C. elegans nematode is a well-established research tool suitable for radiobiological studies. With a transparent body that can be easily observed under a microscope, it has a relatively small diameter (50 µm) and can be completely traversed by the charged particles generated at the Columbia microbeam whose maximum beam penetration is 450 µm.
C. elegans Irradiation Sample Experiment
An initial irradiation experiment irradiating the head of a worm results in a heat shock response throughout the whole worm 24 hours after irradiation. This experiment is a basic experiment looking for whole body response to irradiation. We are developing techniques to target individual cells in the worm and/or organ systems with integrated observation for acute radiation responses.
C. elegans Immobilization for High-Throughput Irradiation
We have developed a microfluidic worm clamp to immobilize the samples in a specific orientation for high throughput irradiation at the microbeam.
(A) A 16-channel microfluidic device for C. elegans observation and irradiation at the microbeam. (B) Diagram of a single channel system. The width of each microchannel gradually decreases along the 5-mm channel to 10 µm so that young adult worms are immobilized without the use of anesthesia. (C) Once loaded in the inlet (10× view), worms move into the microfluidic channels through liquid flow between inlet and outlet. Few minutes after initiating the liquid flow, the worms fill up the channels of the clamp (D) 10x view and (E) 20x view.
The green cross identifies the nominal location of the beam center and is used as a reference point for manual positioning of the worms. The red crosses show the actual targeted positions.
By using our microfluidic device that allows simultaneous immobilization and imaging for irradiation of several whole living samples on a single clamp, we have shown that 4.5 MeV proton microbeam irradiation induced DNA damage in wild-type C.elegans, as assessed by the formation of Rad-51 foci that are essential for homologous repair of radiation-induced DNA damage
Bertucci, A., Pocock, R.D., Randers-Pehrson, G. and Brenner, D.J. Microbeam irradiation of the C. elegans nematode. J Radiat Res (Tokyo) 50 Suppl A: A49-54, (2009). PMCID: PMC2950932. [abstract] [PDF]
Buonanno M, Garty G, Grad M, Gendrel M, Hobert O, Brenner DJ., Microbeam irradiation of C. elegans nematode in microfluidic channels. Radiat Environ Biophys. 2013 Aug 13. [NIHMS515583 Epub ahead of print]