September R&D Round UpSeptember 2, 2011 By: Melanie Martella, Sensors
This month's interesting research items include an implantable chip to monitor tumors in situ, a microscope that uses holograms rather than lenses, and an alloy that can catalyze the production of hydrogen from water.
A Chip to Monitor Tumors
The location of cancerous tumors dictates, to a certain extent, what kind of treatment and removal options exist. If a tumor can be removed it generally will be. But sometimes the tumors are in difficult locations, say inside the brain, or sometimes they grow very slowly, such as some tumors of the prostate. Ideally, you'd like to know what's happening with the tumor and that's where a recently developed wireless sensor chip comes in. Prof. Bernhard Wolf and his team of medical engineers at the Technische Universitaet Muenchen (TUM) have developed a small, implantable sensor chip that can be placed close to the tumor and that can measure the dissolved oxygen content of the tissue. Data are transmitted wirelessly from the chip to the receiver, carried by the patient, and then forwarded to the doctor. A drop in the oxygen content of the tissue may signal that the tumor is growing or that the cancer is becoming more aggressive and the chip can provide a far faster alert that things are changing than is possible using the existing imaging and diagnostic methods. The sensor isn't as small as they want it to be yet but the researchers have crammed an amazing amount of clever functionality into a tiny package. To learn more, read "Sensor chip for monitoring tumors".
A Holographic Microscope
Researchers led by Aydogan Ozcan, an associate professor of electrical engineering and bioengineering at UCLA, have been working on creating small, portable diagnostic instruments to help doctors, nurses, and field workers who are working to keep people healthy around the world. Their latest breakthrough creates a palm-sized microscope with a spatial resolution of <2 µm but that uses holograms rather than lenses. Light from a laser diode is sent through a pin hole where it is split into two beams. One beam hits the sample, the other one doesn't. Bringing the beams back together creates an interference pattern that is recorded on a CMOS image sensor. The hologram image is processed to create an image of the sample. The end result is a dual-mode microscope that can be used to check blood and water samples, among other things, and doesn't cost a huge amount. For far more detail, including some excellent photos, read the PhysOrg article "Microscope on the go: Cheap, portable, dual-mode microscope uses holograms, not lenses".
Hydrogen from Sunlight
Abundant sunlight used to convert water (of which we have lots) to its component atoms and thus liberating hydrogen, the wonder-renewable fuel that burns clean. From an alternative energy standpoint, that scenario of inexpensive and abundant clean fuel is enough to make you drool and it's the driving force behind research into a process called photoelectrochemical (PEC) water splitting that uses a catalyst to help sunlight to do just that. A research collaboration between the University of Louisville Conn Center for Renewable Energy Research and the University of Kentucky's Center for Computational Sciences wanted to find an appropriate catalytic material for this, and rather than focusing on tailor-making a complex chemical compound for the purpose, instead looked at readily available materials that could, so they hoped, have their structure tweaked to achieve the desired properties. They found that an alloy of gallium nitride and antimony—an alloy that's easy to make, no less—can theoretically help sunlight to do just that.
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