Medical devices having mems functionality and methods of making same

Abstract

Implantable medical devices, including stents, grafts, covered stents, catheters, patches or the like having regions of the device which are functionalized employing microelectromechanical systems that are capable of acting as electromechanical sensors or biosensors in response to either an endogenous event, such as tissue growth, biochemical binding events, pressure changes, or respond to an externally applied stimulus, such as RF energy, to cause a change in the state of the device, such as to induce an oscillation signal which may be interrogated and interpreted external the body or may generate an induced electrical or electromagnetic potential in the device to activate micromotors to effect a geometric change in the device.

1 . An endoluminal stent having a plurality of structural elements defining luminal and abluminal wall surfaces thereof, a central lumen, and a plurality of openings passing through the luminal and abluminal wall surfaces, comprising at least one microelectromechanical system formed within at least a portion of the at least one of the plurality of structural elements  
     
     
         2 . The endoluminal stent according to  claim 1 , wherein the at least one microelectromechanical system is selected from the group of cantilevers, nanothermometer, accelerometers, galvanotactic assemblies, impedance spectrometers, amperometric measurement, antibody/ion-channel sensors, electrocorrosive sensors, microvalves, micropumps, micromotors, microactuator and drive assemblies.  
     
     
         3 . The endoluminal stent according to  claim 1 , wherein the stent further comprises a plurality of recesses in at least one of the plurality of structural members, each of the plurality of recesses further having at least one cantilever member projecting over an associated recess, wherein the at least one cantilever member is capable of oscillating upon application of an external energy thereto.  
     
     
         4 . The endoluminal stent according to  claim 3 , wherein each of at least one cantilever member further comprises a piezoelectric element.  
     
     
         5 . The endoluminal stent according to  claim 3 , wherein binding of at least one of cellular and sub-cellular components to the at least one cantilever member sufficiently attenuates is capability to oscillate upon application of an external energy thereto, such that interrogation of the oscillation returns a signal representative of the attenuated oscillation.  
     
     
         6 . The endoluminal stent according to  claim 5 , wherein the interrogation of the oscillation occurs at an ultrawideband frequency.  
     
     
         7 . The endoluminal stent according to  claim 1 , further comprising a plurality of openings passing through at some of the plurality of structural elements and a plurality of electrodes electrically coupled to one another and positioned proximate the plurality of opening to impart an electrical field gradient across the plurality of openings when a voltage is applied to the plurality of electrodes.  
     
     
         8 . A system for actuating an endoluminal stent, comprising at least one actuator member operably associated with the endoluminal stent, at least one communication circuit in operably communicating with the at least one actuator member, at least one logic circuit electrically coupled to the communication circuit, and at least one power source.  
     
     
         9 . The system for actuating the endoluminal stent according to  claim 8 , wherein the at least one actuator member further comprises at least two interlacing comb members, each of the at least two comb members being operably coupled to a contact, and having a plurality of drive projections for interfacing with a structural member of the endoluminal stent.  
     
     
         10 . The system for actuating the endoluminal stent according to  claim 9 , wherein the contact is in operable communication with the communication circuit.  
     
     
         11 . The system for actuating the endoluminal stent according to  claim 8 , wherein the at least one power source further comprises an external power source which is inductively coupled to the at least one actuator member.  
     
     
         12 . A method of making a galvanotactic stent having a plurality of structural elements defining luminal and abluminal wall surfaces thereof, a central lumen, and a plurality of openings passing through the luminal and abluminal wall surfaces, comprising fabricating the stent at least partially by multi-layer physical vapor deposition, wherein the method further comprises, 
 depositing a first substrate layer,    depositing an intermediate conductive layer,    forming interdigitated electrodes in the conductive layer,    depositing a final top insulating layer, and    forming a plurality of openings patterned to match the position of the interdigitated electrodes in the intermediate conductive layer,    wherein at least one microelectromechanical system is formed within at least a portion of the at least one of the plurality of structural elements.    
     
     
         13 . The method as in  claim 12 , wherein the interdigitated electrodes that are adjacent to each other are being separated by a dielectric material.  
     
     
         14 . The method as in  claim 12 , wherein the conductive layer comprises of a polymer.  
     
     
         15 . The method as in  claim 14 , wherein the polymer is selected from the group consisting of polypyrroles and polypyrrolidones.  
     
     
         16 . The method as in  claim 14 , wherein the polymer further comprises a biological element that forms an embedded circuit.  
     
     
         17 . The galvanotactic stent prepared by the method of  claim 12 .  
     
     
         18 . The galvanotactic stent as in  claim 17 , comprising a power source selected from the group consisting of externally applied electromagnetic field, ultrasound, UV light, photoemissive energy, and thermal energy.  
     
     
         19 . The galvanotactic stent as in  claim 17 , wherein the conductive layer of the stent binds oxidases to provide electrical current.  
     
     
         20 . The galvanotactic stent according to  claim 17 , wherein the at least one microelectromechanical system is selected from the group of cantilevers, nanothermometer, accelerometers, galvanotactic assemblies, impedance spectrometers, amperometric measurement, antibody/ion-channel sensors, electrocorrosive sensors, microvalves, micropumps, micromotors, microactuator and drive assemblies.