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Title: DNA programmed assembly of active matter at the micro and nano scales
Author: Gonzalez, Ibon Santiago
ISNI:       0000 0004 6501 0285
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 2017
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Small devices capable of self-propulsion have potential application in areas of nanoscience where autonomous locomotion and programmability are needed. The specific base-pairing interactions that arise from DNA hybridisation permit the programmed assembly of matter and also the creation of controllable dynamical systems. The aim of this thesis is to use the tools of DNA nanotechnology to design synthetic active matter at the micro and nano scales. In the first section, DNA was used as an active medium capable of transporting information faster than diffusion in the form of chemical waves. DNA waves were generated experimentally using a DNA autocatalytic reaction in a microfluidic channel. The propagation velocity of DNA chemical waves was slowed down by creating concentration gradients that changed the reaction kinetics in space. The second section details the synthesis of chemically-propelled particles and the use of DNA as a 'programmable glue' to mediate their interactions. Janus micromotors were fabricated by physical vapour deposition and a wet-chemical approach was demonstrated to synthesise asymmetrical catalytic Pt-Au nanoparticles that function as nanomotors. Dynamic light scattering measurements showed nanomotor activity that depends on H2O2 concentration, consistent with chemical propulsion. Gold nanoparticles/Origami hybrids were assembled in 2D lattices of different symmetries arranged by DNA linkers. The third section details the design process and synthesis of nanomotors using DNA as a structural scaffold. 3D DNA Origami rectangular prisms were functionalised site-specifically with bioconjugated catalysts, i.e. Pt nanoparticles and catalase. Enzymatic nanomotors were also conjugated to various cargoes and their motor activity was demonstrated by Fluorescence Correlation Spectroscopy. In the final section, control mechanisms for autonomous nanomotors are studied, which includes the conformational change of DNA aptamers in response to chemical signals, as well as a design for an adaptive dynamical system based on DNA/enzyme reaction networks.
Supervisor: Turberfield, Andrew J. Sponsor: Engineering and Physical Sciences Research Council ; Department of Education and Culture ; Basque Government
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Soft Condensed Matter ; Physics ; Biophysics ; DNA nanotechnology ; Reaction-diffusion ; Single-molecule biophysics ; Active matter ; Self-diffusiophoresis ; Self-Assembly ; Microswimmers ; Nanomotors ; Dynamic Light Scattering ; Fluorescence Correlation Spectroscopy