Tuesday, January 6, 2009
Silk Harnessed to Build Implantable Medical Devices
Filed under: in the news...
Silkworms are known for their contribution to scarves, ties, and sarees everywhere. But the natural qualities of silk allow it to be used to make implantable optical sensors and other devices that don't produce an immune response, while being biodegradable by the body over time.
The MIT Technology Review profiles the work of Associate Professor Fiorenzo Omenetto at Tufts University's Department of Biomedical Engineering:
Omenetto's recipe begins with cocoons spun by the silkworm Bombyx mori. First, he says, "you cut the cocoon and remove the worm--much to the chagrin of vegans." Senior research technician Carmen Preda then boils the cocoons in a solution containing the salt sodium carbonate. This helps dissolve sericin, a gluey glycoprotein that holds the cocoons together but causes immune reactions in humans. After the silk fibers dry, they're dissolved in a solution of lithium bromide. When it cools, Preda uses a syringe to load it into a dialysis cartridge. She sets this inside a beaker of water, which draws out the salt.What's left in the cartridge is a clear, viscous solution of the purified protein silk fibroin. Preda removes this silk "syrup" from the cartridge with a syringe and loads it into a row of test tubes; this is the starting material for Omenetto's optical components. If he wants to use the components in a biosensor, he can add a protein targeting a particular molecule--say, oxygen-binding hemoglobin--at this stage. "You have this nice water-based solution that you can mix anything into," Omenetto says.
Dr. Omenetto describing his new manufacturing technique:
More from MIT Technology Review...
Image credit: Natmandu
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Water Power in Developing World to Cure Poor Eyesight
Filed under: Ophthalmology
An Oxford University physics professor Dr. J D Silver has developed water filled glasses that have a variable optical strength thanks to a small pump dial. The idea is that the services of an optician would not be needed since "the wearer can adjust the power of each lens to his or her own requirements."
From the technology page at Adaptive Eyecare, the manufacturer of the device:
The approach of Adaptive Eyecare has been to develop a completely new ophthalmic lens technology which permits us to manufacture revolutionary new spectacles which are universal, in the sense that one pair may be used to correct the vision of over 90% of people requiring correction. The special feature is that the wearer can adjust the power of each lens to his or her own requirements - this is particularly useful for developing world populations in areas which do not have adequate numbers of those specially trained personnel normally associated with the provision of vision correction.The lenses in Adaptive Eyecare's spectacles operate in a manner which is somewhat similar in its optical function to the crystalline lens in the human eye - our lenses have the feature that the curvature of the lens surfaces is under the control of the wearer of the spectacles, and a simple manual adjustment is all that is needed to vary the power of each lens. In use, the wearer adjusts each lens so as to get clearest vision. This process takes less than a minute for both eyes. Having found the best setting, the lenses are then set, and the ancillary device used for lens adjustment is removed and discarded.
Adaptive Eyecare's adaptive lenses are fluid- filled and the power is changed by varying the amount of fluid in the lens. The power range of our lenses is +6 to -6 Dioptres, and the optical quality is similar to that of the typical human eye.
Of course, we'd like to see the quality that glasses made of stretchable membranes and liquid water can provide. They, obviously, can't be all bad if 30,000 have already been distributed.
More from the Guardian...
Adaptive Eyecare - Technology...
(hat tip: Core77)
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Military Aims to Design Virtual Moms and Dads
Filed under: Society
The Pentagon is initiating a project to build a virtual parent, a software application that would be used by children with military parents out on deployment that don't have the time to communicate with their kids. As the Department of Defense is building simulated moms and dads, the Orwellian aroma is unmistakable. But fear not, this project is currently only at the stage of seeking proposals from companies interested in tackling the idea in practice.
From the DOD project overview:
The challenge is to design an application that would allow a child to receive comfort from being able to have simple, virtual conversations with a parent who is not available "in-person". We are looking for innovative applications that explore and harness the power of advanced interactive multimedia computer technologies to produce compelling interactive dialogue between a Service member and their families via a pc- or web-based application using video footage or high-resolution 3-D rendering. The child should be able to have a simulated conversation with a parent about generic, everyday topics. For instance, a child may get a response from saying "I love you", or "I miss you", or "Good night mommy/daddy." This is a technologically challenging application because it relies on the ability to have convincing voice-recognition, artificial intelligence, and the ability to easily and inexpensively develop a customized application tailored to a specific parent. We are seeking development of a tool which can be used to help families (especially, children) cope with deployments by providing a means to have simple verbal interactions with loved ones for re-assurance, support, affection, and generic discussion when phone and internet conversations are not possible. The application should incorporate an AI that allows for flexibility in language comprehension to give the illusion of a natural (but simple) interaction. The current solicitation is not aiming to build entertainment, but a highly accurate and advanced simulation platform. Voice-recognition and voice-interaction are required. The User Interface is a critical component for this program. Application must be user friendly and application must be easy to install and maintain. Verbal interactions should be as normal as current technology will allow. Proven track record for creating similar types of applications is desired, but not required. Development plans should include the use of trained psychological health and family advocacy experts with experience providing services to military populations. Project MUST include discussion of how personal information would be collected, recorded, and rendered as well as address issues about information content and complexity of proposed simulation application. If using a web-based application, security and maintenance issues must be addressed. Application must run on typical family-owned computer systems.
