer.
Fractional laser treatment, a laser ablation method of surgery, moves in that direction. Using an array of depth-tunable micro-cuts, up to 40 percent of tissue is removed with no permanent scarring.
A similar small-cut array approach to skin grafting produced audible gasps from the audience, in reaction to images of epidermal repair of damaged tissue. With fractional blistering, epidermal tissue was harvested painlessly with an array of 128.
Anderson uses fractional blistering with beta blockers to treat radiation burns of children in Southeast Asia. The lesions result from radioactive phosphorus doctors apply directly to skin disorders, as part of a treatment regimen.
Anderson concluded by describing his "Magic Wand Project," focused on recruiting clinicians to take an active role in identifying medical challenges, crucial to effective medical development.
3D imaging revolution
Optical tomography techniques have enabled imaging of morphological and chemical features of living organisms, through use of ultrasound, optical coherence tomography (OCT), and confocal microscopy, which was used in the early days of 3D imaging. However, a bottleneck developed, as limited spatial resolution and depth resolution and lack of functional imaging shortened the capabilities of 3D imaging.
In a keynote talk (8948-3), Karsten König, CEO of JenLab GmbH and professor at Saarland University, described how optical response from specific electronic transitions in atoms led to a revolution in the world of 3D imaging. Multiphoton absorption processes, nonlinear molecular response with second harmonic generation (SHG), and coherent anti-Stokes Raman scattering (CARS) enabled the development of nondestructive, label-free, high-resolution imaging performed within seconds.
König's lab has developed a 3D imaging system consisting of a multifunctional detection head fixed to an articulated arm enabling localized imaging of living tissues and culture cells for in vivo multiphoton tomography with chemical fingerprints. Using the combination of two-photon excited autofluorescence with a CARS module, the unit can image both fluorescent (NAD(P)H, flavins, porphyrins, elastin, keratin, and melanin) and nonfluorescent biomolecules (water and lipids) in seconds with submicron resolution, for an extremely broad range of applications from skin-aging measurements to live-cell imaging.
Who wants to be an entrepreneur?
|From left, photonics industry veterans Andrea Belz, Simon Poole, and Jim Fisher
shared career advice with students.
Photonics industry insiders gave job interviewing tips, a crash course in feasibility analysis, and their perspectives on entrepreneurship and other non-academic careers to about 100 students attending one of several industry events at Photonics West Sunday.
Simon Poole, director of new business ventures for Finisar in Australia, advised optics and photonics experts who want to start their own business to "identify the opportunity, get into the market fast, and iterate."
The serial entrepreneur who turned to the commercial side of photonics after running an academic research group for seven years emphasized the importance of speed in many areas of a new business, such as getting to market rapidly and quickly terminating employees who don't work out. But Poole also recommended taking time to hire the right people -- and to "smell the roses."
Andrea Belz, CEO of Belz Consulting, and Jim Fisher, vice president of optical components and the Vibration Control Group at Newport, also underscored the importance of finding a good work-life balance.
Job seekers must be able to "ask the right questions to the right people," Fisher said, but they should first take the time to answer the most important questions: what really drives you, and where do you want to end up.
Celebrating Institute of Optics contributions
Institute of Optics director Xi-Cheng Zhang, above, detailed some of the many accomplishments over the past year of the Rochester institute's distinguished faculty and driven alumni at a well-attended reception Sunday. The institute is working to track the number of optics businesses started by alumni, with the latest tally showing 193 companies created by 129 faculty and alumni.
Featured speaker David Williams, Director of the Center for Visual Science, William G. Allyn Professor of Medical Optics, and professor of Optics, Brain and Cognitive Sciences, Ophthalmology, and Biomedical Engineering, described some recent work. One area of research at the multidisciplinary center involves studies in adaptive optics technology to obtain microscopic images of the eye, particularly the retina, with the goal of developing noninvasive vision correction techniques that restore vision without removing tissue.
Poster sessions on Sunday drew large audiences to discuss new work one-on-one with authors. See more photos in the event photo gallery.
