Investigation of radiation damage in DNA by using atomic force microscopy

Area of Science:

• Biophysics
• Molecular Biology
• Radiation Science

Background:

• Radiation exposure can cause significant damage to DNA molecules.
• Understanding DNA radiosensitivity is crucial for radiation protection and therapy.
• Traditional methods for analyzing DNA damage have limitations in resolution and quantitative accuracy.

Purpose of the Study:

• To investigate the effects of alpha and X-ray radiation on supercoiled plasmid DNA.
• To evaluate the capability of Atomic Force Microscopy (AFM) for detecting and quantifying radiation-induced DNA strand breaks.
• To determine the radiosensitivity of DNA as a function of scavenger concentration.

Main Methods:

• Supercoiled plasmid DNA was exposed to alpha and X-ray radiation at various doses and scavenger concentrations.
• DNA samples were analyzed using Atomic Force Microscopy (AFM) to visualize molecular topology changes.
• AFM results were compared with data obtained from gel electrophoresis.

Main Results:

• AFM successfully detected DNA fragments (open circular and linearised strands) corresponding to single and double strand breaks.
• Quantitative analysis of DNA topology classes provided a measure of radiosensitivity for both radiation types.
• AFM enabled precise measurement of DNA strand sizes, offering advantages over gel electrophoresis.

Conclusions:

• Atomic Force Microscopy is a powerful tool for qualitative and quantitative assessment of radiation-induced DNA damage.
• AFM provides single-molecule resolution, revealing detailed information difficult to obtain with traditional techniques.
• The study established a method for determining DNA radiosensitivity using AFM, with results consistent with gel electrophoresis.