Fabrication Of Up-conversion@Mesoporous Silica Multifunctional Nanocomposites And Its Applications For Tumor Theranostic

As a common desease, tumor threatens hunman health and life seriously. Whiletraditional medicine still face the limitations in the accurate diagnosis and effectivetreatment of the tumor. With the rapid development of nanotechnology in the recent severaldecades, the applications of functional nanomaterials have an increasing significant impacton the tomor diagnose and therapy. On the one hand, nanoparticles with unique imagingsignals, such as superparamagnetic iron oxide nanoparticles, quantum dots, up-convertionnanoparticals and other nanomaterials loading fluorochromes provide an opportunity intumor early diagnosis. On the other hand, the involved superparamagnetic iron oxidenanoparticles, gold nanoparticals, liposomes, carbon nanoparticals and mesoporous silicananoparticles make it possible to improve the treatment effect in tumor therapy. Therefore,it is a gradual trend in the medical domain to realize the tumor diagnose and therapysimultaneously via construct multifunctional nanomaterials. Based on this, aiming todevelop multifunctional nanomaterials for tumor diagnose and therapy, a core-shellstructured nanocomposite of gold nanorod capped up-convertionluminescence@mesoporous silica has been built and used as the theranostic probe forcancer chemothermal treatment in this paper. The main work is as following:Firstly we synthesised the NaYF4nanocrystals doped with Yb3+, Er3+by a classic high-temperature solvent method, and then coated it with a layer of mesoporous silica to formcore-shell nanomaterials, in which the UCNP core could realize the up-convertionluminescence and mSiO2could work as a drug carrier. To obtain the ability of drugcontrolled release and multi-therapy, gold nanorods were synthesised via previous seed-induced growth. We found that under neutral condition, the AuNRs are positively charged(+17.6mV) while the UCNP@mSiO2are negatively charged (-40mV). However, underacid condition (pH=4), the negative charge of UCNP@mSiO2decreases severely to-10mV. Based on the electrostatic interaction between AuNRs and UCNP@mSiO2, werealized the pH responsive control of the carrier. Furthermore, due to its characteristic ofSPR, AuNR could transform NIR light to thermal energy, which could realize the heattreatment of tumor. The results of in vitro experiments demonstrated that thismultifunctional nanomaterial could be taken in by tumor cells, and realized up-convertionluminescence, drug controlled release, chemothermal at a cellular level Preliminary in vivoimaging research proved its ideal effect for low background signal and high noise-signal ratio, which confirmed its further application for in vivo tumor diagnose and therapy.