| Molecular recognition lies at the main heart of sensor chemistry. The process itself involves the interaction between two substances, often termed as a host and a guest, a lock and a key or a receptor and a substrate. Importantly, recognition is not just defined as a binding event but requires selectivity between the host and the guest. Recently, considerable researches have been focused on molecular sensing of biological analytes with metabolic action in living organisms.Saccharides are important biological molecules that are essential in processes such as nutrition, metabolism and cell structure. Saccharides are also physiologically active substances and play fundamental roles in controlling an individual's birth, differentiation and immunity. Therefore, the study of glucose and other monosaccharide gradients and continuous monitoring of glucose levels in vivo is important in managing diabetes. Due to these important properties, it is a need to develop methods for in-situ sugar sensing in aqueous solution. Fluorescent sensor is among the most sensitive methods because of high sensitivity, high selectivity and nonlnvasive.Compared with one-component ensemble of saccharides sensing ensembles, the two-component ensemble of saccharides has many advantages. Therefore, in the paper, we have developed nine two-component sensing systems. The sensing actions of these ensembles for monosaccharides are studied by fluorescence and absorption spectra. This thesis consists of five chapters as follows:The first chapter: The fluorescence analytical methods for the determination of saccharide have been introduced. The mechanisms of the fluorescence prode containing boronic acid group for saccharides recognition are summaried. Lastly, a briefly introduction of sugar sensor and main topic of this work are reviewed. The second chapter:The breakdown of glucose transport has been correlated with certain diseases:renal glycouria,cystic fibrosis diabete and also human cancer.Therefore,we develop four sensing systems for D-glucose.The ensembles are comprised of an anionic fluorescent dye NAHBDS and four boronic acid-functionalized viologens(three small molecules and one polymer),which serves as fluorescence quencher and receptor in.Polymer q-BBV is firstly developed and acts as both quencher and receptor in the ensemble.Compared with small molecules(BBVs/NAHBDS)sensing ensembles,the q-BBV/NAHBDS sensing ensemble has higher sensitivity and good linear relationship(even at low concentration of D-glucose)for D-glucose sensing.The appropriate quencher/fluorochrome ratios of these ensembles were0-BBV/NAHBDS=50:1,m-BBV/NAHBDS=50:1and q-BBV2+/NAHBDS=10:1.The third chapter:The excitation energy along the whole backbone of water-solubility conjugated polymet transferring to the reporter results in the amplified fluorescence signal,which makes them to be used as the optical platfirms in highly sensitive chemical and biological sensor.Therefore,a water-soluble conjugated polymer(PP-S-BINOL)that serves optic signal report section is developed.In addition,due to stronger binding action and architectural space position of receptor,a tetraboronic acid functionalized benzyl viologen(ToBV) is designed and applied. In this chapter, we synthesize four sensing systems included BBVs/PP-S-BINOL and ToBV/PP-S-BINOL.At physiological conditions,the sensing actions of these ensembles for nonosaccharides are studied by nuorescent spectra.The results show o-BBV/PP-s-BINOL has high sensitiVity and good linear relationship (D-glucose<10mM)for D-glucose sensing；m-BBV/PP-S-BINOL alSO has linear relationship (D-glucose<160mM)；Owing to the weak quenching capability of p-BBV to PP-S-BINOL dye,the signal response of the sensing ensemble is very weak；Fortunately,ToBV/PP-S-BINOL shows a high selectivity and sensitivity only for D-fructose in familiar D-monosaccharides. The appropriate quencher/fluorochrome ratios are o-BBV/PP-S-BINOL=10:1,m-BBV/PP-S-BINOL=3:1,ToBV/PP-S-BINOL=250:1.The fourth chapter:Carbazole and its derivatives are an important type of nitrogen-containing aromatic heterocyclic compounds, which has desirable electronic and charge-transport properties, as well as large π-conjugated system with rigid fused rings. These special structures of carbazole compounds endow their distinct carious functions, properties and biological activities. To confirm the influence of reported section of the sensing ensembles with ToBV for D-fructose, a new water solubility polymer PPC-SO3Na with carbazole unit is designed and synthesized. At physiological conditions, the sensing actions of ToBV/PPC-SO3Na ensemble D-fructose are studied by fluorescent spectra. The results show the two-component sensing ensemble has high sensitivity for D-fructose; the selectivity influence of reproted sections in ToBV/dye ensembles for D-fructose is small, howere the sensitivity influence for sensing D-fructose is great. The appropriate quencher/fluorochrome ratios was ToBV/PPC-SO3Na=11.25:1.The fifth chapter:Summary and prospects. |
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