| Abstract [eng] |
3D printing technology has greatly contributed to the fabrication of distinct customizable units regardless of application. Though previously used to fabricate components for machinery, said technology can be utilized for the fabrication of biologically active constructs. These come in handy in reconstructive surgery, which relies on autologous transplantation of either skin, cartilage or bone grafts, associated with donor site morbidity. 18 studies in total were included, 14 in vivo and 4 in vitro. Integration of bioprinted skin tissue was consistently tested in in vivo studies. Cartilage reconstruction was tested once in vivo, the other studies limited themselves to in vitro testing. As for osseointegration of bone tissue, 6 studies were conducted in vivo while 1 study was carried out in vitro. Printing of multilayered skin grafts with autologous cells displayed good integration into skin defects. A higher rate of epithelialization and decreased wound contraction of the autograft could be observed in all studies. Utilizing M2 exosomes resulted in a dampened immune response leading to less inflammation, further contributing to an enhanced integration of the graft without graft rejection. Angiogenesis could be enhanced by supplementing the skin graft with stem cells, endothelial cells and pericytes, increasing blood vessel density and graft perfusion. Cartilage reconstruction was improved by including autologous chondrocytes within a printed scaffold. ADSC were capable of differentiation into chondrocytes leaving preformed cartilage tissue intact. The most suitable ADSC for chondrocyte differentiation were found to be located in the IPFP. Bone reconstruction could be accomplished with permanent grafts composed out of titanium alloy, or biodegradable ones. The latter of which can be composed out of a multitude of materials, the ones included here being iron and manganese, as well as PLA. All experimental groups of scaffolds were able to display enhanced signs of osseointegration and new bone formation, contributing to mechanical strength of the bone. All included studies show a strong preference towards utilization of 3D printing technology to replace or at least enhance the current gold standard, namely autologous transplantation and grafting. Autologous cells, especially stem cells, can be more efficiently harvested and incorporated into bioink, giving rise to a vast collection of scaffolds intended to replace a multitude of tissues. These processes greatly reduce donor site morbidity of autologous transplantation, as is seen in skin flaps, cartilage retrieval, or iliac crest bone grafts. |
