Optimizing fabrication parameters via Taguchi method for production of high yield hydroxyapatite microsphere...

Area of Science:

• Biomaterials Engineering
• Additive Manufacturing
• Tissue Engineering

Background:

• The drop on demand (DOD) inkjet method offers a cost-effective approach for fabricating hydroxyapatite (HAp) microsphere scaffolds with controlled size distribution.
• Optimizing DOD fabrication parameters is crucial for yield and scaffold characteristics but can be experimentally intensive.
• The Taguchi method presents a predictive tool to efficiently optimize key fabrication parameters, minimizing experimental trials.

Purpose of the Study:

• To investigate the influence of DOD fabrication parameters on HAp microsphere characteristics.
• To determine optimal parameter conditions for producing high-yield HAp microsphere scaffolds with desired properties for bone substitution.
• To achieve HAp microspheres with high production yield, size <230 μm, micropore size <1 μm, rough surface morphology, and high sphericity.

Main Methods:

• Utilized the Taguchi method with an L9 orthogonal array to systematically test parameter combinations.
• Investigated four key parameters: operating pressure, shutter speed duration, nozzle height, and CaCl2 concentration, each at three levels.
• Analyzed results using signal-to-noise (S/N) ratio to identify optimal parameter settings and employed ANOVA for validation.

Main Results:

• Identified optimal parameter conditions: operating pressure (0.9-1.3 bar), shutter speed duration (100 ms), nozzle height (8 cm), and CaCl2 concentration (0.4 M).
• Achieved HAp microspheres with an average size of 213 μm, 0.45 μm micropore size, a sphericity index of 0.95, and a high production yield of 98%.
• In vitro studies demonstrated cell viability and proliferation (1.2-fold increase over 7 days) with significant alkaline phosphatase (ALP) activity (1.5-fold increase), indicating osteogenic potential.

Conclusions:

• The Taguchi method effectively optimized HAp microsphere fabrication via DOD inkjet printing, yielding high production rates and desired characteristics.
• The optimized HAp microspheres exhibit excellent biocompatibility, cell proliferation, and osteogenic potential, making them suitable for bone tissue engineering applications.
• This study validates the Taguchi method as a powerful tool for optimizing additive manufacturing processes in biomaterial scaffold development.