15X images of an early print of Jurkat cells onto poly-L-lysine slides without the use of WGA-biotin. Left panels: DIC images acquired immediately after printing.

A 30% sucrose print buffer prevented complete liquid evaporation after printing. Other panels show nuclear stain (center) and immunofluorescence (right) against cleaved caspase 3, an indicator of apoptosis. Top row, untreated; bottom row, treated with staurosporine, 4 h. Yellow circles indicate one printed spot; arrows indicate cells outside the circle translocated during the immunofluorescence protocol. As a consequence, all subsequent prints were conducted with WGA-biotin-decorated cells printed on streptavidin-coated slides.