title: pH-switchable bacteria detection using zwitterionic fluorescent polymer.
abstract: A zwitterionic fluorescent polymer with high sensitivity to pH changes was constructed for the detection and imaging of both gram-positive and gram-negative pathogenic bacteria. A detection probe using the zwitterionic fluorescent polymer was synthesized with single boron dipyrromethane (BODIPY) as a hydrophobic dye and bromoethane as a cationic group for bacteria binding with conjugated poly(sulfobetaine methacrylate) (BOD/BE-PSM). The zwitterionic fluorescent polymer bound to bacteria through ionic complexes between anionic groups on the bacterial surface and cationic BOD/BE-PSM groups after 1h incubation. This finding demonstrated that the fluorescence on/off system operated via changes in the hydrophilic and hydrophobic nature of the zwitterionic fluorescent polymer, depending on the pH (6.0, 7.4, or 9.0), at a fixed 1mg/mL polymer concentration. The system showed good stability with a limit of detection of 1mg/mL. Quenching caused by interactions with the hydrophobic BODIPY dye was also observed, enabling bacteria detection, as shown by fluorescence spectroscopy and confocal microscopy images. Our results indicated that the zwitterionic fluorescent polymer could be used to detect bacteria over a wide range of pH values.
authors.affiliation: Department of IT Convergence, Korea National University of Transportation, Chungju 380-702, Republic of Korea.
authors.lastname: Khoerunnisa
authors.affiliation: Department of IT Convergence, Korea National University of Transportation, Chungju 380-702, Republic of Korea.
authors.forename: Zihnil A I
authors.initials: ZA
authors.lastname: Mazrad
authors.affiliation: Department of IT Convergence, Korea National University of Transportation, Chungju 380-702, Republic of Korea; Department of Polymer Science and Engineering, Korea National University of Transportation, Chungju 380-702, Republic of Korea. Electronic address: In1@ut.ac.kr.
authors.forename: Insik
authors.initials: I
authors.lastname: In
authors.affiliation: Department of IT Convergence, Korea National University of Transportation, Chungju 380-702, Republic of Korea; Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju 380-702, Republic of Korea. Electronic address: parkchem@ut.ac.kr.
authors.forename: Sung Young
authors.initials: SY
authors.lastname: Park
mesh_terms: D001419:Bacteria / Q000302:isolation & purification*; D015374:Biosensing Techniques; D001895:Boron / Q000737:chemistry; D001896:Boron Compounds / Q000737:chemistry; D002412:Cations; D005456:Fluorescent Dyes / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D011108:Polymers / Q000737:chemistry; D013050:Spectrometry, Fluorescence
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D002412:Cations; D005456:Fluorescent Dyes; D011108:Polymers; D001895:Boron
keywords: Gram-negative bacteria; Gram-positive bacteria; Ionic complex; Zwitterionic fluorescent polymer