Scientists have developed a ceramic-based ink made of calcium phosphate to 3D print bone parts complete with living cells that could be used to repair damaged bone tissue. The 3D printer method is ceramic omnidirectional bioprinting in cell-suspensions (COBICS), which enables surgeons to print bonelike structures that harden in a matter of minutes when placed in water. The material can be created at room temperature — complete with living cells — and without harsh chemicals or radiation.
The fact that living cells can be part of the 3D-printed structure, together with its portability, make it a big advance on current state-of-the-art technology. Up until now, making a piece of bone-like material to repair bone tissue of a patient involves first going into a laboratory to fabricate the structures using high-temperature furnaces and toxic chemicals.
This produces a dry material that is then brought into a clinical setting or into a laboratory, where it is washed profusely and then living cells are added to it. With the new technique, the material can be extruded directly into a place where there are cells, blood vessels, and fat, enabling the bone-like structure to be printed that already contains living cells.
The novel ink was developed in a microgel matrix with living cells. The ink takes advantage of a setting mechanism through the local nanocrystallization of its components in aqueous environments, converting the inorganic ink to mechanically interlocked bone nanocrystals. In other words, it forms a structure that is chemically similar to bone-building blocks. The ink is formulated in such a way that the conversion is quick, nontoxic in a biological environment, and only initiates when ink is exposed to the body fluids, providing an ample working time for the surgeon.
When the ink is combined with a collagenous substance containing living cells, it enables in-situ fabrication of bone-like tissues that may be suitable for bone tissue engineering applications, disease modeling, drug screening, and in-situ reconstruction of bone and osteochondral defects.