2.2. Colloidal chitin preparation

Colloidal chitin was prepared using the modified method of Roberts and Selitrennikoff as follows [28]. Briefly, 5 g of chitin (Sigma-Aldrich, St. Louis, MO, USA) were added slowly to 90 mL of 12 M HCl. The mixture was vigorously stirred for 2 h. 500 mL of 0.82 g/mL ethanol was added to this suspension and then centrifuged at 6000 rpm and 4 °C for 20 min. The pellets were washed with distilled water until the supernatant reached a neutral pH. The prepared colloidal chitin was stored at 4 °C until use.