Study of Temperature Effects on Lambda DNA Structure Using Atomic Force Microscopy

الملخص

The aim of this study was to discover the temperature influences on DNA structure using Atomic Force Microscopy (AFM) technique. For AFM measurements, a λ DNA solution was used to align individual molecules on silicon wafers modified with chlorotrimethylsilane (Me3SiCl). AFM imaging was conducted on DNA samples before and after being heated at 373.15, 413.15, and 443.15 K for 60 minutes. At room temperature, AFM images reveal individual structures with linear and regular morphology. At 373.15 K, DNA appears with morphologies analogous to those observed at room temperature, and structures with a small number of particles can also be seen inside the DNA structure. The globular structures might be the result of the separation and recombination of DNA segments that contain more adenine-thymine base pairs than others. With increasing temperature to 413.15 K, a number of grains were observed inside the DNA chains, which is due to the complete separation of DNA strands. At higher temperatures (443.15 K), DNA undergoes serious degradation, forming small fragments of DNA molecule. This study indicates that structural changes occur in DNA at higher temperatures when aligned on a solid substrate than when DNA is in solution. This finding may be useful in the preparation of nanostructured materials using surface-based DNA nanofabrication approach.