Recent developments and characterization techniques in 3D printing of corneal stroma tissue

Abstract

Corneal stroma has a significant function in normal visual function. The corneal stroma is vulnerable because of being the thickest part of the cornea, as it can be affected easily by infections or injuries. Any problems on corneal stroma can result in blindness. Donor shortage for corneal transplantation is one of the main issues in corneal transplantation. To address this issue, the corneal tissue engineering focuses on replacing injured tissues and repairing normal functions. Currently, there are no available, engineered corneal tissues for widely accepted routine clinical treatment, but new emerging 3D printing applications are being recognized as a promising option. Recent in vitro researches revealed that the biocompatibility and regeneration possessions of 3D‐printed hydrogels outperformed conventional tissue engineering approaches. The goal of this review is to highlight the current developments in the characterization of 3D cell‐free and bioprinted hydrogels.

Biopolymeric corneal lenticules by digital light processing based bioprinting: a dynamic substitute for corneal transplant

“…The cylindrical discs printed using the same parameters as the bioprinted lenticule had a compressive modulus of 535.42 ± 29.05 kPa. This is slightly higher than the reported modulus of the corneal stroma, 300 kPa [19]. Biocompatibility studies discussed in the later sections confirm that the cells in the bioprinted lenticule formulation were alive and proliferating (figure 4).…”

“…The successful bioengineering of bioprinted corneal lenticules for medical applications relies heavily on optimizing their mechanical properties. It is crucial for a lenticule to have similar mechanical strength as native tissue to provide adequate structural support for complete and effective healing [19]. Achieving this requires careful consideration of factors such as polymer concentration, photo-initiators, and other print-related parameters, which directly influence the mechanical strength of the bioprinted structures.…”

“…When designing a corneal substitute or artificial cornea (keratoprosthesis), it is essential to mimic the native properties of the cornea to ensure successful integration and functional performance [17]. These targeted properties include controlled swelling (∼20%), compressive modulus (100-300 kPa), transparency (∼90%), biocompatibility, controlled biodegradation, and refractive index mimicking the native cornea [18,19].…”

Emerging tissue engineering strategies for the corneal regeneration

“…New scaffold‐based strategies include 3D (bio)printing (Jiménez et al., 2019; Ulag et al., 2021), 4D bioprinting (Esworthy et al., 2019), and 5D printing (Foresti et al., 2020; Gillaspie et al., 2016), and organ‐on‐a‐chip 3D structures (Bai et al., 2020). The 3D, 4D, and 5D printing methods are subsets of additive manufacturing (AM) technologies that produce in vitro models of organs, layer by layer medical imaging as well as computer‐assisted manufacturing (CAM) and/or computer‐aided designing (CAD; Esworthy et al., 2019; Foresti et al., 2020; Gillaspie et al., 2016; Jiménez et al., 2019; Vanderburgh et al., 2017).…”

Fabrication of Gentamicin Sulfate‐Loaded 3D‐Printed Polyvinyl Alcohol/Sodium Alginate/Gelatin‐Methacryloyl Hybrid Scaffolds for Skin Tissue Replacement

“…[5,6] Utilizing extrusion-based 3D printing technology which has many advantages, such as producing porous and complex structures that mimic natural architecture, providing vascularization, and it is unique to the person. [7,8] It is a fast and easy operation at low cost, ease of sterilization, [9] and precise printing of complex geometries with computer-aided design. [10] Polyvinyl alcohol (PVA) is generally used in biomedical applications due to its good biocompatibility, water-soluble, and nontoxicobility, and it can be crosslinked using X-ray irradiation.…”