Advanced Materials 3

Surface Modification of Polymeric Optical Fibres for Chemo- and Biosensor Technology

Dr Anthony M Granville
Prof Gang-Ding Peng
Prof Francois Ladouceur

    Innovative fiber optic sensor technologies are evolving and rapidly superseding conventional electronic sensor technologies. Fiber optics exhibit several desirable qualities such as an intrinsic compactness, immunities to electromagnetic and radio interferences, and the potential to sense rapidly, continuously and remotely. In addition, fiber optic sensors such as those based on Surface Plasmon Resonance (SPR-FOS) and Localized Surface Plasmon Resonance (LSPR-FOS) with gold coatings as the sensing element are reputed for their sensitivity in detecting low concentrations of analytes (≤ nanograms/liter) or single biological and chemical molecules (≤ 1-2Å). The main principle of these fiber optic sensors relies on the changes in the refractive index of the sensing element when immobilized with analytes. These refractive index changes alter the spectrum of the evanescent field at the interface of the sensing element which can be easily interrogated by spectral, intensity or resonance measurements.
    Polymer Optical Fibers (POFs) possess structural and light-guide properties analogous to conventional glass fibers, especially poly(methyl methacrylate) (PMMA), polystyrene (PS), and polycarbonate (PC) based fibers. Furthermore, these polymeric fibers are more versatile in terms of processing, transformations, handling and compatibility with emerging nano/biotechnologies. In particular, the surface properties of POFs can be easily manipulated via simple polymer chemistry techniques to increase their compatibilities with various organic, inorganic nano/biosensing elements or compounds. The combination of using polymer based optical fibers and modifying their surface to incorporate different sensing elements or compounds have the potential to produce sensors with enhanced sensing properties for detecting diverse analytes ranging from chemical to biological molecules.


Figure 1. Reaction designs for POF surface modification and binding tests


In this research area, we utilize rather facile surface modification techniques on PMMA POFs to generate gold coated surfaces as a platform for various polymerisation and surface binding techniques (Figure 1)