title: Inherently fluorescent polystyrene microspheres for coating, sensing and cellular imaging.
abstract: Commercially available polystyrene (PS) fluorescent microspheres are widely used in biological field for tracing, in vivo imaging and calibration of flow cytometry, among other applications. However, these particles do suffer from some drawbacks such as the leakage and photobleaching of organic dyes within them. In the present study, inherently fluorescent properties of PS based microspheres have been explored for the first time. Here we find that a simple chloromethylation reaction endows the polystyrene particles with inherent fluorescence without any subsequent conjugation of an external fluorophore. A possible mechanism for fluorescence is elucidated by synthesizing and investigating p-ethylbenzyl chloride, a compound with similar structure. Significantly, no photobleaching or leaking issues were observed owing to the stable structure of the microspheres. Chloromethylated PS (CMPS) microspheres can keep their perpetual blue fluorescence even in dry powder state making them attractive as a potential coating material. Furthermore, the chloromethyl groups on CMPS microspheres make them very convenient for further functionalization. Poly(ethylene glycol) (PEG) grafted microspheres showed good biocompatibility and negligible cytotoxicity, and could be used to image intracellular Fe3+due to the selective fluorescence quenching effect of aqueous Fe3+in cytoplasm.
authors.affiliation: State Key Laboratory of Heavy Oil Processing, Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, PR China. Electronic address: jbqu@upc.edu.cn.
authors.forename: Jian-Bo
authors.initials: JB
authors.lastname: Qu
authors.affiliation: State Key Laboratory of Heavy Oil Processing, Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, PR China.
authors.forename: Yu-Liang
authors.initials: YL
authors.lastname: Xu
authors.affiliation: Department of Pediatrics, Qingdao Huikang Hospital, Qingdao 266520, PR China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Heavy Oil Processing, Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, PR China.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Heavy Oil Processing, Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, PR China.
authors.forename: Yuanhong
authors.initials: Y
authors.lastname: Sui
authors.affiliation: State Key Laboratory of Heavy Oil Processing, Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, PR China.
authors.forename: Jian-Guo
authors.initials: JG
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Heavy Oil Processing, Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, PR China. Electronic address: xwang@upc.edu.cn.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Wang
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D003952:Diagnostic Imaging / Q000379:methods*; D008863:Microspheres; D011092:Polyethylene Glycols / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*
chemical_list: D020099:Coated Materials, Biocompatible; D011137:Polystyrenes; D011092:Polyethylene Glycols
keywords: Cellular imaging; Chloromethylated polystyrene microspheres; Coating; Fe(3+); Fluorescence