Multi-Objective Optimizations of Biodegradable Polymer Stent Structure and Stent Microinjection Molding Process.

Area of Science:

• Biomaterials Engineering
• Medical Device Design
• Polymer Science

Background:

• Biodegradable poly-l-lactic acid (PLLA) stents offer biocompatibility but suffer from low radial stiffness and foreshortening.
• The intricate meshed structure of stents presents manufacturing challenges, particularly for polymeric materials.

Purpose of the Study:

• To optimize the structure and microinjection molding process of biodegradable PLLA stents.
• To enhance stent mechanical properties, such as radial stiffness and reduce foreshortening.
• To improve the quality of stent microinjection molding.

Main Methods:

• A finite element analysis-based optimization method was combined with Kriging surrogate modeling.
• Kriging surrogate models were developed to approximate relationships between design variables and objectives.
• Expected improvement was utilized for global optimization of stent design and manufacturing.

Main Results:

• Optimization significantly improved the mechanical properties of the polymeric ART18Z stent during expansion in a stenotic artery.
• The microinjection molding quality of the stent was enhanced through the proposed optimization process.
• Numerical results validated the effectiveness of the optimization method for stent design and manufacturing.

Conclusions:

• The integrated finite element analysis and Kriging surrogate modeling approach effectively optimizes biodegradable stent design and microinjection molding.
• This computational method provides a pathway for achieving measurable optimality in stent structure and manufacturing processes.
• The study demonstrates a viable strategy for overcoming limitations of PLLA stents and improving their clinical applicability.