Biomolecule-compatible support structures for biomolecule coupling to physical measuring principle surfaces

As part of studies on biomolecule-compatible interfacial structures for practice-relevant biosensor and biochip developments, new film-forming aminocelluloses of the ´P-CH₂-NH-(X)-NH₂´ type (P=cellulose) with spacer structures (X=special oligoamine residues) at C6 and solubilising groups (S=tosylate or carbanilate) at C2/C3 of the anhydroglucose unit (AGU) were synthesised and their film properties and covalent coupling with enzyme protein examined. Depending on the nature and degree of substitution (DS_(S)) of the ester groups (S) at C2/C3, the new aminocellulose derivatives are soluble either in DMA and DMSO (with S=carbanilate) or in water (with S=tosylate). The aminocellulose derivatives form transparent films from their solutions. AFM investigations of the film surfaces have either shown very flat (topography <1 nm) films or tubular topographies of nanostructure size, depending on structural and environment-induced factors of influence. Especially in the case of films from water-soluble aminocelluloses with oligoamine residues at C6, inter alia, enzyme-specific pH values and different positive charge distributions can be adjusted by partial protonation of the NH₂ end groups. By means of the covalent coupling of the new aminocelluloses with glucose oxidase (GOD) it was shown that the enzyme coupling efficiency can be decisively optimised by the interplay of aminocellulose structure, coupling structure and enzyme protein.