3D printing of bio-implants is nothing new. Skin and more recently bones are being printed every day in many hospitals around the world. Depending on what needs to be printed a specific ink, or set of inks, need to be used.
In the case of skin tissue the printing is done using a solution of cells from the same patient but in this case it is more a 2D than a 3D printing. In case of bones it is a real 3D printing.
To create a 3D structure inks made of collagen, thermoplastic, alginate, silicon are used but they all have some limitations, particularly the process required to provide strength to the 3D structure can affect the cells once the “piece” is implanted.
Researchers at Tuft University have managed to combine silk proteins (produced by a number of insects, and now also artificially) with glycerol, a non toxic sugar alcohol already used in food and pharmaceutical products, to produce a transparent ink resulting, once printed, in a flexible structure fully compatible with bio-tissues.
They expect their result to be used in implants for the delivery of drugs (in this case the 3D printer will combine drugs with the ink and the 3D architecture will regulate the rate of release of the drug) and for printing artificial tissues of the desired shape.