DOD request from proposals: Virtual Dialogue Application for Families of Deployed Service Members
Image: deryckh
(hat tip: InformationWeek)
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Model Helps Develop Better Cardiac Stent Designs
Filed under: in the news...
MIT engineers have been working on a mathematical model that can be used to map out the patterns of turbulence formed by drug eluting stents. With this knowledge it is possible to predict which designs will be less favorable to the formation of stent induced clots, and so let engineers work around potentially bad shapes.
From MIT press office:
Stents affect the fluid dynamics of blood flowing past them and cause drugs to accumulate in certain areas. Too much drug buildup promotes clot formation.The MIT model shows that the dynamics of blood flowing around a stent is similar to whitewater rapids, said Edelman. When water in a river flows over a boulder, some of the water strikes the base of the boulder, flies up in the air and comes back down, instead of flowing over the rock. This water continuously recirculates in the same area.
The same thing happens when blood flows across a stent: Drugs tend to accumulate and spin around in the recirculation zone. This is most likely to happen with stents that protrude further into the artery. "Until now, the degree to which recirculation zones impact the distribution of drugs was not appreciated," said Edelman.
This is the first time that a mathematical model has successfully predicted stent performance based on changes in arterial blood flow and design, and the researchers hope the model and concepts it establishes could aid efforts to design stents that allow drugs to be more evenly distributed throughout the area.
The model could also help the FDA in its approval processes, by helping regulators figure out which stents are most likely to be safe or harmful, based on their size and shape, which controls how they will affect blood flow.
More from MIT: Model predicts how to build a better stent ...
Study abstract: Luminal flow patterns dictate arterial drug deposition in stent-based delivery
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Review: Gunnar Optiks Glasses for The Digital World
Filed under: OTC
Gunnar Optiks is a San Diego, California firm that focuses on manufacturing specialty glasses for people who experience eye strain from using computers for long periods of time. Last month we received a couple pairs of the firm's glasses to try out, and if you noticed a slight improvement in the writing quality of this blog, it might be because a good deal was done while wearing them. But seriously, though these aren't divine miracles sent from above, we've enjoyed using Gunnar glasses in our work.
Gunnar has essentially taken classic reading glasses and added a few helpful twists for the digital world of computer screens. The lenses give somewhere around +1.25 magnification, which seems to be almost like increasing screen size up a level while keeping pixel count the same. The view seems to be more magnified toward the center of the lens, and this does morph the image ever so slightly on the sides. Generally this is unnoticeable, especially after a few minutes of wearing the glasses.
The second helpful quality of the glasses is the yellowish tint coating on the lenses. This reduces the harsh blue color that most monitors emit when displaying a lot of white on the screen. Though the real world looks strangely yellow through these glasses, the images viewed on the laptop seem to exhibit a bit more richness and the picture has a good deal more contrast. This effect reminded us of the old Blu-Blockers we used to see ads on TV, and probably they both take advantage of the same concept of filtering out the blue.
Overall, the build quality is not supreme, but it was acceptable to us. The materials used in glasses are surprisingly light, but they don't feel cheap, and they do offer the advantage of being comfortable to wear all day long even by those of us who don't normally wear glasses.
There's also a bit of glare reduction, though the glasses are not polarized. You simply can't use polarizers with most digital screens as they will look black at different orientations in polarized glasses.
Lastly, and maybe the most important for many, is that you neither have to look like an old fashioned grammar teacher while wearing them, nor have to squint and suffer all day long while laboriously blogging, coding or working on your computer.
Flashback: Gunnar i-AMP Technology Takes on Digitial Eye Fatigue
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Light Used to Trap, Move DNA
Filed under: in the news...
Cornell University scientists used light to trap DNA and other nanoparticles in moving water. The technology should find itself useful in lab-on-chip devices and other clinical testing tools.
From the National Science Foundation:
Light has been used to manipulate cells and even nanoscale objects before, but the new technique allows researchers to manipulate the particles more precisely and over longer distances."At the nanoscale, we can think of light like a series of massless particles called photons," says Cornell engineer David Erickson, one of the co-authors of the study. "We've demonstrated a way to condense these photons down to a very small area and stream them along a special type of waveguide, a device that acts like a nanoscale optical fiber. When pieces of matter, like DNA or nanoparticles, float near these streaming photons, they are sucked in and pushed along with the flow. The effect is sort of like moving a truck by throwing baseballs at it. The trick is that we found a way to have a large number of highly efficient "collisions" between the photons and the nanoparticles, getting them to stay in our device and keep them moving along it."
Erickson and fellow Cornell engineer Michal Lipson, along with their graduate students Allen Yang, Sean Moore and Bradley Schmidt, and colleagues in Erickson's and Lipson's research groups, crafted a wave guide to shunt light into a narrow beam, laying a trap for the DNA and other small pieces of material.
