Development Of Multifunctional Polymer Microspheres And Application In Cancer Theranostics

In recent years, multifunctional polymer microspheres have been widely used in biological field, because of homogeneous dispersion, controllable particle size, large specific surface area, and good stability. The development of nanotechnology has provided new tools to synthesizevarieties of polymer-based composite systems at the nanoscale, with outstanding demonstrations in multi-modal imaging of tumorsand administration of theranostics. This thesis is mainly focused on the development of multifunctional polymer microspheres and application in cancer theranostics.Based on double emulsions, we developedan interesting nanospheres containing bovine serum albumin(BSA) capped gold nanoclusters and indocyanine green(ICG) for various imaging or potential therapeutic applications. Those nanosphers can be applied for multimodal imaging including one-photon imaging, two-photon imaging, photoacoustic imaging, and photothermal therapy. RGD peptides were conjugated onto the surface of the nanospheres, which can actively target the integrin ανβ3over-expressed on the surface of the cancer cells. In the two-photon mode, the organization of the background fluorescence can be greatly reduced. So multi-functional nanospheres were prepared, which were promising nanocomposites in the field of cancer diagnosis and treatment.Fluorescence microscopy and flow cytometry are important methods for life science and cancer research, but the instruments need regular calibration. Here a gradual solvent evaporation method was employed to prepare fluorescent microspheres with highbrightness, mono-dispersed and wide spectrum fluorescent signals.We examined different conditions for optimization of the staining procedure. Acridine orange and rhodamine b were dissolved in isopropyl alcohol.Chloroform was used as swelling agent.The dye moleculeswere penetratedinto the interior of the microspheres. Then the solvent gradually evaporated.The experimental results suggested that the as-prepared fluorescent microspheres exhibited wide fluorescence spectrum, narrow particle size distribution andhigh fluorescence intensity, therefore promising good performance in the calibration of flow cytometry and fluorescence microscopy.