Saturday 1 February
Opening day, opening talks
With more than 4,700 talks scheduled during the week, the SPIE team set out to cover a wide selection from throughout the various symposia. The first write-ups appear below; revisit this page throughout the week for more.
Silk biomaterials for photonics
Early-Sunday talks included a keynote by Fiorenzo Omenetto, Tufts University, on "Silk biomaterials: a versatile material platform for photonics," (8958-1) in the Bioinspired, Biointegrated, Bioengineered Photonic Devices conference.
Omenetto reported on recent progress on the use of silk fibroin as the material base for micro- and nanostructured optical materials. He described fabrication strategies and devices such as silk-based 2D and 3D photonic crystals, lasers, therapeutic mirrors, and biologically active photonics in discussing examples of the possible applications that this water-processed, biocompatible material offers.
Biomaterials offer opportunities for devices that operate at the interface of the biological and technological worlds, Omenetto said. Stringent requirements on material form and function are imposed when operating at the nanoscale in a photonic or optoelectronic context.
DNA-coated gold nanoparticles
In "Toward efficient modification of large gold nanoparticles with DNA," (8955-3) in the conference on Colloidal Nanoparticles for Biomedical Applications, Ron Gill, Universiteit Twente, reported on work with DNA-coated gold nanoparticles, one of the most researched nano-bio hybrids.
Traditionally their synthesis has been a long and tedious process, involving slow salt addition and long incubation steps. This stems from the fact that both DNA and gold particles are negatively charged, rendering efficient interaction possible only at high salt concentration. However, high salt concentration tends to aggregated the particles.
More recent modification methods involve the use of surfactants to stabilize the nanoparticles against aggregation, enabling faster modification. Gill presented his team's result on an alternative route: reduction of the charge of DNA to reach fast modification in low salt conditions. for the synthesis process.
Light for pain relief?
Michael Hamblin and coauthors from the Wellman Center for Photomedicine and Universidade de São Paulo reported on their work on low-level laser therapy (LLLT) for pain relief in their talk, "Can light interact with neurons to decrease pain?" (8932-17).
LLLT continues to be a field of great interest as investigators try to understand not only if this technique results in pain relief but also the mechanisms that could drive this effect.
Hamblin provided an overview on the role of mitochondria movement along microtubules for transfer of neurotransmitters and described how light therapy may interrupt that transfer, concluding that mitochondria-rich areas of the body including muscles, neurons, and certain organs such as the liver and kidneys may best benefit from this treatment method.
In Hamblin's lab, co-author Marcelo Victor Pires de Sousa conducted studies of LLLT on pain thresholds using a von Frey filament stimulation method in a mouse model. Using an 808nm light source and providing irradiance levels up to 30J/cm2 in the L4/L5 region of the back, the team observed as much as a six-fold increase in pain threshold. Interestingly, this increase in tolerance was not observed immediately after irradiation but, rather, approximately three hours later. Daily testing on the subject demonstrated the repeatability of the effect over a seven-day period.
The team further observed varying effects of LLLT on pain sensitivity with irradiance at different targets on the subject seeing both a variation in the effectiveness of the treatment -- for example radiating the tail had no effect on the pain threshold -- and on the delay time for maximum increase in the pain threshold when an effect was seen.
Exploring the bio world with optical probes
University of Dayton
The interdisciplinary connection between the optical and biological worlds was under the spotlight in the conference on Frontiers in Biological Detection: From Nanosensors to Systems. The next generation of optical nanodevices employed to probe the bio world was highlighted in the "Fibers and Interferometry" session via the work of three leading research groups, those directed by Paul Laibinis, Vanderbilt University, (8933-12); Karolyn Hansen, University of Dayton (8933-2); and Benjamin Miller, University of Rochester Medical Center (8933-3).
The three groups emphasized the current need for label-free, cost-effective, highly sensitive, scalable, and simple-to-use probes to track and uncover dynamic biological systems such as protein and DNA binding.
In particular, as emphasized by the Dayton group, optical probes employing tapered optical fibers offer an attractive non-destructing and re-usable alternative to probe biological events occurring at the surface.
