title: "Chemical nose" for the visual identification of emerging ocular pathogens using gold nanostars.
abstract: Ocular pathogens can cause serious damages in the eye leading to severe vision loss and even blindness if left untreated. Identification of pathogens is crucial for administering the appropriate antibiotics in order to gain effective control over ocular infection. Herein, we report a gold nanostar based "chemical nose" for visually identifying ocular pathogens. Using a spectrophotometer and nanostars of different sizes and degrees of branching, we show that the "chemical nose" is capable of identifying the following clinically relevant ocular pathogens with an accuracy of 99%: S. aureus, A. xylosoxidans, D. acidovorans and S. maltophilia. The differential colorimetric response is due to electrostatic aggregation of cationic gold nanostars around bacteria without the use of biomolecule ligands such as aptamers or antibodies. Transmission electron microscopy confirms that the number of gold nanostars aggregated around each bacterium correlates closely with the colorimetric response. Thus, gold nanostars serve as a promising platform for rapid visual identification of ocular pathogens with application in point-of-care diagnostics.
authors.affiliation: Department of Chemical Engineering, University of Waterloo, 200 University Avenue W, Waterloo, Ontario, Canada N2L 3G1; Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue W, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: Mohit S
authors.initials: MS
authors.lastname: Verma
authors.affiliation: Department of Chemical Engineering, University of Waterloo, 200 University Avenue W, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: Paul Z
authors.initials: PZ
authors.lastname: Chen
authors.affiliation: Department of Chemical Engineering, University of Waterloo, 200 University Avenue W, Waterloo, Ontario, Canada N2L 3G1; Center for Contact Lens Research, University of Waterloo, 200 University Avenue W, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: Lyndon
authors.initials: L
authors.lastname: Jones
authors.affiliation: Department of Chemical Engineering, University of Waterloo, 200 University Avenue W, Waterloo, Ontario, Canada N2L 3G1; Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue W, Waterloo, Ontario, Canada N2L 3G1. Electronic address: frank.gu@uwaterloo.ca.
authors.forename: Frank X
authors.initials: FX
authors.lastname: Gu
mesh_terms: D001419:Bacteria / Q000302:isolation & purification*; D015374:Biosensing Techniques / Q000295:instrumentation*; D003124:Colorimetry / Q000295:instrumentation; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007634:Keratitis / Q000175:diagnosis / Q000382:microbiology*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: D006046:Gold
keywords: Color change; Contact lens cases; Gold nanoparticles; Microbial keratitis; Point-of-care; Visual detection