Patent Publication Number: US-2019183665-A1

Title: Stent Using Wireless Transmitted Power and External Operating Apparatus Thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application in the U.S. National Phase of PCT/KR2016/009884, filed on Sep. 5, 2016, which claims priority to Korean Patent Application No. 10-2016-0109264, filed on Aug. 26, 2016, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     Technical Field 
     The present invention related to a medical stent. In particular, the present invention related to a stent using wireless transmitted power and an external driving apparatus thereof. 
     Description of the Related Art 
       FIG. 8  is a top plane view of a conventional medical stent. As shown in  FIG. 8 , a self-expanding metal stent using a shape memory alloy has been widely used in the therapy of blockages in blood vessels, digestive canals, etc. The stent expands the interior of a passageway by physical force, allowing preventing the passageway from a blockage and also restoring the flow of blood or other fluids. Further, the stent is shrunk either when placed in the exterior or while being inserted, allowing reducing the external diameter thereof. Alternatively, the stent is expanded depending on the temperature when placed in a surgical position, allowing increasing the external diameter thereof. Therefore, the conventional stent, as shown in  FIG. 8 , has either a cylindrical mesh shape or a cylindrical net shape using metal wires. 
     However, the conventional stent has only a function to expand by mechanical force the interior of blood vessels or digestive canals, which have become narrow depending on the tumor proliferation, but is irrelevant to the active therapy such as anticancer therapy. Thus, there are drawbacks that a tumor proliferates in openings of the mesh (or net), resulting in the blockage. A polymer coated stent is provided so as to prevent such drawbacks. However, the stent is restrictively used because of the drawback that the stent is detached from the original position by gastrointestinal peristalsis. 
     Meanwhile, various conventional anticancer therapies, such as hyperthermia, photodynamic therapy, anticancer drug delivery, etc., are performed separately or in combination with each other. However, according to such conventional anticancer therapies, a surgical instrument should have approached a tumor. Also, wiring or piping for signals, power, and drugs should have been connected with wires. Thus, there are drawbacks that a patient cannot be provided with continuous anticancer therapy and suffers from much pain and inconvenience. 
     SUMMARY OF THE INVENTION 
     Therefore, the present invention is provided to overcome the aforementioned drawbacks. The present invention is directed to providing a stent using wireless transmitted power and an external driving apparatus thereof, wherein the power is wireless transmitted to a stent inserted into the human body, allowing performing the original function of the stent as well as anticancer therapy. 
     Further, the present invention is directed to a stent using wireless transmitted power and an external driving apparatus thereof, wherein a sensor detects and transmits various physiological states of a tumor and the surroundings thereof to the exterior, allowing monitoring a state of the tumor in real time. 
     According to the first aspect of the present invention, a stent using wireless transmitted power includes a power receiving portion  230  which wirelessly receives power from the exterior, wherein the stent is a heating stent  250 , allowing heating using the power. 
     According to another aspect of the present invention, the stent further includes a power storage portion  240  which stores the power between the power receiving portion  230  and the heating stent  250 . 
     According to another aspect of the present invention, the stent further includes: a second communication part  270  which receives a control command from the exterior; and a second control portion  210  which controls the heating stent  250  based on the control command. 
     According to another aspect of the present invention, the stent further includes an electrical stimulation portion  290  which generates electrical stimulation using the power, wherein the electrical stimulation  290  applies the generated electrical stimulation to the heating stent  250 . 
     According to another aspect of the present invention, the stent further includes: a photosensitizer which is coated on the heating stent  250 ; and an LED  220  which emits light to the surroundings of the heating stent  250 , wherein the second control portion  250  controls the LED  220  based on the control command. 
     According to another aspect of the present invention, the stent further includes a sensor  260  which measures a biochemical environment of the surroundings of the heating stent  250 , wherein the second control portion  210  transmits an output of the sensor  260  to the exterior through the second communication portion  270 . 
     According to another aspect of the present invention, at least one of the power receiving portion  230 , the power storage portion  240 , the second communication portion  270 , the second control portion  210 , and the electrical stimulation portion  290  is coated with a nontoxic silicone layer  280  or Teflon. 
     According to another aspect of the present, the silicone layer  280  or the Teflone is placed on an inner or outer surface of the heating stent  250  or in a mid-point of a cross-sectional surface thereof. 
     According to the second aspect of the present invention, an external operating apparatus of the stent using wireless transmitted power includes: a first communication portion  150  which is capable of wirelessly communicating with the second communication portion  270 ; an RF signal generation portion  110  which generates the power and an RF amplification portion  120 ; a power transmission portion  130  which wirelessly transmits the amplified power to the power receiving portion  230 ; and a first control  100  which controls the first communication portion  150  and the RF signal generation portion  110 . 
     According to one example embodiment of the present invention, it is possible to wirelessly transfer power to a stent inserted into the human body, thereby performing anticancer therapy continuously. Further, it is possible to inhibit tumor proliferation, thereby preventing detachment of the stent or a blockage of the internal cavity. 
