Among ratiometric fluorescent sensors1, polymer assemblies can allow for the noninvasive and real-time optical imaging of cellular dynamics and processes, received much attention recently. Herein, we introduced aggregation-induced emission (AIE)2 and aggregation-induced Förster resonance energy transfer (FRET) into two different polymer systems, respectively, resulted in efficient aggregation-based polymer platforms for ratiometric fluorescence sensing and imaging. We designed and synthesized an amphiphilic conjugated polymer based on 2,2’-biimidazole and 2,1,3-benzothiadiazole units. In the light of the unique feature of aggregation-dependent FRET, this polymer has been demonstrated to be an excellent multifunctional sensing platform with multicolor fluorescence response for detection of water, Ag+, Hg2+ ions, and cysteine. On the other hand, we prepared a tunable ratiometric fluorescent pH nanosensor by incorporating aggregation-induced emission-active fluorophores to hyperbranched polylatide (PLA) nanoparticles (Fig.1), which exhibits excellent sensing properties for intracellular pH. More importantly, quantitative analysis of intracellular pH in HeLa cells has been successfully performed with this ratiometric nanosensor. In summary, two aggregation-based polymer sensing platforms have been constructed by introducing AIE and aggregation-induced FRET effect, respectively, which provide new choices for future development of ratiometric fluorescent nanosensors, targeting various analytes of biological interest. Acknowledgements: Ministry of Science and Technology of China (2007CB936401) and Tsinghua-KUL Bilateral Scientific Cooperation (BIL09/08) are acknowledged for financial support. References 1. Han, J.; Burgess, K. Chem. Rev. 2010, 110, 2709–2728. 2. Hong, Y.; Lam, J. W. Y.; Tang, B. Z. Chem. Soc. Rev. 2011, 40, 5361−5388.

Aggregation-based polymer platforms for ratiometric fluorescence sensing and imaging

251st National Meeting (2016)

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