US 12,420,104 B2
Stretchable encapsulation material with high dynamic water resistivity and tissue-matching elasticity
Xudong Wang, Middleton, WI (US); and Yan Shao, Madison, WI (US)
Assigned to Wisconsin Alumni Research Foundation, Madison, WI (US)
Filed by Wisconsin Alumni Research Foundation, Madison, WI (US)
Filed on Jan. 21, 2022, as Appl. No. 17/580,890.
Prior Publication US 2023/0233869 A1, Jul. 27, 2023
Int. Cl. A61N 1/375 (2006.01); A61N 1/36 (2006.01); C08L 23/22 (2006.01)
CPC A61N 1/3758 (2013.01) [A61N 1/36014 (2013.01); C08L 23/22 (2013.01); C08L 2203/16 (2013.01); C08L 2203/206 (2013.01)] 15 Claims
OG exemplary drawing
 
1. An implantable medical device comprising:
a device body;
a flexible encapsulation adapted for retention on human tissue, the encapsulation providing an encapsulation film adapted to surround the device body and having a first surface configured to face the human tissue and a second surface opposite the first surface;
wherein the encapsulation film:
is a polyisobutylene blend comprising:
a first polyisobutylene component comprising H-PIB (high molecular weight polyisobutylene) having a first molecular weight from 75,000 to 600,000 and
a second polyisobutylene component comprising L-PIB (low molecular weight polyisobutylene) having a second molecular weight that is less than 3,000; and
wherein the first molecular weight of the first polyisobutylene component H-PIB is at least 200 times greater than the second molecular weight of the second polyisobutylene component L-PIB.