December 14, 2011
Physics News Highlights of the American Institute of Physics (AIP) contains summaries of interesting research from the AIP journals, notices of upcoming meetings, and other information from the AIP Member Societies. Copies of papers are available to journalists upon request.
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TOPICS IN THIS ISSUE:
1. Plasma treatment zaps viruses before they can attack cells
Adenoviruses can cause respiratory, eye, and intestinal tract infections, and, like other viruses, must hijack the cellular machinery of infected organisms in order to produce proteins and their own viral spawn. Now an international research team made up of scientists from Chinese and Australian universities has found a way to disrupt the hijacking process by using plasma to damage the viruses in the laboratory environment, before they come into contact with host cells.
The researchers prepared solutions containing adenoviruses and then treated the samples with a low-temperature plasma created by applying a voltage to a gaseous mixture in a syringe. The strong electric field energized electrons that collided with molecules in the gas, generating charged particles and highly reactive species such as oxygen atoms that likely etched away the protein shell of the viruses and damaged or destroyed the viral DNA. When the virus solutions were later added to colonies of embryonic kidney cells, the plasma-treated samples showed much less viral activity, as measured by the amount of a florescent virus protein the infected kidney cells produced. If the virus solution was covered during treatment to maximize plasma-virus interactions, more than 99 percent of the viruses could be deactivated in eight minutes. The technique is described in a paper accepted for publication in the AIP’s journal Applied Physics Letters.
Adenoviruses pose life-threatening risks to patients undergoing stem-cell therapy, so the anti-viral plasma treatment may help pave the way to safer therapies, the researchers write. Because plasma jets have multiple biomedical applications, the team is also developing a portable device that generates plasma by using a 12 V battery to decompose and ionize air, says Dr. XinPei Lu at the HuaZhong University of Science and Technology in China and leader of the team. The device might be used in rural areas and battlefields, according to Lu.
Article: “Room-temperature, atmospheric plasma needle reduces adenovirus gene expression in HEK 293A host cells” is accepted for publication in Applied Physics Letters.
Authors: Z. Xiong (1), X. Lu (1), Y. Cao (2), Q. Ning (3), K. Ostrikov (4), Y. Lu (5), X. Zhou (2), and J. Liu (3).
(1) State Key Laboratory of Advanced Electromagnetic Engineering and Technology, HuaZhong University of Science and Technology, China
2. New device creates lipid spheres that mimic cell membranes
Opening up a new door in synthetic biology, a team of researchers has developed a microfluidic device that produces a continuous supply of tiny lipid spheres that are similar in many ways to a cell’s outer membrane. “Cells are essentially small, complex bioreactors enclosed by phospholipid membranes,” said Abraham Lee from the University of California, Irvine. “Effectively producing vesicles with lipid membranes that mimic those of natural cells is a valuable tool for fundamental biology research, and it’s also an important first step in the hoped-for production of an artificial cell.” The researchers have taken an important step in advancing this field by developing a single system that quickly and efficiently performs all the necessary steps to create stable lipid vesicles. Current multistep production methods create vesicles that have inconsistent sizes and layers and short usable lifespans, and they are often contaminated with solvents used in their production. A paper accepted for publication in the AIP’s journal Biomicrofluidics reports that the new microfluidic design overcomes these previous hurdles by generating and manipulating precisely sized droplets of water in an oil environment. This produces an oil-and-water membrane that serves as a scaffold around which lipids molecules assemble. As the membrane dissolves over time, the accumulated lipids form a stable, uniform vesicle that shares many of a natural cell membrane’s chemical and physical attributes.
Authors: Shai-Yen The (1), Ruba Khnouf (2), Hugh Fan (2, 3), Abraham Lee (1, 4).
(1) Department of Biomedical Engineering, University of California at Irvine
3. New system may one day steer microrobots through blood vessels for disease treatment
Microscopic-scale medical robots represent a promising new type of therapeutic technology. As envisioned, the microbots, which are less than one millimeter in size, might someday be able to travel throughout the human bloodstream to deliver drugs to specific targets or seek out and destroy tumors, blood clots, and infections that can’t be easily accessed in other ways. One challenge in the deployment of microbots, however, is developing a system to accurately “drive” them and maneuver them through the complex and convoluted circulatory system, to a chosen destination. Researchers from Korea’s Hanyang University in Seoul and Chonnam National University in Gwangju now describe, in the AIP’s Proceedings of the 56th Annual Conference on Magnetism and Magnetic Materials, a new navigation system that uses an external magnetic field to generate two distinct types of microbot movements: “helical”, or corkscrew-like, motions, which propel the microbots forward or backward, or even allow them to “dig” into blood clots or other obstructions; and “translational,” or side-to-side motions, which allow the ‘bots to, for example, veer into one side of a branched artery. In lab tests, the researchers used the system to accurately steer a microbot through a mock blood vessel filled with water. The work, the researchers say, could be extended to the “precise and effective manipulation of a microbot in several organs of the human body, such as the central nervous system, the urinary system, the eye, and others.”
Article: “Magnetic Navigation Systems for the Precise Helical and Translational Motions of a Microrobot in Human Blood Vessels” is part of the Proceedings of the 56th Annual Conference on Magnetism and Magnetic Materials, to be published in the Journal of Applied Physics in April.
Authors: Seungmun Jeon (1), Gunhee Jang (1), Hyunchul Choi (2), Sukho Park (2), and Jongoh Park (2).
(1) Hanyang University, Korea,
Upcoming Conferences of Interest
Physics Today: December Articles
1. Insights from the great 2011 Japan earthquake: The diverse set of waves generated in Earth’s interior, oceans, and atmosphere during the devastating Tohoku-oki earthquake reveal some extraordinary geophysics.
AIP Science Communication Awards: Call for Entries
Entries are requested for the American Institute of Physics’ 2012 Science Communication Awards, which recognize effective science communication, both in print and new media, that improves the general public's appreciation of physics, astronomy, and allied science fields.
Categories: Science Writing (books), Children’s Writing, New Media