Pelegrino, Milena T.
Pieretti, Joana C.
Goncalves, Marcelly Chue
Moreira, Jose Carlos
Seabra, Amedea B.
Total Authors: 6
 Univ Fed ABC, Ctr Nat & Human Sci, Santo Andre, SP - Brazil
 Londrina State Univ UEL, Biol Sci Ctr, Dept Microbiol, Londrina, Parana - Brazil
 Univ Fed ABC, Ctr Engn Modeling & Appl Social Sci, Santo Andre, SP - Brazil
Total Affiliations: 3
NITRIC OXIDE-BIOLOGY AND CHEMISTRY;
JAN 1 2021.
Web of Science Citations:
The aim of the current study is to report a simple and efficient method to chemically modify chitosan in order to form S-nitroso-chitosan for antibacterial applications. Firstly, commercial chitosan (CS) was modified to form thiolated chitosan (TCS) based on an easy and environmental-friendly method. TCS was featured based on physicochemical and morphological techniques. Results have confirmed that thiol groups in TCS formed after CS's primary amino groups were replaced with secondary amino groups. Free thiol groups in TCS were nitrosated to form S-nitrosothiol moieties covalently bond to the polymer backbone (S-nitroso-CS). Kinetic measurements have shown that S-nitmso-CS was capable of generating NO in a sustained manner at levels suitable for biomedical applications. The antibacterial activities of CS, TCS and S-nitroso-CS were evaluated based on the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time-kill curves determined for Escherichia coli, Staphylococcus aureus and Streptococcus mutans. MIC/MBC values reached 25/25, 0.7/0.7 and 3.1/3.1 mu g mL(-1) for CS/TCS and 3.1/3.1, 0.1/0.2, 0.1/0.2 mu g mL(-1) for S-nitroso-CS, respectively. Decreased MIC and MBC values have indicated that S-nitroso-CS has higher antibacterial activity than CS and TCS. Time-kill curves have shown that the bacterial cell viability decreased 5-fold for E. coli and 2-fold for S. mutans in comparison to their respective controls, after 0.5 h of incubation with S-nitroso-CS. Together, CS backbone chemically modified with S-nitroso moieties have yielded a polymer capable of generating therapeutic NO concentrations with strong antibacterial effect. (AU)