Shape memory materials are considered mechanically active smart materials. They are defined by their ability to recover large deformations to their original shape on command in a controlled manner.
Medical devices utilizing shape memory materials can be implanted through small incisions and be deployed to a larger size or different shape within the body to fixate tissues, repair fractures or restore normal anatomy.
Shape Memory Polymers (SMPs)
Shape memory polymers (SMPs) are a relatively new class of “smart” materials. Though researchers have developed numerous formulations of SMPs, MedShape Solutions is the only company to have developed and introduced FDA cleared devices manufactured from shape memory polymers based on PEEK (polyetheretherketone) and PMMA (polymethylmethacrylate) chemistries. SMP devices can be deployed using either thermal or mechanical activation. MedShape Solutions’ proprietary biocompatible PEEK Altera™ material allows biomedical devices to deploy into different shapes easily and reproducibly with minimal mechanical force.
Shape Memory Alloys (SMAs)
Shape memory alloys (SMAs) have been successfully used in biomedical devices such as self-expanding cardiac stents and guide wires. Nickel-titanium is the most commonly used SMA and is capable of recovering strains up to 10 times more than traditional metals and alloys.
SMAs are capable of demonstrating two unique modes of recovery:
- Pseudoelasticity refers to when a SMA recovers deformation like a rubber band, returning to its relaxed state when the distraction force is removed.
- Shape memory occurs when a deformed or compressed device is heated to body temperature to induce recovery of a permanent shape.
Fixation devices incorporating shape memory alloys can respond to changes in the site of implantation, maintaining constant compression across fractures and fusions zones.
