Stock solutions of LAP (1.0% w/v) and DTT (5.0% w/v) were prepared in PBS and added right before the addition the polymer solution to prevent disulfide formation in DTT. To thiol-ene inks, DTT was added as dithiol crosslinker in an equimolar ratio of n(SH) and n(ene). As last step, the photoinitiator was added to obtain a final concentration of 0.1% w/v.