Microelectrophoresis of Semiconductive Quantum Dots By Mengke Han A thesis submitted for the fulfilment of the degree of Master of Philosophy in the Faculty of Sciences School of Physical Sciences Aug 2017 Declaration of Authorship I certify that this work contains no material which has been accepted for the award of any other degree or diploma in my name in any university or other tertiary institution and, to the best of my knowledge and belief, contains no material previously published or written by another person, except where due reference has been made in the text. In addition, I certify that no part of this work will, in the future, be used in a submission in my name for any other degree or diploma in any university or other tertiary institution without the prior approval of the University of Adelaide and where applicable, any partner institution responsible for the joint award of this degree. I give consent to this copy of my thesis when deposited in the University Library, being made available for loan and photocopying, subject to the provisions of the Copyright Act 1968. I also give permission for the digital version of my thesis to be made available on the web, via the University's digital research repository, the Library Search and also through web search engines, unless permission has been granted by the University to restrict access for a period of time. Signed: Date: II Table of contents Declaration of Authorship .................................................................................. II Abstract ............................................................................................................... VII Acknowledgements ............................................................................................. IX List of Figures ...................................................................................................... XI List of Tables ................................................................................................... XVII Abbreviations and Symbols for Units ........................................................... XIX 1 Introduction ................................................................................................ 1 1.1 Background and Motivation .............................................................. 1 1.1.1 Semiconductive QDs ....................................................................... 4 1.1.2 Microelectrophoresis technique ..................................................... 7 1.2 State-of-the-art ..................................................................................... 9 1.2.1 Surface functionalization of semiconductive QDs ....................... 9 1.2.2 Iontophoresis and zeta potential .................................................. 11 1.2.3 Size distribution of semiconductive QDs .................................... 17 1.2.4 Micropipettes and electrodes ....................................................... 19 1.2.5 Microinjection technique and agarose gel ................................... 22 1.3 Research Objectives ........................................................................... 25 1.4 Thesis structure ................................................................................. 26 1.5 References .......................................................................................... 28 2 Suspension preparation of semiconductive QDs ................................ 32 2.1 Introduction ....................................................................................... 32 2.2 Experimental procedures ................................................................. 34 2.2.1 Materials ......................................................................................... 34 2.2.2 Preparation of QDs suspension for TEM imaging ..................... 35 III 2.2.3 Intracellular recording tests for the determination of KCl concentration ................................................................................. 37 2.2.4 Preparation of QDs samples with varying pH ........................... 40 2.2.5 Preparation of QDs samples by the first method ....................... 42 2.2.6 Preparation of QDs samples by the second and third methods 43 2.2.7 Measurement procedure for the size distribution of QDs ......... 44 2.3 Results and discussion ...................................................................... 45 2.3.1 The impact of KCl concentration on intracellular recording ..... 45 2.3.2 Size, shape and density of QDs .................................................... 49 2.3.3 Relation between pH and the zeta potential of QDs .................. 52 2.3.4 Results and comparison of the three methods for QDs suspension preparation................................................................. 54 2.3.5 The size distribution of QDs ......................................................... 59 2.4 Conclusions........................................................................................ 62 2.5 References .......................................................................................... 64 3 Manufacture of micropipettes ................................................................ 66 3.1 Introduction ....................................................................................... 66 3.2 Experimental procedures ................................................................. 69 3.2.1 Manufacture of micropipettes ...................................................... 69 3.3 Results and discussion ...................................................................... 70 3.3.1 Tip sizes of micropipettes ............................................................. 70 3.4 Conclusions........................................................................................ 72 3.5 References .......................................................................................... 73 4 Microinjection of semiconductive QDs ................................................ 74 4.1 Introduction ....................................................................................... 74 4.2 Materials and Method ....................................................................... 76 4.2.1 Measurement procedure for the fluorescence spectrum of QDs ......................................................................................................... 76 4.2.2 Preparation of agarose gels .......................................................... 77 4.2.3 Microinjection of QDs ................................................................... 78 IV 4.2.4 Fluorescence microscopy: measurement of the fluorescence signals of ejected QDs ................................................................... 80 4.3 Results and discussion ...................................................................... 80 4.3.1 Fluorescence spectra of QDs......................................................... 80 4.3.2 Fluorescence image of agarose gels doped with QDs ................ 81 4.3.3 Microinjection of QDs ................................................................... 82 4.4 Conclusions........................................................................................ 87 4.5 References .......................................................................................... 87 5 Microelectrophoresis of semiconductive QDs ..................................... 89 5.1 Introduction ....................................................................................... 89 5.2 Experimental procedures ................................................................. 90 5.2.1 Preparation of QDs in 3 M KCl solutions .................................... 90 5.2.2 Preparation of agarose gels .......................................................... 90 5.2.3 Microelectrophoresis of QDs ........................................................ 91 5.2.3.1 Long-term ejection method: measurement of the accumulation of ejected QDs on the counter electrode ..................... 92 5.2.3.2 3M KCl accumulation method: measurement of the accumulation of ejected QDs under agarose gels............................... 93 5.2.3.3 Fluorescence microscopy: measurement of the fluorescence signals of ejected QDs ........................................................................... 94 5.3 Results and discussion ...................................................................... 94 5.3.1 Aggregation of QDs in 3 M KCl solutions .................................. 94 5.3.2 Microelectrophoresis of QDs ........................................................ 96 5.3.2.1 Long-term ejection method: detection of ejected QDs on the counter electrode ................................................................................... 96 5.3.2.2 3 M KCl accumulation method: detection of ejected QDs under agarose gels ................................................................................ 98 5.4 Conclusions...................................................................................... 101 5.5 References ........................................................................................ 102 6 Conclusions ............................................................................................ 103 V Appendix ........................................................................................................ 105 Materials and Instruments ......................................................................... 105 Zetasizer parameter setting ......................................................................