Their approach consists of tapering a conventional singlemode step-index optical fiber. With the taper inserted into a protective housing containing several channels in contact with the probe, biological flows can be applied. As active biologic agents bind to the surface, their interaction with the evanescent tails of the EM field propagating in the taper results in measurable shifts of the periodic function.
After analyzing the spectral changes measured with the optical probe, specific properties of the binding agent can be identified. This compact, robust and inexpensive approach shows promising performances to operate as a biosensing platform for biological flow measurements.
Temporal brain mapping
Launched in April, the BRAIN initiative has already made great strides towards revolutionizing spatial and temporal brain mapping. Optical approaches towards this end provide multiple advantages over older, electronic methods and even newer fMRI techniques. Darcy Peterka from Columbia University started off the Optogenetics conference of BiOS on Saturday (8928-81) describing some of these benefits and recent advancements by the initiative and his group, led by Rafael Yuste.
There are many structural similarities among mammal brains, leading groups like Yuste's to look for a common basic computational element that could explain how the components of the brain interact and function. This "singular cortical microcircuit" can be thought of as "the DNA of the brain," Peterka said.
A main motivation of these optical mechanisms lies in the scale at which cortical activity is monitored. Sharp electrode measurements of neural activity interrogate neuron by neuron. Newer techniques such as fMRI map more macroscopic brain activity in full regions. Microscopy, however, allows imaging at the "modular" scale of the proposed "DNA," looking at the activity of 104-105 neurons at a time.
Using dyes reactive to the Ca++ signatures that follow neuron action potentials, two-photon IR fluorescence microscopy provided Saturday's audience with real-time movies of a live (and relatively unscathed) mouse's brain activity as it reacted to stimuli.
This second-order method provides optimal spatial localization while the long wavelength light also scatters less, permitting minimally invasive probing up to a few centimeters into the mouse's brain. With both wavefront coding and beamsplitter based directive optics, the movies show 3D, simultaneous imaging of multiple areas of activity. This, along with the temporal freedom allowed by optical techniques, provides a powerful tool for mapping the ordering of neuron firing and patterns of brain activity.
With directed optical perturbing of neural dynamics, Peterka hopes not only to more fully understand brain functions, but also to control this network activity and influence the mouse's decisions.
Greater success in burn healing
In "Terahertz spectroscopy for classification of burn wounds in a standardized porcine model" (8941-5), Hassan Arbab et al. from the University of Washington noted that there are 500,000 burn wounds every year and 45,000 of them require hospitalization. Current standard treatment consists of four clinical grades of burns and three distinct treatments, each very specific for the grade of burn. Their success rate depends on them being appropriately applied, so it is important to be able to accurately distinguish between the medium grade burns.
The old standard considered that if the burn penetrated more than halfway through the epidermis it was considered severe. The proposed standard divides this into two categories: damage above the hair follicles and damage below the hair follicles.
Damage above can be self-regenerative, but below this requires treatment. If the level can be definitively determined treatment would be made more effective. The use of terahertz spectroscopy coupled with an accurate model of the dynamical processes of human skin reaction to burns is shown to be effective in accurately determining the differentiation of these two burn grades.
Graphene for VECSEL improvements
Vertical external cavity semiconductor lasers (VECSELs) are a combination of a semiconductor gain medium coupled to a high Q external cavity. They offer high power, low noise, physical stability, and laser operation over a significant bandwidth. The motivation for work reported by Christian Zaugg (ETH Zurich) et al. in "Graphene modelocked VECSELs" (8966-5) is to broaden the tunable bandwidth for mode-locked operation.
To achieve modelocked operation requires that a saturable absorber be used somewhere in the cavity. Graphene has some unique properties (zero bandwidth, ease of fabrication and flexibility) that suggested it would be a good candidate as a material for use in this device. It cannot be used intracavity as its double-pass loss is too high. But it can be introduced onto the rear surface of the high-reflective mirror on the semiconductor material. Here the amount of field enhancement can be controlled by the thickness of a SiO2 spacer level between the graphene and the mirror.
The graphene is grown on a copper substrate and then has a polymer applied to the top surface. The copper is etched away and the graphene polymer layers are picked up onto the semiconductor surface, and finally the polymer is dissolved away.
