Masters student in Mechanical Engineering at Northeastern University
DESIGN OF A BIOMATRIX STENTS
Overview and Aim
I worked on this project as a part of my academic project.The final outcome of the project is to design an implantable stent to meet the present unmet clinical needs of the stent and meeting the FDA requirements of the stent.
Filed a patent application for the design and concept
Description
A stent is a Medical device that is meant for treating Coronary Artery Disease(CAD) which is blockage of one or more arteries that supply blood to heart.
Stent is a Class 3 device in the FDA classification of the medical devices
As stent being a class 3 device a lot of factors need to be considered in designing and for FDA approval
The considerations taken into account for the design of the stents are
1. Biocompatibility
2. Functional Performance
3. Patient Friendliness
Design process
Our design process is taking into account the presently available stents that are FDA approved, researching on the various designs, materials, limitations and then how we can be overcome them.
Our main aim is to design a biodegradable stent as a permanent stent can cause problem at any time
Based on the consideration our design ideas considered
1. Designing a drug eluding stent based on Poly-l-Lactic acid material
2. A polymer layered stent such as Magnesium alloy stent which can be degraded at a particular time
3. Possibility of clearing the blockage without the use of stent
Considering the above design Ideas we have opted for using Magnesium alloy for the design of our stent because of the following reasons.
1. Use of Poly-l-Lactic acid material is causing a late thrombosis example for that is the recent withdraw of Abbott Stent
2. Magnesium stent provides a great scaffolding ability compared to the other absorbable stents.
Design
We designed the stent such that it has the more longitudinal strength it is capable of the scaffolding ability in spite of the degradation of the stent.
My contribution to the project was to design the stent for maximum scaffolding ability for at least 4 months of period and also analyze the stent for the scaffolding ability of the stent.
Below figures show the initial and final designs of the stent
Initial Design of the BioMatrix Stent of 130-micrometer strut thickness
Final Design of the BioMatrix Stent of 100-micrometer strut thickness
The Designed Stents are validated using the ANSYS Software
Following factors are considered for the Verification of the stent
1. Degradation rate of the stent
2. Material of the stent
3. Scaffolding ability of the stent
Following figures show the validation done in ANSYS
Graph of Stress in the Stent Vs the time(inflation and deflation of the balloon)
Total Deformation of the stent during the implantation process
Total Von misses stress of the stent during the implantation process
The Designed Stents are 3D printed for the evaluation purpose to validate the design purpose
