Ole Thaden (Heidelberg, DE), Nicole Schneider (Heidelberg, DE), Prof. Dr. Kerstin Göpfrich (Heidelberg, DE), Prof. Dr. Daniela Duarte Campos (Heidelberg, DE)
Abstract text (incl. figure legends and references)
Introduction
In the field of tissue engineering, 3D bioprinting is used for generating functional 3D tissues that can be exploited for the restoration of damaged tissues. Giant unilamellar lipid vesicles (GUVs) can be synthesized as a micron-sized container surrounded by a lipid bilayer that allows the encapsulation of hydrophilic biomolecules, surface functionalization, and a tailored cargo release.
Objectives
In this study, we investigate the feasibility of bioprinting GUVs biomedical applications. We evaluated the structural integrity of GUVs during the printing process and characterized the stability of GUVs in hydrogel over time, as well as the interaction of pegylated GUVs with cells (Figure 1a).
Materials & methods
A protocol for printing GUVs was established, consisting of production, filtration, and printing with a bioprinter. After bioprinting at pressures between 0.2 and 1 bar, the number and size of the GUVs were determined by fluorescence microscopy and the structural integrity was calculated.
Results
We showed that GUVs formed with 5% pegylated lipids have a 40% increased stability compared to unpegylated GUVs when encapsulated in 1% (w/v) agarose hydrogel for a period of three days (Figure 1b). In addition, up to 65.7 ± 16.1% of unpegylated GUVs and 52.6 ± 15.4% of 5% pegylated GUVs remained intact during the printing process. Therefore, demonstrating that GUVs can be printed using drop-on-demand and extrusion methods.
Conclusion
Pegylation of GUVs has shown to increase their stability under physiological conditions encapsulated in a hydrogel. However, a trade-off needs to be met between increased physiological stability and reduced mechanical stability. The proposed GUV bioprinting protocol can be utilized in multiple biomedical applications combined with the ability to functionalize the bilayer and the spatiotemporal control of biomolecule release in the fabricated tissue.