Synthesis and characterization of citrate-based fluorescent small molecules and biodegradable polymers

Publication date: Available online 6 January 2017
Source:Acta Biomaterialia
Author(s): Zhiwei Xie, Jimin P. Kim, Qing Cai, Yi Zhang, Jinshan Guo, Ranjodh S. Dhami, LiLi, Bin Kong, Yixue Su, Kevin A. Schug, Jian Yang
Novel citric acid based photoluminescent dyes and degradable polymers are synthesized via a facile "one-pot" reaction. A comprehensive understanding of the fluorescence mechanisms of the resulting citric acid-based fluorophores is reported. Two distinct types of fluorophores are identified: a thiozolopyridine family with high quantum yield, long lifetime, and exceptional photostability, and a dioxopyridine family with relatively lower quantum yield, multiple lifetimes, and solvent-dependent band shifting behavior. Applications in molecule labeling and cell imaging were demonstrated. The above discoveries contribute to the field of fluorescence chemistry and have laid a solid foundation for further development of new fluorophores and materials that show promise in a diversity of fluorescence-based applications.Photoluminescent materials are pivotal for fluorescence based imaging, labeling and sensing applications. Understanding their fluorescence mechanism is challenging and imperative. We develop a new class of citric acid-derived fluorescent materials in forms of polymers and small molecular dyes by a one-step solvent free reaction. We discovered two different classes of citric acid-derived fluorophores. A two-ring thiozolopyridine structure demonstrates strong fluorescence and exceptional resistance to photo-bleaching. A one-ring dioxopryridine exhibits relative weak fluorescence but with intriguing excitation and solvent-dependent emission wavelength shifting. Our methodology of synthesizing citric acid-derived fluorophores and the understanding on their luminescence are instrumental to the design and production of a large number of new photoluminescent materials for biological and biomedical applications.

Graphical abstract

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