Upconversion And Magnetic Nanocomposites With Multifunctions And The Biological Applications

Due to the special properties in optics, electronics and magnetics, nanomaterials have attracted much attention in recent years. Compared with bulk materials, nanomaterials, like upconversion and magnetic nanoparticles(NPs), show great advantages and potentials in biological and medical detection. However, there are still some difficulties on clinical applications. Here, based on the hydrophobic upconversion and magnetic nanoparticles, we demonstrate a facile method to fabricate hydrophilic nanocomposites with multifunction, which can be utilized in detecting intracellular oxygen, cell capturing and photodynamic therapy. The results are showed as below:[1] Multifunctional upconversion(UC) composites were designed based on Na YF4:Yb3+/Er3+ NPs via an amphiphilic silane coating method, which can involve the organic functional molecules. Na YF4:Yb3+/Er3+ UCNPs were prepared through the solvothermal method, and then modified with amphiphilic silane to be hydrophilic. In the meantime, some functional hydrophobic molecules, such as anticancer drug, PTX, and oxygen sensing molecule, Pt OEP, can be loaded in the thin hydrophobic interspace between UCNPs and silane. The optimal amount of PTX was explored. Under the confocal microscope, the therapy caused by PTX was monitored. The dead cells, which were stained by PI, showed red color due to the broken membrane and the red spots increased due to the therapy effect. Pt OEP-loading nanocomposites were synthesized to monitor the amount of intracellular oxygen. After incubation with two kinds of nanocomposites, the amount of intracellular oxygen in the cancer cells was found increased based on the decreased luminescent signal from Pt OEP and reached a maximum as cells were affected by PTX-loading nanocomposites.[2] Hydrophobic magnetic NPs can also be modified by silane as above mentioned, and fluorescent dye, C6, and photosensitizer(Ce6) were loaded in this structure simultaneously. The production of singlet oxygen was proved by the detection probe of singlet oxygen, ADMA. Photodynamic therapy function of Ce6 was convinced by the red light emitted by EB dyes, after irradiated by 635 nm laser for 1 min, while those surrounding cells stained by AO dyes, remained alive with emitting bright green light. By combining with the microfluidic chips, which were modified with specific targeting antibody(anti-Ep CAM), circulating tumor cells(CTCs) were captured with high efficiency in culture media and whole blood(over 90% with the speed of 2 ml/h). In the meantime, the photodynamic therapy in situ was realized.