Preparation and Characterization of Chitosan-Based Conjugates

Folin–Ciocalteu reagent, gallic acid, limonene standard solution, 1-ethyl-3-(3-dimethylaminopropyil) carbodiimide hydrochloride, cellulose membrane tubing MW cut-off 12.5 kDa, low-molecular-weight chitosan, dimethyl sulfoxide (DMSO), 1,6-hexamethylene diisocyanate (HMDI), and triethylamine (TEA) were purchased from Merck (Darmstadt, Germany). BEO was from Alidans (Pisa, Italy). QA-Ch was synthesized according to [16 (link)] and conjugated with MCD as already described [17 (link)]. The resulting QA-Ch-MCD had a molecular weight of 603 kg/mol and the following features: 8.8% acetylation degree, 33.1% degree of quaternarization with n = 4 (diethyldimethylene ammonium) length pendant chains, and 45.5% MCD degree of functionalization. All aqueous solutions/dispersions were prepared in deionized water.