Transforming Tendon Reconstruction: The GeSiM BioScaffolder’s Role in Hybrid Scaffold Innovation

Tendons are connective tissues that attach muscles to bones and enable joint movement. However, tendon injuries are common and often difficult to heal, requiring surgical intervention with autologous materials and long-term rehabilitation. The use of regenerative grafts, which mimic mechanical properties while supporting the growth and alignment of cells to rebuild the native structure of the tendon, could be an option to improve medical treatment.

In a recent study published in the journal Biomaterials Advanced, authors proposed a new approach to fabricate 3D scaffolds for tendon reconstruction using a combination of two biofabrication techniques: embroidery and melt electrowriting (MEW).

Embroidery, a process employing robotic sewing machines and biodegradable polymer threads, has shown promise in promoting tissue formation and therefore, mimicking the mechanical properties of tendons. However, these scaffolds lack the potential to moderate the cell interaction within cellular dimensions. MEW, on the other hand, is a 3D printing technology that enables the creation of microscale structures  that directly influence  cell behavior. The technique’s ability to deposit microscale fibers very precisely on a collector stage complements the limitations of embroidery.

An embroidered fiber structure was made from a co-polymer, namely PLA and PCL, using an industrial embroidery machine.  Embroidering was done on a watersoluble PVA-membrane which was subsequently dissolved. Subsequently, the embroidered structure was placed on the GeSiM BioScaffolder for the deposition of MEW-fibers on top.

These hybrids achieved a hierarchical pore design with fiber alignment and outperformed pure embroidered or MEW scaffolds, showing better mechanical and biological properties like tensile strength, stiffness, and porosity, while promoting cell attachment, proliferation, and alignment.

This innovative approach not only holds promise for tendon reconstruction but also for other tissues requiring anisotropic structures, such as ligaments, nerves, and blood vessels.

In conclusion, the study highlights the collaborative effort of interdisciplinary techniques in tissue engineering. The GeSiM Bioscaffolder enables innovation by completing embroidery with MEW techniques, offering new avenues for enhanced tendon reconstruction and broader tissue engineering applications.

 

MEW process small
Taken from Fig. 5. Melt electrowritten fibers were placed on top of the embroidery structure with the 30° and the Mixed pattern and collagen coated afterwards (A). The experimental PCL fiber diameters were as intended (B), but the deviation of the fiber spacing increased, leading to a decrease of the mean spacing (C). The 90° of the Mixed (5 μm sized fibers are shown vertically) pattern was maintained whereas the intended 30° pattern was widened (D).[1]

 

[1] Max von Witzleben, Judith Hahn, Ron F. Richter, Bianca de Freitas Machado, Emily Steyer, Kathleen Schütz, Corina Vater, Anne Bernhardt, Cindy Elschner, Michael Gelinsky, Tailoring the pore design of embroidered structures by melt electrowriting to enhance the cell alignment in scaffold-based tendon reconstruction, Biomaterials Advances, Volume 156, 2024, 213708, ISSN 2772-9508, https://doi.org/10.1016/j.bioadv.2023.213708.