Modification of glucose oxidase for the development of biocatalytic solvent inks

Inkjet printing of enzymes onto hydrophobic polymeric material offers the potential for economical rapid deposition and patterning of biocatalysts for biosensor, microarray, and intelligent packaging applications. Non-polar solvent based inks provide simple vehicles for direct printing on these materials; however, enzymes are not readily soluble in such inks. Glucose oxidase (Aspergillus niger) was made soluble in toluene by hydrophobic ion pairing with didodecyldimethylammonium bromide. Following modification, single enzyme composites with a mean diameter of 12.5 nm were formed. The enzymes showed no significant change in K'(m) and a 46% decrease in k'(cat) compared to the native enzyme. Modification allowed for direct printing and patterning on PET using piezoelectric inkjet printing. Specific activity of the modified enzyme was reduced from 889 × 10³ μmol/min/g to 2×10³ μmol/min/g after printing. These results suggest that direct inkjet printing of enzymes onto hydrophobic polymers may be accomplished using enzyme modification as a means to induce solubility in solvent inks.