Each of the tiny channels within the waveguide is only 60-120 nanometers (billionths of a meter) wide, thinner than the 1,500 nanometer wavelength of the infrared laser light channeling through them. The channels keep the light waves focused and enhance their ability to interact with the DNA particles, preventing them from flowing by.
The breakthrough is the use of the slot waveguide, which condenses a light wave's energy to scales as small as the target molecules, overcoming prior limitations caused by light diffraction. Because the waveguide is also a "nanochannel" it can both trap and transport objects using light.
For their experiments, the researchers used water solutions containing either DNA or tiny nanoparticles, washing the fluids over the waveguide microchannels. At a speed of 80 micrometers per second, the system traps less than a fourth of the target particles flowing by, but with smaller channel sizes, slower flows and higher energy lasers, the success rate increases.
"What we're hoping to do now is better understand some of the underlying physics to see what else might be possible with this approach," adds Erickson. "Ultimately we imagine being able to take all the ultrafast and highly efficient optical devices that have been developed for communications and other applications over the last 20 years and apply them to the manipulation of matter in different types of nanosystems. Hopefully in the future we can shuttle around individual strands of DNA the same way we now shuttle around light."
Press release: Nano "Tractor Beam" Traps DNA ...
Image: DNA molecules suspended in a stream of water flowing through a nanoscale channel
Watch video from the experiment...
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The 2008 Medical Weblog Awards: The Polls Are Open!
Filed under: Medgadget Exclusive
, Net News
The polls are now open in the Fifth Annual Medical Weblog Awards.
Please vote here...
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Reflections by Dr. Bruce Campbell
Running for My Life: Fighting cancer one step at a time
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Stuart Laidlaw's Medical Ethics blog
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Brass and Ivory: Life with Multiple Sclerosis
Running for My Life: Fighting cancer one step at a time
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The 2008 Medical Weblog Awards are proudly sponsored by Epocrates.
The 2008 Medical Weblog Awards announcement...
The 2008 Medical Weblog Awards Nominees...
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Monday, January 5, 2009
EyeSeeCam: See What The Surgeon Sees
Filed under: ENT
, Neurology
, Surgery
Biomed engineers and clinical neurologists at the University of Munich Hospital are working on commercialization of a head mounted camera designed to store and transmit the exclusive point of view of its wearer's eyes. The EyeSeeCam moves along with the pupils of the user, and as such allows "for the first time, to literally see the world through somebody else's eyes." The device will be presented at the upcoming MMVR 17 NextMed conference (Jan 19-22, in Long Beach, CA).
The possibilities for the camera are endless. Here's what its designers think it could be used for:
Health Care and Industry: Documentation, e.g., of Surgery; Teaching and Education; Quality AssuranceNeurology, ENT: Diagnosis of eye movement disorders; Diagnosis of vestibular disorders and vertigo
Movie and Video Making: Documentary and fictional movies; News and Videoart
Security: Quality assurance of special forces training; Documentation by a "third eye"
Sports: Sportsnews; Movie from the Athlete's perspective
(Neuro-) Marketing:Shopping behavior; Advertisement perception; Ergonomy
Research: Studies on attention; "Body language" during conversation
Consumer Applications: Sightseeing; Events
(hat tip: ScienceRoll)
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Scientists Develop Microfluidic Method of Cell Fusion
Filed under: Genetics
Investigators from MIT developed a new method to sort and pair cells inside a specially designed microchip. This new technology should simplify and enable a new wave of research on chimeric cells:
The researchers, led by a collaboration between Joel Voldman, associate professor of electrical engineering and computer science, and Rudolf Jaenisch, professor of biology and a member of the Whitehead Institute, report the new technique in the Jan. 4 online edition of Nature Methods.The team's simple but ingenious sorting method increases the rate of successful cell fusion from around 10 percent to about 50 percent, and allows thousands of cell pairings at once.
Though cell fusion techniques have been around for a long time, there are many technical limitations, said Voldman.
Getting the right cells to pair up before fusing them is one major obstacle. If scientists are working with a mixture of two cell types, for example A and B, they end up with many AA and BB pairings, as well as the desired AB match.
Researchers had previously trapped cells in tiny cups as they flow across a chip. Each cup can hold only two cells, but there is no way to control whether the cups capture an A and a B, two As or two Bs.
In contrast, the cell-trapping cups on Voldman and Jaenisch's new sorting device are arranged strategically to capture and pair up cells of different types.
First, type A cells are flowed across the chip in one direction and caught in traps that are large enough to hold only one cell. Once the cells are trapped, liquid is flowed across the chip in the opposite direction, pushing the cells out of the small cups and into larger cups across from the small ones.
Once one A cell is in each large cup, type B cells are flowed into the large cups. Each cup can only hold two cells, so each ends up with one A and one B. After the cells are paired in the traps, they can be joined together by an electric pulse that fuses the cell membranes.
In addition to helping with studies of stem cell reprogramming, this technique could be used to study interactions between any types of cells. "It's a very general type of device," said Voldman.
Study abstract: Microfluidic control of cell pairing and fusion
MIT press release: Getting cells to pair off...
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