Magnetically responsive shape memory polymers for biomedical applications

This project pursues the design of new shape-memory polymers whose shape-change can be triggered in-vivo by exposure to an oscillating magnetic field.

Magnetically-addressable shape-memory polymers (SMPs) whose shape-change can be triggered in-vivo by exposure to an oscillating magnetic field are useful for biomedical implants. In these materials, the magnetic nanoparticles serve as inductive heaters, which allow one to remotely trigger the change between two or more discrete shapes of an object via application of an alternating magnetic field. The traditional approach to create such materials is to physically incorporate superparamagnetic iron oxide nanoparticles (SPIONs) into an SMP, but it has proven to be non-trivial to prevent aggregation of the magnetic nanoparticles. We have therefore designed a family of SMPs in which SPIONs serve in a dual function as cross-links of a polymeric network and as inductive heating components. To that end, a series of SPIONs, capped with polymerizable norbornene surface groups, was synthesized. Ring-opening metathesis polymerization was used as a method to provide efficacious dispersion. The incorporation of SPIONs resulted in the appearance of a rubbery plateau, and the new materials exhibited magnetically-addressable shape-memory effect, even at a SPION content of below 1% w/w.

Adolphe Merkle Institute - Chemin des Verdiers 4 - CH-1700 Fribourg - Phone +41 26 300 9254