title: Photonic nanosensor for colorimetric detection of metal ions.
abstract: The real-time sensing of metal ions at point of care requires integrated sensors with low energy and sample consumption, reversibility, and rapid recovery. Here, we report a photonic nanosensor that reversibly and quantitatively reports on variation in the concentrations of Pb(2+) and Cu(2+) ions in aqueous solutions (<500 μL) in the visible region of the spectrum (λ(max) ≈ 400-700 nm). A single 6 ns laser pulse (λ = 532 nm) was used to pattern an ∼10 μm thick photosensitive recording medium. This formed periodic AgBr nanocrystal (ø ∼ 5-20 nm) concentrated regions, which produced Bragg diffraction upon illumination with a white light source. The sensor functionalized with 8-hydroxyquinoline allowed sensing through inducing Donnan osmotic pressure and tuning its lattice spacing. The sensor quantitatively measured Pb(2+) and Cu(2+) ion concentrations within the dynamic range of 0.1-10.0 mM with limits of detection of 11.4 and 18.6 μM in under 10 min. The sensor could be reset in 3 min and was reused at least 100 times without compromising its accuracy. The plasmonic nanosensor represents a simple and label-free analytical platform with potential scalability for applications in medical diagnostics and environmental monitoring.
authors.affiliation: †Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom Street, Boston, Massachusetts 02114, United States.
authors.forename: Ali K
authors.initials: AK
authors.lastname: Yetisen
authors.affiliation: ‡Centre of Molecular Materials for Photonics and Electronics, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom.
authors.forename: Yunuen
authors.initials: Y
authors.lastname: Montelongo
authors.affiliation: ‡Centre of Molecular Materials for Photonics and Electronics, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom.
authors.forename: Malik M
authors.initials: MM
authors.lastname: Qasim
authors.affiliation: §School of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: Haider
authors.initials: H
authors.lastname: Butt
authors.affiliation: ‡Centre of Molecular Materials for Photonics and Electronics, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Wilkinson
authors.affiliation: ∥Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Monteiro
authors.affiliation: †Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom Street, Boston, Massachusetts 02114, United States.
authors.forename: Seok Hyun
authors.initials: SH
authors.lastname: Yun
mesh_terms: D003124:Colorimetry; D003300:Copper / Q000032:analysis*; D020100:Hydrogels / Q000737:chemistry; D007854:Lead / Q000032:analysis*; D008958:Models, Molecular; D008968:Molecular Conformation; D053758:Nanoparticles / Q000737:chemistry; D036103:Nanotechnology / Q000295:instrumentation*; D017785:Photons; D014867:Water / Q000737:chemistry
chemical_list: D020100:Hydrogels; D014867:Water; D007854:Lead; D003300:Copper