The chitosan oligomer was prepared from high MW (310–
375 kDa) chitosan (Sigma–Aldrich Ltd., USA) based on the method
outlined by Allan and Peyron (1995), to produce an oligomer with
an average degree of polymerization of 14 (molecular weigh range
1.5–6 kDa). A 2% stock solution of this oligo chitosan was prepared
as described by Torr et al. (2005).