title: Carbon quantum dots-based recyclable real-time fluorescence assay for alkaline phosphatase with adenosine triphosphate as substrate.
abstract: A convenient, reliable, and highly sensitive real-time assay for alkaline phosphatase (ALP) activity in the continuous and recyclable way is established on the basis of aggregation and disaggregation of carbon quantum dots (CQDs) through the competitive assay approach. CQDs and adenosine triphosphate (ATP) were used as the fluorescent indicator and substrate for ALP activity assessment, respectively. Richness of carboxyl groups on the surface of CQDs enables their severe aggregation triggered by cerium ions, which results in effective fluorescence quenching. Under the catalytic hydrolysis of ALP, ATP can be rapidly transformed to phosphate ions. Stronger affinity of phosphate ions to cerium ions than carboxyl groups is taken advantage of to achieve fluorescence recovery induced by redispersion of CQDs in the presence of ALP and ATP. Quantitative evaluation of ALP activity in a broad range from 4.6 to 383.3 U/L with the detection limit of 1.4 U/L can be realized in this way, which endows the assay with high enough sensitivity for practical detection in human serum. The assay can be used in a recyclable way for more than three times since the generated product CePO4 as a precipitate can be easily removed from the standard assay system. This strategy broadens the sensing application of fluorescent CQDs with excellent biocompatibility and provides an example based on disaggregation in optical probe development.
authors: College of Chemistry and Life Science, Zhejiang Normal University , Jinhua 321004, China.
authors: Zhaosheng
authors: Z
authors: Qian
authors: Lujing
authors: L
authors: Chai
authors: Cong
authors: C
authors: Tang
authors: Yuanyuan
authors: Y
authors: Huang
authors: Jianrong
authors: J
authors: Chen
authors: Hui
authors: H
authors: Feng
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000032:analysis* / Q000378:metabolism; D001681:Biological Assay; D002244:Carbon / Q000737:chemistry*; D002563:Cerium / Q000737:chemistry; D005453:Fluorescence; D005456:Fluorescent Dyes; D006801:Humans; D057230:Limit of Detection; D045663:Quantum Dots
chemical_list: D005456:Fluorescent Dyes; D002563:Cerium; D002244:Carbon; D000255:Adenosine Triphosphate; D000469:Alkaline Phosphatase