多重响应性大分子荧光探针的合成与性能

Synthesis and properties of multiple responsive macromolecule fluorescent probe

由偶氮二异丁腈(AIBN)引发N-异丙基丙烯酰胺(NIPAM)和N-丙烯酰氧基丁二酰亚胺(NA-SI)及3-丙烯酰氧基荧光素(Ac-Flu)进行三元共聚,得到P(Flu-co-NASI-co-NIPAM)三元共聚物。进而在碱性条件下使荧光小分子9-氨基吖啶(9AA)与共聚物中的丁二酰亚胺酯基反应,制得了温度和pH值多重响应性大分子荧光探针P(Flu-co-9AA-co-NIPAM)。利用FT-IR、1 H NMR、GPC、UV-Vis等对大分子荧光探针的结构及分子量进行表征,并用荧光光谱测定其水溶液的荧光强度。结果表明,当体系温度和pH值变化时,荧光颜色均可发生可逆转变,T<33℃(LCST)或pH值=8.9时呈现黄绿色,当T≥33℃或pH值=3.1时呈蓝色,该大分子荧光探针具有多重响应性。

P（Flu-co-NASI-co-NIPAM） copolymer was prepared by free radical copolymerization of N-isopropy- lacrylamide （NIPAM）, 3-acryloxy fluorescein （Ac-Flu） and N-acryloxysuccinimide （NASI） using azodiisobuty ronitrile （AIBN） as initiator. Then, 9-aminoaeridine was employed as chromophore to successfully modify the P（Flu-co-NASI-co-NIPAM） to form thermo-pH multiple responsible macromolecule fluorescent probe, P（Flu co-9AA-eo-NIPAM） at alkaline condition. Its chemical structure and number-average molecular weight were characterized by FT-IR, 1H NMR, GPC and UV-Vis. The fluorescence intensity was measured using fluores- cence spectra. Results revealed that when T〈33 ℃ （LCST） or pH=8.9, a yellowgreen fluorescence emission of copolymer is observed. Upon adjusting to T≥33℃ or pH=3.1, the emission is blue. Moreover, the emis- sion transition of copolymer showed reversibly and efficiently by changing temperature and pH.