基于三线态一三线态湮灭上转换发光的比率型pH纳米探针

Ratiometric pH nanoprobe based on triplet-triplet annihilation upconversion

通过将pH荧光探针分子异硫氰酸荧光素(FITC)引入三线态―三线态湮灭上转换(TTA-UC)体系中,使TTA-UC的发射与FITC的吸收重叠,从而实现从TTA-UC到FITC的能量传递过程。TTA-UC由光敏剂四苯基四苯骈铂(PtTPBP)和湮灭剂9,10-双苯乙炔基蒽(BPEA)组成,可以实现“红转青”上转换发光。将上述有机染料负载于两亲性嵌段共聚物Pluronic P123形成的纳米胶束内,能够形成比率型上转换纳米探针,并应用于水溶液中的pH检测。光敏剂PtTPBP的磷光发射由于不受pH影响,可以作为构建比率探针的内参比信号。上转换发射强度与光敏剂磷光发射强度之间的比率信号(I_(507)/I_(770))在pH 5~8范围内呈良好线性。这种新型的比率型上转换pH纳米探针为制备基于TTA-UC的比率型检测传感体系提供了新的思路和视角。

By introducing the pH fluorescent probe fluorescein isothiocyanate(FITC)into the triplet-triplet annihilation upconversion(TTA-UC)system,an energy transfer process from TTA-UC to FITC could be achieved when UC emission overlapped with FITC absorption.The TTA-UC system consisting of the sensitizer Pttetraphenyltetrabenzoporphyrin(PtTPBP)and the annihilator 9,10-bis(phenylethynyl)anthracene(BPEA)could achieve red-to-cyan upconversion luminescence.By encapsulating the above organic dyes in nanomicelles assembled by the amphiphilic block copolymer Pluronic P123,a ratiometric upconversion nanoprobe could be constructed and applied for pH detection in aqueous solution.Since the phosphorescence emission of the sensitizer PtTPBP was not affected by pH,it could be used as an internal reference signal for the ratiometric probe.The ratio signal(I_(507)/I_(770))between UC emission intensity and phosphorescence emission intensity of the sensitizer showed a good linear relationship with pH in the range from 5 to 8.This novel ratiometric upconversion pH nanoprobe provides a new perspective for the construction of ratiometric sensing platforms based on TTA-UC.