| In recent years,due to unique electronic and optical properties,fluorescent conjugated polymers have played an important role in many fields such as fluorescence sensors,chemical sensors,organic solar cells and nonlinear optical materials,which has attracted wide attention from researchers.While acting as a branch of the fluorescent polymer,water-soluble fluorescent polymers have shown great potential in biological applications such as life sciences and medicine.The purpose of this thesis is to design and synthesize a fluorescent probe with high efficiency,sensitivity,good bio-compatibility,high photostability,strong light penetration and less damage to the organism,and let it has a role to play in the biological field.The main contents and results of the thesis are as follows:1.Compounds(B5)containing perylene bisimides-pyrene units were synthesized by Suzuki coupling reaction,and the planar conjugated molecule(B6)containing perylene bisimides-pyrene units were synthesized after the intramolecular scholl reaction.Then the Atom Transfer Radical Polymerization(ATRP)initiator B9 and B12 were obtained by multi-step chemical modification from B6.Later B9 and B12 as initiator,respectively,and 2-(2',3',4',6'-tetra-O-acetyl-?-D-mannopyranosyloxy)ethyl methacrylate(M2)as a monomer,the oil-soluble polymers P1 and P3 were prepared by the ATRP reaction.After removal of the acetyl group,we obtained water-soluble fluorescent polymers P2 and P4 with a perylene bisimides-pyrene conjugated unit.The compounds and polymers were characterized and tested by FTIR,NMR,MALDI-TOF-MS,GPC,UV-Vis and PL.Finally,the results show that the number average molecular weight(Mn)of P1 and P3 are 13000 g·mol-1 and 10200 g·mol-1,respectively,and the polydispersity index(PDI)were 1.10 and 1.27,respectively.Peak molecular weight(Mp)of P2 and P4 are 9000 g·mol-1 and 7700 g·mol-1,respectively.2.The maximum characteristic UV absorption peak wavelength of P2 has a red shift of 21 nm and 25 nm relative to those of P1 and B6;the UV absorption peak of P4 was 25 nm and 31 nm red shift relative to those of P3 and B6.The emission peak of the corresponding fluorescence spectrum also redshifts: the fluorescence emission peak of P2 has a red shift of 39 nm and 42 nm relative to those of P1 and B6;the fluorescence emission peaks of P4 were redshifted by 39 nm and 48 nm with respect to those of P3 and B6.The maximum fluorescence emission peaks of P2 and P4 in aqueous solution are at 682 nm and 688 nm(>650 nm).3.Since P2 and P4 are water soluble and have relatively large number average molecular weight,its relative fluorescence quantum yield is not very high,the fluorescence quantum yield of P2 and P4 in aqueous solution were 0.07 and 0.05,respectively.The results from the fluorescence decay map displayed that the polymers P1 and P2 exhibited dual exponential function decays and two fluorescent lifetimes.The fluorescence lifetime of P1 was 1.8213 ns(9.85%)and 4.6522 ns(90.15%),the variance was 1.148;P2 had fluorescence lifetimes of 1.2776 ns(31.7%)and 7.0472 ns(68.3%),the variance was 1.392.While the small molecule fluorescent compound B6 displayed a single fluorescence decay index and a fluorescence lifetime,the fluorescence lifetime was 4.4928 ns and the variance was 1.100.P3 displayed a single fluorescence decay index and a fluorescence lifetime,the fluorescence lifetime of P3 was 4.7172 ns and the variance was 1.326.The fluorescence lifetime of P4 was 3.7828 ns(12.53%)and 8.1291 ns(87.47%),the variance was 1.012.4.Time within 0-600 s,after P2 and P4 complexed with Concanavalin A(Con A),respectively,the trend of the two UV absorbance is basically similar.While the intensity of fluorescence was enhanced after complexation of P2 and Con A,but P4 fluorescence intensity remained unchanged.5.Laser irradiation of Cy5,P2 and P4 at the same time and at the same conditions through a 635 nm laser,at 12 min,both UV absorbance and fluorescence intensity decay of Cy5 were greater than 50%.While the UV absorbance of P2 and P4 almost kept unchanged,and their fluorescence decay were less than 50%,which indicated that the light stability of P2 and P4 was obviously better than that of Cy5.6.P2 and P4 has excellent water solubility and optical properties,the cytotoxicity and living cell imaging experiments of P2 and P4 revealed that concentration were less than 100 ?g·mL-1and the incubation time was less than 72 h,the cell survival rate was over 80%.300 ?g·mL-1 of P2 and different concentrations(1 ?g·m L-1-300 ?g·m L-1)of P4 was able to enter HeLa cells,and the morphology and number of He La cells did not show any significant change,moreover,intracellular emitted strong fluorescence.Cell experiments showed that P2 and P4 had good cell compatibility,which was the experimental basis for the application of fluorescent probes in the biological field.In this thesis,not only the shortcomings of the perylene bisimides derivatives,which are poorly soluble and difficult to separate,was overcome,but also the biological imaging of perylene bisimides molecules in the near infrared region was realized.Moreover,the fluorescence of the water-soluble fluorescent polymers P2 and P4 obtained by the multi-step modification of the perylene bisimides molecules in the water reached the near infrared region.Utilizing the advantages of strong penetration and low energy optical performance of P2 and P4,we successfully achieved near-infrared light optical cell imaging.Therefore,this thesis provides another possibility for the development of near-infrared probes. |
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