Page 199 - IJB-9-2

International Journal of Bioprinting A regulated GelMA-MSCs scaffold by three-dimensional bioprinting

models, and tissue engineering and is one of the most differentiation . In the CCK-8 cell proliferation experiment
[44]
[33]
versatile bioinks in biofabrication . The previous studies and the Ca-AM/PI live-death experiment, this study
[34]
have demonstrated that GelMA can encapsulate MSCs compared GelMA-MSCs cultured in 2D adherents and 3D
to provide a possible environment for the formation adherents to evaluate the biocompatibility of the GelMA-
of new cartilage [35-37] . GelMA hydrogels show great MSCs bioink. It can be observed that MSCs can achieve
performance in terms of cytocompatibility as well as cell uniform distribution and survival through the migration
adhesion, proliferation, and migration and can change and proliferation of pores in GelMA. Compared with the 2D
[38]
the mechanical strength based on the modulation of adherent culture space, there was a significant increase in the
concentration and cross-link density, thereby allowing 3D adherent cell growth environment due to the reticulated
for simulation of the physical environment of different porous structure, which was very much recapitulate the
tissues. In this study, after comparing the cell proliferation microenvironment inside the cartilage defect. Some studies
experiments of GelMA-60 10% and GelMA-60 5%, it suggested that GelMA can promote wound healing with a
was found that the GelMA-60 5% group had better cell wound closure rate of about 70% on the 14 day and allow
th
proliferation rate, because the higher concentration of for cell migration . Some studies proposed that the porous
[45]
GelMA can be a denser network of cross-linking that forms structure inside the scaffold can significantly increase cell
[46]
inside the gel, thereby limiting the growth and migration proliferation ability of Mader et al. .
of encapsulated cells. The previous studies have pointed In recent years, some studies have reported that in
out that UV curing time will also affect the hardness and the field of stem cell transplantation, only about 2% of
density of the cross-linking network inside the hydrogel . transplanted MSCs can reach the damaged tissues [47,48] .
[39]
UV curing time can be appropriately shortened when the With the development potential, microRNAs have become
research focus is on cell viability and can be used when indispensable ingredients in the regulatory process, which
the research focus is on mechanical strength. UV curing can modify MSCs by regulating the expression levels of
time can be appropriately increased. In this study, through relevant microRNAs in cells to enable them to play the
the measurement of the swelling ratio, it is proven that the corresponding roles . The self-renewal and differentiation
[49]
better expansibility of the stent is conducive to better fitting of stem cells are mediated by different microRNAs. In
between the stent and the defect after stent implantation. terms of affecting chondrogenic differentiation, it has
The previous studies have pointed out that the gap between been reported that microRNA-410 can regulate not
the stent and the defect can be better repaired in the simple only chondrogenic differentiation of MSCs through
stent implantation group . Some studies have indicated transforming growth factor beta-3 (TGF-β3), but also
[40]
that GelMA can exist in the collagenase environment cell migration and proliferation [50,51] . MicroRNA-based
for more than 24 h , indicating that it has a suitable therapy showed strong potential, but structural limitations
[41]
biodegradability, which is sufficient to enable MSCs to presented a challenge in fully exploiting its biomedical
exert biological behaviors, such as proliferation, migration, functionality. Recent studies presented a novel microRNA
and differentiation and meet the basic requirements of the inhibitor delivery system, termed BiRDs. This system
experimental scaffold condition. maximized their loading capacity and avoided uncertainty

The biocompatibility and cell adhesion growth of associated with RNA exposure in traditional loading
scaffolds have always been the focuses of 3D bioprinting protocols, and the RNase H-responsive sequence at the
research. 3D cell culture technology is an emerging tail enabled the BiRDS to transform from a 3D to a 2D
technology of material science and cell biology in recent structure on entering cells, thereby promoting the delivery
years, which enables cells to migrate and grow in 3D space of microRNA inhibitors . In this study, the expression of
[52]
to form 3D cell-material complex . Due to the lack of microRNA-410 in MSCs was upregulated by transfection
[42]
communication between cells and extracellular matrix, method, and the upregulation of microRNA-410 was
the traditional 2D cell culture model is inferior to the 3D verified by scratch experiments. The upregulation of
cell culture model in terms of physiological morphology, microRNA-410 can promote the migration, proliferation,
gene expression, and function. 3D cell culture can be and cartilage differentiation of MSCs in vitro through
designed to simulate the physiological microenvironment scratch experiments, living and dead proliferation
so that the cell behavior is closer to the actual physiological experiments, and cartilage differentiation experiments.
environment. The transition from 2D culture to 3D culture 3D bioprinting is considered one of the most advanced
will become an inevitable development trend . tools for tissue engineering and regenerative medicine .
[43]
[53]
GelMA is one of the most widely used bioink materials, Among them, 3D extrusion bioprinting technology is
and its pore structure is suitable for cell growth and widely used. Through the combination of mechanical

Volume 9 Issue 2 (2023) 191 https://doi.org/10.18063/ijb.v9i2.662