Fluorescent Probes Based On Boron Dipyrromethene Structures And Their Applications In Bioanalysis

Fluorescence measurement is one of the important detecting technology due to it is fast, highly accurate, sensitive. So the fluorescence measurement was greatly applied in biology, medicine, industry, agriculture, health and other fields. The properties of the fluorescent probes play an important role in fluorescence measurement. Their sensing capabilities can be improved through modification on the structure of functional groups, such as increasing quantum yield; enhancing water soluble; changing the spectral properties and so on. The fluorescent probes can directly contact with the samples in homogenous phase that it is simple and convenient. However, the tunable factors are limited in homogeneous phase leading to low selectivity and sensitivity. In the past decade, the optical sensor has been rapidly developed, specially applied to biological analysis. The fluorescent probe can be incorporated into the optical sensors which can improve its selectivity and sensitivity, even avoid contaminating the samples by optimize the components of sensors. This thesis is divided into three parts to study the application of new fluorescent probes in optical sensor.(1) Boronic acid functionalized boron dipyrromethene (BABDP) was studied as a new fluorescent probe for the detection of catechols and catecholamines. Dopamine (DA) and catechol induced a strong fluorescence quenching effect due to the photoinduced electron transfer (PET) process. In homogeneous assay, the fluorescence changes were observed in the solutions with dopamine concentration from 10-8M to 10-2M at pH 7.4, and the catechol induced less but still significant response. The selectivity toward dopamine was greatly improved by using hydrophobic polymer films containing BABDP and cation exchanger. Positively charged dopamine was exchanged into the membrane and interacted with BABDP to produce the signal change, while the interference from neutral catechol was eliminated. The results measured from both optical and electrochemical sensors confirmed the selective measurement of dopamine in the range of 10-4M to 10-2 M at physiological pH.(2) Based on boric acid modified BODIPY fluorescent probe (BABDP) of sugar compounds. It has good response for detecting monosaccharide and the intensity of fluorescent rises. But the fluorescence is quenched when the probe reacts with glycogen. In order to improve the sensitivity of BABDP fluorescent probe for detecting monosaccharides. So we used glycogen parceling BABDP fluorescence probe and the fluorescence was quenched, then adding gold nanoparticles to the above mixture, and the fluorescence was quenched more obvious. The fluorescent probe of BABDP can detect monosaccharides in the concentration range of 0.1 to 100 mM. While we use the modified fluorescent probe to detect monosaccharides, with response range in 0.01 to 100 mM which indicated we have improved the sensitivity.(3) Fluorescent probes based on boron dipyrromethene functionalized with a phenylamino group (BODIPY-NH2) were synthesized of the fluorescence quantum yield varying widely, and it was utilized as a charged fluorescent chromoionophore in ion optodes. Such probes have been used to measure heavy metal ions due to its low pKa value. The optode films for Pb2+ and Cu2+ were prepared containing NH2-BODIPY as the fluorescent chromoionophore, NaTFPB as ion-exchange and Lead ionophore Ⅳ for Pb2+, N,N,N’,N’-tetracyclohexyl-3-thiaglutaric diamide for Cu2+ as ionophore. These metal selective optodes was applied to measured ions based on ion-exchange mechanism. The fluorescence intensity of optode increased when the concentration of Pb2+ became higher in the solution. But the fluorescence intensity of Cu2+ selective optode decreased due to its paramagnetic nature when the target ion increased in the membrane by ion-exchange between Cu2+ in the solution and H+ in the film. Such sensors respond to Pb2+/Cu2+ in the range of 10-6～10-1 M.