TU‐C‐BRB‐08: Preliminary Study of DNA Damage and Repair of Tumor Cells under Microbeam Radiation Therapy Using an Integrated Carbon Nanotube‐Based Field Emission and Micropallet Array System

Purpose: This study aims at integration of carbon nanotube‐based field emission and micropallet array technologies to investigate the effects of microbeam radiation therapy(MRT) irradiation on the DNA damage and repair mechanisms of tumor cells in cancerradiation therapy.Methods: A carbon nanotube‐based field emissionelectron beamMRT device was used to deliver a 0.2 – 200 Gy electron MRTbeam to a monolayer of A549 lung cancer cells grown on glass coverslips. Cells were irradiated (100 Gy) and then fixed at various times for analysis. Fixed cells were stained for the stress‐induced protein phospho‐p38 using fluorescently tagged antibodies and fluorescence microscopy. Fluorescence data were analyzed using ImageJ analysis software. Results: The electron MRTbeam has a width of ∼40 microns and a dose rate of ∼100 Gy/s. Following irradiation, levels of phospho‐p38 increased rapidly peaking at six hours and then returning to basal levels by 24 hours. We observed that stress signaling such as phospho‐p38 is upregulated in a remarkably spatially discrete manner in monolayer cells irradiated with the microbeam irradiator. DNA damage as measured by gamma‐H2AX in A549 cells displayed kinetics similar to those for phospho‐p38 following irradiation. Conclusions: We have shown the feasibility of integrating our carbon nanotube‐based field emission and micropallet array system for MRT mechanistic study. Our initial study indicates that the DNA damage and repair from MRT may be different than from conventional therapeutic radiation but the details are still under investigation and clarification. Acknowledgements: This work is partially supported by the North Carolina University Cancer Research Fund. This work is partially supported by the University of North Carolina Cancer Research Fund