Antimicrobial bacterial cellulose and its derived soft gels developed from smectite clay and natural biocides

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Hunter, E, 2019. Antimicrobial bacterial cellulose and its derived soft gels developed from smectite clay and natural biocides. PhD, Nottingham Trent University.

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Abstract

Bacterial cellulose (BC) is a homopolysaccharide synthesised mainly by species of the genera Acetobacter. Due to the porous matrix, BC possesses high water absorption and -holding capacities. This non-toxic, biodegradable and biocompatible material is widely used in medical, cosmological, textile and food industries. In the medical field, BC has found potential in wound, burn and reconstructive surgeries. However, the major drawback of BC is that it does not provide a barrier against infections. Infections are one of the most challenging aspects of burn recovery and wound healing systems that can delay a healing process due to contamination by foreign bodies, such as bacteria. There is, thus, a need to generate BC with additional antibacterial activity. While most antibacterial agents are harmful to mammalian cells, they can also leach, which causes the uncontrolled release of the agents into the environment.

Therefore, the overall aim of this project was to use nanofillers such as smectite clay and natural biocides such as chitosan to give BC permanent, non-toxic, antimicrobial properties without biocide leaching. This research has made three major findings that are based on natural and non-toxic minerals or biomaterials. One of the major results obtained was that natural Cloisite Na+ and synthetic SWN clays showed antibacterial activity against both Gram-positive MRSA and Gram-negative E. coli bacteria in its exfoliated state. Exfoliated clays were then incorporated into BC to provide such antibacterial properties to the final composite. Another major finding was the synthesis of new BC-based material, named bacterial chitosan. Bacterial chitosan was developed using chitosan as the main carbon source. This material showed antibacterial activity against MRSA and E. coli. Bacterial chitosan cannot be dissolved in acid. This can solve problems associated with using chitosan in antibacterial applications. The third major finding was the enhancement of antibacterial activity of BC/chitosan hybrid hydro and hydrated gels by using exfoliated Cloisite Na+ clay. In addition to these major findings, other results were obtained using clay with organo-modifiers and chitosan as biocides. Some of these synthesised materials had strong antibacterial activity. However, the leaching behaviour of biocides may have potential health and safety concerns.

Item Type:	Thesis
Creators:	Hunter, E.
Date:	July 2019
Rights:	This work is the intellectual property of the author and supervisors: Fengge Gao and Michael Loughlin. You may copy up to 5% of this work for private study, or personal, non-commercial research. Any re-use of the information contained within this document should be fully referenced, quoting the author, title, university, degree level and pagination. Queries or requests for any other use, or if a more substantial copy is required, should be directed in the owner of the Intellectual Property Right.
Divisions:	Schools > School of Science and Technology
Record created by:	Jeremy Silvester
Date Added:	17 Jun 2021 15:28
Last Modified:	17 Jun 2021 15:28
URI:	https://irep.ntu.ac.uk/id/eprint/43113