Its name an acronym for "portable bioactive ink for tissue healing," the PAINT technology is being developed by scientists from China's Nanjing University.

The system is centered around a 3D-printing pen which contains a sodium alginate gel and particles known as extracellular vesicles (EVs). The latter are naturally produced by white blood cells, and play a large role in the reduction of inflammation and formation of new blood vessels at injury sites.

The gel and the EVs mix with one another at the tip of the pen, forming a sturdy viscous ink which is extruded into cuts of any shape or size.