Snoring is very common among mammals including humans. Snoring is a noise produced while breathing during sleep due to the vibration of the soft palate and uvula. Not all snoring is bad, except when it bothers the bed partner or others near the person who is snoring. If the snoring gets worst over time and goes untreated, it could lead to apnea.
Those with apnea stop breathing in their sleep, often hundreds of times during the night. Usually apnea occurs when the throat muscles and tongue relax during sleep and partially block the opening of the airway. When the muscles of the soft palate at the base of the tongue and the uvula relax and sag, the airway becomes blocked, making breathing labored and noisy and even stopping it altogether. Sleep apnea also can occur in obese people when an excess amount of tissue in the airway causes it to be narrowed.
In a given night, the number of involuntary breathing pauses or “apneic events” may be as high as 20 to 60 or more per hour. These breathing pauses are almost always accompanied by snoring between apnea episodes. Sleep apnea can also be characterized by choking sensations.
Sleep apnea is diagnosed and treated by primary care physicians, pulmonologists, neurologists, or other physicians with specialty training in sleep disorders. Diagnosis of sleep apnea is not simple because there can be many different reasons for disturbed sleep.
The specific therapy for sleep apnea is tailored to the individual patient based on medical history, physical examination, and the results of polysomnography. Medications are generally not effective in the treatment of sleep apnea. Oxygen is sometimes used in patients with central apnea caused by heart failure. It is not used to treat obstructive sleep apnea.
Nasal continuous positive airway pressure (CPAP) is the most common treatment for sleep apnea. In this procedure, the patient wears a mask over the nose during sleep, and pressure from an air blower forces air through the nasal passages. The air pressure is adjusted so that it is just enough to prevent the throat from collapsing during sleep. The pressure is constant and continuous. Nasal CPAP prevents airway closure while in use, but apnea episodes return when CPAP is stopped or it is used improperly. Many variations of CPAP devices are available and all have the same side effects such as nasal irritation and drying, facial skin irritation, abdominal bloating, mask leaks, sore eyes, and headaches. Some versions of CPAP vary the pressure to coincide with the person's breathing pattern, and other CPAPs start with low pressure, slowly increasing it to allow the person to fall asleep before the full prescribed pressure is applied.
Dental appliances that reposition the lower jaw and the tongue have been helpful to some patients with mild to moderate sleep apnea or who snore but do not have apnea. A dentist or orthodontist is often the one to fit the patient with such a device.
Some patients with sleep apnea may need surgery. Although several surgical procedures are used to increase the size of the airway, none of them is completely successful or without risks. More than one procedure may need to be tried before the patient realizes any benefits. Some of the more common procedures include removal of adenoids and tonsils (especially in children), nasal polyps or other growths, or other tissue in the airway and correction of structural deformities. Younger patients seem to benefit from these surgical procedures more than older patients.
Uvulopalatopharyngoplasty (UPPP) is a procedure used to remove excess tissue at the back of the throat (tonsils, uvula, and part of the soft palate). The success of this technique may range from 30 to 60 percent. The long-term side effects and benefits are not known, and it is difficult to predict which patients will do well with this procedure.
Laser-assisted uvulopalatoplasty (LAUP) is done to eliminate snoring but has not been shown to be effective in treating sleep apnea. This procedure involves using a laser device to eliminate tissue in the back of the throat. Like UPPP, LAUP may decrease or eliminate snoring but not eliminate sleep apnea itself. Elimination of snoring, the primary symptom of sleep apnea, without influencing the condition may carry the risk of delaying the diagnosis and possible treatment of sleep apnea in patients who elect to have LAUP. To identify possible underlying sleep apnea, sleep studies are usually required before LAUP is performed.
Somnoplasty is a procedure that uses RF to reduce the size of some airway structures such as the uvula and the back of the tongue. This technique helps in reducing snoring and is being investigated as a treatment for apnea.
Tracheostomy is used in persons with severe, life-threatening sleep apnea. In this procedure, a small hole is made in the windpipe and a tube is inserted into the opening. This tube stays closed during waking hours and the person breathes and speaks normally. It is opened for sleep so that air flows directly into the lungs, bypassing any upper airway obstruction. Although this procedure is highly effective, it is an extreme measure that is rarely used.
Patients in whom sleep apnea is due to deformities of the lower jaw may benefit from surgical reconstruction, Surgical procedures to treat obesity are sometimes recommended for sleep apnea patients who are morbidly obese. Behavioral changes are an important part of the treatment program, and in mild cases behavioral therapy may be all that is needed. Overweight persons can benefit from losing weight. Even a 10 percent weight loss can reduce the number of apneic events for most patients. Individuals with apnea should avoid the use of alcohol and sleeping pills, which make the airway more likely to collapse during sleep and prolong the apneic periods. In some patients with mild sleep apnea, breathing pauses occur only when they sleep on their backs. In such cases, using pillows and other devices that help them sleep in a side position may be helpful.
Recently, Restore Medical, Inc., Saint Paul, Minn. has developed a new treatment for snoring and apnea, called the Pillar technique. Pillar System is a procedure where 2 or 3 small polyester rod devices are placed in the patient's soft palate. The Pillar System stiffens the palate, reduces vibration of the tissue, and prevents the possible airway collapse. Stiff implants in the soft palate, however, could hinder patient's normal functions like speech, ability to swallow, coughing and sneezing. Protrusion of the modified tissue into the airway is another long-term concern.
As the current treatments for snoring and/or apnea are not effective and have side-effects, there is a need for additional treatment options.
In a first embodiment, the present invention provides an implant for stabilizing the tongue, including: a first anchoring portion for securing a first end of the implant with the mandibula; a control portion connected with the anchoring portion, configured for selectively activating the implant; a flexible portion connected at its proximal end with the control portion, the flexible portion having three-dimensional flexibility in a non-energized state and the flexible portion having a lesser three-dimensional flexibility in a energized state, the flexible portion being selectively switchable between the non-energized and energized states by the control portion, wherein the flexible portion can be an electroactive polymer element having: a composite layer having a polymer substrate and a biocompatible conductive material, wherein the composite layer also can be opposing surfaces; and a conductive polymer layer disposed on at least one of the opposing surfaces of the composite layer; and a second anchoring portion connected with the flexible portion, the second anchoring portion being configured for connecting the implant with the base of the tongue.
