Tuneable microfibrillar collagen structures within dense chitosan hydrogels.

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Biotechnology

Background:

• Chitosan-collagen hydrogels are promising biomaterials, but achieving high concentrations in interpenetrated networks is difficult.
• Polysaccharide-protein assemblies require advanced methods for robust network formation.

Purpose of the Study:

• To develop a novel method for preparing concentrated chitosan-collagen hydrogels (>20 mg mL^-1).
• To investigate the impact of different neutralization techniques on hydrogel structure, properties, and gelation kinetics.

Main Methods:

• Combined chitosan and collagen solutions at 25 mg mL^-1.
• Utilized two distinct neutralization methods: ammonia vapor and liquid ammonia immersion.
• Characterized hydrogel morphology, mechanical behavior, and fibroblast interactions.

Main Results:

• Ammonia vapor neutralization yielded composite hydrogels with branched collagen fibers within a chitosan network.
• Liquid ammonia immersion produced hybrid networks with associated collagen microfibrils and chitosan nanoaggregates.
• Structural differences significantly altered mechanical properties and biological performance in fibroblast cultures.

Conclusions:

• A new route for creating dense binary biopolymer hydrogels was established.
• Gelation kinetics play a crucial role in dictating the final network architecture and properties.
• The findings offer insights into controlling hydrogel formation for tailored biomaterial applications.