Antibacterial activity and mechanism of chitosan with ultra high molecular weight

Published Date
Received 29 January 2016, Revised 22 March 2016, Accepted 6 April 2016, Available online 19 April 2016.

Author
Jianhui Li. Author links open the author workspace.Opens the author workspacea. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceb. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceYiguang Wu. Author links open the author workspace.Opens the author workspaceOpens the author workspacea. Numbers and letters correspond to the affiliation list. Click to expose these in author workspaceLiqing Zhao. Author links open the author workspace.Opens the author workspaceOpens the author workspacea. Numbers and letters correspond to the affiliation list. Click to expose these in author workspace

a

College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China

b

Department of Chemistry, School of Science, Xi’an Jiaotong University, Xi’an 710049, China

Highlights

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Ultra high MW squid pen chitosan was proposed as a new antibacterial biomaterial.

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Comprehensive investigation on its antibacterial activity & mechanism was done.

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The optimal pH value was proved to be 6.0 for the highest bactericidal activity.

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It was proved that the antibacterial activity enhanced as its DD increased.

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Its ultra long chain was proved to be propitious to coat and bind bacteria.

Abstract

Chitosan with different degree of deacetylation (DD) and ultra high molecular weight (MW >106) was prepared from β-chitin by mild deacetylation. The effects of DD of chitosan and pH value of its solution/suspension on its antibacterial activity were investigated. The results showed that the optimal pH value was 6.0 for the highest bactericidal activity. The antibacterial activity against Escherichia coli and Staphylococcus aureus of chitosan solution at pH 6.0 enhanced as the DD of chitosan increased. Same as chitosan with low MW, the antibacterial activity of chitosan with high MW in acidic solution was also due to the amino protonation and subsequently cationic formation. Its ultra long molecular chain was propitious to coat and bind the E. coli and S. aureus, and highly enhanced its antibacterial activity. E. coli and S. aureus were at first restrained and then killed by chitosan and the cells were ruptured and decomposed gradually.

Keywords

Chitosan

Ultra high molecular weight

Bacteriostatic and bactericidal activity

Antibacterial mechanism

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