Chitosan has been used in a number of forms, both native and chemically modified, to immobilized enzymes with broad success in terms of enhanced activity and stability . However, the mechanism by which the modified chitosan has imparted greater stability and activity has been largely assumed from indirect and ex-situ measurements. For example, the authors have quantitatively shown that the introduction of hydrophobic alkyl side chains (of varying carbon chain length) along the hydrophilic chitosan backbone will ncrease the relative hydrophobicity of the overall polymer and in the otherwise polar microenvironments surrounding the immobilized enzyme . Although this technique has, in some cases, retained activity for up to 60 to 70 days and increased electrochemical activity by a factor of four , the authors have only assumed that these outcomes result from the hydrophobic modification inducing the formation of amphiphillic regions that can retain, stabilize, and ncrease enzyme activity .
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