# name
An experimental study of the temperature-dependent DNA elasticity using optical tweezers

# metadata.dc.description[].value
Màster Oficial en Física Avançada, Facultat de Física, Universitat de Barcelona, Curs: 2014, Tutor: Félix Ritort Farran

# metadata.dc.description.abstract[].value
Temperature plays a key role in all biological processes. Slight changes of temperature may lead
to completely di erent behaviors of biological systems. In fact, living matter carry out its function
in a small range of temperature. Therefore, it is interesting to study and understand what is the effect
of temperature in biological systems. Single-stranded DNA (ssDNA) is one of the most relevant
molecules in biological processes, providing us an excellent scenario to understand how the temperature
a ect its properties. In this project we aim to understand and characterize the elastic response
of ssDNA at di erent temperatures. We have used the Laser Optical Tweezers (LOT) technique in
order to measure the Force-Distance Curves (FDC) of ssDNA under the e ect of a mechanical force
at di erent temperatures. By  tting the stretching response of ssDNA to two semi
exible polymer
models we have obtained the temperature dependence of the elastic parameters. We have found
that persistence length and Kuhn length increase with temperature while the stretching modulus
seems to be insensitive to temperature changes. Finally, we have found that the persistence length
is proportional to the Debye screening length and that it varies with temperature according to a power law with exponent < 1.

# metadata.dc.title[].value
An experimental study of the temperature-dependent DNA elasticity using optical tweezers