Nanochitin surface charge modulates nisin composite self-assembly: A multiscale simulation-experimental exploration

Area of Science:

• Biomaterials Engineering
• Antimicrobial Peptides
• Nanotechnology

Background:

• Nisin, a GRAS-approved antimicrobial peptide, has limited aqueous solubility, restricting its practical applications.
• Developing effective delivery systems is crucial for enhancing nisin's functionality.

Purpose of the Study:

• To engineer surface-deacetylated chitin nanofibers (S-ChNF) and oxidized chitin nanowhiskers (O-ChNW) as nanocarriers for nisin.
• To evaluate the encapsulation efficiency, loading capacity, and antimicrobial activity of nisin-loaded nanochitin composites.

Main Methods:

• Synthesis and characterization of S-ChNF and O-ChNW.
• Encapsulation of nisin onto nanochitin carriers.
• Spectroscopic and molecular dynamics analyses to elucidate binding mechanisms.
• Antimicrobial assays against E. coli and S. aureus.
• Cytotoxicity evaluation.

Main Results:

• S-ChNF and O-ChNW achieved high encapsulation efficiency (92.23% and 79.62%) and loading capacity (30.74% and 26.53%) for nisin.
• Nisin binding was confirmed via hydrogen bonding and electrostatic interactions, with distinct mechanisms for each nanocarrier.
• Both nisin@S-ChNF and nisin@O-ChNW composites demonstrated potent antimicrobial activity, significantly reducing bacterial survival.
• Cytotoxicity assays confirmed the biocompatibility of the composites.

Conclusions:

• Nanochitin-nisin composites are effective, non-toxic antimicrobial systems.
• The study provides structure-function insights into nisin delivery via chitin nanocarriers.
• These advanced composites hold promise for food preservation and biomedical applications.