In-situ formation of silver nanostructures within a polysaccharide film and its application as a potential biocompatible fluorescence sensing medium

N Donaldson, M Toury, D McLoskey, A Sheila Holmes-Smith, G Hungerford

    Research output: Contribution to conferencePoster


    There has been increased interest of the use of metal surfaces in conjunction with fluorescence molecules employing a plasmon effect, sometimes referred to as metal enhanced fluorescence[1]. This can be advantageous as some photophysical properties, such as the emission intensity of the fluorophore, can be enhanced. We have previously shown that it is possible to form, in-situ, silver nanostructures in silica sol-gel derived media making use of a semiconductor diode laser on a compact time-resolved fluorescence microscope, which showed the effect of these particles on the fluorescence of FITC tagged BSA[2]. The use of light irradiation to form the silver particles allows better particle localisation, which can be advantageous for sensing applications.

    In this work we investigate simple to manufacture polysaccharide films containing a silver salt, from which silver nanostructures can be produced via light irradiation. This is illustrated in a schematic manner from a microscope measurement in the figure below.

    Effect of irradiation time on a silver ion containing gellan gum film made using a compact time-resolved fluorescence microscope, illustrating the area affected for seven different laser irradiation times. These ranged from 15 seconds (top left) to 5 minutes (bottom right)

    The films were produced using gellan gum, which consists of a linear tetrasaccharide repeating unit [¿4)-L-rhamnopyranosyl-(a-1¿3)-D-glucopyranosyl-(ß-1¿4)-D-glucuronopyranosyl-(ß-1¿4)-D-glucopyranosyl-(ß-1¿]). This versatile polysaccharide has many applications, ranging from the food industry to drug delivery and tissue engineering applications. We have previously reported the use of fluorescence lifetime probes to monitor viscosity changes in gellan gum[3] and also make use of this in film characterisation. The presence of silver structures produced in-situ was confirmed using UV-vis, AFM and SEM techniques. The influence of the silver nanostructure containing film on the fluorescence of a protein label was monitored using fluorescence microscopy, thus helping to elucidate the potential of these films as biocompatible sensing media.
    Original languageEnglish
    Number of pages1
    Publication statusPublished - 11 Sep 2011



    • silver nanostructures
    • polysaccharide film
    • fluorescence

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