Surface Modification Of Rare Earth Ion Doped LDH And HAp And Their Applications In Cell Imaging

Layered double hydroxide(LDH)and hydroxyapatite(HAp)are two typical inorganic nanomaterials that were synthesized through the formation of ionic bonds between the cationic metal ions and inorganic anionic ions.These inorganic nanomaterials have been extensively investigated utilized for different applications ranging from adsorption,drug delivery and optical sensors and other fields owing to the following characteristics,including low cost of precursors,facile for preparation and well designability of morphology and performance.Moreover,these inorganic nanomaterials are of good biocompatibility and biodegradability,and can be endowed them fluorescence after incorporation with rare earth ions or organic fluorescence organic molecules.Therefore,these fluorescent inorganic nanomaterials could be potentially utilized for the biomedical applications.However,the as-prepared LDH or HAp are of lack of surface functional groups and poor aqueous suspension capacity,which largely restrict their utilization in the biomedical fields.In this thesis,we synthesized the fluorescent LDH and HAp nanomaterials through the replacement of some metal ions with the rare earth ions,such as Tb3+ and Eu3+ during the synthesis procedures.To improve the aqueous dispersibility of these fluorescent nanomaterials,the biocompatibility and hydrophilic polymers were introduced on the surface of these fluorescent nanomaterials via several surface functionalization strategies.The results demonstrated that the fluorescence of materials is retained after surface functionalization.The resultant fluorescent materials could also display improvement of aqueous stability and biocompatibility,which makes them promising for the biological imaging.The main contexts of this thesis can be divided into the following parts.In chapter 2,polyethylene glycol(PEG)was grafted onto Tb3+doped LDH through metal-free RAFT polymerization.The final product LDH-PEG maintained the fluorescence of Tb3+-LDH while displayed enhanced water dispersibility and low toxicity owing to the surface grafting of PEG.In chapter 3,O-cyclodextrin containing hyperbranched polymers were introduced on the surface of Tb3+-LDH through the host-guest interaction between ?-cyclodextrin and amantadane.In chapter 4,poly(2-ethyl-2-oxazoline)was grafted on the surface of Eu3+-HAp through the cationic ring-opening polymerization.The resultant fluorescent HAp-PEOTx show desirable biocompatibility and high aqueous dispersibility and can be utilized for cell imaging.We believe that these surface functionalization strategies should be useful for the fabrication of multi-functional fluorescent LDH and HAp composites and will impede the biomedical applications of these fluorescent composites.