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International Journal of Bioprinting 3D bioprinting for corneal regeneration

Table 3. (Continued)
Stroma Corneal origin decellular- Extrusion Turbinate- Good transparency, keratocytes Rabbit 90,127,131,132
izes ECM bioink derived mesenchy- activated after transplantation
mal stem cells by
keratocyte induc-
tion
Alginate-nanocellu- Extrusion Human adipose Good transparency, High viability, No 94
lose-type I collagen tissue-, bone mar- ECM production
hydrogel row-, and corneal
stroma-derived
mesenchymal stem
cells
Endothelium Gelatin-RGD bioink; Extrusion Human corneal No data Rabbit 90,127,133
amniotic membrane endothelial cells
decellularizes ECM
Abbreviations: ECM: extracellular matrix; PCL: poly(caprolactone); PEG: poly(ethylene glycol); RGD: arginyl-glycyl-aspartic acid.

to acknowledge the overarching challenge that currently types and organs using 3D printing, such as the skin or
there are no medical devices or Good Manufacturing liver, underscoring the complexity of the field. 36,39
Practice (GMP)-certified tissue printers capable of mass- To date, stem cells or progenitor cells are the most
producing artificial tissues with the requisite clinical and commonly utilized cell types in research, primarily due to
therapeutic quality. Consequently, only a fraction of the their expansive differentiation potential and wound-healing
localized and personalized therapeutic needs are presently capabilities. The immunomodulation effect exhibited by
met. These challenges underscore the need for continued these cells further positions them to potentially mitigate
advancements in technology and regulatory frameworks inflammation during transplantation.
to fully realize the potential of 3D bioprinting in meeting
broader clinical demands for corneal regeneration. The future commercialization of 3D-bioprinted
tissues necessitates the consideration of additional
11. Conclusion criteria, including the control of production processes,
standardization of protocols, cost-effectiveness, and
Studies revealed that 3D bioprinting holds significant the logistics of manufactured products. For biological
promise in advancing regenerative medicine research. products, challenges related to storage and potential
Among the myriad printing techniques available, extrusion ethical considerations await resolution. However,
processes predominate in research owing to their relative ongoing research, in parallel with the development of
cost-effectiveness. However, despite notable progress, tissue 3D-bioprinted tissues in vitro and further investigations
printing with 3D bioprinting remains in its nascent phases. into in vivo applications, will collectively contribute to the
While the majority of research focuses on developing advancement of 3D bioprinting for clinical use. 90
stromal substitutes, promising results are also emerging in
the reconstruction of the epithelial and endothelial layers.
Acknowledgments
Materials utilized in bioprinting must meet stringent
criteria, encompassing bifunctionality, stability, and the All figures were generated using Biorender
ability to foster appropriate biochemical and physiological (www.app.biorender.com).
interactions with cells. Equally critical is the requirement Funding
that these materials do not induce autoimmune reactions
in the body. Frequently, 3D-printed cornea analogs This work was supported by the National Research,
are limited to using only one or two cell types and can Development, and Innovation Office (NKFI PD 132570,
successfully print in only one or two layers. Consequently, awarded to Z.V.). Z.V. was also the recipient of the Bolyai
artificial corneas fall short of wholly resembling native János Postdoctoral Fellowship (BO/00190/20/5), funded
tissue. An additional important consideration before by the New National Excellence Program of the Hungarian
clinical application revolves around the challenges Ministry for Innovation and Technology through the
of vascularization and the implantation of artificially National Research Development and Innovation Fund.
95
produced tissue. These issues are pervasive not only in Projects TKP2021-EGA-28 and TKP2021-EGA-32 were
artificial corneas but also in the exploration of other tissue carried out with support from the Ministry of Innovation

Volume 10 Issue 2 (2024) 124 doi: 10.36922/ijb.1669