To ensure accessibility to a broad scientific community, we chose commercially available acrylated PDMS products as the core of the new soft elastomer inks. However, when it comes to commercial PDMS products, it is often difficult to obtain exact data on its composition, making it difficult to evaluate the suitability of the acrylated PDMS for 2PLP. Thus, in order to overcome this challenge, 1 H NMR spectroscopy was used for the chemical characterization and more importantly, to determine their acrylate composition, which is key for printability. In particular, the ratio between the PDMS core protons (-Si(CH 3 ) 2 ) and the acrylate protons (-CH=CH 2 , Table and Figure ) for all the PDMS sources was calculated. For this study, two acrylated PDMS based commercially available materials, namely TEGO ® RAD 2500 (A) and DMS-U21 (B), were identified and selected (Figure ) to prepare the series of soft inks (see next section)