Inkjet printing methodologies for drug screening

We show for the first time a contactless, low-cost, andrapid drug screening methodology by employing inkjetprinting for molecular dispensing in a microarray format.Picoliter drops containing a model substrate (D-glucose)/inhibitor (D-glucal) couple were accurately dispensed ona single layer consisting of the enzymatic target (glucoseoxidase) covalently linked to a functionalized silicon oxidesupport. A simple colorimetric detection method allowedone to prove the screening capability of the microarraywith the possibility to assay with high reproducibility atthe single spot level. Measurements of the optical signalas a function of concentration and of time verified theoccurrence at the solid-liquid interface of the competitiveenzymatic inhibition with a similar behavior occurring forthis system in a solution phase along with overcomingcompetition effects. We propose this methodology as ageneral application for drug screening purposes, since itmay be extended to any kind of enzyme-substrate/inhibitor or ligand-target biochemical system