Veromagenta

The CAD models were translated to the printer in a printable Standard Tessellation Language (STL) format. First, the STLs of the 11 cubic samples (C00–C100) were transferred to the PolyJet^TM printer Connex3 Objet500 (Stratasys Ltd., EdenPrairie, MN, USA). Then, 11-cubes in sets of two were printed, each set with a different material for the grid structure: solid bio-compatible MED610 (Stratasys, EdenPrairie, MN, USA) with a Shore hardness of 83-86 (Scale D) and flexible TangoPlus (Stratasys Ltd., EdenPrairie, MN, USA) with rubber-like properties with a Shore hardness of 26-28 (Scale A). SUP706 (Stratasys Ltd., Eden Prairie, MN) was chosen as the support material. The samples were printed with different matrix thicknesses as designed in the CAD software, yielding a specific partial volume contribution C% of the MRI-signal generating material to the voxel.
The spherical tumour models were printed using a different material for the grid structure, TangoPlus, VeroClear and VeroMagenta (Stratasys Ltd.). The general properties of VeroClear and VeroMagenta were similar to those of MED610 but not approved biocompatible. The same support material as for the cubic samples, SUP706, was used.

Thermoplastics were selected for chamber fabrication based on chemical, and auto fluorescence compatibility. Small 5 mm × 5 mm × 2 mm 3D printed sections of PETG (polyethylene terephthalate glycol copolymer), P430 ABS, ABS M30 (Acrylonitrile butadiene styrene), nylon and vero magenta (Stratasys®, Israel) were used for compatibility testing. For chemical compatibility testing printed samples were weighed before and after solvent treatments (at 1 h and 24 h post treatments). The test included the following five solvents at neat concentrations- distilled Milli-Q™ water, acetone (analytical reagent), chloroform (analytical reagent), 2- propanol (analytical reagent), and acetonitrile (HPLC grade); all solvents purchased from Thermofisher Scientific^®, Australia. A similar test was conducted against neat concentrations of four surfactants esterified vegetable oil (EVO), fatty acid ethoxylate (FAE), organosilicone (OS), and alcohol alkoxylate (AA) supplied by Victorian Chemical Company^®, Australia.