Piezoelectric ink jet printing of horseradish peroxidase on fibrous supports

Abstract

In solid phase bioanalysis a highly selective and sensitive layer of bioagent deposited on a solid support is used to recognize specific target analytes. Using ink jet technology bioagents can be precisely patterned over surfaces with controlled uniformity. Solid supports, however, can affect the biological activity, the spatial distribution and the binding capacity of the bioagent causing detection problems. In this study a bioink containing horseradish peroxidase and a chromogen was deposited using a piezoelectric-based ink jet printer on various fibrous supports. Reflectance spectrophotometry was used to quantify the colour developed by the printed areas upon exposure to hydrogen peroxide solutions. Colour intensity, detection limits, linear range and sensitivity were examined as indicators of bioanalytical performance. Different fibrous supports exhibited significant differences in biodetection performance, and the wood-free uncoated paper gave the best overall performance. The cross-sectional distribution of the active enzyme, visualized using confocal laser scanning microscopy, helped explain differences amongst the paper supports.