title: Colorimetric/fluorescent bacterial sensing by agarose-embedded lipid/polydiacetylene films.
abstract: OBJECTIVE
  Development of a new chromatic (colorimetric/fluorescence) bacterial sensor, for rapid, sensitive and versatile detection of bacterial proliferation.
  
  
  RESULTS
  We constructed agarose-embedded chromatic films which produce dramatic colour changes and fluorescence transformations in response to bacterial growth. The sensing constructs comprise glass-supported Langmuir-Schaeffer phospholipid/polydiacetylene films that undergo both blue-red transformations and induction of intense fluorescence following interactions with bacterially secreted amphiphilic compounds that diffuse through the agarose. The agarose matrix coating the sensor film further contains growth nutrients, facilitating signal amplification through promotion of bacterial culture proliferation. The agarose layer also constitutes an effective barrier for reducing background signals not associated with the bacteria. We demonstrate the applications of the new sensor for the detection of Gram-negative and Gram-positive bacteria, and for screening specimens of physiological fluids (blood and urine) and foods (meat) for bacterial contaminations.
  
  
  CONCLUSIONS
  The experiments demonstrate that the new agarose-embedded film constructs are capable of bacterial detection through visible colour transitions and fluorescence emission recorded in conventional apparatuses.
  
  
  CONCLUSIONS
  This work demonstrated a new simple chromatic platform for bacterial detection, based on the generation of easily recorded colour and fluorescence changes. The new bacterial detection scheme is highly generic and could be employed for varied practical uses, in which, rapid reporting on bacterial presence is required.
authors.affiliation: Department of Chemistry and Ilse Katz Institute for Nanotechnology, Ben Gurion University, Beer Sheva, Israel.
authors.forename: D
authors.initials: D
authors.lastname: Meir
authors.forename: L
authors.initials: L
authors.lastname: Silbert
authors.forename: R
authors.initials: R
authors.lastname: Volinsky
authors.forename: S
authors.initials: S
authors.lastname: Kolusheva
authors.forename: I
authors.initials: I
authors.lastname: Weiser
authors.forename: R
authors.initials: R
authors.lastname: Jelinek
mesh_terms: D000327:Adsorption; D001419:Bacteria / Q000302:isolation & purification*; D040761:Biomimetic Materials; D003124:Colorimetry / Q000379:methods; D005516:Food Microbiology; D008081:Liposomes; D036103:Nanotechnology; D000078789:Polyacetylene Polymer; D011108:Polymers; D053279:Polyynes; D012685:Sepharose; D013050:Spectrometry, Fluorescence
chemical_list: D008081:Liposomes; D000078789:Polyacetylene Polymer; D011108:Polymers; D053279:Polyynes; C082361:polydiacetylene; D012685:Sepharose