Integrated Tissue-Organ Printer
An integrated tissue-organ printer, referred to as an ITOP, takes bioprinting to the next level by allowing for the fabrication of scalable tissues, such as cartilage, bone, and skeletal muscle (1).
Figure 1: (from Wake Forest University) Left: The ITOP printing into a petri dish. Right: A 3D printed bone segment and ear lay in media.
The team at Wake Forest University used the custom-built ITOP with matrix, sacrificial and support bioinks to develop human-scale tissues with desired mechanical and degradation properties. The cell laden matrix bioink, consisting of gelatin, fibrinogen, hyaluronic acid, glycerol and Dulbecco’s Modified Eagles Medium (DMEM), was prepared with varying concentrations and cell types to mimic distinct tissues (table 1). This matrix reagent was printed alongside the support material polycaprolactone (PCL) and sacrificial material pluronic F127. After printing, pluronic F127 was removed to create a porous structure. PCL strengthens the mechanical properties of the printed structure and provides control over degradation.
|Gelatin||Protein||specific cellular interactions|
|Fibrinogen||Protein||specific cellular interactons|
|Hyaluronic Acid||Glycosaminoglycan||specific cellular interactions and to increase viscosity|
|Glycerol||Polyol||thickening agent to improve printability|
Table 1: Reagents used in matrix bioinks with ITOP printer. Each reagent serves a specific purpose, such as providing specific cellular adhesion sites or improving printability. Varying ratios of these reagents are used for different tissue types.
Multimaterial bioprints can increase mechanical strength and long-term cell viability of printed constructs. Likewise, matrix bioinks with multiple reagents create enhanced biological reactions with more specific cellular environments.
- Kang, Hyun-Wook et al, “A 3D bioprinting system to produce human-scale tissue constructs with structural integrity,” Nature Biotechnology, vol. 3, no. 34, February 2016.