Change in torsional elastic constants of DNA under axial tension

• Main Author: Muhammad Ameer Han Rahaman
• Other Authors: Wu Mao See
• Format: Final Year Project
• Language: English
• Published: 2019
• Subjects: Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/78735
• Institution: Nanyang Technological University

Deoxyribose-nucleic acid (DNA) is one of the most unique things that attracts researchers and scientists to study about it. It is an interesting molecule which has a geometry of that it could amazingly pack and fit its actual length of about 7 centimetres long into the cells in our bodies. Understanding the twisted molecule could open many possibilities in the future; especially in medical science and engineering. Experiments have been done on DNAs, but it is still unknown to why the molecules behave in its own way. Stretching and twisting of the DNA could lead to many different forms; old and new. It happens to be elastic due to its ability to retrieve its shape sometimes, without breaking or overstretching. However, in some experiments, it was found that under a certain force, the molecule happens to be stronger and more resistant to twisting. This study attains to understand the phenomena behind the change of its apparent torsional stiffness involving first- and second- order elasticity theory. Simulations of several materials— from elements like silver to one of which is as close to a DNA (the cells found in the heart)— are done to investigate the possible reasons of change in the apparent torsional stiffness of a DNA. It is also compared with some previous studies done on DNA. This project theoretically suggests that the second-order elasticity theory may be a reason to the mentioned activity and characteristics of a DNA. Torsional stiffness of a specimen varies with the forces applied on it. Hence, with this knowledge, researchers and scientist could take into consideration of this matter, and progress further.