title: Near-infrared optical response of thin film pH-sensitive hydrogel coated on a gold nanocrescent array.
abstract: A hydrogel-based chemiresponsive sensor for monitoring H(+) (pH) has been developed by coating the surface of a gold nanocrescent array structure with a thin film of a poly(2-hydroxylethyl methacrylate)-based (poly-HEMA) hydrogel. The transmission measurement results of the close-packed gold nanocrescent array fabricated via electron beam lithography demonstrate near-infrared localized surface plasmon resonance peaks with sensitivities up to 332 nm/RIU in detecting refractive index change. Measurements of the hydrogel under solutions of increasing pH show the plasmon peak blueshifts by 17 nm and the integrated transmission increases by 1.8 in the operating range of 4.5 - 6.4 pH, which is ideal for biochemical sensor applications.
authors.affiliation: Department of Electrical and Computer Engineering, the University of Western Ontario, London, Ontario, Canada.
authors.forename: Hao
authors.initials: H
authors.lastname: Jiang
authors.forename: Jan
authors.initials: J
authors.lastname: Markowski
authors.forename: Jayshri
authors.initials: J
authors.lastname: Sabarinathan
mesh_terms: D001671:Biochemistry / Q000295:instrumentation*; D015374:Biosensing Techniques; D002384:Catalysis; D004867:Equipment Design; D006046:Gold / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry*; D055095:Optics and Photonics; D011102:Polyhydroxyethyl Methacrylate / Q000737:chemistry; D011522:Protons; D012031:Refractometry
chemical_list: D020100:Hydrogels; D011522:Protons; D011102:Polyhydroxyethyl Methacrylate; D006046:Gold