In a second embodiment, the present invention provides a method of treating a disease using an airway implant device, including: implanting in a subject's tongue a device having a first anchoring portion for securing a first end of the implant with the mandibula; a control portion connected with the anchoring portion, configured for selectively activating the implant; a flexible portion connected at its proximal end with the control portion, the flexible portion having three-dimensional flexibility in a non-energized state and the flexible portion having a lesser three-dimensional flexibility in a energized state, the flexible portion being selectively switchable between the non-energized and energized states by the control portion, wherein the flexible portion can be an electroactive polymer element having: a composite layer having a polymer substrate and a biocompatible conductive material, wherein the composite layer also can be opposing surfaces; and a conductive polymer layer disposed on at least one of the opposing surfaces of the composite layer; a second anchoring portion connected with the distal end of the flexible portion, the second anchoring portion being configured for connecting the implant with the base of the tongue; and supporting the subject's tongue by selectively activating the control portion of the implant.
In a third embodiment, the present invention provides a method of treating a disease using an airway implant device including: implanting in a subject's tongue a device having a first anchoring portion for securing a first end of the implant with the mandibula; a control portion connected with the anchoring portion, configured for selectively activating the implant; a flexible portion connected at its proximal end with the control portion, the flexible portion having three-dimensional flexibility in a non-energized state and the flexible portion having a lesser three-dimensional flexibility in a energized state, the flexible portion being selectively switchable between the non-energized and energized states by the control portion, wherein the flexible portion can be an electroactive polymer element having: a composite layer having a polymer substrate and a biocompatible conductive material, wherein the composite layer also can be opposing surfaces; and a conductive polymer layer disposed on at least one of the opposing surfaces of the composite layer; a second anchoring portion connected with the distal end of the flexible portion, the second anchoring portion being configured for connecting the implant with the base of the tongue; an inductive powering mechanism coupled with the control portion and configured to maintain the flexible portion in either of the non-energized and energized states, the device being adapted and configured to support the tongue upon being energized; and supporting the subject's tongue by selectively activating the control portion of the implant using the inductive powering mechanism.
For a further understanding of the nature and advantages of the invention, reference should be made to the following description taken in conjunction with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the embodiments of the present invention.
The present invention provides an airway implant device including an electroactive polymer element that is flexible in a non-energized state and that is stiff in an energized state. The electroactive polymer element does not require constant power in order to maintain the energized state, and can maintain the energized state even when the power to the electroactive polymer element is turned off. In this fashion, a subject using the airway implant device of the present invention need only provide power for a short time to the electroactive polymer element, thus avoiding having to wear a power source throughout the night.
In some embodiments, the present invention provides an airway implant device including an electroactive polymer element having a composite layer having a polymer substrate and a biocompatible conductive material, wherein the composite layer also can be opposing surfaces; and a conductive polymer layer disposed on at least one of the opposing surfaces of the composite layer, wherein the implant device is adapted and configured to modulate an opening of an air passageway.
A first aspect of the invention is a device for the treatment of disorders associated with improper airway patency, such as snoring or sleep apnea. The device can be an actuator element to adjust the opening of the airway. In a preferred embodiment, the actuator element can be an electroactive polymer (EAP) element. The electroactive polymer element in the device assists in maintaining appropriate airway opening to treat the disorders. Typically, the EAP element provides support for the walls of an airway, when the walls collapse, and thus, completely or partially opens the airway.
The device functions by maintaining energized and non-energized configurations of the EAP element. In preferred embodiments, during sleep, the EAP element is energized with electricity to change its shape and thus modify the opening of the airway. Typically, in the non-energized configuration the EAP element is flexible and in the energized configuration is less flexible. The EAP element of the device can have a pre-set non-energized configuration wherein it is substantially similar to the geometry of the patient's airway where the device is implanted.
In some embodiments, the device, in addition to the EAP element, can be an implantable receiver in electrical communication with the EAP element. A conductive lead connects the EAP element and the implantable receiver to each other. The device of the present invention typically can be a power source in electrical communication with the EAP element and/or the implantable receiver, such as a battery or a capacitor. The battery can be disposable or rechargeable.
Preferred embodiments of the invention include a non-implanted portion, such as a mouthpiece, to control the implanted EAP element. The mouthpiece is typically in conductive or inductive communication with an implantable receiver. In one embodiment, the mouthpiece is a dental mouthpiece with an induction coil and a power source. The dental mouthpiece can also include a pulse-width-modulation circuit. When a dental mouthpiece is used it is preferably custom fit for the individual biological subject. If the implantable receiver is in inductive communication, it will typically include an inductive receiver, such as a coil. The implantable receiver can also include a conductive receiver, such as a dental filling, a dental implant, an implant in the oral cavity, an implant in the head or neck region. In one embodiment, the device can be a dermal patch with a coil, circuit and power source, in communication with the implantable receiver. The dermal patch can also include a pulse-width-modulation circuit.
Another aspect of the invention is a method to modulate air flow through airway passages. Such modulation is used in the treatment of diseases such as snoring and sleep apnea. One method of the invention is a method for modulating the airflow in airway passages by implanting in a patient a device having an actuator element and controlling the device by energizing the actuator element. The actuator element preferably can be an electroactive polymer element. The actuator element can be controlled with a mouthpiece inserted into the mouth of the patient. The energizing is typically performed with the use of a power source in electrical communication, either inductive communication or conductive communication, with the actuator element. A receiver can be used to energize the actuator element by placing it in electrical communication with the power source. Depending on the condition being treated, the actuator element is placed in different locations such as soft palate, airway sidewall, uvula, pharynx wall, trachea wall, larynx wall, a tongue and/or nasal passage wall.
A preferred embodiment of the device of the present invention can be an implantable actuator element; an implantable receiver; an implantable lead wire connecting the actuator element and the receiver; a removable receiver; and a removable power source; wherein the actuator element can be an electroactive polymer element.
In some embodiments, the device of the present invention also can be an anode, a cathode, a first inductor, a controller and a non-implanted portion. In some other embodiments, the non-implanted portion can be a mouthguard, a power supply and a second inductor. In still other embodiments, the first inductor and the second inductor are configured to interact. In yet other embodiments, the electroactive polymer element also can have wires for connection with the first inductor. In still yet other embodiments, the electroactive polymer element is configured for implantation into a soft palate, a lateral pharyngeal wall, a tongue or combination thereof.
In another embodiment, the present invention provides a device that also can be a coating to prevent or promote tissue growth. In other embodiments, the device also can be a coating of polypropylene, poly-L-lysine, poly-D-lysine, polyethylene glycol, polyvinyl alcohol, polyvinyl acetate, polymethyl methacrylate, hyaluronic acid and combinations thereof.
In a further embodiment, the airway implant device is controlled by an inductive coupling mechanism.
