Photo of SMP's (Shape Memory Polymer).
Professor James H. Henderson and PhD candidate Shelby L. Buffington. (Credit: Syracuse University)

Researchers a new kind of shape memory polymer that could have major implications for healthcare. The polymer can change its shape in response to exposure to enzymes and is compatible with living cells. It requires no additional trigger, such as a change in temperature. Given these properties, it can respond to cellular activity like healing.

SMPs are soft, rubbery, “smart” materials that can change shape in response to external stimuli like temperature changes or exposure to light. They can hold each shape indefinitely and turn back when triggered to do so.

SMPs have many potential biomedical applications. For example, they are ideal as cardiovascular stents because they can be one shape for surgical insertion and another once positioned in a blood vessel. The warmth of the patient’s body is all that is required to trigger the shape change.

The team created the material using a process called dual electrospinning, in which a high-voltage current is applied to two needle tips pumping two separate polymer solutions. The voltage draws out the polymer fibers, and they are blended into a fiber polymer mat. The proper combination of fibers gives the material its shape memory qualities.

They analyzed the material’s properties, shape memory performance and cytocompatibility. Their experiments successfully demonstrated that the SMP’s original shape could be recovered through a degree of reversal, or degradation, of the shape-fixing phase.

The team is examining their SMP in cancer and macrophage cell cultures. They hope that with additional research, they will uncover practical uses for their material using lower concentrations of enzymes, produced by less extreme cellular activity.

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