The bioink used in this study was composed of the following: print solution (or PBS for control), glycerol, EDC/NHS and either BSA-FITC or DAb. First GLYMO epoxy or glycerol was serially diluted in print solution or PBS. Then EDC was measured at 5mg (± 0.3mg) and NHS was measured at 3mg (± 0.3mg). The EDC/NHS combination was then dissolved in solution of glycerol and print solution. After each of the mentioned steps, the solutions were mixed via vortex at maximum speed for 10-20 seconds. Finally, the EDC/NHS solution was mixed with BSA-FITC, also diluted in print solution, with a stock concentration of 3mg/mL during the optimization tests. For anti-IL-6 and/or anti-TNF RI DAb, they were prepared at a concentration of 200µg/mL. The final solution, containing either BSA-FITC or DAb was mixed via pipette. In the separate printing test, EDC/NHS and BSA-FITC were not mixed in this method, but individually printed, either immediately after one another or with a 1min, 2min, 3min or 4min incubation between separate prints.