The electroactive polymer element of the present invention can be a composite layer and a conductive polymer layer. The composite layer of the present invention can be a polymer substrate and a biocompatible conductive material.
Electroactive polymer is a type of polymer that responds to electrical stimulation by physical deformation, change in tensile properties, and/or change in hardness. There are several types of electroactive polymers like dielectric electrostrictive polymers, conducting polymers, ion exchange polymers and ion exchange polymer metal composites (IPMC). The particular type of EAP used in the making the disclosed device can be any of the aforementioned electroactive polymers.
A. Composite Layer
The composite layer of the present invention can be a polymer substrate and a biocompatible conductive material.
1. Polymer Substrate
Polymer substrates useful in the device of the present invention can be any suitable polymer material. Suitable materials for the polymer substrate portion of the electroactive polymer element include, but are not limited to, an ion exchange polymer, an ion exchange polymer metal composite, an ionomer base material. In some embodiments, the polymer substrate is perfluorinated polymer such as polytetrafluoroethylene, polyfluorosulfonic acid, perfluorosulfonate, and polyvinylidene fluoride. Other suitable polymers include polyethylene, polypropylene, polystyrene, polyaniline, polyacrylonitrile, cellophane, cellulose, regenerated cellulose, cellulose acetate, polysulfone, polyurethane, polyvinyl alcohol, polyvinyl acetate, polyvinyl pyrrolidone.
In some embodiments, the polymer substrate can be polytetrafluoroethylene, polyfluorosulfonic acid, perfluorosulfonate, polyvinylidene fluoride, polyethylene, polypropylene, polystyrene, polyaniline, polyacrylonitrile, cellulose, regenerated cellulose, cellulose acetate, polysulfone, polyurethane, polyvinyl alcohol, polyvinyl acetate, polyvinyl pyrrolidone, polymethyl methacrylate, silicon and combinations thereof. In some other embodiments, the polymer substrate can be polyurethane. One of skill in the art will appreciate that other materials are useful as the polymer substrate of the present invention.
Suitable shapes of the composite layer include three dimensional shape, substantially rectangular, substantially triangular, substantially round, substantially trapezoidal, a flat strip, a rod, a cylindrical tube, an arch with uniform thickness or varying thickness, a shape with slots that are perpendicular to the axis, slots that are parallel to the longitudinal axis, a coil, perforations, and/or slots.
IPMC is a polymer and metal composite that uses an ionomer as the base material. Ionomers are types of polymers that allow for ion movement through the membrane. There are several ionomers available in the market and some of the suited ionomers for this application are polyethylene, polystyrene, polytetrafluoroethylene, polyvinylidene fluoride, polyfluorosulfonic acid based membranes like NAFION® (from E.I. Du Pont de Nemours and Company, Wilmington, Del.), polyaniline, polyacrylonitrile, cellulose, cellulose acetates, regenerated cellulose, polysulfone, polyurethane, or combinations thereof. A conductive metal, for example gold, silver, platinum, palladium, copper, carbon, or combinations thereof, can be deposited on or embedded in the ionomer to make the IPMC. The IPMC element can be formed into many shapes, for example, a strip, rod, cylindrical tube, rectangular piece, triangular piece, trapezoidal shape, arch shapes, coil shapes, or combinations thereof. The IPMC element can have perforations or slots cut in them to allow tissue in growth.
2. Biocompatible Conductive Material
The device of the present invention can be any suitable biocompatible conductive material. Biocompatible conductive material useful in the present invention can be, but is not limited to, metals, including metal alloys and metal oxides, ceramics, conducting polymers and conductive carbon, such as graphite and graphite-like carbon materials.
Metals useful in the present invention include the alkali metals, alkali earth metals, transition metals and post-transition metals. Alkali metals include Li, Na, K, Rb and Cs. Alkaline earth metals include Be, Mg, Ca, Sr and Ba. Transition metals include Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg and Ac. Post-transition metals include Al, Ga, In, Tl, Ge, Sn, Pb, Sb, Bi, and Po. One of skill in the art will appreciate that the metals described above can each adopt several different oxidation states, all of which are useful in the present invention. In some instances, the most stable oxidation state is formed, but other oxidation states are useful in the present invention. In addition, several metals can be mixed together to form an alloy, such as brass and steel.
In some embodiments, the biocompatible conductive material is platinum, gold, silver, palladium, copper, and/or carbon. In some other embodiments, the biocompatible conductive material is conductive carbon, Ag, Au, Cu, Pt, Pd, Rh, Ir, Ru, Os and Re. In still other embodiments, the biocompatible conductive material can be Pt.
In other embodiments, the composite layer can be polyurethane and Pt.
B. Conductive Polymer Layer
The conductive polymer layer can be any conducting polymer. Conducting polymers useful as the conductive polymer layer of the instant invention include, but are not limited to, poly(acetylene)s, poly(pyrrole)s, poly(thiophene)s, poly(aniline)s, poly(fluorene)s, poly(3-alkylthiophene)s, polytetrathiafulvalenes, polynaphthalenes, poly(p-phenylene sulfide), and poly(para-phenylene vinylene)s. In some embodiments, the conductive polymer layer can be polypyrrole, polyaniline and polyacetylene. In some other embodiments, the conductive polymer layer can be polypyrrole.
In some embodiments, the conductive polymer layer includes a copolymer. The copolymer can include any conductive polymer, such as those described above. In other embodiments, the copolymer is prepared using at least two of the following comonomers: pyrrole, 3,4-ethylene-dioxythiophene, 4-(3-pyrrolyl)-butyric acid, 3-methylpyrrole, 1H-pyrrole-1-propanoic acid, 1-(phenylsulfonyl)pyrrole, N-methylpyrrole, 1H-pyrrole-3-methyl carboxylate, N-benzylpyrrole, 4-(1H-pyrrol-1-yl)benzoic acid and 3-acetyl-1-methylpyrrole. In some other embodiments, the copolymer includes pyrrole and N-methylpyrrole. The copolymer can be a block copolymer, an alternating copolymer or a random copolymer. Other types of copolymers are also useful in the present invention. The copolymers can include comonomers at a variety of relative amounts. In some embodiments, the ratio of the monomers can be 100:1, 50:1, 25:1, 20:1, 15:1, 10:1, 5:1, 4:1, 3:1, 2:1 or 1:1. Other ratios of the monomers are useful in the present invention.
