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A Vertical Comet Assay for Measuring DNA Damage to Radiation


University of Alaska/NASA Glenn Research Center, Human Exploration and Operations Mission Directorate, International Space Station

NASA needs a reliable and sensitive technique to collect data at ground and in-flight for assessing risk to astronauts from radiation exposure during spaceflight. We aim to develop such a technique to measure DNA damage, considered the first and foremost step in the malignant transformation of a normal cell into a cancerous one. While Earth’s magnetic field protects its inhabitants from space radiation, astronauts traveling beyond low Earth orbit are at greater risk of malignancies due to chronic, low-dose exposure to galactic cosmic rays, and random, short-term exposures to energetic particles from the Sun. Radiation exposure produces single and double strand-breaks in cellular DNA. The amount of strand-breaks can be correlated to the extent of damage to cells from radiation. One of the most convenient models to study DNA damage and

repair processes in live cells is the “comet assay,” or single-cell gel electrophoresis. Unfortunately, this technique requires laboratory set-ups so, at present, we have no reliable techniques to measure DNA damage aboard spacecraft. (This concern is addressed in NASA’s 2012 roadmap in the domain of Human Health, Life Support and Habitation Systems). We will develop, prototype and test a new, “in the field” technique we call “ vertical comet,” or “v-comet.” This new assay will use small scales of microchamber configuration in an integrated approach that combines the sensitivity of a traditional comet-assay technique with the versatility and subtle precision of a microfluidics technique. Development of this simple, sensitive technique for use in-flight or at mission control should provide increased safety for our astronauts during short spaceflight or long-term interplanetary exploration.

Schematic views of traditional and v-comet assays. Cellular density can be increased 5–10 times with the vcomet assay compared with the traditional comet assay. Because analysis is done after electrophoresis, in the traditional assay, each cell is analyzed separately from others, and the prior concentration of cells should be adjusted such that the extended tails do not cover/touch each other.

Cheng-fu Chen, Science PI, University of Alaska, Fairbanks

Cross-sectional schematic of the proposed v-comet assay.

Dr. Yuri Griko, NASA Technical Monitor, Ames Research Center, Life Science Division

NASA EPSCoR Stimuli 2014-15



EPSCoR Stimuli 2014-15  

NASA Office of Education’s Aerospace Research & Career Development (ARCD) is pleased to release NASA EPSCoR Stimuli, a collection of univers...

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