Cartilage is a deceptively complex tissue to build, due to the small-scale structure that determines its mechanical and load-bearing properties - getting that structure right has proven to be a challenge. Researchers have nonetheless been making progress towards this goal in recent years, and the lessons learned will be carried forward to other tissue engineering projects:
The printing of three-dimensional tissue has taken a major step forward with the creation of a novel hybrid printer that simplifies the process of creating implantable cartilage. [The] printer is a combination of two low-cost fabrication techniques: a traditional ink jet printer and an electrospinning machine.
In this study, the hybrid system produced cartilage constructs with increased mechanical stability compared to those created by an ink jet printer using gel material alone. The constructs were also shown to maintain their functional characteristics in the laboratory and a real-life system. The key to this was the use of the electrospinning machine, which uses an electrical current to generate very fine fibres from a polymer solution. Electrospinning allows the composition of polymers to be easily controlled and therefore produces porous structures that encourage cells to integrate into surrounding tissue.
The constructs [were] inserted into mice for two, four and eight weeks to see how they performed in a real life system. After eight weeks of implantation, the constructs appeared to have developed the structures and properties that are typical of elastic cartilage, demonstrating their potential for insertion into a patient.