In other embodiments, the conductive polymer layer also can be a dopant. Dopants useful in the conductive polymer layer include, but are not limited to, metals, ceramics and salts. In some embodiments, the dopants can be ionic dopants having mobile cations or anions, such as metals, ammonium salts, carboxylates, phosphate and sulfonates. In some other embodiments, the ionic dopant can be a biocompatible ionic dopant. In still other embodiments, the biocompatible ionic dopant can be a salt including Na+ ions. In another embodiment, the dopant can be dodecyl benzenesulfonic acid sodium salt. Other dopants useful in the present invention include, but are not limited to, Li+, tetrabutylammonium (TBA+), K+, PF6−, trifluoromethanesulfonamide (TFSI−), polystyrenesulphonate (PSS−), tetrafluoroborate (TFB−) and CF3SO3−.
In some embodiments, the conductive polymer layer can be polypyrrole doped with dodecyl benzenesulfonic acid. In other embodiments, the electroactive polymer element can be a composite of polyurethane and Pt, and polypyrrole doped with dodecyl benzenesulfonic acid. In some other embodiments, the electroactive polymer element can be two conductive polymer layers each deposited on one of the opposing faces of the composite layer. In still other embodiments, at least one of the opposing surfaces is patch coated with one of the conductive polymer layers. In yet other embodiments, both of the opposing surfaces are patch coated with the conductive polymer layers.
In another embodiment, the present invention provides a device having a plurality of composite layers and a plurality of conductive polymer layers in alternating layers such that each conductive polymer layer is disposed on an opposing face of one of the composite layers.
C. Additional Components
The electroactive polymer element can also include a silicone rubber coating. For example, the silicone rubber coating can coat all of or portions of the composite layer. The silicone coating can coat only the composite layer, or both the composite layer and the conductive polymer layer. In addition, the silicone coating can coat none of the conductive polymer layer, a portion of, or all of the conductive polymer layer.
The electroactive polymer element has, in some embodiments, multiple layers of the electroactive polymer with or without an insulation layer separating the layers of the electroactive polymer. Suitable insulation layers include, but are not limited to, silicone, polyurethane, polyimide, nylon, polyester, polymethylmethacrylate, polyethylmethacrylate, neoprene, styrene butadiene styrene, or polyvinyl acetate.
In some embodiments, the actuator element, the entire device, or portions of the airway implant have a coating. The coating isolates the coated device from the body fluids and/or tissue either physically or electrically. The device can be coated with polypropylene and polyvinylidene fluoride to minimize tissue growth, or with poly-L-lysine, poly-D-lysine, polyethylene glycol, polyvinyl alcohol, polyvinyl acetate, hyaluronic acid, and/or methylmethacrylate to promote tissue growth.
In other embodiments, the electroactive polymer element also includes an ion source disposed on one of the opposing surfaces of the composite layer. The ion source of the present invention can be a salt, such as sodium chloride, phosphonic acid sodium salt or sulfonic acid sodium salt. The ion source can be mixed in a gel electrolyte, like agar gel, polyvinyl alcohol etc. Ions useful as the ion source include, but are not limited to, lithium, sodium, potassium, ammonium, magnesium and calcium. Other ions are useful in the electroactive polymer element of the present invention. In some embodiments, the dopant in the conductive polymer layer is a salt having a sodium counterion. In other embodiments, the dopant in the conductive polymer layer has the same counterion as the ion of the ion source. In some other embodiments, the ion source is a sodium ion source.
The electroactive polymer element includes both a composite layer and a conductive polymer layer.
In some embodiments, the composite layer is an IPMC strip which is made from a polymer substrate base material of an ionomer sheet, film or membrane. The ionomer sheet is formed using ionomer dispersion. IPMC is made from the base ionomer of, for example, polyethylene, polystyrene, polytetrafluoroethylene, polyvinylidene fluoride (PVDF) (e.g., KYNAR® and KYNAR Flex®, from ATOFINA, Paris, France, and SOLEF®, from Solvay Solexis S.A., Brussels, Belgium), hydrophilic-PVDF (h-PVDF), polyfluorosulfonic acid based membranes like NAFION® (from E.I. Du Point de Nemours and Company, Wilmington, Del.), polyaniline, polyacrylonitrile, cellulose, cellulose acetates, regenerated cellulose, polysulfone, polyurethane, and combinations thereof.
The polymer substrate can be any material, such as those described above. The polymer substrate can be coated or embedded with the biocompatible conductive material. In some embodiments, the biocompatible conductive material is in the form of wires or particles.
When the biocompatible conductive material is in the form of wires, the wires can have any thickness and pitch. In some embodiments, the wires have a pitch of from about 1 μm to about 1 mm. In addition, the wires can be in any configuration, such as parallel, lattice, zig-zag, etc. (see
When the biocompatible conductive material is in the form of particles, the particles can be of any size and shape. In some embodiments, the particles are from about 0.1 μm to about 100 μm in size.
A. Coating the Polymer Substrate with the Biocompatible Conductive Material
In some embodiments, the polymer substrate is coated with the biocompatible conductive material.
The conductive material that is deposited on the polymer substrate can be gold, platinum, silver, palladium, copper, graphite, conductive carbon, or combinations thereof. Conductive material is deposited on the polymer substrate either by electrolysis process, vapor deposition, sputtering, electroplating, spraying, coating, dipping, brushing or combination of processes.
In some embodiments, the composite layer is an IPMC strip which is made from a polymer substrate base material of an ionomer sheet, film or membrane. The IPMC can be cut into the desired implant shape for the EAP element. The electrical contact (e.g., anode and cathode wires for EAP element) can be connected to the EAP surfaces by, for example, soldering, welding, brazing, potting using conductive adhesives, or combinations thereof. The EAP element is configured, if necessary, into specific curved shapes using mold and heat setting processes.
In some embodiments, the EAP element is insulated with electrical insulation coatings. Also, the EAP element can be insulated with coatings that promote cell growth and minimize fibrosis, stop cell growth, or kill nearby cells. The insulation can be a biocompatible material. The EAP element is coated with polymers such as polypropylene, poly-L-lysine, poly-D-lysine, polyethylene glycol, polyvinyl alcohol, polyvinyl acetate, polymethyl methacrylate, or combinations thereof. The EAP element can also be coated with hyaluronic acid.
The coating is applied to the device by standard coating techniques like spraying, electrostatic spraying, brushing, vapor deposition, dipping, etc.
In one example, a perfluorosulfonate ionomer, PVDF or h-PVDF sheet is prepared for manufacturing the EAP element. In an optional step, the sheet is roughened on both sides using, for example, about 320 grit sand paper and then about 600 grit sand paper; then rinsed with deionized water; then submerged in isopropyl alcohol (IPA); subjected to an ultrasonic bath for about 10 minutes; and then the sheet is rinsed with deionized water. The sheet is boiled for about 30 minutes in hydrochloric acid (HCl). The sheet is rinsed and then boiled in deionized water for about 30 minutes.
