carbodiimide/N-hydroxysuccinimide (EDC/NHS) crosslinker solution was used to induce covalent immobilization onto carbon dioxide plasma-treated polyethylene substrates. Yet, owing to the limited control previously reported protocols for microcontact printing offer over biomolecule orientation, insignificant changes in fluorescence intensity were observed following NaOH exposure. Thus, to better mediate fNAP orientation we introduced two modifications to our protocol (Figure ). First, the volume of residual solution present on stamps prior to deposition was increased. While this reduced print quality at times, it increased bio-ink transfer onto the target substrate. Second, printing was performed under 65% humidity. Both these measures increased moisture in the printing environment, yielding increased moisture on the target substrate. We hypothesize that this moisture allowed for some degree of fNAP and crosslinker mobility postdeposition, thus facilitating proper crosslinking and fNAP orientation.