Bloch surface wave-enhanced fluorescence biosensor

Koji Toma, Emiliano Descrovi, Mana Toma, Mirko Ballarini, Pietro Mandracci, Fabrizio Giorgis, Anca Mateescu, Ulrich Jonas, Wolfgang Knoll, Jakub Dostálek

Research output: Contribution to journalArticlepeer-review

70 Citations (Scopus)

Abstract

A new approach to signal amplification in fluorescence-based assays for sensitive detection of molecular analytes is reported. It relies on a sensor chip carrying a one-dimensional photonic crystal (1DPC) composed of two piled up segments which are designed to increase simultaneously the excitation rate and the collection efficiency of fluorescence light. The top segment supports Bloch surface waves (BSWs) at the excitation wavelength and the bottom segment serves as a Bragg mirror for the emission wavelength of used fluorophore labels. The enhancement of the excitation rate on the sensor surface is achieved through the resonant coupling to BSWs that is associated with strong increase of the field intensity. The increasing of collection efficiency of fluorescence light emitted from the sensor surface is pursued by using the Bragg mirror that minimizes its leakage into a substrate and provides its beaming toward a detector. In order to exploit the whole evanescent field of BSW, extended three-dimensional hydrogel-based binding matrix that is functionalized with catcher molecules is attached to 1DPC for capturing of target analyte from a sample. Simulations supported by experiments are presented to illustrate the design and determined the performance characteristics of BSW-enhanced fluorescence spectroscopy. A model immunoassay experiment demonstrates that the reported approach enables increasing signal to noise ratio, resulting in about one order of magnitude improved limit of detection (LOD) with respect to regular total internal reflection fluorescence (TIRF) configuration.

Original languageEnglish
Pages (from-to)108-114
Number of pages7
JournalBiosensors and Bioelectronics
Volume43
Issue number1
DOIs
Publication statusPublished - 2013 May 15
Externally publishedYes

Keywords

  • Biosensor
  • Bloch surface wave
  • Bragg mirror
  • Enhanced fluorescence
  • Immunoassay
  • Photonic crystal

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry

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