Speaker
Description
Gelatin-based hydrogels are known to be excellent materials for cell encapsulation and growth, mimicking the properties of the natural extra-cellular matrix. In order to create complex, three-dimensional cell-containing structures which overcome limitations related to the isotropy of the hydrogel, we present a novel method to locally and precisely modify its physical properties.
After UV cross-linking cell laden gelatin methacryloyl (gelMA) with the aid of a photoinitiator, we soaked the hydrogel pellet overnight in a solution containing 4,4′-diazido-2,2′-stilbenedisulfonic acid (DSSA). Upon femtosecond laser irradiation, DSSA forms reactive species that can bind to the hydrogel backbone, following an arbitrarily defined 3D pattern with micron-scale resolution. The change in stiffness and hydrophobicity of the material can be used to align and guide cell migration, as we demonstrated with a series of experiments.
We first encapsulated human adipose-derived stem cells (hASC) in gelMA, and grafted DSSA in a grid-like pattern. After two weeks of culture we could quantify the preferential orientation of hASCs along the horizontal and vertical directions, compared to the non-grafted control.
Then, we encapsulated hASC spheroids and grafted star-shaped patterns around them, varying the laser power for each beam of the pattern. The cells preferentially migrated into the grafted regions, with a higher migration speed measured where the laser power was increased.
Finally, we prepared co-culture spheroids of hASCs and human umbilical vein endothelial cells (HUVECs), and observed the formation of HUVEC sprouts following the hASCs migration, which is the first step towards the formation of a microvascular network.
The achieved results can be translated to other hydrogels with no need for a specialized functionalization of the material, thanks to the fact that the photoactivated reactive species can bind to C-H or N-H bonds of the hydrogel backbone.
| Speaker Country | Austria |
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