Patients with terminal bladder disease can be treated by using genetically modified bladder tissues to rebuild the damaged organ. This technology can also potentially be applied to bone, skin, cartilage and muscle tissue. The printing process is followed by a post-processing step that includes cell proliferation and the maturation of the printed skin construct. The biological ink chosen for printing must have the desired biomechanical properties that help deposit the ink in the patterns specified in the STL file created through CAD modeling.
The printing of primary human keratinocytes and fibroblasts in the wound of naked athymic mice was done by inkjet printing, which led to the complete re-epithelization of the wound within 8 weeks. In addition, the number of components involved in the printing process is one of the major problems of 3D bioprinting. However, this process is quite random in nature and does not allow for a specific custom 3D distribution of cells or matrices (Bose et al. Maintaining cell viability in the formulation of biological ink and then printing them with precise geometries requires the standardization of printing methods and meticulous quality control to maintain the quality of the printed construction.
The printability of bioink is governed by the rheological properties of ink in both forms of printing mechanisms. Several types of additive manufacturing techniques have been developed for the selective modeling of cells and biomaterials for the manufacture of viable tissue constructs, such as 3D inkjet-based bioprinting (Cui and Boland, 200), 3D extrusion-based bioprinting (Jones, 201), laser-assisted 3D bioprinting (Keriquel et al. However, traditional tissue engineering approaches, consisting of scaffolds, growth factors and cells, showed limited success in the manufacture of complex three-dimensional shapes and in the regeneration of organs in vivo, making them not feasible for clinical applications from a logistical and economic point of view. This process is often referred to as “reversible freeform embedding” (FRE) or embedded 3D printing (e-3D printing).
Mostly, 3D bioprinting can be used for several biological applications in the fields of tissue engineering, bioengineering and materials science. Bioinspired hydrogel composed of hyaluronic acid and alginate as a possible biological ink for 3D bioprinting of engineered structures of articular cartilage. When Northrop Grumman's 18th Commercial Resupply Services (NG-1) mission launches to the ISS, it will transport an improved version of the Redwire Space biofabrication plant, or BFF, a 3D bioprinter capable of printing human tissue. Currently, most of the biopolymers used in bioprinting come from polymers generally used for tissue engineering and rarely have optimal rheological and cross-linking properties ideal for a bioprinting process.
