Implantable intraocular pressure sensors and methods of use

Abstract

Intraocular pressure sensors, systems, and methods of use. Implantable intraocular pressure sensing devices that are hermetically sealed and adapted to wirelessly communicate with an external device. The implantable devices can include a hermetically sealed housing, the hermetically sealed housing including therein: an antenna in electrical communication with a rechargeable power source, the rechargeable power source in electrical communication with an ASIC, and the ASIC in electrical communication with a pressure sensor.

1 . An implantable pressure sensor assembly, comprising:
 a flexible membrane including a parylene polymer and forming a hermetic seal sealing a chamber;   a pressure sensor disposed within the chamber;   an inert fluid disposed in the chamber and in direct contact with the pressure sensor; and   a coating disposed on an outer surface of the flexible membrane,   wherein the flexible membrane is adapted to transmit pressure from an external environment to the inert fluid inside the hermetic seal.   
     
     
         2 . The assembly of  claim 1 , wherein the flexible membrane has a thickness of about 2 μm to about 50 μm. 
     
     
         3 . The assembly of  claim 1 , wherein the inert fluid is configured to transmit hydrostatic pressure to the pressure sensor through the flexible membrane. 
     
     
         4 . The assembly of  claim 1 , wherein the pressure sensor is configured to measure a pressure of about ambient pressure ±1 mmHg to about ambient pressure+50 mmHg. 
     
     
         5 . The assembly of  claim 1 , wherein the coating comprises at least one of ceramic or parylene. 
     
     
         6 . The assembly of  claim 1 , wherein the coating comprises a hydrogel with a gradient in at least one of number density of hydroxyl groups or cross-link density. 
     
     
         7 . The assembly of  claim 6 , wherein the hydrogel is infused with a therapeutic agent configured to be released from the hydrogel over a period of at least 10 days following implantation of the assembly into a body. 
     
     
         8 . The assembly of  claim 6 , wherein the hydrogel is impregnated with at least one therapeutic agent to reduce clotting and/or inflammatory response. 
     
     
         9 . The assembly of  claim 1 , wherein the parylene polymer is parylene C. 
     
     
         10 . The assembly of  claim 1 , further comprising:
 a rechargeable power source electrically coupled to the pressure sensor;   an antenna electrically coupled to the rechargeable power source; and   an application-specific integrated circuit (ASIC) electrically coupled to the rechargeable power source and the pressure sensor.   
     
     
         11 . The assembly of  claim 10 , wherein the antenna is part of a first circuit adapted to supply power to the rechargeable power source, and the antenna is also part of a second circuit adapted to transmit data to an external device. 
     
     
         12 . The assembly of  claim 10 , wherein the ASIC comprises a microcontroller, a flash memory, a non-volatile memory, and a logic circuit. 
     
     
         13 . A method of forming an assembly comprising:
 creating a hermetic seal around a chamber containing a pressure sensor with a flexible membrane including a parylene polymer;   disposing an inert fluid inside of the chamber and in direct contact with the pressure sensor; and   depositing a coating on an outer surface of the flexible membrane.   
     
     
         14 . The method of  claim 13 , wherein depositing the coating comprises depositing at least one of a ceramic layer or a parylene layer. 
     
     
         15 . The method of  claim 13 , wherein depositing the coating comprises depositing a hydrogel with a gradient in at least one of number density of hydroxyl groups or cross-link density. 
     
     
         16 . The method of  claim 13 , wherein depositing the coating comprises depositing a hydrogel infused with a therapeutic agent configured to be released from the hydrogel over a period of at least 10 days following implantation of the assembly into a body. 
     
     
         17 . The method of  claim 13 , wherein depositing the coating comprises depositing a hydrogel impregnated with at least one therapeutic agent to reduce clotting and/or inflammatory response. 
     
     
         18 . The method of  claim 13 , further comprising:
 electrically coupling a rechargeable power source to the pressure sensor;   electrically coupling an antenna to the rechargeable power source; and   electrically coupling an application-specific integrated circuit (ASIC) to the rechargeable power source and the pressure sensor.   
     
     
         19 . A method comprising:
 implanting a pressure sensor assembly into a mammalian body, the pressure sensor assembly including a flexible membrane forming a hermetic seal about a chamber, a pressure sensor disposed in the chamber, and an inert fluid disposed in the hermetic seal and in direct contact with the pressure sensor;   transmitting a hydrostatic pressure from the body to the inert fluid via the flexible membrane;   transmitting the hydrostatic pressure from the inert fluid to the pressure sensor; and   measuring the hydrostatic pressure with the pressure sensor.   
     
     
         20 . The method of  claim 19 , wherein the pressure sensor assembly further includes a pressure sensor, a rechargeable power source, and an antenna and the method further comprises:
 wirelessly recharging the rechargeable power source electrically coupled to the pressure sensor via the antenna; and   wirelessly transmitting pressure data measured by the pressure sensor to an external device via the antenna.   
     
     
         21 . The method of  claim 19 , further comprising:
 following implanting, releasing a therapeutic agent from a coating disposed on the pressure sensor assembly over a period of at least 10 days.