Origami-inspired thin-film shape memory alloy devices

Prasanth Velvaluri,Eckhard Quandt,Richard D James,Rodrigo Lima De Miranda,Paul Plucinsky,Arun Soor

doi:10.1038/s41598-021-90217-3

Abstract

We describe the design and fabrication of miniaturized origami structures based on thin-film shape memory alloys. These devices are attractive for medical implants, as they overcome the opposing requirements of crimping the implant for insertion into an artery while keeping sensitive parts of the implant nearly stress-free. The designs are based on a group theory approach in which compatibility at a few creases implies the foldability of the whole structure. Importantly, this approach is versatile and thus provides a pathway for patient-specific treatment of brain aneurysms of differing shapes and sizes. The wafer-based monolithic fabrication method demonstrated here, which comprises thin-film deposition, lithography, and etching using sacrificial layers, is a prerequisite for any integrated self-folding mechanism or sensors and will revolutionize the availability of miniaturized implants, allowing for new and safer medical treatments.

Highlights

We describe the design and fabrication of miniaturized origami structures based on thin-film shape memory alloys
A key example is the treatment of brain aneurysms
The fabrication route for implant design needs to provide the possibility for miniaturization, cost-effective fabrication, and a short processing time, the latter being a prerequisite for any patient-specific implants

Summary

Introduction

We describe the design and fabrication of miniaturized origami structures based on thin-film shape memory alloys These devices are attractive for medical implants, as they overcome the opposing requirements of crimping the implant for insertion into an artery while keeping sensitive parts of the implant nearly stress-free. Through proper design and fabrication, origami panels may be suitable as support structures for sensitive components They are theoretically modeled as stress-free, the experimental case is not ideal and can result in specific stresses usually in the vicinity of the hinges. A main challenge associated with origami-based implant design is that at least two stable configurations are needed, one with maximum possible folding (to place into the catheter) and the second one, consisting of a stable 3D shape upon unfolding (deployed) Changing between these two states requires the application of forces, which is often realized through balloon dilatation in the case of implants. The fabrication route for implant design needs to provide the possibility for miniaturization, cost-effective fabrication, and a short processing time, the latter being a prerequisite for any patient-specific implants

Methods

Results

Conclusion