title: Polymer-templated perylene-probe noncovalent self-assembly: a new strategy for label-free ultrasensitive fluorescence turn-on biosensing.
abstract: A new label-free fluorescence turn-on strategy for highly sensitive biosensing has been developed. A negatively charged perylene probe was synthesized. Polycations could induce aggregation of the perylene probe through noncovalent interactions and the fluorescence of the probe's monomer was efficiently quenched. Upon addition of a single-stranded nucleic acid, competitive binding of the negatively charged nucleic acid (a polyanion) to the cationic polymer resulted in the release of a monomer and thus a turn-on fluorescence signal was detected. Without the use of any amplification techniques, a detection limit of 2 pM DNA was obtained. Based on these results, an assay strategy for the highly sensitive detection of alkaline phosphatase (ALP) activity has been demonstrated. λ Exonuclease (λ exo) could degrade 5'-phosphorylated single-stranded DNA. However, when the DNA sample was treated with ALP, the phosphate functional group was removed by ALP and it could no longer be degraded by λ exo. Binding of the DNA to the perylene probe-polycation complex resulted in a turn-on fluorescence signal, which could be used for sensing of ALP. The method is highly sensitive, a limit of detection as low as 0.02 mU mL(-1) ALP was obtained. Our method is simple, convenient, highly sensitive, and inexpensive.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (P.R. China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (P.R. China).
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.forename: Huping
authors.initials: H
authors.lastname: Jiao
authors.forename: Yang
authors.initials: Y
authors.lastname: Chen
authors.forename: Wenying
authors.initials: W
authors.lastname: Li
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Zhang
authors.forename: Cong
authors.initials: C
authors.lastname: Yu
mesh_terms: D000469:Alkaline Phosphatase / Q000032:analysis; D015374:Biosensing Techniques; D004277:DNA, Single-Stranded / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D010569:Perylene / Q000737:chemistry*; D000071228:Polyelectrolytes; D011108:Polymers / Q000737:chemistry*
chemical_list: D000469:Alkaline Phosphatase; D004277:DNA, Single-Stranded; D005456:Fluorescent Dyes; D010569:Perylene; D000071228:Polyelectrolytes; D011108:Polymers
keywords: biosensors; enzyme activity; fluorescence; nucleic acid; self-assembly