Studies On Vesicle Formation Through Self-assembly Of Fluorinated Oligo(ethylene Glycol)Terminated Small Surface Ligand Modified Gold Nanoparticles

Gold nanovesicles?Au NVs?with a hollow structure have great potential applications in drug encapsulation,targeted delivery and controlled release,photothermal therapy and so on.Therefore,the preparation of Au NVs in solution is a very important theme.So far,there were some reports on the templated self-assembly of gold nanoparticles?AuNPs?modified by amphiphilic block copolymers into Au NVs,but there are few reports related to Au NVs through the self-assembly of AuNPs using small molecule ligand as building block.Based on our previous work,I designed and synthesized a new kind of small molecular ligand with a fluorinated oligo?ethylene glycol?head in this thesis.The newly designed surface ligand tethered AuNPs can spontaneously self-assemble into Au NVs in solution.The main contents of this thesis include:The first chapter systematically reviews on the self-assembly of molecules and molecule modified AuNPs,and describes the formation of AuNPs assembly with different structures and their applications.The second chapter focus on the design and synthesis of the fluorinated oligo?ethylene glycol?terminated small molecule ligands.The surface ligands constitute of fluorinated oligo?ethylene glycol??FTEG?head,oligo?ethylene glycol??OEG2,OEG3,OEG4?in the middle and C11 alkyl chain with a thiol?C11-SH?terminal,namely FTEG-OEG-C11-SH.The OEG-C11-ene was synthesized through a substituted reaction of OEG and 11-bromo-1-undecene.Ts O-OEG-C11-ene was obtained via a sulfonylation reaction of OEG-C11-ene.Subsequently,a substituted reaction between Ts OEG-C11-ene and FTEG produces FTEG-OEG-C11-ene,which further reacted with thiolacetic acid by a click reaction to produce FTEG-OEG-C11-SAc.Finally,the objective ligand,FTEG-OEG-C11-SH,was synthesized by alcoholysis of FTEG-OEG-C11-SAc.All intermediates and target ligands were confirmed by HR MS,FT IR,¹H NMR,¹³C NMR and ¹⁹F NMR.The third chapter studies on the effect of solvent and water content,types and concentration of surface ligand,the size and concentration of AuNPs on the self-assembly of FTEG-OEG-C11-SH and AuNPs by UV-vis,dynamic light scattering?DLS?,scanning electron microscopy?SEM?and transmission electron microscopy?TEM?.The data showed that the three surface ligands can respectively self-assemble with 10 nm AuNPs to form spherical Au NVs in THF.The type of ligands showed no obvious effect on the formation and size of Au NVs.As a representative ligand,FTEG-OEG4-C11-SH,was used for further investigation.The results showed that the water content in THF influenced the size of Au NVs.The concentration of AuNPs influenced the size of Au NVs while the concentration of surface ligand showed independence on the size of Au NVs.FTEG-OEG4-C11-SH ligand can self-assemble with 5,10nm AuNPs into Au NVs,but form aggregations in the case of 15 or 20 nm AuNPs.Time course study of self-assembly process by UV-vis,DLS and TEM indicated that incomplete Au NVs with defected surface formed after initial mixing.With time going by,the surface of Au NVs becomes more compact,and finally,Au NVs with a closely packed surface is obtained.The data of dialysis showed that the structure of Au NVs is stable in water.The fourth chapter summarizes the study content and experimental results of this thesis and prospects for future work.