3D Printability of Silk/Hydroxyapatite Composites for Microprosthetic Applications

Area of Science:

• Biomaterials Engineering
• Additive Manufacturing
• Biomedical Device Fabrication

Background:

• Micro-prosthetics demand mechanically robust, personalized components with high feature accuracy.
• Biocompatibility limits material selection in 3D printing for biomedical applications.
• Hydroxyapatite (HA) is used for bone-like structures, but its brittleness is a challenge.

Purpose of the Study:

• To investigate the rheology, printability, and mechanical properties of HA and HA-silk protein composites for micro-prosthetics.
• To understand how composition and water content affect the performance of HA-based inks.
• To correlate rheological parameters with printing outcomes and material properties.

Main Methods:

• Rheological analysis (linear and nonlinear shear) of HA and HA-silk protein inks.
• 3D printing of micro-scale components using developed inks.
• Mechanical testing (compressive strength, elastic modulus) of printed parts.
• Correlation of ink properties with geometric accuracy and structural integrity.

Main Results:

• Silk protein inclusion improves the ductility and printability of HA inks.
• Silk reduces underextrusion by lowering elastic modulus and reduces slumping by increasing yield stress.
• Silk-HA composites exhibit higher elastic modulus and compressive strength than pure HA inks.
• A printing map was developed to guide the manufacturing of HA-based inks.

Conclusions:

• Silk protein is a promising additive for fabricating mechanically robust and accurate micro-prosthetics using HA-based inks.
• Optimized HA-silk formulations enable high-quality 3D printing of sub-millimetric features for biomedical applications.
• The developed printing map facilitates the design of advanced HA-based materials for personalized medical devices.