Waveguide-Based Biosensors for Pathogen Detection

Abstract

Optical phenomena such as fluorescence, phosphorescence, polarization, interference and non-linearity have been extensively used for biosensing applications. Optical waveguides (both planar and fiber-optic) are comprised of a material with high permittivity/high refractive index surrounded on all sides by materials with lower refractive indices, such as a substrate and the media to be sensed. This arrangement allows coupled light to propagate through the high refractive index waveguide by total internal reflection and generates an electromagnetic wave—the evanescent field—whose amplitude decreases exponentially as the distance from the surface increases. Excitation of fluorophores within the evanescent wave allows for sensitive detection while minimizing background fluorescence from complex, “dirty” biological samples. In this review, we will describe the basic principles, advantages and disadvantages of planar optical waveguide-based biodetection technologies. This discussion will include already commercialized technologies (e.g., Corning’s EPIC® Ô, SRU Biosystems’ BIND™, Zeptosense®, etc.) and new technologies that are under research and development. We will also review differing assay approaches for the detection of various biomolecules, as well as the thin-film coatings that are often required for waveguide functionalization and effective detection. Finally, we will discuss reverse-symmetry waveguides, resonant waveguide grating sensors and metal-clad leaky waveguides as alternative signal transducers in optical biosensing.

The Detection Method ofEscherichia coliin Water Resources: A Review

“…The demand for high throughput label-free multiplexed biosensors for biological sensing has increased in the last decades. Therefore, the circumstances have led to the development of fiber optics [38][39][40][41], planar waveguides [42][43][44] and surface plasmon resonance [45][46][47][48][49][50] in the area of optical biosensor. These techniques are modified by the interaction of bio-recognition element, such as enzymes, antibodies, antigens, or receptors of E. coli used on it to make it highly selective.…”

Membrane Insertion for Direct Detection of Lipoteichoic Acid

“…Here we describe the development of a rapid immunoassay strategy for the detection of Gram-positive bacterial pathogens in human serum utilizing an ultrasensitive waveguide-based optical biosensor developed at Los Alamos National Laboratory [1]. The platform uses single mode planar optical waveguides made of silicon oxynitride to couple laser light via a grating etched on the surface.…”

Detection of Lipomannan in Cattle Infected with Bovine Tuberculosis

“…[7][8][9][10][11] This biosensor relies on evanescent sensing on a planar waveguide surface to amplify the transduction signal of the fluorescently labeled antibodies to the target antigen. 7,12 We have also developed novel surface functionalization chemistries and target pull-down strategies to increase the sensitivity and specificity of our assays. 10,[13][14][15][16] Specifically, our work has targeted the detection of pathogen-specific biomarkers with exquisite sensitivity and specificity, with minimal sample processing, so as to facilitate the rapid point-of-care diagnosis of infection.…”