title: A sensitive and selective chemosensor for ascorbic acid based on a fluorescent nitroxide switch.
abstract: Ascorbic acid (AsA), also known as vitamin C, is a vital small-molecule antioxidant with multiple functions in vivo. It's the major natural antioxidant found in plants and is also an essential component of human nutrition. AsA plays a key role in many diseases-related biological metabolism. Therefore, sensitive and selective detection of AsA is greatly important in pharmaceutical, clinical and food industry. Here a sensitive and selective sensor for ascorbic acid detection based on the recovered fluorescence of NAPS-NO (N-propyl-triethoxysilane-4-(4-ylamino-1-oxy-2,2,6,6-tetramethylpiperdine)- naphthalimide) probe is described. The fluorescence of the naphthalimide moiety of NAPS-NO is inhibited by the nitroxide group, which is covalently linked to the fluorophore. Then, ascorbic acid reacts rapidly with the nitroxide moiety of NAPS-NO to form hydroxylamine, and the fluorescence properties of the naphthalimide moiety are recovered and the ESR signal decayed. Over a wide range from 80 nM to 50 μM, a good linear relationship between the fluorescence intensity and the concentration of ascorbic acid was found and the detection limit was estimated to be as low as 20 nM. To confirm the practical usefulness of the fluorophore-nitroxide probe, we demonstrated the use of NAPS-NO for the measurement of AsA in human blood serum and also successfully determined the concentration of AsA in HEK 293 cell lysate. Results from confocal laser scanning microscopy experiments demonstrated that this chemosensor is cell permeable and can be used as a fluorescent probe for monitoring ascorbic acid in living cells.
authors.affiliation: College of Chemistry, Sichuan University, No. 29 Wangjiang Road, Chengdu, PR China.
authors.forename: Tian
authors.initials: T
authors.lastname: Yang
authors.affiliation: College of Chemistry, Sichuan University, No. 29 Wangjiang Road, Chengdu, PR China.
authors.forename: Baozhan
authors.initials: B
authors.lastname: Zheng
authors.affiliation: Chengdu Product Quality Supervision and Inspection Institute, Chengdu 610041, PR China.
authors.forename: Hengxing
authors.initials: H
authors.lastname: Liang
authors.affiliation: Chengdu Product Quality Supervision and Inspection Institute, Chengdu 610041, PR China.
authors.forename: Yuping
authors.initials: Y
authors.lastname: Wan
authors.affiliation: College of Chemistry, Sichuan University, No. 29 Wangjiang Road, Chengdu, PR China. Electronic address: lxdj@vip.sina.com.
authors.forename: Juan
authors.initials: J
authors.lastname: Du
authors.affiliation: College of Chemistry, Sichuan University, No. 29 Wangjiang Road, Chengdu, PR China; College of Chemical Engineering, Sichuan University, No. 29 Wangjiang Road, Chengdu, PR China. Electronic address: xiaodan@scu.edu.cn.
authors.forename: Dan
authors.initials: D
authors.lastname: Xiao
mesh_terms: D001205:Ascorbic Acid / Q000097:blood*; D001692:Biological Transport; D002457:Cell Extracts / Q000737:chemistry; D005453:Fluorescence; D057809:HEK293 Cells; D006801:Humans; D057230:Limit of Detection; D015335:Molecular Probes / Q000737:chemistry* / Q000378:metabolism; D053644:Naphthalimides / Q000737:chemistry* / Q000378:metabolism; D009589:Nitrogen Oxides; D010880:Piperidines / Q000737:chemistry* / Q000378:metabolism; D013050:Spectrometry, Fluorescence
chemical_list: D002457:Cell Extracts; D015335:Molecular Probes; D053644:Naphthalimides; D009589:Nitrogen Oxides; D010880:Piperidines; C039900:nitroxyl; D001205:Ascorbic Acid
keywords: AsA; Chemosensor; Fluorescence; Nitroxide