     As using a heating stent, it is possible to select a therapy such as hyperthermia therapy, photodynamic therapy, electrical stimulation, etc., easily from the exterior, thereby performing a variety of anticancer therapies according to the circumstance of a patient. 
     In addition, various sensors can be mounted on a circuit portion, thereby detecting and transmitting various physiological states of a tumor and the surroundings thereof to the exterior in real time. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing features of the present invention will become more fully apparent from the following description, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only typical embodiments of the invention and are, therefore, not to be considered limiting of its scope, the invention will be described with additional specificity and detail through use of the accompanying drawings in which: 
         FIG. 1  is a schematic block diagram of a stent using wireless transmitted power and an external operating apparatus thereof according to one example embodiment of the present invention; 
         FIG. 2A  is a front view of a stent according to a first example embodiment of the present invention, wherein a circuit portion is placed in the interior thereof; 
         FIG. 2B  is a front view of a stent according to a second example embodiment of the present invention, wherein a circuit portion is placed in the exterior thereof; 
         FIG. 3  is a cross-sectional view of an A-A part in  FIG. 2A ; 
         FIG. 4  is a cross-sectional view of a B-B part in  FIG. 2B ; 
         FIG. 5  is a cross-sectional view of a stent according to a third example embodiment of the present invention, wherein a circuit portion is placed in a mid-point of a cross-sectional surface thereof. 
         FIGS. 6A-6F  show photographs of a heating stent according to one example embodiment of the present invention and of various heating experiments; 
         FIGS. 7A-7E  show graphs which indicate correlation between power and temperature obtained through the heating experiments according to  FIGS. 6A-6F ; and 
         FIG. 8  is a plain view of a conventional stent. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The above and other features, objects and advantages of the present invention will now be more clearly understood from the following preferred example embodiments with the accompanying drawings. However, the present invention is not limited to the example embodiments set forth herein and may be embodied in many different forms. Rather, these embodiments are provided so that this invention will be thorough and complete and will fully convey the scope of the invention to those skilled in the art, 
     It will be understood that the terms, such as ‘comprises’ and/or ‘comprising’, are intended to designate described features, numbers, steps, operations, elements, parts, or combinations thereof, hut do not preclude the presence or addition of one or more features, numbers, steps, operations, elements, parts, or combinations thereof. 
     Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one ordinary skilled in the art to which the present disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
       FIG. 1  is a schematic block diagram of a stent using wireless transmitted power and an external operating apparatus thereof according to one example embodiment of the present invention. As shown in  FIG. 1 , the stent inserted into a tube may include a heating stent  250  and a circuit portion  200 . 
     The heating stent  250  may be coupled with a second control portion  210  and a power storage portion  240 . The heating stent may generate heat according to a control operation of the second control portion  210 , allowing transferring the heat to the surroundings thereof. That is, electrodes may be coupled to both ends of the heating stent  250 , allowing applying an electric current. Thus, the heating stent  250 , as a resistor, may function like a heater. The heating stent  250  is adapted for hyperthermia therapy. 
     The therapeutic effect of Hyperthermia Therapy (hereinafter, referred to as HTT) has been undervalued because it is impossible to transfer a heat of high temperature, i.e., 42° C. or above (particularly, 45° C.-50° C.) to the tumor area. Such temperatures are well known to be the most effective for killing the cancer cell. The aforesaid underestimate results from technical problems and circumstances around the tumor area. Meanwhile, there is an academic report that cancer can be reduced merely by increasing the temperature of a tumor to 40° C.-41° C., enough that immune cells can be activated by action of the heat. Accordingly, the heating stent  250  of the present invention may reach the tumor directly, allowing increasing therapeutic effects of HTT. Further, the heating stent may control the temperature in real time according to patient&#39;s feeling or suspend HTT, allowing increasing convenience. Examples of the heating stent  250  are shown in  FIGS. 6A-6C . 
     The circuit portion  200  may he equipped with an electrical stimulation portion  290 , an LED  220 , a power receiving portion  230 , a power storage portion  240 , a second control portion  210 , a sensor  260 , a second communication portion  270 , etc. 
     The electrical stimulation  290  may be coupled with the heating stent  250  and the second control portion  210  and the power storage portion  240 . The electrical stimulation portion  290  may convert, the power stored in the power storage portion  240  into electrical stimulation (electric shockwave) according to control action of the second control portion  210 . The electrical stimulation portion  250  may transfer the converted electrical stimulation to the stent  250 . The metal stent  250  may transfer the transferred electrical stimulation to the tumor and surrounding tissues thereof, allowing performing electrical stimulation therapy. The second control portion  210  may command the amplitude, duration, and pulse rate of the electrical stimulation on the basis of the external command transmitted to the second communication portion. 
     The LED  220  may he coupled to the power storage portion  240  and the second control portion  210  and may emit a predetermined wavelength of light. The LED  220  is adapted for PhotoDynamic Therapy (hereinafter, referred to as PDT), and thus the surface of the stent  250  is coated with photosensitizer. The PDT is a form of phototherapy to apply a photosensitizer sensitive to light onto a region to be treated, followed by irradiating a particular wavelength of light thereto, allowing accumulating the light selectively on the diseased cell. The light energy which reaches the photosensitizer-absorbing tumor or the lesion may facilitate the generation of active oxygen in the relevant cell, allowing destroying the cell. Particularly, the stent set in the body is not limited to the duration of irradiation of the LED  220 . 
