Speaker
Description
Introduction
3D in-vitro models offer a more accurate simulation of in-vivo conditions than traditional 2D cell cultures. Vascularization is currently a hot topic in tissue modeling, helping to mimic the in-vivo environment, adding physiological relevance, and aiding the supply of nutrient and oxygen as the removal of metabolic waste1. Also, perfused vascular networks allow better biomimicry drug screening, emulating the drug passage through the endothelial barrier2. Different techniques have been employed to introduce a vascular compartment in various tissue models, including self-assembly, microfluidic platforms, sacrificial templating, and 3D bioprinting3.
Microporous hydrogels are promising biomaterials for tissue modeling, offering enhanced biomimicry. Introducing tunable micropores within hydrogels can significantly improve their structural and biological performance. Aqueous two-phase emulsions (ATPE) consist of a matrix material mixed with a porogen, which is later removed after crosslinking. ATPE are appealing systems as they offer a completely aqueous environment, eliminating the need for oil-phase solvents4.
In this study, different combinations of Gelatin Methacryloyl (GelMA) and Polyvinyl Alcohol (PVA) were characterized and tested for different uses, such as Extrusion Based Bioprinting (EBB), demonstrating its versatility in the introduction of a vascularized compartment in tissue models.
Methods
In this study, an ATPE is obtained combining GelMA as the matrix and PVA as porogen. Different PVA molecular weights have been tested based on the application. A preliminary study evaluated porogen removal by means of FTIR analysis, followed by biological metabolic tests on A549 and HUVEC cell. SEM imaging was also employed to visualize differences in the micropore sizes. Rheological and photorheological characterization of different ATPE formulations were conducted to assess their mechanical properties and printability. EBB tests have been performed to evaluate modifications in the micropore morphology induced by the printing process.[CGG2] [CGG3] Sacrificial templating has also been investigated to assess HUVECs response under dynamic conditions. Core-Shell structures obtained via microfluidic EBB are currently under investigation.
Results
PVA is successfully removed after the first washes with PBS, as demonstrated by FTIR analysis. The size of the micropores can be tuned by varying the PVA molecular weight, as demonstrated by SEM imaging, and the rheological properties are in line with a printable biomaterial. Extrusion-based bioprinting has been demonstrated to influence pores morphology, which elongates along the printing direction. Metabolic tests showed enhanced metabolic activities in A549 cell line.
The results demonstrate that the GelMA-PVA ATPE is a versatile and promising alternative to plain GelMA, offering enhanced tunability for specific uses. Potential applications include the use of this ATPE in core-shell bioprinting to create microporous vessel scaffolds for angiogenesis studies.
References
1. Makode et al., Biofabrication 16(2), 2024.
2. Kolesky et al., PNAS 113(12), 2016.
3. Dellaquila et al., Adv. Sci. 8(19), 2021.
4. Wang et al., Adv. Healthc. Mater. 12(19), 2023.
Acknowledgements
This publication is part of the project PNRR-NGEU, which has received funding from the MUR – DM 118/2023. Project PNC 0000001 D3 4 Health, - CUP B83C22006120001, National plan for complementary investments to the PNRR, funded by European Union – NextGenerationEU".
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