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International Journal of Bioprinting 3D-Printed GelMA biomaterials in cartilage repair

Figure 6. Modification of GelMA through introduction of other materials or groups for better articular cartilage repair.

strength by adding poly(lactic acid) (PLLA) to alginate/ These modified hydrogels significantly enhanced the
GelMA and incorporating PLLA, which improved performance and broadened the application of GelMA-
the printing fidelity and mechanical strengths. This based hydrogels as the mechanical properties of GelMA-
microfiber-reinforced alginate/GelMA scaffold supported based biomaterials directly impact the performance and
bone marrow-derived mesenchymal stem cells (BMSCs) functionality of the resulting engineered cartilage.
proliferation and chondrogenesis in vitro, thereby showing
the potential in cartilage tissue engineering applications. 4.2. Integration and adhesion

Generally, GelMA contains cell attachment sites, GelMA hydrogels have shown potential for generating
but it does not possess controlled degradation rate like hyaline cartilage when combined with stem cells, but
synthetic polymers. These characteristics are regarded seamlessly integrating the newly formed cartilage with
as the vital parameters for developing “smart” scaffold the local tissue is challenging. Therefore, it is crucial to
that has cell attachment sites and allows controlled drug modify the integration and adhesion of GelMA hydrogels
release. Recently, it is a vital parameter to develop “smart” with in situ tissues for their effective use in cartilage tissue
scaffold that can allow cell attach and possess controlled engineering.
drug release. Many materials were added to control the To enhance the adhesion and integration of GelMA
degradation rate of GelMA hydrogels. Guan et al. hydrogels with in situ cartilage, researchers have explored
[19]
incorporated polyethylene glycol diacrylate (PEGDA) and various approaches by introducing different components.
chondroitin sulfate methacrylate (CSMA) into GelMA Trengove et al. used microbial transglutaminase
[21]
hydrogels, and this PEGDA-GelMA-CSMA scaffold (MTG) to improve the integration of GelMA scaffolds
possessed suitable compressive elastic modulus and with surrounding tissue. When MTG is applied to a
degradation rate. In addition, the differentiation lineage biomaterial, it catalyzes the formation of covalent bonds
toward chondrocytes or osteocytes could be controlled by between amino acid residues in the biomaterial and the
adjusting the percentage of CSMA, suggesting that it could surrounding host tissue, resulting in a stronger and more
be used in bone and cartilage repair. Han et al. developed stable interface between biomaterial and host tissue. Suo
[20]
a GelMA-based biohybrid hydrogel by incorporating et al. [22,23] grafted gelatin and glucosamine molecules onto
polymerizing acrylamide (PAM). One advantage of PAM acrylate groups to form GelMA/acryloyl glucosamine
is the controlled mechanical property. The GelMA/PAM (AGA) hydrogels in order to improve adhesion and
hydrogels demonstrated a controlled degradation rate cartilage repair. Glucosamine is a naturally occurring
and continued protein release without affecting the cell amino sugar and a key component of the extracellular
behavior in vitro. Additionally, these biomixed hydrogels matrix (ECM) of cartilage, and it normally cannot
showed promising cartilage repair abilities in vivo. improve the adhesion between biomaterials and host

Volume 9 Issue 6 (2023) 244 https://doi.org/10.36922/ijb.0116