The fabricated device was pumped at 808 nm and lased at nominally 960 nm with a 2.5 Ghz repetition rate and pulse widths of 466 femtoseconds over a modelocked range of 935 nm to 981 nm, the broadest yet reported. Course tuning is achieved by rotation of an internal silica etalone and fine tuning is accomplished by thermal control of the heat sink temperature at the mirror.
Bioinspiration: a photonic eye
Lobsters and other decapod relatives see through eyes that focus light by reflection, and not refraction as is typical of most other lenses and eyes. Reflective optics are not prone to the absorption and chromatic aberration challenges of refractive optics, motivating Chi-Chieh Huang's work developing an artificial eye similar to that of the lobster. In Saturday afternoon's Photonics of the Eye session, Huang described this work (8958-7).
Although typical reflective optics pay the price for minimal aberration with a limited field of view, the array of micro-components comprising the decapod's eye arrange for a free ride. Light entering the convex face of a hemispherical array of square micro-tubes reflects off the tubes' inner walls to the structure's focal point. As well as the broad light spectrum reflection gives the crustacean, the superposition of these reflections has high sensitivity and the parallel processing provides motion tracking.
With security and medical imaging in mind, Huang et al. at University of Wisconsin, Madison, have fabricated a life-size "eye" with a 165° field of view using lithography and a novel peeling technique. Their micro-tubes were arranged on a hemispherical PDMS substrate and the upright images formed by the eye were captured with a commercial camera. Although post-processing wasn't necessary to remove chromatic aberrations, it could be used to improve dynamic range and spatial aberration in future applied uses.
Controlling cells and the path of discovery
In a keynote talk (8928-88) in the conference on Optogenetics and Optical Control of Cells, Beckman Laser Institute co-founder Michael Berns (University of California, Irvine, and University of California, San Diego), surveyed the past, present and future of optical control of cells -- and spun a fascinating story illustrating the path of scientific discovery in the process.
Along with improvements in output performances of early laser systems delivering short pulses (from pico- to femtosecond duration) with the ability to focus light to smaller spot sizes (< 0.5 mm), came major advances in particle manipulations. Video demonstrations showed the effect of light on biological elements such as the controlled cut of chromosomes using a femtosecond laser as well as the study of cells dynamics by fluorescence emission of laser-induced shock waves.
Novel discoveries and unexplored scientific phenomena were part of the development of the fields of optogenetics and optomanipulation. For example, the study of the spring constant of chromosomes, dynamics of cells self-reconstruction, and directional response of neurons to circularly polarized light are collateral effects of the optical manipulation of cells.
Financing for healthcare: success for a diligent few
In 2013, a reported $3.6billion of private placements went to work commercializing technology and scaling businesses with core enabling technology in biophotonics. The panel discussed the plethora of financing options available to entrepreneurs starting-up and leaders of an established businesses.
The panel included Jim Haack, Senior Vice President at Citibank; Jeremy Salesin, Vice President of Acquisitions at Intellectual Ventures; Faz Bashi, Life Science Syndication Chair at Angel Capital Association; and Jonathan Wyler, Venture Partner at SV Life Sciences Advisers. Moderator was Linda Smith, president of Ceres Tech Advisors.
Faz Bashi, representing angel groups, the early investors who typically provide a bridge to venture capital with up to $1 million at the R&D or startup stages., provided insightful advice for entrepreneurs preparing for their first round of equity financing. Jonathon Wyler provided prospective on expected returns and life science ventures sought today by venture capitalists that typically provide $5 to $50 million or more at the early growth stage. Jim Haack educated us on a low cost debt options for financing working capital and capital equipment expenses. Jeremy Salesin presented a unique financing alternative – licensing your IP and partnering with a technology incubator.
Facing the highest risk, angels and venture capitalists invest at a significantly higher cost of capital than do strategic partners, late stage private equity and banks and other lenders.
Among tips from panelists:
- Sources of capital have different preferences and practices, including how much money they will provide, when in a company's life cycle they will invest, and the cost of capital or expected rate of return.
