Electrospun microfibers enhance nutrient supply in bioinks and 3D-bioprinted tissue

3D bioprinting holds great potential in the field of regenerative medicine to produce miniaturized tissues and organ precursors with biological functionality. Today, however, scientists are still working on the challenge of producing a printable and compatible starting material.

Researchers at the NMI Natural and Medical Sciences Institute in Reutlingen, TU Darmstadt and Black Drop Biodrucker GmbH have developed a new type of bioink that improves the transport of nutrients in printed tissue. The research is published in the journal Biofabrication.

3D printing has now found its way into many technologies. It is a process in which a 3D object is printed using a special starting material. In 3D bio-printing, this starting material is bioink, which contains living cells and is combined with hydrogels and biological factors, for example, to print organic objects. In addition, electrospinning can be used to produce wafer-thin fibers.

“With a diameter of 5–10 µm, these fibers are in the range of blood capillaries and are the significant advance in our bioink,” explains Dr. Hanna Hartmann, Head of Division at the NMI and inventor in the joint patent.

Until now, the transport of nutrients in 3D-printed tissue has been a major problem. “The fibers now measurably improve this transport. The particularly exciting finding for us is that they don’t even have to be hollow on the inside,” reports Jannik Stadler, site manager of Black Drop Biodrucker GmbH, which played a key role in the development of the bioink.

This bio-ink also has particularly advantageous properties, including its mechanical strength and the fact that it swells less. Annabelle Neuhäusler, a doctoral student at the Institute for Printing Machines and Printing Processes at TU Darmstadt, was able to demonstrate this in the joint publication.

In the future, these improved bioinks could be used to produce tissue models for pharmaceutical research, for example. This could eliminate the need for animal testing and allow patient-specific active ingredients to be tested. Another application lies in the area of regenerative medicine. In addition to increasing nutrient diffusion, fiber integration helps to improve the mechanical properties of bioinks. This is particularly important for surgical applications, where handling, dimensional stability and primarily strength play a key role.