利用聚(N-异丙基丙烯酰胺-co-丙烯酸)银纳米团簇构建宽pH响应范围的激发比率型荧光探针

An excitation ratiometric fluorescent probe with wide-range pH response constructed by poly(N-isopropylacrylamide-co-acrylic acid)silver nanoclusters

以N-异丙基丙烯酰胺(NIPAM)和丙烯酸(AA)为pH敏感单体,合成聚(N-异丙基丙烯酰胺-co-丙烯酸),并以此作为模板制备了pH敏感的聚(N-异丙基丙烯酰胺-co-丙烯酸)银纳米团簇。结合了时间分辨荧光、透射电镜(TEM)、红外光谱(FT-IR)方法,对团簇的光学性能进行了研究。团簇的荧光对不同的pH具有灵敏的响应。团簇的荧光强度与pH在4.95~11.02的范围内呈线性关系,高pH(11.02)与低pH(4.95)相比,荧光强度降低约62.4%。同时,305 nm与453 nm处荧光激发强度的比值(I;/I;)与pH在5.94~11.02的宽范围内成线性关系,利用该荧光比率可以对pH进行定量检测。

The pH-sensitive silver nanoclusters(Ag NCs)were successfully synthesized using poly(N-isopropylacrylamide-co-acrylic acid)as template polymer,in which N-isopropylacrylamide(NIPAM)and acrylic acid(AA)were used as pH-sensitive monomers.The properties of the Ag NCs were investigated by time-resolved fluorescence spectroscopy,transmission electron microscope(TEM),fourier transform infrared spectroscopy(FT-IR).The fluorescence intensity of the Ag NCs was sensitive to pH value and was linearly related to the pH in a wide range of 4.95-11.02.Compared with the fluorescence intensity at low pH value(4.95),the fluorescence intensity decreased by 62.4%at the high pH value(11.02).The ratio of fluorescence intensity excited at 305 nm and 453 nm(I;/I;)showed a linear relationship with pH value in a wide range of 5.94-11.02.Thus the Ag NCs can be used to detect pH value quantitatively.