title: Chemical redox modulated fluorescence of nitrogen-doped graphene quantum dots for probing the activity of alkaline phosphatase.
abstract: Alkaline phosphatase (ALP) as an essential enzyme plays an important role in clinical diagnoses and biomedical researches. Hence, the development of convenient and sensitivity assay for monitoring ALP is extremely important. In this work, on the basis of chemical redox strategy to modulate the fluorescence of nitrogen-doped graphene quantum dots (NGQDs), a novel label-free fluorescent sensing system for the detection of alkaline phosphatase (ALP) activity has been developed. The fluorescence of NGQDs is firstly quenched by ultrathin cobalt oxyhydroxide (CoOOH) nanosheets, and then restored by ascorbic acid (AA), which can reduce CoOOH to Co2+, thus the ALP can be monitored based on the enzymatic hydrolysis of L-ascorbic acid-2-phosphate (AAP) by ALP to generate AA. Quantitative evaluation of ALP activity in a range from 0.1 to 5U/L with the detection limit of 0.07U/L can be realized in this sensing system. Endowed with high sensitivity and selectivity, the proposed assay is capable of detecting ALP in biological system with satisfactory results. Meanwhile, this sensing system can be easily extended to the detection of various AA-involved analytes.
authors.affiliation: Key Laboratory of Design and Assembly of Functional Nanostructures, Chinese Academy of Sciences, Fuzhou 350002, PR China; Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, PR China.
authors.forename: JingJing
authors.initials: J
authors.lastname: Liu
authors.affiliation: Key Laboratory of Design and Assembly of Functional Nanostructures, Chinese Academy of Sciences, Fuzhou 350002, PR China; Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, PR China; College of Chemistry, Fuzhou University, Fuzhou, Fujian 350002, PR China.
authors.forename: Duosi
authors.initials: D
authors.lastname: Tang
authors.affiliation: College of Chemistry, Fuzhou University, Fuzhou, Fujian 350002, PR China; Fuqing Entry-Exit Inspection and Quarantine Bureau, Fuqing, Fujian 350002, PR China.
authors.forename: Zhitao
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Key Laboratory of Design and Assembly of Functional Nanostructures, Chinese Academy of Sciences, Fuzhou 350002, PR China; Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, PR China; College of Chemistry, Fuzhou University, Fuzhou, Fujian 350002, PR China.
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Yan
authors.affiliation: Key Laboratory of Design and Assembly of Functional Nanostructures, Chinese Academy of Sciences, Fuzhou 350002, PR China; Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, PR China.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Zhong
authors.affiliation: Key Laboratory of Design and Assembly of Functional Nanostructures, Chinese Academy of Sciences, Fuzhou 350002, PR China; Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, PR China. Electronic address: longtiank@fjirsm.ac.cn.
authors.forename: Longtian
authors.initials: L
authors.lastname: Kang
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China. Electronic address: jnyao@iccas.ac.cn.
authors.forename: Jiannian
authors.initials: J
authors.lastname: Yao
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry / Q000302:isolation & purification*; D015374:Biosensing Techniques / Q000379:methods*; D002244:Carbon / Q000737:chemistry; D005453:Fluorescence; D006108:Graphite / Q000737:chemistry*; D057230:Limit of Detection; D009584:Nitrogen / Q000737:chemistry; D010084:Oxidation-Reduction; D045663:Quantum Dots / Q000737:chemistry*
chemical_list: D002244:Carbon; D006108:Graphite; D000469:Alkaline Phosphatase; D009584:Nitrogen
keywords: Alkaline phosphatase; Chemical redox; Fluorescence; Nitrogen-doped graphene quantum dots; Ultrathin cobalt oxyhydroxide nanosheets