Universidade de Lisboa Repositório da Universidade de Lisboa

Repositório da Universidade de Lisboa >
Faculdade de Ciências (FC) >
FC - Dissertações de Mestrado >

Please use this identifier to cite or link to this item: http://hdl.handle.net/10451/5946

Título: Tethered particle motion in close proximity to a polystyrene surface
Autor: Martins, Filipe Mauel Pedro
Orientador: Van IJzendoorn, L. J.
Godinho, Margarida, 1948-
Palavras-chave: TPM
SPT
Superparamagnetic bead
Brownian motion
Magnetic tweezers
Teses de mestrado - 2010
Issue Date: 2010
Resumo: Tethered particle motion is a powerful technique to study the dynamics and mechanics of macromolecules, e.g. Deoxyribonucleic acid (DNA). It involves the analysis of Brownian motion of a particle (bead) tethered to a surface by a DNA molecule. In this work we describe the method to construct the system of a magnetic bead tethered to polystyrene surface by a DNA linker molecule. As tether we used a double helix DNA chain which is cut from a DNA plasmid form (circular shape) and provided with two different specific groups to connect the beads and the polystyrene surface respectively. Using magnetic tweezers we submit 500 nm diameter superparamagnetic beads to different magnetic forces and record the Brownian motion of the beads. Using an in-house made Matlab™ script we were able to track the 2 dimensional bead’s movement in order to study the influence of the magnetic force on the Brownian motion, with emphasis to the maximum mean radius of the bead’s excursion. We determined the mean radial displacement by calculating the 2-dimensional mean square displacement and fitting it with a modified relation from the work of Kusumi et al [1]. describing restricted diffusion. These results were verified by comparing them to the probability distribution function of the bead displacement plots. The observed results shown that the radial distance of the project center of the bead has a dependency of 1∕√Fmag with the magnetic force and the DNA spring constant depends linearly of the applied force. This results allows us to draw conclusions about the quality of the different methods used for the sample preparation and data analysis.
Descrição: Tese de mestrado, Engenharia Física, Universidade de Lisboa, Faculdade de Ciências, 2010
URI: http://hdl.handle.net/10451/5946
Appears in Collections:FC - Dissertações de Mestrado

Files in This Item:

File Description SizeFormat
ulfc100064_tm_Filipe_Martins.pdf3,84 MBAdobe PDFView/Open
Statistics
FacebookTwitterDeliciousLinkedInDiggGoogle BookmarksMySpaceOrkut
Formato BibTex mendeley Endnote Logotipo do DeGóis 

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

 

  © Universidade de Lisboa / SIBUL
Alameda da Universidade | Cidade Universitária | 1649-004 Lisboa | Portugal
Tel. +351 217967624 | Fax +351 217933624 | repositorio@reitoria.ul.pt - Feedback - Statistics
DeGóis
  Estamos no RCAAP Governo Português separator Ministério da Educação e Ciência   Fundação para a Ciência e a Tecnologia

Financiado por:

POS_C UE