Additive manufacturing and design of bioresorbable mechanical metamaterials

EPSRC alignment:

This project falls within the EPSRC 'Engineering' and 'Healthcare Technologies' research themes. It aligns with the EPSRC's strategic focus on developing transformative healthcare technologies that address clinical challenges and improve patient outcomes. By developing bioresorbable, metamaterial orthopaedic implants with advanced mechanical properties, this research aims to contribute to the creation of next-generation medical devices that improve the quality of life for patients recovering from orthopaedic trauma.

Context:

Orthopaedic fixations are an important tool in surgical treatments for musculoskeletal trauma, but current solutions are typically fabricated from non-resorbable, permanent materials like stainless steel, titanium or polyether ether ketone. These materials can cause long-term complications due to the accumulation of wear particles, or require follow-up surgeries for removal.

Recent advances in additive manufacturing, particularly Powder Bed Fusion (PBF), offer the potential to overcome these limitations by enabling the fabrication of complex, metamaterial structures from degradable and resorbable polymer materials.

This project explores the creation of novel orthopaedic fixation implants that degrade in tandem with bone regrowth, eliminating the need for secondary surgeries. By optimising the material composition and metamaterial multiscale design of lattice structures, this research has the potential to significantly improve some orthopaedic treatments. The successful development of bioresorbable implants could reduce patient recovery times, lower healthcare costs, and improve clinical outcomes.

Aims and objectives:

The primary aim of this project is to develop topologically optimised metamaterial structures for orthopaedic implants, using PBF additive manufacturing and biodegradable polymers. These structures will be designed to: 1. Improve mechanical compatibility with bone, optimising both strength and stiffness.

2. Gradually degrade over time, synchronising with the bone regrowth. 3. Eliminate the need for follow-up surgeries by being fully absorbed by the body. To achieve this, the project will focus on the following objectives: 1. Design and optimise lattice structures through finite element analysis and topological optimisation techniques.

2. Manufacture prototypes using resorbable polymer materials such as poly-L-lactic acid, which have been demonstrated to have suitable biocompatibility and strength for orthopaedic applications.

3. Conduct mechanical testing, microstructure analysis, and in vitro tests to assess the implants' performance and biocompatibility. Novelty of the research methodology:

This project will use a novel combination of additive manufacturing techniques and topological optimisation to create highly specific lattice structures with tunable mechanical and biological properties. The use of PBF 3D printing allows for the fabrication of complex geometries that would be otherwise impossible to achieve using traditional manufacturing methods.

The topological optimisation methods employed in this research will generate hierarchical lattice structures that mimic natural bone, providing enhanced osteoconductivity and better integration with the body. With these functionally graded materials I aim to control the rate of resorption, ensuring that the implants degrade at a rate that aligns with the bone regrowth.

This approach will be unique in its ability to precisely tailor both mechanical properties and degradation rates to specific orthopaedic needs.