The Rheology and Printability of Cartilage Matrix-Only Biomaterials.

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Cartilage matrix holds potential for cartilage repair due to chondroinductivity.
• Existing cartilage matrix hydrogels lack mechanical strength and printability for effective use.
• A need exists for robust, printable cartilage matrix hydrogels for surgical applications.

Purpose of the Study:

• To enhance the stiffness and develop paste-like precursor rheology for bioprinting of methacryl-modified solubilized and devitalized cartilage (MeSDVC) hydrogels.
• To compare methacrylic anhydride (MA) and glycidyl methacrylate (GM) for modifying MeSDVC.
• To optimize MeSDVC for improved mechanical properties and printability.

Main Methods:

• Two methacryloylating reagents (MA and GM) were used to modify MeSDVC.
• The molar excess (ME) of MA was varied (2 to 20) to assess its impact.
• Hydrogel stiffness, precursor rheology, printability, and cell viability were evaluated.

Main Results:

• MA modification resulted in greater methacryloylation compared to GM.
• Paste-like rheology was observed in most hydrogel precursors, with 2 ME MA and GM MeSDVC showing superior printability.
• The 2 ME MA MeSDVC hydrogel achieved a stiffness of 1.55 ± 0.23 MPa, nearing native cartilage modulus, and supported cell viability for 15 days.

Conclusions:

• Methacrylic anhydride (2 ME) effectively improved methacryloylation, stiffness, and printability of MeSDVC hydrogels.
• A stand-alone, printable MeSDVC biomaterial was developed.
• MeSDVC shows significant potential as a bioink for cartilage repair with clinical relevance.