3D (Bio) printing Integrated Touch-Spinning of Hybrid Bioink – Nanofiber Constructs for Tissue Engineering Applications

W. Kitana1*, V. Levario-Diaz2, E. A. Cavalcanti-Adam2,3, L. Ionov1,4

1 Professorship of Biofabrication, Faculty of Engineering Science, University of Bayreuth, Ludwig-Thoma-Straße 36A, 95447 Bayreuth, Germany, 2 Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstraße 29, 69120 Heidelberg, Germany, 3 Professorship of Cellular Biomechanics, Faculty of Engineering Science, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany, 4 Bavarian Polymer Institute, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany 

*waseem.kitana@uni-bayreuth.de

Biofabrication as a multidisciplinary field of study applies a multitude of technologies for the fabrication of biologically relevant constructs with tailored properties that mimic the complexity of many tissues. A promising biofabrication technology is 3D (bio) printing, which uses cell encapsulated hydrogels for the fabrication of tissue-like constructs. [1,2] However, hydrogels do not resemble the composition of many tissues’ extracellular matrix, which is composed of both gel-like and fibrous components. Additionally, hydrogels are isotropic in nature and have poor mechanical properties.[2,3] This isotropic nature of hydrogels results in non-controlled or random cell orientation which eventually results in improper functioning of the fabricated tissue-like construct. A wide range of approaches have been employed for the fabrication of these composite structures in combination with 3D (bio) printing, such as electrospinning and melt electrowriting. [2,4,5] These techniques have shown limitations such as the use of high voltages and temperatures. Thereby, touch-spinning was used, which is based on mechanically pulling fibers from a polymer droplet to deposit highly aligned fibers on a stationary substrate without the need for high voltages and/or temperatures.[5,6] This technology enables the fabrication of composite multilayered bioink-nanofibers construct with its integration with 3D (bio) printing. Additionally, it provides a cell-friendly environment for the biofabrication of such constructs in a multilayered fashion and all in a single device with minimal human intervention [7]. The cells within the biofabricated constructs have shown a preferred orientation along the fiber’s main direction, with an alignment degree of higher than 60 % and a maximum of 93 %. All bioink formulations have shown a high cell viability of higher than 80 %, confirming the non-toxicity of the system. Finally, time-lapse videos of fibroblasts have shown an average displacement of 3.5 μm s-1 with a directed movement along the fibers [7]. In conclusion, biomaterial inks play a crucial role in fibroblast behavior. In which, cells show a preferred orientation along the nanofiber’s main direction, while cells tend to form aggregates in bioinks with higher viscosity. Finally, fibroblast motility using time-lapse microscopy shows a directed movement of the cells along the fibers.

References

[1] J. Malda, Advanced Materials, 2013, 25, 5011.

[2] B. Kong, Nature Communications, 2020, 11, 1435.

[3] J. Visser, Nature Communications, 2015, 6, 6933.

[4] A. L. Butcher, Trends in Biotechnology, 2014, 32, 564.

[5] D. Asheghali, Nanomedicine: NBM, 2020, 24, 102152.

[6] A. Tokarev, Advanced Materials, 2015, 27, 6526.

[7] W. Kitana, Adv. Healthcare Mater., 2023, 2303343.