Indirect additive manufacturing as an elegant tool for the production of self-supporting low density gelatin scaffolds

Abstract

The present work describes for the first time the production of self-supporting low gelatin density (<10 w/v%) porous scaffolds using methacrylamide-modified gelatin as an extracellular matrix mimicking component. As porous scaffolds starting from low gelatin concentrations cannot be realized with the conventional additive manufacturing techniques in the abscence of additives, we applied an indirect fused deposition modelling approach. To realize this, we have printed a sacrificial polyester scaffold which supported the hydrogel material during UV crosslinking, thereby preventing hydrogel structure collapse. After complete curing, the polyester scaffold was selectively dissolved leaving behind a porous, interconnective low density gelatin scaffold. Scaffold structural analysis indicated the success of the selected indirect additive manufacturing approach. Physico-chemical testing revealed scaffold properties (mechanical, degradation, swelling) to depend on the applied gelatin concentration and methacrylamide content. Preliminary biocompatibility studies revealed the cell-interactive and biocompatible properties of the materials developed.

Beyond the Modification Degree: Impact of Raw Material on Physicochemical Properties of Gelatin Type A and Type B Methacryloyls

“…Additional modification of gelatin with inert acetyl functions (GMA) has been introduced by our group to tune viscosity and gelation of aqueous GM solutions independently from its cross‐linking potential . Formulations of GM(A) with adjusted properties are also increasingly used for sophisticated fabrication techniques such as inkjet‐printing, robotic dispensing, fused deposition modeling, or two‐photon polymerization . Differences in mechanical properties of resulting GM hydrogels and tissue‐specific additives are utilized to emulate most diverse tissues such as bone, cartilage, adipose tissue, cardiac tissue, and as matrix for formation of capillary structures .…”

Indirect Solid Freeform Fabrication of an Initiator‐Free Photocrosslinkable Hydrogel Precursor for the Creation of Porous Scaffolds

“…The templates were produced in a similar fashion as previously reported . More specifically, G‐codes were obtained using in‐house‐developed software written in visual basic for applications.…”

“…Gelatin methacrylamide (GM) was prepared similar to a previously reported protocol . In brief, 100 g gelatin B was dissolved in 1 L phosphate buffer (0.1 mmolar, pH 7.4) at 40 °C.…”

“…However, in general, synthetic materials exhibit little to no cell adhesion . In contrast, natural hydrogels often show high cell adhesion, but are concomitant with poor reproducibility and inferior mechanical properties …”

“…In conventional SFF, the viscosity requirements of the printing solution limit the applicable concentration range substantially. In contrast, with the iSFF method, fluid viscosity is not a critical factor as concentrations which are too high or too low to be applied for conventional SFF can still be used in a straightforward manner . Therefore, the great advantage of this approach is its versatility: it allows the straightforward generation of high‐precision 3D structured materials that are challenging or even unsuitable to be processed using conventional SFF.…”