The Syntheses And Applications Of Fluorescent Nanomaterials Based On L-DOPA

L-DOPA is the precursor of dopamine in the human body,and many studies on L-DOPA are mainly in the treatment of Parkinson's disease.L-DOPA is involved in the regulation of central motor functions,which have a beneficial effect on the Parkinson's disease.However,more and more researches are focused on developing the application of L-DOPA in the field of materials.In this thesis,we prepared two kinds of fluorescent materials based on L-DOPA by simple methods,and they were applied in the research fields of metal ion detection,fluorescent labeling and anticancer drug loading.1.The synthesis of nitrogen-doped carbon dots with L-DOPA as precursor and the applications of L-DOPA in the detection of copper ions and fluorescent labeling.Nitrogen doped carbon dots(N-CDs)based on L-DOPA were prepared by a simple and mild method at room temperature.The N-CDs are well dispersed in the solution and have a narrow size distribution with diameters in the range of 1-4 nm.The XPS results illustrated that the N-CDs consisted of C,N and O elements and the surface possessed functional groups,including-COOH,-OH and-NH2.The N-CDs exhibited an excitation-dependent photo-luminescence behavior,which gave a blue emission color when excited at 360 nm.Moreover,the N-CDs exhibited excellent stability under different conditions,enabling a wide range of applications.The N-CDs could be potentially employed as a selective and sensitive sensor for Cu2+ in aqueous media,and the limit of detection of N-CDs towards Cu2+ was estimated as 1.1 ?M.In addition,the N-CDs can also be excellent probes for A549 cellular imaging due to low toxicity,which proofs that the as-prepared N-CDs have good prospects for bioimaging and other biomedical applications.2.The synthesis of pH-responsive fluorescent L-DOPA polymer nanoparticles and the applications in pH-responsive bioimaging and drug deliveryThe fluorescent nanoparticles were prepared using L-DOPA as raw material through a simple water bath heating method.The L-DOPA polymer nanoparticles(LPNs)showed a special pH-responsive fluorescence conversion characteristic.When the pH value changed to a certain range,the fluorescent emission of LPNs changed accordingly.Moreover,the TEM data showed that the size of LPNs was also affected by the pH value.The analysis showed that the surface of LPNs contained phenolic hydroxyl and benzoquinone structure.When the pH value changed,the transformations of phenolic hydroxyl and benzoquinone affected the hydrogen bonding interactions between molecules,which influenced the morphology of LPNs.The pH-responsive fluorescence conversion characteristics of LPNs could be attributed to the changes of the surface functional groups and the aggregation states of LPNs.The LPNs materials can be used as excellent pH fluorescent probes because of low toxicity.The phenolic hydroxyl groups on the surface of LPNs can react with bortezomib(BTZ)to form boric acid ester bond and obtain the LPNs-BTZ fluorescent drug-carried materials.The prepared LPNs-BTZ materials not only can act as fluorescent probes to play an important part in biological tracer,but also can be used as carrier materials to deliver the drugs in cancer cells.In summary,the prepared LPNs-BTZ materials are multifunctional fluorescent drug loading materials,and have a great potential in medical field.