Preparation And Application Of Novel Janus Nanocomposite Particles Based On Silica

Janus particles are a type of composite nanoparticles with two or more functions in a single particle,and these functions are arranged in an asymmetric manner in a single particle.Janus particles,as a new type of nano-material,show broad application prospects in various fields such as surfactants,catalysts,imaging sensors and biomedicine due to their unique anisotropic characteristics.In this paper,a series of Janus particles based on different silica nanoparticles were constructed by Pickering emulsion method,and their asymmetric structures were characterized.After further modification,it was applied to intracellular pH imaging and detection,dual drug delivery / photothermal combination therapy,and photothermal / photodynamic / chemical combination therapy,respectively.The specific research work is as follows:Chapter 1 The structure,classification,properties and preparation methods of Janus particles are summarized.The research progress of Janus particles in key application areas such as imaging analysis,sensor analysis,and diagnosis and treatment of diseases is reviewed.Chapter 2: The influencing factors for the formation of Pickering emulsions using amino-modified silica nanoparticles(Si O2-NH2 NPs)were investigated.Based on the ratio of water to wax,the type and amount of surfactant,and the amount of nanoparticles,the stable Pickering conditions were obtained.Then,the silica nanoparticles-based Janus particles were prepared by the Pickering emulsion method.Chapter 3: One side of the surface of SiO2-NH2 NPs was modified with fluorescein isothiocyanate(FITC)and the other was modified with rhodamine B(RB)by Pickering emulsion method.Due to the spatial separation of the two dyes,the prepared probes exhibit dual emission characteristics of 530 nm and 580 nm under single excitation at 488 nm,and the ratio fluorescence intensity increases with increasing pH.The p Ka value of this probe is 6.64,which is suitable for the detection of H+ in living cells.In human liver cancer cells(SMMC-7721),the probes show good biocompatibility and cell membrane permeability,and can be used as a new type of pH fluorescent probe for effective imaging studies of H+ in living cells.Chapter 4: The paclitaxel-gold-mesoporous silica-doxorubicin Janus particles(PTX-Au-MSN-DOX JNPs)were prepared by Pickering emulsion method for dual drug delivery / photothermal treatment of cancer.Au NPs are used as photothermal therapeutic agents and are selectively functionalized with mercapto-?-dextrin(SH-?-CD)to achieve the loading of the hydrophobic anticancer drug PTX.And MSN as an effective carrier of antitumor drugs used to load the hydrophilic anticancer drug DOX.By examining the in vitro photothermal effect and drug release ability of PTX-Au-MSN-DOX JNPs,it is shown that PTX-Au-MSN-DOX JNPs have strong near-infrared absorption and excellent drug loading capacity.In addition,when PTX-Au-MSN-DOX JNPs were used in tumor treatment of tumor-bearing mice,the Janus particles showed significant tumor growth inhibition and had less toxic side effects in vivo.Chapter 5: The gold-hollow mesoporous silica @ methylene blue @ doxorubicin Janus particles(Au-HMSN @ MB @ DOX JNPs)were prepared by Pickering emulsion method for photothermal-photodynamic-chemical synergy of tumor cells.Au NPs are used as photothermal therapeutic agents,MB is used for photodynamic therapy of photosensitizers,and HMSN is used as an effective carrier for drugs and photosensitizers.Au-HMSN @MB @ DOX JNPs have excellent drug loading ability,strong near-infrared absorption,can release single-line oxygen for photodynamic therapy,and have excellent biocompatibility.