Flexibility of backbone fibrils in α-chitin crystals with different degree of acetylation

Zechuan Yu; Denvid Lau

doi:10.1016/j.carbpol.2017.06.099

Flexibility of backbone fibrils in α-chitin crystals with different degree of acetylation

Carbohydr Polym. 2017 Oct 15:174:941-947. doi: 10.1016/j.carbpol.2017.06.099. Epub 2017 Jun 27.

Authors

Zechuan Yu¹, Denvid Lau²

Affiliations

¹ Department of Architecture and Civil Engineering, City University of Hong Kong, Hong Kong, China.
² Department of Architecture and Civil Engineering, City University of Hong Kong, Hong Kong, China; Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. Electronic address: denvid@mit.edu.

PMID: 28821151
DOI: 10.1016/j.carbpol.2017.06.099

Abstract

Acetyl groups are backbone outreaches that enhance inter-fibril connection in chitin and chitosan fibril bundle. Removal of acetyl groups affects flexibility of chitosan fibril bundle, thereby affecting mechanical strength of chitosan-based products. Understandings of relationship between degree of acetylation and flexibility of chitin fibril bundle conduce to optimization of synthetic chitin materials. Here, the relationship is examined by performing molecular dynamics simulations. Coiling of chitin and chitosan fibril bundle with different degree of acetylation is observed and flexibility of fibrils is measured. Number and alignment of acetyl groups are found to be important factors determining the flexibility of chitin and chitosan fibril bundle. Structural instability can be caused by incompatible alignment of acetyl groups. Our findings on synthetic chitin-based materials indicate that adding a small amount of acetyl groups to chitosan can significantly enhance the integrity of fibril bundle.

Keywords: Chitin; Chitosan; Degree of acetylation; Flexibility; Persistent length.