Therefore, the two photoinitiators selected are relatively cytocompatible based on literature reports. The photoinitiator influence on the materials cross-linking density was characterized by Raman spectroscopy. By monitoring the decrease of the acrylate C=C signal (1637 cm -1 ) relative to the O-C=O ester signal (1734 cm -1 ) before and after printing between the nonprinted ink formulations and 3D printed pillars (d = 100 µ, h= 20 µm), the degree of acrylate conversion was calculated. For ink 2, prepared from PDMS source B and the efficient DEABP photoinitiator, the relative conversion of the acrylate was calculated to be 83% (Figure , and Figure )) while for ink 4, prepared from the same PDMS source but with 2-ITX as photoinitiator, the acrylate conversion was calculated to be 66% (Figure and Figure ). The same trend was observed for inks 1 and ink 3, both prepared from PDMS source A but using different photoinitiators. For ink 1, with DEABP the acrylate conversion between the formulation and printed structures was calculated to be 78.2% (Figure ) while for ink 3 with 2-ITX the acrylate conversion was found to be 74.8% (Figure ). This Raman characterization shows the increased efficiency of DEABP over the microscale 3D printed materials. Thus, using the optimal printing parameters for ink 1 and ink 3 as exemplary materials, 'standard' nanoindentation experiments employing a Berkovich tip were performed on sets of 3D printed cylindrical pillars (d= 100 µm, h= 20 µm) as the first step in our approach (Figure , Figure , Table ). The pillars were indented to a peak displacement of 2000 nm. For analysis, the OP model was employed. The reduced moduli obtained for the pillars printed with ink 1 and ink 3 were 10.23 ± 0.44 MPa and 6.88 ± 1.95 MPa, respectively. Notably, the reduced modulus for the structures printed with ink 3 exhibited a high standard deviation, accounting for nearly 30% of the average value. The pronounced variability in the results suggested that the use of a such 'standard' nanoindentation procedure is suboptimal for soft materials. Unlike rigid microscale materials, that show little to no adhesion ,