title: Fluorescent pH sensor based on Ag@SiO2 core-shell nanoparticle.
abstract: We have demonstrated a novel method for the preparation of a fluorescence-based pH sensor by combining the plasmon resonance band of Ag core and pH sensitive dye (HPTS). A thickness-variable silica shell is placed between Ag core and HPTS dye to achieve the maximum fluorescence enhancement. At the shell thickness of 8 nm, the fluorescence intensity increases 4 and 9 times when the sensor is excited at 405 and 455 nm, respectively. At the same time, the fluorescence intensity shows a good sensitivity toward pH value in the range of 5-9, and the ratio of emission intensity at 513 nm excited at 455 nm to that excited at 405 nm versus the pH value in the range of 5-9 is determined. It is believed that the present pH sensor has the potential for determining pH real time in the biological sample.
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, 637457, Singapore.
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Bai
authors.forename: Rui
authors.initials: R
authors.lastname: Chen
authors.forename: Peng
authors.initials: P
authors.lastname: Si
authors.forename: Youju
authors.initials: Y
authors.lastname: Huang
authors.forename: Handong
authors.initials: H
authors.lastname: Sun
authors.forename: Dong-Hwan
authors.initials: DH
authors.lastname: Kim
mesh_terms: D005456:Fluorescent Dyes / Q000032:analysis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D005456:Fluorescent Dyes; D012834:Silver; D012822:Silicon Dioxide