Properties of Quantum Dots and Their Biological Applications

<p>Quantum dots have applications in biomedical fields such as bio-imaging and drug delivery systems. This thesis describes research on silicon and germanium nanoparticles (quantum dots) synthesis and surface modification for biological applications. Purification methods of these quantum dots were also explored. In chapter 6 the application of silica nanoparticles into dry eye diagnosis was studied. The purpose of this research is to contribute the application of nanotechnology into biological fields. The crystalinity of the quantum dots was characterised by Transmission Electron Microscopy (TEM) and Selected Area Electron Diffraction analysis (SAED). The molecules on the surface of the quantum dots were characterised by Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR). Silicon quantum dots were synthesised with a microemulsion system and various types of molecules were attached on the surface of the silicon quantum dots. However, some of the capping molecules which have oxygen atoms tend to form bonds between oxygen and silicon. Therefore, in the later chapter (chapter 4) various chemical reactions were conducted on the molecules attached to the silicon quantum dots. The silicon quantum dots were capped with diene molecules and one of the double bonds was left on the terminal end. The terminal end double bonds were converted to the functional groups which contain oxygen atoms to form peptide bonds. In this way it was confirmed that it can reduce the risk of oxygen atoms to be attached on the surface of the silicon quantum dots. The molecules on the surface of the silicon quantum dots were characterised mainly by FTIR and ¹H NMR. Optical properties and cyto-toxicity of these silicon quantum dots were also measured and analysed depending on the surface molecules. Two synthetic approaches were taken to produce germanium quantum dots. The first approach was the microemulsion system at room temperature. Different combinations of the surfactant and capping molecules were tested. For the second approach, high temperature bench top system was applied. In this method the bio-friendly molecules which have high boiling points were chosen as capping agents. The surface molecules were characterised by FTIR spectroscopy. In chapter 6 the synthesis of dye molecules conjugated silica nanoparticles was described. The purpose of this research is to produce biologically safe nanoparticles which can be applied in dry eye diagnosis. Three different dyes were used to conjugate with the silica nanoparticles. Only fluorescein isothiocyanate (FITC) succeeded in conjugating with the nanoparticles. Optical properties of this sample were measured and compared with the free dye molecule. Also the sample was applied in human eyes to analyse the tear film layer. An overall conclusion and future plans for the research were given in the last chapter.In this chapter, ideas of overcoming the problems and improving the techniques conducted in the research were described.</p>

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Biocompatible Quantum Dots for Biological Applications

Chemistry & Biology ◽

10.1016/j.chembiol.2010.11.013 ◽

2011 ◽

Vol 18 (1) ◽

pp. 10-24 ◽

Cited By ~ 334

Author(s):

Sandra J. Rosenthal ◽

Jerry C. Chang ◽

Oleg Kovtun ◽

James R. McBride ◽

Ian D. Tomlinson

Keyword(s):

Quantum Dots ◽

Biological Applications

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Graphene Quantum Dots: Syntheses, Properties, and Biological Applications

Comprehensive Nanoscience and Nanotechnology ◽

10.1016/b978-0-12-803581-8.04133-3 ◽

2016 ◽

pp. 171-192 ◽

Cited By ~ 1

Author(s):

T.A. Tabish ◽

S Zhang

Keyword(s):

Quantum Dots ◽

Graphene Quantum Dots ◽

Biological Applications

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Quantum Dots Based Material for Drug Delivery Applications

Materials Research Foundations - Quantum Dots - Properties and Applications ◽

10.21741/9781644901250-8 ◽

2021 ◽

pp. 191-215

Keyword(s):

Drug Delivery ◽

Quantum Dots ◽

Particle Size ◽

Physical Properties ◽

Semiconductor Nanoparticles ◽

Cellular Imaging ◽

Biological Applications ◽

Distinct Class ◽

Imaging Probes ◽

Biomedical Field

Quantum dots (QDs) have shown promising potential to many biomedical and biological applications, mainly in drug delivery or activation and cellular imaging. These semiconductor nanoparticles, QDs, whose particle size is in the range of 2-10 nanometer with unique photo-chemical and -physical properties that are not possessed by any other isolated molecules, have become one of the distinct class of imaging probes and worldwide platforms for manufacturing of multifunctional nanodevices. In this chapter, properties, applications of QDs, and importance in the biomedical field especially in drug delivery is presented.

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