Study On The Synethesis And Properties Of A Novel Amphiphilic O-Quarternary Ammonium Salt-N, N-Dialkylated Chitosan

The quaternary ammonium salt of chitosan is one of the important chitosan derivatives. It can be applied in various fields involving cosmetics, pharmaceutical, medical applications and treatment of waste water because of its good water solubility, moisture absorption property, antibacteria activity and flocculating property. In the paper our objective was to synthesize and characterize a novel chitosan-based material used as potential amphiphilic biomaterials: O-quarternary ammonium salt-N,N-dialkylated chitosan (QADCS). O-substituted chitosan quarternary ammonium salts were synthesized, then aldehydes with different length of chain were grafted onto the C-2 amino group, the QADCS were obtained. The structure of the QADCS was testified by FTIR, 1H NMR and EA techniques.The solubility and surface property of QADCS were studied. The experimental result indicated that the solubility of QADCS was obviously better than N,N-dialkylated chitosan (DCS); the contact angles of water on the QADCS films were significantly decreased than DCS. These results means the hydrophilicity of QADCS is improved obviously as well as the amphiphilicity.The properties of QADCS monolayers have been investigated by using different kinds of QADCS. They could form stable monolayers on sub-phase surface, which had higher collapse pressure (Ï€c), smaller extrapolated area (Aex) and higher maximum compressibility modulus (Cs, Max-1) than DCS. It means QADCS could form more rigidder and compacter monolayers than DCS.The characteristic of QADCS self-assemble vesicles have also been investigated by using different kinds of QADCS. Quternarization of DCS had slower drug-releasing rate of vesicles and equilibrium drug-releasing ratio than DCS. With increasing lengthen of alkyl chain, the rigidities of QADCS monolayers are enhanced which backbone molecular weight is 500kDa and the quaternarization degree is approximately equal.The result of the antimicrobial experiments showed that the QADCS had good antibiotic ability. QADCS had the best germ resistance for E. coli, better for Staphylococcus aureus, and then for Candida albicans. The antimicrobial activities were dependent on the positive-charged group of quternarization group of QADCS.