FIG. 1.

Experimental flowchart. Left: Two materials (TangoPlus [FLX] and VeroClear [RGD]) and a 50:50 (vol/vol) mixture (HYB) of the two were 3D printed in the form of millimeter-sized plastic rings. Center: The rings were treated using three different methods to reduce cytotoxicity. Untreated (Raw) materials were used as control. Right: An indirect-contact cytotoxicity assay was used to evaluate the treatment method on two different fibroblast cell lines (HEL and L929). FLX, Flexible; HYB, Hybrid; PDMS, polydimethylsiloxane; RGD, Rigid.