An evanescent wave biosensor--Part II: Fluorescent signal acquisition from tapered fiber optic probes. Academic Article uri icon

Overview

abstract

  • A biosensor was developed using antibodies, fluorescence and the evanescent wave to detect antigen binding at the surface of an optical fiber. Cladding was removed from the core along the distal end of a step-index optical fiber, and recognition antibodies were immobilized on the declad core to form the probe sensing region. Immersing the declad probe in aqueous solution creates a V-number mismatch between the immersed probe and the clad fiber. Probes created with reduced sensing region radius exhibited improved response by decreasing the V-number mismatch. Tapering the radius of this region has further improved probe response. Ray tracing analysis of the tapered probe demonstrated that the evanescent wave penetration depth increases along the length of the taper. Experiments correlating position of refraction along the taper with launch angle at the proximal end were realized in the ray tracing model. An evanescent wave immunoassay was performed with a series of the tapered fiber probes, each tapered from the fiber core radius (100 microns) to different end radii. An end radius of 29 microns was found to produce maximal signal from the tapered probe. Factors leading to the determination of the optimized probe are discussed.

publication date

  • June 1, 1994

Research

keywords

  • Biosensing Techniques
  • Fiber Optic Technology
  • Fluorescence Polarization Immunoassay
  • Signal Processing, Computer-Assisted

Identity

Scopus Document Identifier

  • 0028449332

Digital Object Identifier (DOI)

  • 10.1109/10.293246

PubMed ID

  • 7927378

Additional Document Info

volume

  • 41

issue

  • 6