Author : Zhicheng Jin
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (134 download)
Book Synopsis Functional Colloidal Nanoparticles by : Zhicheng Jin
Download or read book Functional Colloidal Nanoparticles written by Zhicheng Jin and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Developing functional inorganic nanocrystals for biomedical uses, such as cellular labeling, bio-imaging and optical sensing, has attracted great momentum and many activities in both academia and industry over the past two decades. Many efforts were made starting from the choice of appropriate nanoparticles (NPs) that provide desired photophysical and chemical properties, tailoring the surface coating with modular organic ligands, ensuring compact size and biocompatibility, to finally realizing their bio-applications. The aim of this dissertation is to provide a better understanding of the synthesis and growth of inorganic NPs, to explore various surface conjugations strategies in aqueous media, and to use the control over optical features for application in biomedical sensing. The dissertation is organized into seven chapters, as follows: Chapter 1 provides basic optical, physical and chemical properties of quantum dots (QDs) and gold colloids. The synthetic chemistry and surface coating strategies are briefly introduced, with emphasis on the recent progress on ligand design. We then discuss several effective bioconjugation approaches on the particle surfaces and review representative examples of using energy transfer-based bio-nano hybrids for sensing and intracellular delivery purpose. Chapter 2 first presents the exact transformation of the anhydride rings, in a poly(isobutylene-alt-maleic anhydride) block copolymer, PIMA, upon reaction with primary amino nucleophiles. We find that the ring opening reaction occurs under mild conditions. Conversely, cyclic imide formation is promoted when the reactions are carried out at high temperatures, or the use of a protic solvent, such as methanol, or addition of thionyl chloride. Based on this work, in Chapter 3 the as-prepared multi-coordinating polymer ligands, LA-PIMA-PEG under ring-opening conditions, are then applied for coating on various gold colloids and the effectiveness of a photoligation strategy is tested. We find that photoligation on gold surfaces occurs within 1 h and consumes a fraction of ligands often required in a large amount using a conventional ligation strategy. In Chapter 4, we show that the natural swelling of polymer macromolecules on particle surfaces leaves a fraction of the lipoic acid groups in coordination free, which are targeted for activation and conjugation to other molecules, using the reliable sulfhydryl-to-maleimide reaction. The next part of the dissertation shows the application of nanomaterials (e.g., QDs and AuNPs) for biosensing purpose. In Chapter 5, we exploit the use of PEGylated AuNPs, covalently coupling with dye-labelled peptides, as optical-addressed nanoprobes for detecting the activities of MMP-14 enzyme. Quantitative analyses based on a jammed Michaelis-Menten model show a slow proteolysis at interfaces and theoretical calculations within diffusion-collision framework is employed to describe the complexity and irregularity of interfacial enzymatic reactions. Furthermore, Chapter 6 presents a Förster resonance energy transfer (FRET)-based QD-peptide-dye assemblies that are able to detect the proteolytic activity of matrix metalloproteinases-14 (MMP-14) enzyme. The sensing capability is enabled by correlating the FRET efficiency changes with the alternation of donor-acceptor spatial separation, which is induced by the enzyme proteolysis on the surface-docked peptides. The last part of the dissertation focuses on investigating the growth mechanisms of anisotropic gold nanorods. In Chapter 7, ex-situ TEM images indicate that the shape anisotropy is due to truncated octahedral single crystals favor the deposition of gold precursors on (111) facets and therefore present preferential growth along (100) direction. In-situ liquid-cell TEM show the complex dynamics of growth which includes oriented attachment and formation of filament structures, yielding striking aspects on the symmetry breaking at early growth stages. This emphasizes the importance of integrating nonclassical crystallization models to the traditional interpretations of how post-nucleates grow in synthetic systems.
