title: Fluorescent Strips of Electrospun Fibers for Ratiometric Sensing of Serum Heparin and Urine Trypsin.
abstract: "Turn-on" or "turn-off" probes remain challenges in the establishment of sensitive, easily operated, and reliable methods for in situ monitoring bioactive substances. In the current study, electrospun fibrous strips are designed to provide straightforward observations of ratiometric color changes with the naked eye in the presence of serum heparin or urine trypsin. A tetraphenylethene (TPE) derivative is constructed and along with phloxine B is grafted on fibers, followed by protamine adsorption to induce static quenching of phloxine B and aggregation-induced emission of the TPE derivative. The presence of heparin or trypsin removes protamine to restore the fluorescence of phloxine B at 574 nm (I574) and relieve the emission of the TPE derivative at 472 nm (I472). The grafting densities of phloxine B and the TPE derivative are essential to achieve the optimal fluorescence-intensity ratio of I574/I472for the ratiometric detection of heparin and trypsin. Under illumination by an ultraviolet lamp, the fibrous mats turn from cyan to green in the presence of heparin at 0.4 U/mL and to a bright yellow at 0.8 U/mL, which is feasible in sensing serum heparin levels during postoperative and long-term care of patients after cardiovascular surgery. The protamine digestion results in similar color transitions with increasing trypsin levels up to 8 μg/mL, indicating the potential for monitoring urine trypsin levels of pancreas transplant patients. The color strips based on the ratiometric fluorescent response indicate advantages in lowering the detection limit and improving the accuracy and reproducibility, bearing great potential for a real-time and naked-eye detection of bioactive substances as self-test devices.
authors.affiliation: Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu 610031, PR China.
authors.forename: Long
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu 610031, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.affiliation: Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu 610031, PR China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu 610031, PR China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu 610031, PR China.
authors.forename: Zhoujiang
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu 610031, PR China.
authors.forename: Xiaohong
authors.identifier: http://orcid.org/0000-0003-1312-0215
authors.initials: X
authors.lastname: Li
mesh_terms: D005456:Fluorescent Dyes / Q000737:chemistry*; D006493:Heparin; D006801:Humans; D015203:Reproducibility of Results; D013050:Spectrometry, Fluorescence; D014357:Trypsin
chemical_list: D005456:Fluorescent Dyes; D006493:Heparin; D014357:Trypsin
keywords: aggregation-induced emission; electrospun fibrous mats; fluorescent color strip; ratiometric detection; static quenching