Speaker
Description
The use of xeno-free (animal origin-free) hydrogels to support the growth of cells significantly increased in the recent years. The advantage of these materials in comparison with animal derivates is the reproducibility of structural, mechanical and biological properties and, additionally, overcoming of potential immunological complications and disease transmission in vivo. Many novel commercially available bioinks intended for extrusion bioprinting contain nanofibrillated cellulose (NFC) derived from plants. We performed the comparative testing of several NFC-based hydrogels for their printability and biocompatibily: GrowDexT and GrowInk T (UPM Biomedical) and Laminink+ (CellInk), where the last one is composed of NFC with addition of sodium alginate and laminin. To assess the biocompatibility of tested bioinks, the survival and behavior of immortalized human adipose derived stem cells (hASCs, Evercyte) encapsulated in the bioinks was observed over 14 days using laser confocal microscopy (LSM 700, Carl Zeiss) and metabolic activity testing (PrestoBlue, Invitrogen). The main tuning parameter was the concentration of the bioinks, as it affects the printability of the ink and the viability of the cells inversely. Therefore, not only the printing parameters – pressure, movement speed, preflow delay, nozzle size for extrusion bioprinting (BioX, CellINK) but also the right mixing ratio of bioink and cell suspension were established to obtain stable structures with favorable conditions for proliferation and migration of cells. Performed experiments showed that optimization of the bioprinting parameters and material formulation for each hydrogel are essential for obtaining durable structures and long-term survival of encapsulated cells. From the tested bioinks, GrowDex-T with a concentration of 0.8% w/v, stood out as the best candidate for bioprinting of hASC, as we observed better proliferation and change of cell morphology from round to the spindle shape. An additional advantage of this material is its transparency and non-fluorescence, that facilitates microscopy of 3-dimensional cell loaded structures.
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