The prototype of an amperometric glucose biosensorwas realized by thermal inkjet printing using biological and electronicwater-based inks,
containing a glucose oxidase (GOD) from Aspergillus niger and the conducting polymer blend poly(3,4-ethylenedioxythiophene/polystyrene
sulfonic acid) (PEDOT/PSS), respectively. The biosensor was fabricated microdepositing PEDOT/PSS and GOD, in sequence, on ITO-glass,
by a commercial inkjet printer, with the help of a commercial software. High density microdots matrices were so-realized, with a calculated
resolution of about 221×221 dpi (dot per inch). By means of a rapid and easy assay it was demonstrated that no activity loss occurred upon
the printing of GOD, despite of the use of a thermal printhead. The device was encapsulated in a semipermeable membrane of cellulose
acetate, applied by dip-coating, in order to prevent dissolution of the enzyme and/or PEDOT/PSS in water. The preliminary response of the
electrode was measured in an aqueous glucose solution in the presence of ferrocenemethanol (FeMeOH) as a mediator, and resulted linear up
to 60mM in glucose. The best sensitivity value achieved was 6.43AM−1 cm−2 (447 nAM−1 U−1 cm−2). The characteristics of the device,
and the possible performance improvements have been analyzed and discussed. The reported findings indicate that inkjet printing could be a
viable instrument for the easy construction of a working biosensor via direct digital design using biological and conductive polymer based
inks. Such an approach may be seen as an example of “biopolytronics”.
