Ink Formulation for Inkjet Printing of Streptavidin and Streptavidin Functionalized Nanoparticles

Aqueous inks containing the protein streptavidin (SAv) or nanoparticles carrying surface-attached SAv were formulated for piezoelectric inkjet printing, using glycerol and 2-propanol to adjust their dynamic viscosity and their surface tension by variation of concentration and relative ratio of the two organic components. SAv-containing inks were transferred to epoxy-functionalized glass slides by inkjet printing or spotting and the SAv compatibility of the inks and the printing process was evaluated with regard to the ligand binding capability of the transferred SAv at the glass slide surfaces: Binding of fluorescein-4-biotin and fluorescence microscopy revealed surface-patterns of SAv and SAv-covered nanoparticles and demonstrated that glycerol and 2-propanol are suitable for the formulation of complex biofunctional inks.