Surface modification of a solid-state cellulose matrix with lactose by a surfactant-enveloped enzyme in a nonaqueous medium

Glyco-modification of a solid cellulose surface with lactose via an enzymatic reaction was successfully achieved using a surfactant-enveloped enzyme (SEE) in a lithium chloride/dimethylacetamide solvent system. The unique biocatalyst, SEE, which is active in organic media, was prepared by protecting the surface of cellulase with the specific nonionic surfactant dioleyl-N-D-glucona-L-glutamate. Lactose, a second cellulase substrate, was introduced onto cellulose surfaces via SEE-mediated enzymatic reaction. Fluorescent labeling and imaging revealed the presence of galactose residues from lactose on the modified cellulose surface. X-Ray diffractometry showed that the crystal structure of cellulose remained unchanged even after glyco-modification. Cell adhesion assays were carried out using rat liver cells on which galactose-specific receptors are present, and the initial cell attachment (within 12 h) on the lactose-modified cellulose filter was greater than that on an original (unmodified) cellulose matrix. The SEE-mediated biocatalysis enabled efficient glyco-modification of the solid cellulose surface in a one-step reaction, without complicated pre-treatment of the cellulose matrix and donor sugar. Consequently, this simple and effective approach to surface modification of a solid cellulose matrix with bio-functional sugars would be expected to have wide potential applications in glycomaterials engineering.