Development of Novel Wound Dressings using Seaweed Derived Antimicrobial Compounds Characterised against Emergent Clinically Relevant Bacteria

Annabel Higgins

    Research output: Types of ThesisDoctoral Thesis

    Abstract

    Seaweeds and their derivatives have recently been hailed for their impressive production of secondary metabolites for the purpose of self-preservation, and have been noted for their many bioactive activities. The emergence of antimicrobial-resistant (AMR) strains of pathogens has increasingly become an issue in the treatment of infections and has been reported to have been a driving force in the increasing cost of hospital care and higher risk of complications associated with the treatment of once trivial infections. The O'Neill report, commissioned by then UK Prime Minister David Cameron, in 2016 estimated that by 2050 more people will die of multi-drug resistant infections than of cancer. As a result, new sources of antimicrobials which could be developed into new antibiotics to combat AMR infections are being sought after. An initial screen was carried out using solvent extracts from the seaweeds Fucus serratus and Fucus vesiculosus which were extracted using the solvents; water, methanol, acetone and ethyl acetate. These crude extracts were established to be antimicrobial against a range of bacterial wound pathogens including methicillin-resistant Staphylococcus aureus (MRSA) clinically isolated from University Hospital Waterford. The most promising extract (water extracted Fucus vesiculosus) was analysed for anti-biofilm and cytotoxic activity. This extract demonstrated biofilm disruptive and biofilm preventative activities, but was, however, cytotoxic to all cell lines tested (HaCaT, HepG2 and THP-1). Once bioactivity was established, the method of extraction for the water extract from F. vesiculosus was developed using microwave assisted extraction techniques. This extraction method maintained antimicrobial activity of the extract and established an increase of 224 % in yield generated in 10 min as opposed to the 2 h standard using solvent extraction. This extract was then soaked into inactive Aquacel® wound dressings and compared for antimicrobial activity over time to iodine, silver and honey commercially available antimicrobial wound dressings (Inadine, Aquacel® and Algivon respectively). The dressings soaked in seaweed extract maintained antimicrobial activity for a longer period of time than any of its commercially available counterparts. Additionally several wound dressing formulations were prepared, using naturally sourced polymers, incorporating the seaweed extract and the most structurally viable dressings were formulated for antimicrobial activity and flexibility. The separation and identification of the antimicrobial in the extract was attempted using; TLC, bioautography, semi preparative HPLC, NMR, LC-MS, FTIR and UV-Vis analysis and the bioactive compound was determined to be fucoidan.
    Original languageEnglish
    Awarding Institution
    Supervisors/Advisors
    • Hughes, Helen, Supervisor
    • Mc Loughlin, Peter, Supervisor
    • Tan Shiau Pin, Graece, Supervisor
    Publication statusUnpublished - 2019

    Keywords

    • Novel Wound Dressings, Seaweed Derived Antimicrobial Compounds, Emergent Clinically Relevant Bacteria

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