The Controllable Synthesis Of BiOX Nanostructures For Cancer Theranostic Applications

Cancer is one of the most devastating disease due to high rate of morality and thousands of patients have been suffering from various types of cancers.In the recent two decades,researchers have been trying to defeat and cure cancers using multidisciplinary fields to improve the life quality of cancer patients.However,there are many complexities related to cancer cells which need to be addressed to overcome on this disease.The accurate early diagnosis and treatment is one of the significant factors to cure cancer.This thesis emphasizes on the facile and controlled synthesis of novel BiOX nanostructures which perfectly employed as theranostic agent for various kinds of cancers.First,hydrothermal method was used to prepare two kinds of BiOCl nanostructures?BiOCl nanoplate and BiOCl nanosheet?,which have similar length size?²00nm?but different thickness?²0nm for nanoplate and⁵nm for nanosheet?.The nanoparticles were modified with PEI to adjust their facial electrical property from electric neutrality to electropositivity,which improve their monodispersity in water due to electrostatic interaction.Ultrasonic Cell Disrupyion System is also used to treat the nanomaterials to enhance dispersion.Besides,the modification of PEG improved the biocompatibility of BiOCl nanomaterials.After the successful preparation of BiOCl nanomaterials,MTT method was used to test their biotoxicity.The cell viability results showed that the prepared BiOX based nanostructures had very low toxicity at higher concentration which recommended them to be use in biological system.Therefore,UV triggered tumor photodynamic therapy?PDT?experiments in vitro were performed using prepared BiOCl nanomaterials and compared with commercially used TiO₂ material.The experimental results indicated that both kinds of BiOCl nanomaterials showed significant PDT effect at little dose and low irradiation intensity of UV,while the PDT effect of TiO₂ material was not sufficient to kill cancer cells.This was the first ever report on BiOX nanomaterials for nanomedicine.After the successful use of white BiOCl in PDT,we have tried a series of methods to fabricate black BiOCl.Here the black BiOCl could be known as a kind of defective BiOCl.Several synthesis methods were tried including hydrothermal plus UV irradiation,hydrothermal plus high annealing,and solvothermal plus UV irradiation,etc.Finally,a new and facile method was developed for the preparation of black BiOCl nanomaterials which can also solve the anti-whitening stability of materials.The new method is the combination of traditional solvothermal method and UV irradiation method.And in the process of preparation,the weak reducing reagent sodium citrate with good biocompatibility was introduced.Photo-thermal transition and MTT biotoxicity experiments were conducted using as-synthesized a black BiOCl nanomaterials.These experimental results showed that the black BiOCl nanomaterials are with high photo-thermal transition rate and with high biocompatibility.Based on these two experimental results,photo-thermal therapy experiments were performed on tumor cells?in vitro?and tumor-bearing mice?in vivo?.And the results showed the promising PTT effect of prepared nanomaterials.Finally,based on the study progress in single BiOCl nanomaterials,we have tried to perform some experiments to fabricateBiOX-based composite nanomaterials fortumor imaging and therapy applications.The BiOCl/Bi₂O₃ composite nanomaterials were prepared with the method of in situ redox process.MTT result showed very low biotoxicity.In the future study,biomedical application of BiOCl/Bi₂O₃ nanoparticles for tumor imaging,PDT and PTT effect in vitro and in vivo will be performed.And then will be compared with single white BiOCl and black BiOCl.