Page 496 - IJB-9-5

International Journal of Bioprinting CECM-GelMA bioinks of DLP 3D printing for corneal engineering

Figure 10. (A) HE staining images of corneal defect, CG hydrogel-treated, and normal tissue at 8 weeks after surgery. (B) Quantitative results(epithelial,
stroma, and total thickness) of repaired cornea (* p < 0.05, ** p < 0.01; experiment: CG hydrogel; control: corneal defect and normal tissue). The scale bar
of overall is 200 μm; and the scale bar of part is 100 μm.(C) IHC staining images of corneal defect, CG hydrogel-treated, and normal tissue at 8 weeks after
surgery (* p < 0.05, ** p < 0.01). (D) Quantification of IHC staining results (experiment: CG hydrogel; control: corneal defect and normal tissue). Scale
bars = 100 μm.

microscope (SEM), hydrogels have a soft surface and high- process of GelMA hydrogels are strong, in hydrogels with
water content. Traditional measurement methods cannot a high degree of modification, the increase in the degree
be utilized . As shown by the imaging findings of OCT of crosslinking will lead to an increase in the brittleness
[40]
scanning (Figure 1), the manufactured artificial cornea of the material. Overall, in rheological experiments,
has a smooth hyperbolic structure, achieving a biomimetic CECM-GelMA hydrogels showed weak shear frequency
shape. Although on-demand , extrusion-based printing, dependency, higher gel strength, and shorter viscoelastic
[41]
and mold construction have shown better single- chain sizes (Figure 2A and B). The rheological behavior
[37]
curvature results, this automated, free-form construction remains in a steady state . Since parameters such as the
[43]
will be more attractive for customized manufacturing. size of the indentation tip, the depth of the indentation,
the sample size, and the loading speed affect the results
On the foundation of form bionics, the creation of a [44]
natural corneal microenvironment is also crucial. Based of the compression test , this leads to a huge difference
in the compressive modulus of the cornea (the average
on the photocurable properties of GelMA, it is considered compression modulus of the natural cornea is from 3.54 ±
to be a popular hydrogel material in the field of tissue 0.30 MPa to 3.06~26.38 kPa ).
[46]
[45]
engineering. However, it has poor robustness and a
narrow stiffness range and needs to be compounded with The findings of the subsequent uniaxial compression
other materials to achieve corresponding performance. test in our study served as additional confirmation of
Moreover, dECM, which has excellent physical properties the excellent mechanical qualities of the composite
and a wide range of biochemical factors, has recently hydrogels (Figure 2C and D). Afterward, the promotion
become widely accepted as the best material for simulating in compression of CECM-GelMA is caused by a
complex natural microenvironments and has considerable combination of many factors. Bioink based on CECM
potential for tissue regeneration and biochemical is rich in collagen, which is responsible for conferring
[42]
environment reconstruction . To impart high strength and elasticity, so it is easy to form physical
biocompatibility and photocurable ability, a functional crosslinks through intermolecular interactions. CECM can
bioink with a unique microenvironment, GelMA mixed provide proteoglycans and elastin that confer viscoelastic
[47]
with CECM, was created, which can build corneal tissue properties to the whole cornea . Due to the extremely
with highly adjustable mechanical properties. Although low number of polar residues in elastin and the resistance
the covalent bonds formed during the photocurable due to attachments between proteoglycans or other matrix

Volume 9 Issue 5 (2023) 488 https://doi.org/10.18063/ijb.774