Chitosan has gained much attention as a biomedical product due to its excellent biocompatibility, non-toxicity and biodegradability. One feature detracting from the more widespread in vivouse of chitosan has been its poor solubility particularly at non-acidic pH values [1]. One approach to facilitate solubilization has been to chemically modify the amino functional group, thus yielding a stereoelectronically heterogeneous distribution of chitosan derivatives displaying limited intermolecular H-bonding.Herein, chemical derivatives of chitosan were yielded under freeze-concentration conditions. The results were notable in the sense that freeze-concentrated reactions yielded chitosan derivatives with enhanced chemical, mechanical and surface properties. For instance, N-alkyl derivatives of chitosan were obtained following Micheal addition of aqueous chitosan solutions frozen in the presence of acrylic, maleic, itaconic and citraconic acid. The bimolecular reactions, which actually proceeded in highly-concentrated unfrozen regions within the ice crystals, were compared against the standard Micheal reaction of chitosan in hot aqueous acrylic acid [2]. Suitable candidates were evaluated as potential biomaterials in several applications.In addition to enhanced water solubility, the ability to fine-tune the freeze-concentration method, thus yielding a pleurtha of physical and morphological variations, will enable researchers to design biomaterials bearing targeted traits. Continued development of the freeze-concentration method will potentially seed research towards the fabrication of novel biomaterials.  References: 1. Williams A. C., Macromol. Chem.&Phys., 211, 4, 426�433, 20102. Sashiwa H., Macromol. Biosci. 3, 231�233 2003

Enhanced chitosan derivatives via the freeze concentration technique

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.