Development of super-dense transfected cell microarrays generated by piezoelectric inkjet printing

Super-dense transfected cell microarrays (TCMs) were created by a piezoelectric inkjet printer on a glass substrate that had been grafted with poly(ethylene glycol) (PEG). The micro-spots that contained plasmid and extra-cellular matrix (ECM) protein were separated from one another by a hydrophilic barrier generated by PEG. We successfully constructed the densest TCMs with spots of 50 mm in diameter and 150 mm in pitch.