Author: Jeel Patel
Patel, Jeel, 2024 Investigating the antibacterial and cytotoxic properties of hydrogen peroxide-treated and atmospheric plasma-treated chitosan biopolymer., Flinders University, College of Medicine and Public Health
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Antibiotic-resistant bacteria and microbial contamination pose a serious concern to public health via food, water, hospital-based settings, and many more due to significant increases in antimicrobial and pathogenic microbes. On the other hand, chemical disinfectants or antimicrobials are not safe for humans and the environment. That is why there is an urgent need for a novel antimicrobial agent to overcome the problems. Chitosan is a natural polysaccharide, a non-toxic and biodegradable component that is applied in various fields from the biomedical to the food industry due to its structural, chemical, and mechanical properties. However, there is still a need for further modification of the chitosan to improve its properties. Therefore, the central intent of this study is to investigate the antibacterial effects of hydrogen-peroxide and plasma-treated chitosan biopolymer and to ensure biocompatibility.
Chitosan has been modified with hydrogen peroxide at different concentrations, where it has been found that there are no distinct effects after hydrogen peroxide treatment alone at lower and higher concentrations of hydrogen peroxide. On the other hand, chitosan was treated with atmospheric plasma and the plasma is generated in the bubble reactor where 200 V of power supply and copper stripes are used as an electrode. The argon gas flow at 0.5 standard litters per minute is utilized as a working gas to the chitosan solution in an acetic acid-containing bubble reactor. During the plasma treatment, reactive oxygen-based species such as hydroxyl radicals, hydrogen peroxide, radiation such as UV as well as pH decrease which can be able to eliminate the hydrogen from the β-(1,4) glycosidic bonds in the chitosan which cleavage of the β-(1,4) glycosidic bonds, leads to depolymerization of chitosan. Furthermore, this plasma treatment successfully decreased the molecular weight of the chitosan by depolymerization without substantial chemical structure changes which was detected via the FTIR. The investigation results suggest that plasma-treated chitosan has a substantial effect on antibacterial activity which has been observed by the minimum inhibitory concentration (MIC), colony-forming units (CFU), and live/dead cell viability. MIC of the 30 min plasma-treated chitosan has found 0.02 mg/ml and 0.3 mg/ml for Staphylococcus aureus and Pseudomonas aeruginosa, respectively. There is not any harmful effect observed on the THP-1 cells which has been examined by the MTT assay. Overall, this study assists the potential of the plasma-activated chitosan for enhanced antibacterial as well as safe for use.
Keywords: Chitosan, hydrogen peroxide, atmospheric plasma treatment, argan plasma treated water, antibacterial activity, cytotoxicity.
Subject: Biotechnology thesis
Thesis type: Masters
Completed: 2024
School: College of Medicine and Public Health
Supervisor: A/Prof. Vi Khanh Truong