Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/29550
Title: MICRO AND NANO-FLUIDICS FOR DNA MOLECULES APPLICATIONS
Authors: BIKKAROLLA SANTOSH KUMAR
Keywords: Nano channels,micro channels,graphene,DNA,PDMS,fluorescence microcope
Issue Date: 4-May-2011
Source: BIKKAROLLA SANTOSH KUMAR (2011-05-04). MICRO AND NANO-FLUIDICS FOR DNA MOLECULES APPLICATIONS. ScholarBank@NUS Repository.
Abstract: In chapter 1, we summarize the properties of nucleic acids in bulk and in nanoconfinement. We will be discussing the conformation of DNA in the presence of condensing ligands spermidine, cobalt hexamine and spermine. In chapter 2, we describe the materials and methods used in the experiments. We will describe the procedure for the fabrication of micro-fluidics channels in SU-8, fabrication of a nano-micro fluidic chip in PDMS (Polydimethylsiloxane), injecting molecules in nano-channels, and fluorescence imaging of T4-DNA molecules in nano-channels. In chapter 3 our main interest is to study the conformation of T4 DNA molecule in the presence multivalent cations like spermidine, cobalthexamine and spermine. To observe the conformation of dye labeled T4 DNA molecule we used fluorescence microscope. Our results show that transition from elongated state to collapsed state is discrete. The critical concentration of the cation needed to condense the DNA molecule is lowest for the tetravalent cation and highest for the trivalent cation. The co-existence region is larger for trivalent cation and less for the tetravalent cation In chapter 4 we aim to study the equilibrium conformation of the DNA molecule in nanoconfinement. For this purpose we fabricated nano-channels of 200nm in width and 300nm in height in PDMS and used fluorescence microscope to observe the elongation of the molecule. Our results show that in 1XT buffer (10mM Tris-Hcl pH=8.5) the elongation of T4 DNA molecule is around 12µm 3 In chapter 5, we demonstrate the integration of the PDMS micro-fluidic channel with graphene device as a novel way to achieve electrolyte top gating of graphene. By applying a back gate voltage, carrier concentrations of up to 2.3 x 1012 /cm2 and mobility values of up to 7500cm2/Vs can be obtained in the device at ambient conditions. In the case of electrolyte top gating, significantly higher doping concentrations can be achieved as compared to conventional back gating at low voltages. The effective implementation of electrolyte top gating by using micro channels serves as a compelling proof of concept that graphene can be used as a chemical and biological sensor.
URI: http://scholarbank.nus.edu.sg/handle/10635/29550
Appears in Collections:Master's Theses (Open)

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