Synthesis And Application Of Metal Sulfide-Mesoporous Silica Nanocomposites

Metal sulfide nanomaterials have been widely used in the field of catalysts,light-emitting devices and photovoltaic devices,etc.,due to their excellent catalytic and electrical properties.In addition,metal sulfide nanomaterials also have many unique optical properties,such as high quantum yield,large extinction coefficient,light stability and narrow spectral emission,which further enhance their potential applications in bioimaging,biosensing and biomedical therapy aspects.Besides,it can provide a new diagnostic and therapeutic platform for anti-tumor.However,most of the metal sulfide nanomaterials show poor biocompatibility and uncontrollable characteristics.Thus,preparing metal sulfide nanomaterials with good biocompatibility and functional properties has attracted plenty of attentions.Drug carriers can effectively solve the problem of non-specific toxicity of chemical medicaments.The drug carriers can be triggered from the external to release the chemotherapeutic agents into the tumor to achieve the effect of tumor orthotopic therapy.Mesoporous silica nanoparticles are commonly used as drug carriers.Unfortunately,their poor dispersibility and low drug loading limit their application in biomedicine fields.In regard of the problems above,this paper synthesized hollow mesoporous silica nanoparticles with good dispersion,high drug loading and small particle size,which were proved to be good drug carriers through experiments and characterization analysis.Then,we also synthesized multi-functional drug carrier Ag₂S@mSiO₂-PEG nanoparticles,which not only improved the biocompatibility of silver sulfide?Ag₂S?quantum dots,but also proved that Ag₂S@mSiO₂-PEG nanoparticles showed strong NIR-II fluorescence in aqueous solution.The details are as follows:?1?A simple synthesis method for preparing hollow mesoporous silica nanoparticles by in-situ formation of copper sulfide?CuS?as a template was proposed by our.Adding an aqueous solution of sodium sulfide?Na₂S?and copper chloride?CuCl₂?into cetyltrimethylammonium bromide?CTAB?solution,mixing and stirring to form template copper sulfide nanoparticles,and then silane directly modifying on the surface of the template.Polyethylene glycol?PEG?grafting was carried out in order to improve its dispersibility,which has greatly improved its dispersibility and stability in aqueous solution,showing very important potential for biomedical applications.The copper sulfide can be dissolved and removed by a hot ethanol/nitric acid solution,and the structural directing agent CTAB was removed together,which further simplified the steps of the synthesis.In addition,our method can control the thickness of mesoporous silicon by changing the amount of tetraethyl orthosilicate?TEOS?.It has been experimentally proved that the hollow mesoporous silica nanoparticles have small particle size,good dispersibility,good biocompatibility,high drug loading and pH acid responsiveness drugs,which were suitable for biomedical applications.As a good drug carrier,it has a bright future in the field of biomedical applications.?2?The modified Ag₂S quantum dots are modified by silanization,making it stably dispersed in an aqueous solution and show NIR-II fluorescence.The method of the new modification of Ag₂S quantum dots by oleic acid ligands makes the Ag₂S quantum dots have stronger chemical stability and more uniform morphology.The Ag₂S quantum dot excited by 808 nm laser has a strong fluorescence signal near 1200 nm.This is a typical NIR-II fluorescenceand and has a better imaging effect in vivo.Then,the Ag₂S quantum dot was modified by silanization and grafted with PEG,so that it has good biocompatibility and dispersion,and the 808 nm laser excitation still exhibits strong NIR-II fluorescence.Therefore,Ag₂S@mSiO₂ nanomaterials have strong application value in biomedicine.