Engineering a Chemically Defined Hydrogel Bioink for Direct Bioprinting of Microvasculature

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Vascularizing bioprinted tissues is essential for creating functional constructs.
• Protein-based hydrogels lack defined compositions, leading to batch variability.
• Engineering proangiogenic bioinks with defined properties is crucial for directing microvascular formation.

Purpose of the Study:

• To develop a peptide-functionalized alginate hydrogel bioink with defined properties for bioprinting vascularized tissues.
• To investigate the bioink's ability to promote endogenous microvascular network formation.
• To create a tunable and translational bioink for tissue engineering applications.

Main Methods:

• Conjugating an integrin-binding peptide (RGD) and a VEGF-mimetic peptide onto biodegradable alginate.
• Utilizing partial ionic crosslinking to create a viscoelastic bioink with enhanced printability.
• Fabricating compartmentalized vascularized tissue constructs and analyzing cellular behavior and matrix deposition.

Main Results:

• The peptide-functionalized alginate bioink demonstrated defined mechanical, rheological, and biochemical properties.
• The bioink promoted synergistic vascular morphogenesis and capillary-scale endothelial tube formation.
• Fabricated constructs showed pericyte-endothelial cell colocalization, angiogenic sprouting, and specific matrix deposition.

Conclusions:

• A tunable, off-the-shelf hydrogel bioink with a defined composition was successfully developed for vascularized bioprinting.
• This bioink addresses critical challenges in creating vascularized tissues, offering a promising solution for tissue engineering.
• The study highlights the potential of peptide-functionalized alginates for promoting vascularization in engineered tissues.