Stent with expandable foam
A system comprising first, second, and third shape memory polymers (SMPs); wherein (a) the first SMP is a biodegradable open cell foam that includes a first channel; (b) the second SMP includes a second channel and is included in the first channel; (c) the foam is in a first state and is configured to expand to a second state, radially outward from the second foam, in response to thermal stimulus; (d) the third SMP is between the first and second SMPs and includes a stent having a first strut that includes the third SMP and a second strut that includes the third SMP; and (e) each of the first, second, and third SMPs is coupled to a wire.
1. A system comprising:
first, second, and third shape memory polymers (SMPs);
wherein the first SMP is a biodegradable open cell foam that includes a first channel;
wherein the second SMP includes a second channel and is included in the first channel;
wherein the foam is in a first state and is configured to expand to a second state, radially outward from the second SMP, in response to thermal stimulus;
wherein the third SMP is between the first and second SMPs and includes a stent having a first strut that includes the third SMP and a second strut that includes the third SMP;
wherein each of the first, second, and third SMPs is coupled to a wire.
2. The system of claim 1 , wherein the foam has a glass transition temperature (Tg) between 30° C. and 86° C.
3. The system of claim 2 , wherein the first SMP is cross-linked.
4. The system of claim 3 , wherein the foam is a first thermoset foam and the second SMP is a second thermoset SMP foam.
5. The system of claim 4 , wherein the first SMP includes a reaction product of at least two of Hexamethylene diisocyanate (HDI), triethanolamine (TEA), hydroxypropyl ethylenediamine (HPED), or combinations thereof.
6. A system comprising:
first and second shape memory polymers (SMPs);
wherein the first SMP: (a) is a cross-linked, biodegradable, open cell foam that includes a first channel, (b) is in a first state and is configured to expand to a second state, radially outward from the second SMP, in response to thermal stimulus, (c) has a glass transition temperature (Tg) between 30° C. and 86° C.; and (d) is configured to have hysteresis corresponding to the Tg;
wherein the second SMP: (a) is a frame having a first strut that includes the second SMP and a second strut that includes the second SMP, and (b) is included in the first channel;
wherein the first and second SMPs are coupled to a wire;
wherein the foam adheres to the second SMP via a polyurethane-based adhesive.
7. The system of claim 6 , wherein the foam includes a reaction product of at least two of a diisocyanate, triethanolamine (TEA), hydroxypropyl ethylenediamine (HPED), or combinations thereof.
8. The system of claim 7 , wherein the foam includes a reaction product of the diisocyanate and the diisocyanate includes Hexamethylene diisocyanate (HDI).
9. The system of claim 7 , wherein the foam includes a reaction product of the TEA and the HPED.
10. The system of claim 7 , wherein the foam includes a reaction product of the diisocyanate, the TEA, and the HPED.
11. The system of claim 6 , wherein the wire is configured to guide the first and second SMPs within a vascular system and to a physiological void.
12. The system of claim 7 , wherein the polyurethane-based adhesive is a thermoset polymer.
13. The system of claim 6 , wherein the foam is configured to have, in the second state, a volumetric void fraction greater than 98% and less than 100%.
14. The system of claim 6 , wherein the foam is configured to have the hysteresis corresponding to the Tg in response to absorption of physiological compounds that act as plasticizers.
15. The system of claim 6 , wherein the second SMP is a stent.
16. The system of claim 6 , wherein the foam is a thermoset polyurethane polymer.
17. A system comprising:
a first SMP that is an open cell foam that includes a first channel and has a glass transition temperature (Tg) between 30° C. and 86° C.; and
a second SMP included in the first channel and including a frame which has a first strut that includes the second SMP and a second strut that includes the second SMP;
wherein the first and second SMPs are coupled to a wire;
wherein the first SMP: (a) adheres to the second SMP via a polyurethane-based adhesive; and (b) is configured to have hysteresis corresponding to the Tg.
18. The system of claim 17 , wherein:
the foam is in a first state and is configured to expand to a second state, radially outward from the second SMP, in response to thermal stimulus;
the first SMP is crimped and the second SMP is crimped;
the first SMP is a thermoset polyurethane polymer.