Development of Water Dispersible Lanthanidedoped Nanocrystals and Hydrogel Nanocomposites: Synthesis and Applications

Meesaragandla, Brahmaiah (2017) Development of Water Dispersible Lanthanidedoped Nanocrystals and Hydrogel Nanocomposites: Synthesis and Applications. PhD thesis, Indian Institute of Science Education and Research Kolkata.

PDF (PhD thesis of Brahmaiah Meesaragandla (14RS078)) BRAHMAIAH_MEESARAGANDLA,_THESIS.pdf - Submitted Version Restricted to Repository staff only Download (9MB)

Abstract

Amongst others, the objectives of the present research wok is to develop surface functionalization methods for converting the surface of the Ln³⁺ -doped nanocrystals from hydrophobic to hydrophilic with various functional groups at the surface; to develop simple ligand exchange strategies to chemically functionalize the nanocrystals with a variety of molecules, which are otherwise difficult to use in high temperature synthetic methods like thermal decomposition; to design thermal decomposition methods to synthesize the hydrophilic nanocrystals in one step at low temperature for bio-imaging applications; to use luminescence as a tool for the selective and sensitive detection of reactive oxygen species; to develop simple click chemistry routes for the synthesis of thiol containing luminescent gels and use them as templates for the synthesis of dendrimer like nanostructures; nad to develop upconverting hydrogel composites for photodynamic therapy applications. It starts with illustrating the surface functionalization methods (hydroxylation and thiol-alkene reactions) to improve water dispersibility of Ln³⁺-doped nanocrystals by introducing various functional groups at the surface. Then, it demonstrates the ligand exchange strategy to chemically functionalize the nanocrystals with a variety of molecules, which are otherwise difficult to use in high temperature method. After that, it represents the development of hydrophilic Ln³⁺-doped nanocrystals at low temperature using thermal decomposition and their suitability for bio-imaging applications. It also demonstrates the application of p-PDA capped Ce³⁺/Tb³⁺ doped NaYF₄ microrods for the selective detection of H₂O₂. It then illustrates the click chemistry route for the synthesis of thiol containing luminescent gels and uses them as templates for the synthesis of dendrimer like Au nanostructures. The discussion concludes with a demonstration of the synthesis of upconverting hydrogel nanocomposites for the photodynamic therapy applications.

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