Tunable hydrogel composite with two-step processing in combination with innovative hardware upgrade for cell-based...

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Bioprinting Technology

Background:

• Three-dimensional (3-D) bioprinting requires advanced bioinks for stable construct fabrication.
• Existing bioinks often lack sufficient properties for cell encapsulation and printing fidelity.
• Developing versatile bioinks is crucial for advancing tissue engineering applications.

Purpose of the Study:

• To develop and characterize a novel hydrogel composite bioink for 3-D bioprinting.
• To evaluate the bioink's suitability for cell encapsulation and bone tissue engineering.
• To assess the impact of hydroxyapatite (HA) on the bioink's properties and applications.

Main Methods:

• A hydrogel composite of alginate and gelatin was formulated with varying hydroxyapatite (HA) concentrations.
• Rheological, swelling, and mechanical properties were characterized.
• A two-step crosslinking mechanism (thermosensitive gelatin and chemical alginate crosslinking) was employed.
• Novel syringe tip heaters were utilized for precise temperature control.
• Human mesenchymal stem cells were encapsulated to assess viability post-printing and in vitro culture.
• Micro-computed tomography was used for structural visualization.

Main Results:

• The hydrogel composite demonstrated tunable rheological, swelling, and mechanical properties with varying HA concentrations.
• Instantaneous and long-term structural integrity of printed constructs was achieved.
• The bioink supported high viability (85%) of encapsulated human mesenchymal stem cells after 3 days in vitro.
• Hydroxyapatite facilitated micro-computed tomography visualization and indicated potential for bone tissue engineering.
• The composite showed promise for drug delivery and soft tissue engineering applications with modifications.

Conclusions:

• The developed alginate-gelatin-HA hydrogel composite is a versatile bioink for 3-D bioprinting.
• The bioink ensures high cell viability and structural integrity, suitable for bone tissue engineering.
• This material platform offers potential for diverse applications including drug delivery and soft tissue regeneration.