Composite positive and negative Poisson's ratio materials for medical devices
OwnerJoon Bu Parkinventor
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Abstract
A stent for insertion into a vessel of a patient includes an inner tube comprising a positive Poisson's ratio (PPR) material and defining a lumen extending along a longitudinal axis of the stent; and an outer tube comprising a negative Poisson's ratio (NPR) foam material and disposed around an entirety of the inner tube, the outer tube extending along the longitudinal axis of the stent. The stent is configured to exhibit an auxetic behavior in response to a deformation of the stent. An outer surface of the second portion is configured to apply a pressure to an inner surface of the vessel when the stent is implanted into the vessel and the deformation is removed.
Claims24
A stent for insertion into a vessel of a patient, the stent comprising:
- an inner tube comprising a positive Poisson's ratio (PPR) material and defining a lumen extending along a longitudinal axis of the stent;
- and
- an outer tube comprising a foam material having an anisotropic negative Poisson's ratio (NPR) and disposed around an entirety of the inner tube, the outer tube extending along the longitudinal axis of the stent,
- wherein the anisotropic NPR foam material of the outer tube defines pores on an outer surface of the outer tube, wherein the pores are re-entrant structures that are polydisperse and randomly arranged;
- wherein a hydroxyapatite material is disposed across the anisotropic NPR foam material of the outer tube with the polydisperse and randomly arranged pores that are defined by the re-entrant structures of the anisotropic NPR foam material;
- wherein the stent is configured to exhibit an auxetic behavior in response to a deformation of the stent;
- and
- wherein at least one of the inner tube or the outer tube is configured to deform from a first deformation state to a second deformation state in response to a transition from a first temperature to a second temperature and to deform from the second deformation state to the first deformation state in response to a transition from the second temperature to the first temperature, where the first temperature is lower than the second temperature.
An implantable medical device for implantation into an anatomical structure, the implantable medical device comprising:
- a first cylindrical portion comprising a PPR material;
- and
- a second cylindrical portion comprising a foam material having an anisotropic NPR defining pores on an outer surface wherein the pores are re-entrant structures that are polydisperse and randomly arranged, the second cylindrical portion disposed around an entirety of the first cylindrical portion or disposed within the first cylindrical portion;
- wherein a hydroxyapatite material is disposed across the NPR foam material of the second cylindrical portion with the polydisperse and randomly arranged pores that are defined by the re-entrant structures of the NPR material;
- wherein the implantable medical device is configured to exhibit an auxetic behavior in response to a deformation of the implantable medical device;
- and
- wherein at least one of the first cylindrical portion or the second cylindrical portion is configured to deform from a first deformation state to a second deformation state in response to a transition from a first temperature to a second temperature and to deform from the second deformation state to the first deformation state in response to a transition from the second temperature to the first temperature, where the first temperature is lower than the second temperature.
Dependencies are inferred from the claim text.