Directly implanting healthy cells into patients with tissue damage has been a long standing goal for medical researchers and materials scientists alike. The therapeutic potential of this concept is significant, but technical challenges have prevented derived technologies from finding a practical use in the clinic.

One such challenge is oxygen supply. Cells require oxygen to survive, and in biological environments, this supply is provided by blood vessels. Since implanted cells do not have their own blood vessels, their initial oxygen supply is generally far too low to sustain them.

Blood vessels do grow into the environment of implanted cells, but this process generally takes a few days, and by the time the oxygen supply arrives, the cells may have already died.

A global team spread between three continents have recently worked to address this problem by developing a synthetic technique for maintaining oxygen supply in the days before the blood vessels arrive.

Calcium peroxide was used as the oxygen source, and this was embedded in a gelatin methacryloyl bioink. The properties of this bioink were extensively optimized so that the pH and viscosity of the ink would allow it to be 3D printed, and once prepared, allow oxygen release to occur without damage to the material.

The team then demonstrated the potential of their technology by 3D printing two varieties of the optimized bioink; one with embedded heart cells and one with embedded fibroblasts. These cells were cultured in low oxygen conditions for seven days. The cells cultured in the bioink with embedded calcium peroxide showed significantly improved viability compared with a control.

The applications of this technology could extend beyond the clinic, as co-author Samad Ahadian explained, “By delivering oxygen to the implanted cells, we would be able to improve the tissue functionality and integration to the host tissue. A similar approach can be used to make functional tissues with improved survival for drug screening applications and pathophysiological studies within a long period of time.”

This technology is still very much in the early stages of development, and it will be interesting to see how it develops as it moves into in vivo trials.

Reference: Erdem et al., 3D Bioprinting of Oxygenated Cell-Laden GelatinMethacryloyl Constructs, Adv. Health. Mat. (2020). DOI: 10.1002/adhm.201901794

Quote from press release.