Eco-friendly functionalisation of cellulose-based textiles with antimicrobial nanoparticles

  • Qiaoyi Wang

    Student thesis: Doctoral Thesis

    Abstract

    It is estimated that over 4 million patients in the EU acquire a healthcare-associated infection every year, resulting in approximately 37,000 deaths annually and significant financial burden on the healthcare systems. Due to their large surface area, hospital textiles can provide an ideal substrate for microorganisms to grow and may act as vehicles for the transmission of pathogens. The antimicrobial functionalisation of healthcare textiles using nanomaterials offers an alternative approach for infection control. In this study, selenium nanoparticles (SeNPs) were investigated as promising novel antimicrobial agents to functionalise cellulose-based textiles. Additionally, silver nanoparticles (AgNPs) were employed since they are among the most extensively studied and applied antimicrobial inorganic nanoparticles. In the first stage of the study, the nanoparticles were prepared in aqueous suspensions to investigate the influence of synthetic conditions of the
    nanoparticles on their antimicrobial performance. Based on the literature and findings from this study, it was hypothesised that the presence of chemical stabilisers (polymers, surfactants, etc.) on the surface could hinder the antimicrobial activity of SeNPs against some bacterial species. Therefore, in the second stage, a new method was developed to prepare inorganic nanoparticles in situ on the surface of cationized cellulose without the addition of any stabiliser. The method is simple, rapid and environmentally friendly with the employment of ascorbic acid as the mild reducing agent and microwave irradiation as a green and effective source of energy. The results demonstrated that both Se and AgNPs were successfully prepared on the cationized cellulose fabrics and exhibited excellent laundry durability. The antibacterial tests revealed that the cationic groups and the nanoparticles showed combined effects against the bacteria. The presence of Se or AgNPs clearly improved the antibacterial performance of the cationized cellulose. The nanoparticlefunctionalised cationic cellulose fabrics demonstrated strong antibacterial activity against all the bacterial species tested (Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli), almost no viable bacteria were detected after 24-h contact when tested using the Absorption Method described by ISO 20743:2013. LIVE/DEAD staining and scanning electron microscopy analysis indicated that bacterial cells were visually damaged through contact with the nanoparticlefunctionalised cationic cellulose fabrics. SeNPs prepared in situ showed comparable antimicrobial performance to the AgNPs, indicating its potential as an antimicrobial agent to functionalise cellulose materials. Furthermore, the functionalised fabrics showed low cytotoxicity towards human cells when tested in vitro using an indirect contact method. In conclusion, this study provides a novel approach to prepare cationic cellulose fabrics functionalised with inorganic nanoparticles. The functionalised cellulose fabrics have excellent antimicrobial performance, low cytotoxicity and good laundry durability, demonstrating great potential to serve as an anti-infective material, especially in healthcare settings.
    Date of AwardJul 2021
    Original languageEnglish
    Awarding Institution
    • University of Brighton
    SupervisorIrina Savina (Supervisor), Lara Barnes (Supervisor), Carol Howell (Supervisor), Matthew Illsley (Supervisor) & Patricia Dyer (Supervisor)

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