Iohexol as a refractive index tuning agent for bioinks in high cell density bioprinting

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Bioprinting Technologies

Background:

• Light-based 3D bioprinting is crucial for fabricating complex tissues and organs.
• High cell density (HCD) bioprinting faces challenges with light scattering, impacting resolution and fidelity.
• Tuning bioink refractive index (RI) can mitigate light scattering and enhance printing accuracy.

Purpose of the Study:

• To develop and evaluate an iohexol (IHX)-based bioink for digital light processing (DLP) 3D bioprinting.
• To assess the efficacy of RI matching using IHX in reducing light scattering and improving print fidelity.
• To demonstrate the biocompatibility and utility of IHX-bioink for fabricating HCD constructs.

Main Methods:

• Development of an iohexol (IHX)-based bioink formulation.
• Characterization of bioink RI and printability for DLP bioprinting.
• Assessment of bioink biocompatibility with various cell types (epithelial, endothelial, parenchymal, stem cells).
• Fabrication of tubular constructs with controlled lumen diameters and evaluation of lumen fidelity.

Main Results:

• IHX successfully tuned bioink RI to match cellular components, reducing light scattering.
• The IHX-bioink exhibited excellent biocompatibility and supported cell viability, reorganization, and function post-printing.
• Fabricated tubular constructs demonstrated controlled lumen diameters (400 μm–1.1 mm) with minimized overpolymerization and maintained lumen fidelity.

Conclusions:

• IHX-based bioink is a promising biomaterial for scalable, RI-matching 3D bioprinting.
• This technology enables the creation of perfusable, high cell density constructs for tissue engineering.
• The developed bioink holds potential for regenerative medicine applications requiring intricate tissue fabrication.