Alginate/poly(amidoamine) injectable hybrid hydrogel for cell delivery

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Injectable hydrogels are crucial for cell delivery in tissue engineering.
• Developing biocompatible and functional hydrogels remains a significant challenge.
• Alginate-based hydrogels offer potential but often require modification for enhanced cell interaction.

Purpose of the Study:

• To design and synthesize a novel covalently cross-linked injectable hybrid hydrogel based on alginate and poly(amidoamine) (PAMAM) for cell delivery.
• To evaluate the physicochemical properties, biocompatibility, and cell interaction of the developed hydrogel.
• To investigate the potential of this hydrogel as a scaffold for tissue engineering applications.

Main Methods:

• Synthesis of alginate/PAMAM hydrogels using tetra-amino-functional PAMAM dendrimer as a cross-linker.
• Characterization of hydrogel properties including pore size, swelling ratio, and degradation rate.
• Assessment of cell attachment, proliferation, and viability using MC3T3-E1 pre-osteoblasts via MTT assay and Live-Dead assay.
• Comparison with poly(ethylene glycol) cross-linked hydrogels.
• Evaluation of cell adhesion, extensions, and in situ mineralization using SEM and vinculin assay.

Main Results:

• The alginate/PAMAM hydrogels exhibited tunable pore sizes (57–88 μm) and swelling ratios (110–157%).
• Non-cytotoxicity was confirmed, with >95% cell viability observed.
• Degradation rate decreased with increasing PAMAM content.
• The hydrogels showed enhanced cell encapsulation, attachment, and proliferation compared to PEG-cross-linked counterparts.
• Cationic nature of the hydrogels facilitated electrostatic interaction with cells and promoted mineralization.

Conclusions:

• The developed injectable alginate/PAMAM hydrogel is a promising biomaterial for cell delivery.
• Its biocompatibility, tunable properties, and enhanced cell interaction support its use in tissue engineering.
• The hydrogel's ability to promote mineralization further highlights its potential for bone regeneration applications.