The sheet is then subject to ion-exchange (i.e., absorption). The sheet is submerged into, or otherwise exposed to, a metal salt solution at room temperature for more than about three hours. Examples of the metal salt solution are tetraammineplatinum chloride solution, silver chloride solution, hydrogen tetrachloroaurate, tetraamminepalladium chloride monohydrate or other platinum, gold, silver, carbon, copper, or palladium salts in solution. The metal salt solution typically has a concentration of greater than or equal to about 200 mg/100 ml water. 5% ammonium hydroxide solution is added at a ratio of 2.5 ml/100 ml to the tetraammineplatinum chloride solution to neutralize the solution. The sheet is then rinsed with deionized water. Primary plating is then applied to the sheet. The sheet is submerged in water at about 40° C. 5% solution by weight of sodium borohydride and deionized water is added to the water submerging the sheet at 2 ml/180 ml of water. The solution is stirred for 30 minutes at 40° C. The sodium borohydride solution is then added to the water at 2 ml/180 ml of water and the solution is stirred for 30 minutes at 40° C. This sodium borohydride adding and solution stirring is performed six times total. The water temperature is then gradually raised to 60° C. 20 ml of the sodium borohydride solution is then added to the water. The solution is stirred for about 90 minutes. The sheet is then rinsed with deionized water, submerged into 0.1N HCl for an hour, and then rinsed with deionized water.
In some embodiments, the sheet receives a second plating. The sheet is submerged or otherwise exposed to a tetraammineplatinum chloride solution at a concentration of about 50 mg/100 ml deionized water. 5% ammonium hydroxide solution is added at a rate of 2 ml/100 ml of tetrammineplatinum chloride solution. 5% by volume solution of hydroxylamine hydrochloride in deionized water is added to the tetraammineplatinum chloride solution at a ratio of 0.1 of the volume of the tetraammineplatinum chloride solution. 20% by volume solution of hydrazine monohydrate in deionized water is added to the tetraammineplatinum chloride solution at a ratio of 0.05 of the volume of the tetraammineplatinum chloride solution. The temperature is then set to about 40° C. and the solution is stirred.
A 5% solution of hydroxylamine hydrochloride is then added at a ratio of 2.5 m/100 ml of tetraammineplatinum chloride solution. A 20% solution of hydrazine monohydrate solution is then added at a ratio of 1.25 ml/100 ml tetraammineplatinum chloride solution. The solution is stirred for 30 minutes and the temperature set to 60° C. The above steps in this paragraph can be repeated three additional times. The sheet is then rinsed with deionized water, boiled in HCl for 10 minutes, rinsed with deionized water and dried.
In some embodiments, the polymer base is dissolved in solvents, for example dimethyl acetamide, acetone, methylethyl ketone, toluene, dimethyl carbonate, diethyl carbonate, and combinations thereof. The solvent is then allowed to dry, producing a thin film. While the solution is wet, a low friction, (e.g., glass, Teflon) plate is dipped into the solution and removed. The coating on the plate dries, creating a thick film. The plate is repeatedly dipped into the solution to increase the thickness of the film.
Polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetate or combinations thereof can be added to a PVDF solution before drying, thus contributing hydrophilic properties to PVDF and can improve ion migration through the polymer film during manufacture. Dye or other color pigments can be added to the polymer solution.
B. Embedding the Polymer Substrate with the Biocompatible Conductive Material
In some embodiments, the composite layer includes polymer substrate embedded with the biocompatible conductive material. The amount of biocompatible material embedded in the polymer substrate can be any amount, such as 0.1:1 (w/w), 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1. In some embodiments, the ratio of biocompatible conductive material to polymer substrate is from about 0.1:1 (w/w) to about 5:1 (w/w). In other embodiments, the ratio of biocompatible conductive material to polymer substrate is about 2:1 (w/w).
When the biocompatible conductive material is embedded in the polymer substrate, the biocompatible conductive material can be in particulate form. The particles of biocompatible conductive material can be from 0.1 microns to 100 microns, preferably from 0.5 to 10 microns. The particles of biocompatible conductive material can adopt any useful shape, such as spherical, pyramid, rod etc.
The composite layer of the present invention can be made using any suitable materials described above. For example, the composite layer having Pt particles embedded in polyurethane can be prepared from the following procedure. Mix 2.5 g of polyurethane with 50 ml of N,N-Dimethylacetimide (DMAc) solvent. Stir for 120 minutes or until the polyurethane is completely dissolved. Add 5.0 g of conductive powder (Pt) to the solution. Stir till completely mixed. Then cast films with this solution. Keep in oven for some time till solvent is evaporated. Remove the casted film. Measure surface conductivity.
C. Preparation of the Conductive Polymer Layer
The conductive polymer layer can be prepared using a variety of methods. A platinum wire lattice was applied to one side of a 0.005 inch polyurethane substrate. Platinum particles were then brushed on. A piece of gold foil was used to make electrical contact with the platinum wires at the end of the sample. The end of the sample was then covered with 3M VHB acrylic tape, leaving some gold foil exposed, in order to mask the atmosphere/PPy (DBS) solution interface. Polypyrrole (PPy) doped with dodecyl benzene sulfonic acid (DBS) was grown on the substrate in a solution of 0.2 M PPy, 0.2M DBS in distilled water with a constant 3 mA applied current. Current was removed after six hours when the polypyrrole had achieved 100% coverage of the specimen.
The conductive polymer layer can also be prepared on the composite layer by embedding biocompatible conductive particles in the polymer substrate. A base layer with two composite layers separated by an insulating layer was used as the working electrode in a two electrode electrochemical cell. Two stainless steel plates facing the two conductive composite layers were used as the counter electrode. Polypyrrole (PPy) doped with dodecyl benzene sulfonic acid (DBS) was grown on the substrate in a solution of pyrrole monomer varying from 1×10−3 M to 5×10−1 M concentration with DBS varying from 1×10−3 M to 5×10−1 M concentration in distilled water with a constant 3 mA applied current. A constant voltage between 1 V and 3 V was applied for 2 to 240 hrs or until the target polypyrrole thickness had been achieved.
When the conductive polymer layer includes a copolymer, such as those described above, the comonomers are mixed and polymerized according to the procedure described above. For example, a copolymer of pyrrole and N-methylpyrrole can be prepared by mixing pyrrole, N-methylpyrrole and, optionally, DBS. In some embodiments, the conductive polymer layer includes a copolymer of pyrrole and N-methylpyrrole doped with dodecyl benzenesulfonic acid.
