Preparation And Application Of Fluorescent Materials

After entering the new century, with the developments of high technologies in various areas, especially the life science rapidly growing up, novel fluorescent probes are of great interests in recent years, therefore, developing and designing new-type fluorescent materials attracted increasing attentions, in which semi-conductive nanomaterials and fluorescent conjugated polymer has gained extensive studies in recent years because of their unique and superior properties. However, though the research on CdS, CdSe, CdTe etc has been going to maturity, the studies on CdHgTe are still less reported. For CdHgTe nanoparticles, due to de doping of Hg, its fluorescence red-shifts to NIR region, and almost all atmospheric window has been covered, which will highly facilitate the imaging in vivo. Another fluorescent material--fluorescent conjugated polymers featuring molecular-wire effect can greatly amplified the response signals, therefore were widely applied in chemosensors. In this thesis, the above-mentioned two-type luminescent materials were studied with the focus on their preparation and application. The main contents are described as follows:In Chapter one, the mechanism of luminescence, kinds and main applications of fluorescent materials were explicated. At the same time, semi-conductive nanoparticles and fluorescent conjugated polymers as two kinds of significant materials were reviewed in details, including their unique properties, categories and applications in the fields of biology and medicine.In Chapter two, microwave-assistant synthesis of water-soluble CdHgTe nanocrystal with high quantum yields has been discussed, which is easier and more rapid when compared with traditional heating method. The fluorescent probe based on CdHgTe for copper ion has been developed, and the results indicate that this probe has high sensitivity to Cu2+, less interference and low detection limit.In Chapter three, a novel facile synthetic route for preparing water-soluble fluorescent conjugated polymer PPESO3 has been developed. In this section, both the synthetic scheme that has been reported in literature and the new-developed facile synthetic route by us have been adopted to prepare PPESO3, therefore, a comparison between the two methods has been carried out. And the results revealed that using the newly-developed synthetic route not only the reaction steps were simplified, but most importantly the danger, difficulty and complexity had been greatly reduced due to avoiding the use of BBr3, which would be certainly beneficial to the preparation and application of PPESO3.In Chapter four, the solvent-dependent spectroscopy of PPESO3, as well as its aggregation behaviors in water were discussed. Also, the interactions between PPESO3 and different surfactants were studied, which gave the results that bovine serum albumin (BSA) could disassociate the aggregation state of PPESO3 effectively. This phenomenon was referred as unaggregation. By making use of the process of aggregation/unaggregation, a general method for the detection of protease activity was developed, in which BSA greatly increase the fluorescence of PPESO3, concomitant with a remarkable blue-shift. However, once BSA is hydrolyzed by protease, the fluorescence restores. By determining the fluorescence changes, one can easily monitor the activity of protease. As a demonstration, the activity of trypsin and pepsin was tested in this work.