title: Combined imaging and chemical sensing using a single optical imaging fiber.
abstract: Despite many innovations and developments in the field of fiber-optic chemical sensors, optical fibers have not been employed to both view a sample and concurrently detect an analyte of interest. While chemical sensors employing a single optical fiber or a noncoherent fiberoptic bundle have been applied to a wide variety of analytical determinations, they cannot be used for imaging. Similarly, coherent imaging fibers have been employed only for their originally intended purpose, image transmission. We herein report a new technique for viewing a sample and measuring surface chemical concentrations that employs a coherent imaging fiber. The method is based on the deposition of a thin, analyte-sensitive polymer layer on the distal surface of a 350-microns-diameter imaging fiber. We present results from a pH sensor array and an acetylcholine biosensor array, each of which contains approximately 6000 optical sensors. The acetylcholine biosensor has a detection limit of 35 microM and a fast (< 1 s) response time. In association with an epifluorescence microscope and a charge-coupled device, these modified imaging fibers can display visual information of a remote sample with 4-microns spatial resolution, allowing for alternating acquisition of both chemical analysis and visual histology.
authors.affiliation: Max Tishler Laboratory for Organic Chemistry, Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA.
authors.forename: K S
authors.initials: KS
authors.lastname: Bronk
authors.forename: K L
authors.initials: KL
authors.lastname: Michael
authors.forename: P
authors.initials: P
authors.lastname: Pantano
authors.forename: D R
authors.initials: DR
authors.lastname: Walt
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry; D005336:Fiber Optic Technology; D006863:Hydrogen-Ion Concentration; D007091:Image Processing, Computer-Assisted; D008839:Microelectrodes; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D055100:Optical Fibers
chemical_list: D000110:Acetylcholinesterase