Antimicrobial fibres derived from aryl-diazonium conjugation of chitosan with Harakeke (Phormium tenax) and Hemp (Cannabis sativa) Hurd

• Published in: International journal of biological macromolecules Vol. 264; no. Pt 2; p. 130840
• Main Authors: Joseph, Delsa Pulickal, Rajchakit, Urawadee, Pilkington, Lisa I., Sarojini, Vijayalekshmi, Barker, David
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.04.2024
• Subjects: Antibacterial fibre; Aryldiazonium conjugation; Chitosan; Harakeke; Hemp hurd; HH; BE; PTF; mmol; SA; MBC; SD; CFU; S. aureus; FTIR; Aryldiazonium conjugation; LMw; mg; XPS; Harakeke; PBS; MIC; Antibacterial fibre; KDa; μg; ppm; Hemp hurd; μm; CT; PD13; WCA; ASTM; θ; SEM; Chitosan; PAP
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2024.130840

Surface functionalisation of natural materials to develop sustainable and environmentally friendly antimicrobial fibres has received great research interest in recent years. Herein, chitosan covalent conjugation via aryl-diazonium based chemistry onto Phormium tenax fibres (PTF) and hemp hurds (HH) was investigated. PTF are fibres derived from Harakeke/New Zealand flax, an indigenous and abundant plant source of leaf fibres, which served as an important 19th century export commodity of New Zealand. HH are obtained as a by-product from the hemp (Cannabis sativa) industry and find applications as traditional construction material, animal bedding, chemical absorbent, insulation, fireboard etc. This study reports aryl-diazonium covalent attachment of chitosan and PD13 (6-O-(3-(2-(N,N-dimethylamino)ethylamino)-2-hydroxypropyl)chitosan), a chitosan derivative with improved antibacterial activity, on to PTF and HH. The modification was confirmed using FTIR, XPS, SEM and water contact angle studies. Comparison of aryl-diazonium versus the use of succinic anhydride bridging for chitosan attachment was also investigated, with the diazonium method giving improved results. The treated PTF and HH fibres had good antibacterial activity against Staphylococcus aureus and this study contributes to the development of sustainable antibacterial fibres using bio-based materials. •Phormium tenax fibres and Hemp hurds were converted into antibacterial materials using aryldiazonium-based grafting.•Aryl diazonium chitosan grafting was compared with chitosan conjugation using succinic anhydride.•Chitosan derivative PD13 was covalently conjugated to the natural materials.•Treated materials were active against Staphylococcus aureus, the derivative-conjugated Hemp hurds being the most active.