The conductive polymer layer can coat the composite layer in a variety of configurations. For example, the conductive polymer layer can coat at least one of the opposing surfaces of the composite layer. In addition, when coating one of the opposing surfaces of the composite layer, the conductive polymer layer can fully or partially coat the opposing surface. When one of the opposing surfaces of the composite layer is partially coated by the conductive polymer layer, the conductive polymer layer can be coated in patches; stripes that can be oriented along the length of the device, orthogonal to the length of the device, or diagonally; a checkerboard pattern; or others (see
Each opposing surface of the composite layer can be coated with the conductive polymer layer separately and in a configuration different from, or the same as, the other opposing surface. For example, one opposing surface of the composite layer can be completely coated with the conductive polymer layer, and the other opposing surface can be patch coated with the conductive polymer layer. In addition, the pitch of the patch coating of the conductive polymer layer can be the same or different for the opposing surfaces.
The conductive polymer layer can be patch coated onto the composite layer by a variety of methods known in the art. For example, the composite layer can be coated with a blocking agent in order to prevent growth of the conductive polymer layer where the blocking agent is coated. When the polymerization conditions described above are used, the conductive polymer layer is deposited in those areas of the composite layer not coated with the blocking agent. Any sort of blocking agent is useful in the patch coating of the present invention. Blocking agents useful in the present invention include, but are not limited to, silicone primer (i.e., MED6-161). Other silicone primers and blocking agents are useful in the invention.
The conducting polymer layer can be coated on the polymer substrate with the biocompatible conductive material. It can be coated in either a patch coating form described above or can be coated completely and then the correct shape can be die cut from it. Two such biocompatible polymer substrates with conductive materials coated with conducting polymer layers that have been die cut to the correct shape, can be placed on two sides of the insulating polymer layer and the assembly aligned to stagger the conducting polymer layers as shown in
Instead of or in addition to wire lead 14, the connecting element may be an inductive energy transfer system, a conductive energy transfer system, a chemical energy transfer system, an acoustic or otherwise vibratory energy transfer system, a nerve or nerve pathway, other biological tissue, or combinations thereof. The connecting element is made from one or more conductive materials, such as copper. The connecting element is completely or partially insulated and/or protected by an insulator, for example polytetrafluoroethylene (PTFE). The insulator can be biocompatible. The power source 4 is typically in electrical communication with the actuator element 8 through the connecting element. The connecting element is attached to an anode 10 and a cathode 12 on the power source 4. The connecting elements can be made from one or more sub-elements.
The actuator element 8 is preferably made from an electroactive polymer element, as described above.
Preferably, the airway implant device 2 discussed herein is used in combination with an inductive coupling system 900 such as depicted in
Two preferred embodiments of the airway implant device are shown in
Another preferred embodiment of the airway implant device is shown in
A preferred embodiment of the device of the present invention can be an implanted portion 20 having an implantable actuator element 8, a housing 112, a first inductor 18, and connecting elements 14 connecting the actuator element 8 to the first inductor 18 within the housing 112; and a non-implanted portion 22 having a power source 4 and a second inductor 16 capable of transferring energy to the first inductor 18, wherein the energy of the first inductor 18 energizes the actuator element 8 wherein the actuator element 8 can be an electroactive polymer element. In a preferred embodiment, the actuator element 8 of the device is implanted in the soft palate 84. The housing 112 of the preferred embodiment is implanted inferior to the hard palate 74. In a preferred embodiment of the device, the housing 112 can be at least one of acrylic, polytetrafluoroethylene (PTFE), polymethylmethacrylate (PMMA), Acrylonitrile Butadiene Styrene (ABS), polyurethane, polycarbonate, cellulose acetate, nylon, and a thermoplastic or thermosetting material.
In a preferred embodiment, the non-implanted portion 22 is in the form of a mouthpiece 66. In a preferred embodiment, the non-implanted portion can be a non-implantable wearable element. In some embodiments, the superior side of the housing 112 comports to the shape of a hard palate 74. In some embodiments, the housing 112 is cast from an impression of a hard palate 74. In still other embodiments, the housing 112 is concave on its superior side. In some embodiments, the housing 112 is convex on its superior side. In some embodiments, the housing 112 can be bumps 114 on its superior side lateral to a central axis extending from the housing's 112 anterior to its posterior end. In some embodiments, the housing 112 configuration has a substantially smooth rounded superior side. Other configurations for the housing 112 may be contemplated by one having skill in the art without departing from the invention.
In some embodiments, the actuator element 8 is at least partially within the housing 112. In other embodiments, the actuator element 8 is outside the housing 112. The housing 112 is capable of housing and protecting the first inductor 18 and connecting elements 14 between the first inductor 18 and the actuator element 8. In some embodiments, the housing 112 has a roughened surface to increase friction on the housing 112. In some embodiments, the roughened surface is created during casting of the housing 112. In some embodiments, the roughened surface induces fibrosis.
In some embodiments of the airway implant device having attachment elements 120, the attachment element 120 is a bioabsorbable material. Examples of bioabsorbable materials include, but are not limited to, polylactic acid, polyglycolic acid, poly(dioxanone), Poly(lactide-co-glycolide), polyhydroxybutyrate, polyester, poly(amino acid), poly(trimethylene carbonate) copolymer, poly (∈-caprolactone) homopolymer, poly (∈-caprolactone) copolymer, polyanhydride, polyorthoester, polyphosphazene, and any bioabsorbable polymer.
In another embodiment, the airway implant device can be an attachment element 120, as shown in
In some embodiments, the implant may be secured in place, with or without use of an attachment element 120, using an adhesive suitable for tissue, such as cyanoacrylates, and including, but not limited to, 2-octylcyanoacrylate, and N-butyl-2-cyanoacrylate.
In some embodiments, the non-implanted portion 22 does not include ball clamps 128 for recharging the power source 4. In some embodiments, the power source 4 is a rechargeable battery. In some embodiments, the power source 4 is one of a lithium-ion battery, lithium-ion polymer battery, a silver-iodide battery, lead acid battery, a high energy density, or a combination thereof. In some embodiments, the power source 4 is removable from the non-implanted portion 22. In some embodiments, the power source 4 is replaceable. In some embodiments, the power source is designed to be replaced or recharged per a specified time interval. In some embodiments, replacing or recharging the power source 4 is necessary no more frequently than once per year. In other embodiments, replacing or recharging the power source 4 is necessary no more frequently than once every six months. In yet other embodiments, replacing or recharging the power source 4 is necessary no more frequently than once or every three months. In yet another embodiment, daily replacing or recharging of the power source is required.