- The available sources of capital change dramatically for companies at different stages and rates of growth – from $0 cost of capital strategic alliances to low cost debt to higher cost equity with angels and VC's.
- Create a model that goes beyond "buy low, get a great return."
- Invest time to network, network, network.
- Find a mentor, someone who's done it before.
- Think twice about crowd funding.
It's all about people, Bashi said. "We want friendship, and trust. That's what makes a good investment for us."
Walking the floor
BiOS Expo, the world's largest biomedical optics and biophotonics exhibition, kicked off the Photonics West week. See more photos in the exhibition photo gallery.
Toru Yamada (right), National Institute of Advanced Industrial Science and Technology (Japan), discusses his paper,"Development of a fiber-less fNIRS system and its application to hair-covered head," (8928-27) at the Saturday BiOS poster session. See more photos in the event photo gallery.
Hot Topics: SRO, once again
The perennially popular BiOS Hot Topics session drew a standing-room-only crowd once again, eager to hear the latest news in biomedical optics and biophontonics in a series of brief talks.
With BiOS co-chairs Rox Anderson, Wellman Center for Photomedicine, Massachusetts General Hospital, and Jim Fujimoto, Massachusetts Institute of Technology, welcoming the crowd, SPIE President Philip Stahl opened the evening with the presentation of the SPIE Biophotonics Technology Innovator Award to Naomi Halas, Rice University (see the photo in the awards photo gallery). Stahl also congratulated Brian Wilson, Ontario Cancer Institute, on winning the 2014 SPIE Britton Chance Biomedical Award. Wilson will accept the award at SPIE Photonics Europe in Brussels in April.
Hot Topics Moderator Sergio Fantini, Tufts University, introduced the evening's speakers. See the event photo gallery for more photos.
|Rox Anderson and Jim Fujimoto
Bruce Tromberg (Beckman Laser Institute and Medical Clinic) presented on diffuse optical methods for assessing breast cancer chemotherapy. Current procedures for stages 2-4 breast cancer patients, which comprise approximately 20% of all breast cancer cases, involve approximately six months of chemotherapy in an effort to reduce the size of the tumor and improve the resulting surgical outcome. However, one-in-five patients doesn't respond to the chemotherapy.
Tromberg described a method combining frequency domain photon migration, essentially a method of tracking photon motion in tissue, with a NIR spectroscopy technique using 850nm LEDs. The result is a scatter corrected absorption spectra. The technique takes advantage of elevated blood and water levels and decreased lipid levels in the presence of tumors to provide a more accurate mapping of the breast, allowing more effective treatment.
Tromberg's team recently completed their first full mapping of the breast and have taken the instrument from a standalone unit to a portable one suitable for travel. In addition to providing feedback to enhance breast cancer treatment, Tromberg expects that this technique will be applicable in treating other forms of cancer as well.
Eric Seibel (University of Washington) discussed his team's work using a scanning fiber endoscope (SFE) to provide high-contrast imaging. The instrument consists of red-green-blue illumination sources coupled into a singlemode fiber optic which can be scanned in 2D using a piezoelectric tube as an actuator. The output end of the device consists of a quartz cantilever, an asphere lens, and fluorescence detectors coupling high-resolution spectral imaging with a long depth of focus.
Compared to current state-of-the-art instruments such as a tethered capsule endoscope with outer diameters on the order of 6mm, the SFE has an outer diameter of only 1.2mm making it suitable for procedures in small ducts and the cardiovascular system. Siebel discussed using the instrument for improving biopsy procedures and diagnostics as well as in stent deployment.
Eric Swanson (OCT News) discussed the migration of optical coherence tomography (OCT) into clinical practice. The translation from research to clinical work is challenging and passes through several stages including development, initial sales and iterations, market growth, and, finally, the next generation of a product. Each step can take 3-5 years, requiring persistence and perseverance on the parts of technologists and investors alike. Demonstration of a reliable product enables clinical use fueling publications and helping to drive the cycle to a successful conclusion.
The process began in the early '90 with the acquisition by Carl Zeiss of OCT technology that would eventually form the basis of Carl Zeiss Meditec, with an OCT product launch in 1997 for diagnosis of retinal diseases. Since that time, the number of applications has expanded particularly in the fields of ophthalmology and cardiology.
