The main goal in biofabrication approach is to build living tissue substitutes on demand. In order to create functional tissue structures, additive manufacturing (AM) technologies are being increasingly considered. They allow generating functional structures created out of CAD models within a short period of time and with a very high precision. Different techniques are already established to build three-dimensional (3D) complex cell-loaded structures. One of these robotic additive fabrication techniques is the ink jet technology which is highly promising for biofabrication. This technique allows to process very small amounts of liquids or low-viscous polymer solutions e.g. to set biomolecules and cells in a suitable structure. The aim of this study is to evaluate a piezo inkjet printing device which is integrated in a commercial modular instrument platform together with a bioplotting system for biofabrication. The inkjet device is able to print single ink droplets of different volumes by controlling the applied voltage and the number of drops released to the spot. In this work different selective sets of parameters influencing the droplet formation and the spot size have been investigated. It has been proven that inkjet printing process in combination with fibrin hydrogel and bone marrow stromal cells is cytocompatible. In summary, the applied piezo inkjet printing is shown to be completely programmable, accurate and the resolution of the device allowed printing of various patterns with biomaterials and vital cells.
Hydrogels are gaining interest as scaffolds for bone tissue regeneration due to ease of incorporation of cells and biological molecules such as enzymes. Mineralization of hydrogels, desirable for bone tissue regeneration applications, may be achieved enzymatically by incorporation of alkaline phosphatase (ALP). Additive manufacturing techniques such as bioplotting enable the layer-by-layer creation of three-dimensional hydrogel scaffolds with highly defined geometry and internal architecture. In this study, we present a novel method to produce macroporous hydrogel scaffolds in combination with cell-loaded capsule-containing struts by 3D bioplotting. This approach enables loading of the capsules and strut phases with different cells and/or bioactive substances and hence makes compartmentalization within a scaffold possible. 3D porous alginate scaffolds enriched with ALP and MG-63 osteoblast-like cells were produced by bioplotting struts of alginate which were loaded with pre-fabricated alginate capsules. Two combinations were compared, namely ALP in the struts and cells in the capsules and vice-versa. Both combinations were cytocompatible for cells and mineralization of scaffolds could be detected in both cases, according to an OsteoImage staining. ALP had no adverse effect on cytocompatibility and enhanced mitochondrial activity.
This study evaluated the influence of ionic dissolution products of a novel Ca-enriched silicate bioactive glass compared to commercial available hydroxyapaptite samples (Endobonr) on cell activity and vascular endothelial growth factor (VEGF) release in vitro. Bone marrow stromal cells (ST-2) were cultivated with the supernatant of granules of different sizes and at different concentrations (0-1 wt/vol % of granules) for 48 h. In addition to in vitro studies, Ca-ion release from all as cell morphology observation revealed no cytotoxic effect of the released products from all tested materials. It was found that supernatants from granules in concentrations of 1 wt/vol %enhanced the VEGF release from ST2 cells, which is important as a marker of the vascularisation ability of the glass during the bone healing process.
effects of 3D scaffolds made from 45S5 bioactive glass (BG)
doped with 1 wt. % copper ions in the arteriovenous loop
model of the rat.
Materials and Methods: An arteriovenous loop was built
in the groin of 10 rats and inserted in 1% copper doped
45S5 BG scaffolds and fibrin. The scaffold and the AV loop
were inserted in Teflon isolation chambers and explanted
3 weeks after implantation. Afterwards the scaffolds were
analyzed by Micro-CT and histology regarding vascularization.
Results were compared to plain 45S5 BG-based
scaffolds from a previous study.
Results: Micro-CT and histological evaluation showed consistent
vascularization of the constructs. A tendency towards
an increased vascularization in the copper doped
BG group compared to plain BG constructs could be observed.
However, therewas no significant difference in statistical
analysis between both groups.
Conclusions: This study shows results that support an increased
angiogenetic effect of 1% copper doped 45S5 BG
compared to regular 45S5 BG scaffolds in the rat arteriovenous
loop model although these tendencies are not backed
by statistical evidence. Maybe higher copper doses could
lead to a statistically significant angiogenetic effect.
As an interdisciplinary field, tissue engineering (TE) aims to regenerate tissues by combining the principles of cell biology, material science, and biomedical engineering. Nanotechnology creates new materials that might enable further tissue-engineering applications. In this context, the introduction of nanotechnology and nanomaterials promises a biomimetic approach by mimicking nature. This review summarizes the current scope of nanotechnology implementation possibilities in the field of tissue engineering of bone, muscle, and vascular grafts with forms on nanofibrous structures.