In some embodiments, the power source 4 and second inductor 16 are sealed within the non-implanted portion and the sealing is liquidproof.
The implants described herein are preferably implanted with a deployment tool. Typically, the implantation involves an incision, surgical cavitation, and/or affixing the implant.
In some embodiments, the present invention provides an implant for stabilizing the tongue. The implant can have a first anchoring portion for securing a first end of the implant with the mandibula, such as 5112 in
In some embodiments, the present invention provides a method of controlling an opening of an air passageway, including: implanting an airway implant device proximal to an air passageway, in a wall of an air passageway or in both, the device having an electroactive polymer element having: a composite layer having a polymer substrate and a biocompatible conductive material, wherein the composite layer also includes opposing surfaces; and a conductive polymer layer disposed on at least one of the opposing surfaces of the composite layer, wherein the implant device is adapted and configured to modulate an opening of an air passageway; and energizing the electroactive polymer element for a fixed period of time, such that the electroactive polymer element adopts an energized state and maintains the energized state after the fixed period of time has passed, thereby completely or partially opening the air passageway.
In another embodiment, the method also includes de-energizing the electroactive polymer element to a non-energized state. In other embodiments, the implantation of the airway implant device is in a soft palate, a lateral pharyngeal wall, a tongue or a combination thereof. In still other embodiments, the airway implant device is controlled by an inductive coupling mechanism.
In a further embodiment, the present invention provides a method of treating a disease using an airway implant device, having: implanting an airway implant device proximal to an air passageway or in a wall of an air passageway or in both, the device having an electroactive polymer element having: a composite layer having a polymer substrate and a biocompatible conductive material, wherein the composite layer also includes opposing surfaces; and a conductive polymer layer disposed on at least one of the opposing surfaces of the composite layer, wherein the implant device is adapted and configured to modulate an opening of an air passageway; and energizing the electroactive polymer element for a fixed period of time, such that the electroactive polymer element adopts an energized state and maintains the energized state after the fixed period of time has passed, thereby treating the disease.
In some embodiments, the disease is obstructive sleep apnea and/or snoring. In other embodiments, the airway implant device is controlled by an inductive coupling mechanism. In still other embodiments, the airway implant device is implanted in a soft palate, and the energizing of the electroactive polymer element supports the soft palate. In yet other embodiments, the airway implant device is implanted in a lateral pharyngeal wall, and the energizing of the electroactive polymer element prevents the lateral pharyngeal wall from collapsing. In still yet other embodiments, the airway implant device is implanted in a tongue, and the energizing of the electroactive polymer element prevents the tongue from collapsing.
In another embodiment, the present invention provides an implant for stabilizing the tongue, having: a first anchoring portion for securing a first end of the implant with the mandibula; a control portion connected with the anchoring portion, configured for selectively activating the implant; a flexible portion connected at its proximal end with the control portion, the flexible portion having three-dimensional flexibility in a non-energized state and the flexible portion having a lesser three-dimensional flexibility in a energized state, the flexible portion being selectively switchable between the non-energized and energized states by the control portion, wherein the flexible portion can be an electroactive polymer element having: a composite layer having a polymer substrate and a biocompatible conductive material, wherein the composite layer also includes opposing surfaces; and a conductive polymer layer disposed on at least one of the opposing surfaces of the composite layer; and a second anchoring portion connected with the flexible portion, the second anchoring portion being configured for connecting the implant with the base of the tongue.
In some embodiments, the first anchoring portion includes an anchoring bracket. In other embodiments, the control portion is powered by a non-implanted inductively coupled power source. In some other embodiments, the flexible portion is coated with a hyaluronic acid coating. In still other embodiments, the second anchoring portion can be a first disc connected with the distal end of the flexible portion and a second disc connectible with the base of the tongue. In yet other embodiments, the first and second discs include suture holes disposed around their circumferences. In still yet other embodiments, the first and second discs also include polyester rods having holes extending from the flat surfaces of the discs.
In a further embodiment, the second anchoring portion can be a first proximally extending anchor portion and a second distally extending anchor portion. In other embodiments, the device also includes a coating to prevent tissue in-growth. In some other embodiments, the device also includes a coating to promote tissue growth.
In another embodiment, the present invention provides a method of treating a disease using an airway implant device, having: implanting in a subject's tongue a device having a first anchoring portion for securing a first end of the implant with the mandibula; a control portion connected with the anchoring portion, configured for selectively activating the implant; a flexible portion connected at its proximal end with the control portion, the flexible portion having three-dimensional flexibility in a non-energized state and the flexible portion having a lesser three-dimensional flexibility in a energized state, the flexible portion being selectively switchable between the non-energized and energized states by the control portion, wherein the flexible portion can be an electroactive polymer element having: a composite layer having a polymer substrate and a biocompatible conductive material, wherein the composite layer also includes opposing surfaces; and a conductive polymer layer disposed on at least one of the opposing surfaces of the composite layer; a second anchoring portion connected with the distal end of the flexible portion, the second anchoring portion being configured for connecting the implant with the base of the tongue; and supporting the subject's tongue by selectively activating the control portion of the implant.
In some embodiments, the disease is a sleep disorder. In other embodiments, the sleep disorder is an obstructive sleep apnea or snoring.
In a further embodiment, the present invention provides a method of treating a disease using an airway implant device having: implanting in a subject's tongue a device having a first anchoring portion for securing a first end of the implant with the mandibula; a control portion connected with the anchoring portion, configured for selectively activating the implant; a flexible portion connected at its proximal end with the control portion, the flexible portion having three-dimensional flexibility in a non-energized state and the flexible portion having a lesser three-dimensional flexibility in a energized state, the flexible portion being selectively switchable between the non-energized and energized states by the control portion, wherein the flexible portion can be an electroactive polymer element having: a composite layer having a polymer substrate and a biocompatible conductive material, wherein the composite layer also includes opposing surfaces; and a conductive polymer layer disposed on at least one of the opposing surfaces of the composite layer; a second anchoring portion connected with the distal end of the flexible portion, the second anchoring portion being configured for connecting the implant with the base of the tongue; an inductive powering mechanism coupled with the control portion and configured to maintain the flexible portion in either of the non-energized and energized states, the device being adapted and configured to support the tongue upon being energized; and supporting the subject's tongue by selectively activating the control portion of the implant using the inductive powering mechanism.