Today there are roughly 40 OCT systems companies worldwide. Of those, 80% began as startups and 42% had government funding at some phase thereby highlighting the importance of entrepreneurism and government support in translational work.
Clinical translation has been impactful. It is difficult work and benefits from the ability to focus in the early phases of the transition as demonstrated by the success of a number of startups. Many applications remain which provide the opportunity for clinical translation and the subsequent benefit to healthcare and quality of life.
David Boas (Massachusetts General Hospital) discussed techniques for understanding oxygen delivery through the vascular network. The use of microscopy coupled with modeling techniques to study the heterogeneous and complex oxygen delivery network and blood flow pattern in the vascular network was detailed.
Results from studies using a multimodal microscopy scheme involving two-photon microscopy and optical coherence tomography methods were discussed. The technique allows measurement of oxygen saturation levels combined with red blood cell flow at different points in the vascular network to build a model of oxygen extraction in the network providing new insight into roles of capillaries and arterioles in this function.
A decade of research has pushed photoacoustic computed tomography to the forefront of molecular-level imaging, noted Lihong Wang (Washington University, St. Louis).
Modern optical microscopy has resolution and diffraction limitations. But noninvasive functional photoacoustic computed tomography has overcome this limit, offering deep penetration with optical contrast and ultrasonic resolution of 1 cm depth or more -- up to 7 cm of penetration in some cases, such as evaluating sentinel lymph nodes for breast cancer staging. This opens up applications in whole body imaging, brain function, oxygen saturation, label-free cell analysis, and noninvasive cancer biopsies.
The use of nanometer-sized probes for single-cell studies was presented by Gary Shambat of Adamant Technologies. This work, conducted by Shambat while at Stanford working in Jelena Vukovic's lab, seeks to extend traditional nanoprobe work by being able to insert a nanobeam into a single cell without damaging the cell. By functionalizing the beam, the team enables single-cell studies, essentially taking the lab to the biological system instead of extracting the biological system for study in a lab.
The probe consists of a nanobeam optical cavity resulting from the tapering a GaAs device containing InAs quantum dots and coupled to an optical fiber to enable handling. The team demonstrated the ability to insert and retract the beam from PC3 cells (prostate cancer cells) in a reversible and elastic fashion.
Using this technique allowed a study of the optical properties of the cell. Cell viability in this initial work was 75%. Future work includes in vitro protein sensing and adapting chemistries for studies of intracellular targets such as proteins, all of which may find applications in fields such as drug screening.
The details of synapsis activity in the brain involves chemical receptors that facilitate the creation of the electrical connection between two nerves, noted Paul Selvin (University of Illinois, Urbana-Champaign). In order to understand the details of this neuroscience phenomenon you need to be able to "see" what is happening at the scale of these receptors, which is around 10 nanometers. This is smaller than the diffraction limit of normal microscopy and it takes place on a 3 dimensional structure.
Selvin described the development of small quantum dots (on the order of 6-9 microns) that are surface-sensitized to interact with the receptors. This allows the application of photo-activated localized microscopy (PALM), a superresolution microscopy that can be scanned through focus to develop a 3D map on a scale that is the same size as the emitter, which in this case are the small quantum dots. The quantum dots are stable in time and provide access to the receptors which allows the imaging of the interactions taking place at the synoptic level.
The secrets of brain activity and its control of motion are hidden in the structures, the functionality and the morphology of the physical brain, said Francesco Pavone (European Laboratory for Non Linear Spectroscopy [LENS]). The study of the brain's plasticity, or its ability to change, helps to reveal how it works.
We know synapses are formed through chemical interactions and electrical connections are made. But in order to understand the process we must examine the brain at several different scales. A cadre of optical methods such as correlative microscopy, optical manipulation, 3D tomography, confocal light sheet microscopy, and multimodal camera imaging are used to examine the brain at highly localized regions but at the multiple scales to reveal these inner workings.
Registered and ready to start!
Participants began registering early Saturday morning in anticipation of talks starting promptly at 8 a.m. See more photos in the event photo gallery.