Laser Fabrication of Three-Dimensional CAD Scaffolds from Photosensitive Gelatin for Applications in Tissue Engineering

Abstract

In the present work, 3D CAD scaffolds for tissue engineering applications were developed starting from methacrylamide-modified gelatin (GelMOD) using two-photon polymerization (2PP). The scaffolds were cross-linked employing the biocompatible photoinitiator Irgacure 2959. Because gelatin is derived from collagen (i.e., the main constituent of the ECM), the developed materials mimic the cellular microenvironment from a chemical point of view. In addition, by applying the 2PP technique, structural properties of the cellular microenvironment can also be mimicked. Furthermore, in vitro degradation assays indicated that the enzymatic degradation capability of gelatin is preserved for the methacrylamide-modified derivative. An in depth morphological analysis of the 2PP-fabricated scaffolds demonstrated that the parameters of the CAD model are reproduced with great precision, including the ridge-like surface topography on the order of 1.5 μm. The developed scaffolds showed an excellent stability in culture medium. In a final part of the present work, the suitability of the developed scaffolds for tissue engineering applications was verified. The results indicated that the applied materials are suitable to support porcine mesenchymal stem cell adhesion and subsequent proliferation. Upon applying osteogenic stimulation, the seeded cells differentiated into the anticipated lineage. Energy dispersive X-ray (EDX) analysis showed the induced calcification of the scaffolds. The results clearly indicate that 2PP is capable of manufacturing precisely constructed 3D tissue engineering scaffolds using photosensitive polymers as starting material.

Cellulose Nanofibers for the Enhancement of Printability of Low Viscosity Gelatin Derivatives

“…1B). During the grinding process, due to different flow patterns and different force distribution to the aggregates of fibers, the fibers are heterogeneous (Ovsianikov et al 2011). The differences of the morphological properties between cellulose fibers before and after the grinding process induced the differences in the rheological properties of the cellulose dispersion solutions.…”

“…Highly viscous CNF dispersions with low concentrations of cellulose can be easily produced in a mechanical grinder. Due to their high mechanical strength, CNFs have been widely studied for enhancing the mechanical properties and structural stability of weak hydrogels (Ovsianikov et al 2011;.…”

Hydrogels in Tissue Engineering

“…Reaction kinetics in hydrogel photopolymerization based on ultraviolet light exposure time have been monitored [92]. Low conversion rates due to insufficient ultraviolet light exposure were associated with reduced macrophage viability and increased expression of inflammation markers by the cells [64,93]. This demonstrates that not just formulation changes, but also the efficiency of the system to completely consume the reactive elements utilized for gelation or functionalization can have significant effect on cellular response.…”

Microfabrication of 3D metallic interconnects via direct laser writing and chemical metallization

“…As the majority of the materials are bio-compatible [16,17], this approach was employed for the manufacturing of artificial scaffolds for cell proliferation studies [18,19], medical implants for tissue engineering [20,21] as well as regenerative medicine [22,23]. In all of the mentioned examples the materials were passive polymers sensitized only with a photoinitiator responsible for the efficient photostructuring [24].…”