Abstract In the implantable pressure sensor disclosed herein, a radioopaque liquid is contained within a resiliently compressible vessel of a silastic material, i.e. a silicone rubber, the volume of liquid actually contained within the vessel being then variable as a function of the pressure or force applied to the vessel. The silastic is rendered impervious to the radio-opaque liquid by a treatment which involves expanding and saturating the cured silastic with a mixture of a hydrocarbon solvent such as heptane containing a dissolved wax such as beeswax. The solvent expands and saturates the silastic, carrying beeswax into the silastic. When the solvent evaporates, the beeswax is then trapped within the interstices of the silastic, under tension.
THE METHOD OF MAKING AN IMPLANTABLE PRESSURE SENSOR, SAID METHOD COMPRISING: FORMING A SILASTIC MATERIAL INTO THE FORM OF A VESSEL AND CURING SAID MATERIAL; SOAKING THE CURED SILASTIC VESSEL IN A MIXTURE OF A HYDROCARBON SOLVENT AND A WAX; REMOVING THE VESSEL FROM SAID MIXTURE AND ALLOWING THE ABSORBED SOLVENT TO EVAPORATE; AND AT LEAST PARTIALLY FILLING SAID VESSEL WITH A LIQUID, THE LIQUID BEING DISPLACEABLE WITH RESPECT TO THE VESSEL IN RESPONSE TO PRESSURE APPLIED TO SAID VESSEL.
Claim 2
Independent Claim
80 words
THE METHOD OF MAKING AN IMPLANTABLE PRESSURE SENSOR, SAID METHOD COMPRISING: FORMING A SILASTIC MATERIAL INTO THE FORM OF A VESSEL AND CURING SAID MATERIAL; SOAKING THE CURED SILASTIC VESSEL IN A MIXTURE OF A HYDROCARBON SOLVENT AND A WAX; REMOVING THE VESSEL FROM SAID MIXTURE AND ALLOWING THE ABSORBED SOLVENT TO EVAPORATE; AND AT LEAST PARTIALLY FILLING SAID VESSEL WITH A LIQUID, THE LIQUID BEING DISPLACEABLE WITH RESPECT TO THE VESSEL IN RESPONSE TO PRESSURE APPLIED TO SAID VESSEL.
Claim 3
Independent Claim
79 words
The method of making an implantable pressure sensor, said method comprising: forming a silastic material into the form of a vessel and curing said material; soaking the cured silastic vessel in a hydrocarbon solvent containing dissolved beeswax; removing the vessel from said mixture and allowing the absorbed solvent to evaporate; and at least partially filling said vessel with the liquid, Lipodol F, the liquid being displaceable with respect to the vessel in response to pressures applied to said vessel.
Claim 4
Independent Claim
79 words
The method of making an implantable pressure sensor, said method comprising: forming a silastic material into the form of a vessel and curing said material; soaking the cured silastic vessel in a hydrocarbon solvent containing dissolved beeswax; removing the vessel from said mixture and allowing the absorbed solvent to evaporate; and at least partially filling said vessel with the liquid, Lipodol F, the liquid being displaceable with respect to the vessel in response to pressures applied to said vessel.
Claim 5
Dependent Claim
10 words
The method of claim 2 wherein said solvent is heptane.