One aspect of the invention is an airway implant device with a connecting element. Preferably the connecting element is used to anchor and/or support the airway implant device, in particular, the electroactive polymer element to a rigid structure, such as a bony structure. The invention also includes methods of treating a disease using an airway implant device by implanting in a subject the airway implant device having an electroactive polymer element and a connecting element, the implanting step including fastening the electroactive polymer element to a bony structure of the subject with the connecting element, wherein the electroactive polymer element is capable of modulating the opening of the air passageway. Another method is a method of treating a disease using an airway implant device by implanting an electroactive polymer element in a tongue of a subject and linking the electroactive polymer element to a jaw bone, the electroactive polymer element is capable of supporting the tongue when it is energized. The devices are used to treat sleeping disorders, such as obstructive sleep apnea or snoring.
One embodiment is an airway implant device having a electroactive polymer element and a connecting element, wherein the electroactive polymer element is capable of modulating the opening of an air passageway and the connecting element is used to fasten the electroactive polymer element to a rigid structure. Preferably, the rigid structure is a bony structure. In some embodiments, both the electroactive polymer element and connecting element are made from a polymeric material. The electroactive polymer element can include an ion-exchange polymer metal composite. In other embodiments, the electroactive polymer element can include a conducting polymer such as a polypyrrole, a carbon nanotube or a polyaniline.
One embodiment of the airway implant device with a connecting element is depicted in
In another embodiment, the airway implant device with the connecting element further includes an anode, a cathode, a first inductor, and a controller. The anode and cathode are typically connected to the electroactive polymer element. The electroactive polymer element is energized with a power supply and is activated by electrical energy from the power supply. The electroactive polymer element can be physically connected to the power supply for example with a wire lead or can be connected with an inductive coupling mechanism.
The airway implant device with a connecting element further includes in some embodiments a non-implanted portion. Preferably the non-implanted portion is in the form of a strip and is used to control the electroactive polymer element. Typically this strip includes a power supply and a second inductor, the second inductor capable of interacting with a first inductor.
As set forth above, certain embodiments of the present invention are related to an implantable device for stabilizing the tongue during sleeping.
During sleep, the muscles in the roof of the mouth (soft palate), tongue and throat relax. If the tissues in the throat relax enough, they vibrate and may partially obstruct the airway. The more narrowed the airway, the more forceful the airflow becomes. Tissue vibration increases, and snoring grows louder. Having a low, thick soft palate or enlarged tonsils or tissues in the back of the throat (adenoids) can narrow the airway. Likewise, if the triangular piece of tissue hanging from the soft palate (uvula) is elongated, airflow can be obstructed and vibration increased. Being overweight contributes to narrowing of throat tissues. Chronic nasal congestion or a crooked partition between the nostrils (deviated nasal septum) may be to blame.
Snoring may also be associated with sleep apnea. In this serious condition, excessive sagging of throat tissues causes your airway to collapse, preventing breathing. Sleep apnea generally breaks up loud snoring with 10 seconds or more of silence. Eventually, the lack of oxygen and an increase in carbon dioxide signal causes the person to wake up, forcing the airway open with a loud snort.
Obstructive sleep apnea occurs when the muscles in the back of the throat relax. These muscles support the soft palate, uvula, tonsils and tongue. When the muscles relax, the airway is narrowed or closed during breathing in, and breathing is momentarily cut off. This lowers the level of oxygen in the blood. The brain senses this decrease and briefly rouses the person from sleep so that the airway can be reopened. Typically, this awakening is so brief that it cannot be remembered. Central sleep apnea, which is far less common, occurs when the brain fails to transmit signals to the breathing muscles.
Thus, it can be seen that airway disorders, such as sleep apnea and snoring, are caused by improper opening of the airway passageways. The devices and methods described herein are suitable for the treatment of disorders caused by the improper opening of the air passageways. The devices can be implanted in any suitable location such as to open up the airways. The opening of the passageways need not be a complete opening and in some conditions a partial opening is sufficient to treat the disorder.
In addition to air passageway disorders, the implants disclosed herein are suitable for use in other disorders. The disorders treated with the devices include those that are caused by improper opening and/or closing of passageways in the body, such as various locations of the gastro-intestinal tract or blood vessels. The implantation of the devices are suitable for supporting walls of passageways The devices can be implanted in the walls of the gastro-intestinal tract, such as the esophagus to treat acid reflux. The gastro-intestinal tract or blood vessel devices can be used in combination with the sensors described above. Also, the implants and/or sphincters can be used for disorders of fecal and urinary sphincters. Further, the implants of the invention can be tailored for specific patient needs.
It is apparent to one skilled in the art that various changes and modifications can be made to this disclosure, and equivalents employed, without departing from the spirit and scope of the invention. Elements shown with any embodiment are exemplary for the specific embodiment and can be used on other embodiments within this disclosure.
The devices of the present invention are tested for mechanical fatigue and electromechanical life cycle. Mechanical fatigue is tested using a piston clamped to one end of the test sample and the other end (corresponding to the hard palatal portion) of the sample is fixed by a clamp. The frequency of the piston movement is set at 2 Hz and bending angle is set at −75°. The fatigue data records the number of times the piston moves up and down before the conductive polymer layer cracks. The tests were performed at room temperature and dry state, which is expected to represent the worst case scenario for the stability of the conductive polymer layer.
Using the test above, the sample with the silicone rubber coating is capable of withstanding more than 2 million cycles at 2.2 Hz over 10 days. This corresponds to a lifespan of greater than 5 years. The control device without the silicone rubber coating lasted less than 10 cycles, with an equivalent lifespan of less than 1 month. In addition, the device using a patch coated conductive polymer in a staggered design configuration (see
Electromechanical life cycle was also tested using several means. In one test, samples were cycled between −1.2 to +1.2V by using 1.2V for 1 minute, followed by 2 minute rest and then application of negative 1.2V for 1 minute and resting for 2 minutes. The sample with silicone coating showed more than two times charge capacity than the control sample during the first 400 cycles and gradually decreased the charge capacity similar to that of the controls (
In another test of electromechanical strength, the sample was actuated using 1.2V and 40 uAhr capacity followed by 8 hour holding. The longer the actuation time, the higher the sample impedance. When the actuation time is higher than 1000 seconds, the sample reached the end of the sample's life cycle. With the silicone coating, sample life cycle was more than 30 cycles while the control samples showed less than 20 cycles (
As will be understood by those skilled in the art, the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.
This application claims the benefit of U.S. Application No. 60/984,690, filed Nov. 1, 2007, the disclosure of which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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60984690 | Nov 2007 | US |