     The photosensitizer coated on the surface of the stent  250  is a medicament to be administered into a person suspected to have a malignant tumor for the purpose of diagnosis of early cancer and premalignant and of cancer therapy. The photosensitizer has no effect on the diagnosis or treatment of cancers when used alone but traces the cancer, allowing accumulating in a high concentration within a cancer cell. Thus, if irradiating a particular wavelength of light to a region suspected as a cancer, strong fluorescence may be emitted, allowing selective necrosis of the cancer tissue. 
     The photosensitizer may include, as an example, a hemato-porphyrins derivative, aminolevulinic acid, chlorin, etc., especially Photgem and Phtofrin as a product. Administration method thereof may include intravenous injection, drinking, nasal inhalation, dermal application, spraying, direct administration to the bladder of the uterus etc. According to the conventional PDT, a light source should approach the tumor accompanying a wire. Thus, the conventional PDT has a slightly high effect on only superficial cancers in which the light source is capable of reaching the cancer cell by the endoscope from the exterior through bronchial tubes or gullet. On the other hand, the PDT using the stent  250  according to the present invention has the advantage of application to every position where the stent  250  can be inserted. 
     The power receiving portion  230  may receive RE wireless power transmitted from a power transmission portion  130  that is approximately 2 cm-3 cm apart from the exterior of the body  50 , allowing converting into an electric power. 
     The power storage portion  240  may be coupled between the power receiving portion  230  and the second control portion, allowing storing an electric power output from the power receiving portion  230 . The power storage portion  240  may be adapted to output a stable electric power or, if necessary, high power. The power storage portion  240  may include, as ran example, a condenser, a capacitor, a secondary battery, etc. 
     The sensor  260  may be coupled with the second control portion  210 , and may detect a variety of physiological signals in the region where the stent  250  is inserted, followed by transmitting such detected signals to the exterior through the second communication portion  270 . The sensor  260  may include, as an example, a temperature sensor, a pressure sensor for detecting flow, a pressure sensor using impedance or piezoelectricity for detecting a blockage or detachment, an electromagnetic sensor, a resonant sensor, etc. 
     The second communication portion  270  may be coupled with the second control portion  210 , and is capable of bi-directional wireless communication with a first communication portion  150 . The second communication  270  may receive a control command from the exterior, allowing transferring the received command to the second control portion  210 , and may transmit an output of the sensor  260 , the state of each electronic circuit within the circuit portion  200  or outputs thereof to the exterior through the second control portion  210 . If the second communication portion  270  may he adapted for near field communication, it is possible to apply any types including, as a principle example, ZigBee, Bluetooth, Wi-Fi, LAN, etc. 
     The second control portion  210  may he electrically coupled with the heating stent  250 , the electrical stimulation portion  290 , the LED  220 , the power storage portion  240 , the sensor  260  and the second communication  270 . The second control portion  210  may include as a prime example, Micom (microcontroller). 
     Herein before, described are the respective modules (for example, the electrical stimulation portion  290 , the LED  220 , the power receiving portion  230 , the power storage portion  240 , the second control portion  210 , the sensor  260 , the second communication  270 , etc.) equipped within the circuit portion  200 . However, it is not necessary to have all of such respective modules. It may be possible to omit a part of any such modules or merge together, if necessary in a view of design. For example, if modulating a control signal, followed by incorporation into a wireless power signal (similar to power line modem), the power receiving portion and the second communication portion  270  may be merged together. Further, the LED  220  may be replaced with a laser light source. The heating stent  250  may be coated with an anticancer agent replacing or together with the coated photosensitizer. 
     Hereinafter, described is the configuration of an external operating apparatus for operating the circuit portion  200  from the exterior of the body  50 . 
     A first control portion  100  may be coupled with a first control portion  100  and an RF signal generation portion  110  and a first communication portion  150 , and may have a function of monitoring except the coupled modules. The first control portion  100  may be as a prime example, a notebook computer or a personal computer. 
     The RF signal generation portion  110  may be coupled between the first control portion  100  and an RF amplification portion  120 , and may generate RF signal according to the first control portion, 
     The RF amplification portion  120  may be coupled between the RF signal generation portion  110  and a power transmission portion  130 , and may have a function of amplifying the RF signal output from the RF signal generation portion  110  to a predetermined output. 
     The power transmission portion  130  may be coupled with the RF amplification portion  120 , and may have a function of wireless transmitting the RF signal amplified to a predetermined output. The power transmission portion  130  may be, as a principle example, an induction coil which is 2 cm-3 cm apart from the body  50 . 
     The first communication portion  150  may be coupled with the first control portion  100 . The first communication portion  150  may wireless transmit a control command to the second communication portion  270  according to a control command of the first control portion  100 , or may wireless receive the output of the second communication portion  270 . Further, the first communication portion  150  may maintain the same communication protocol as that of the second communication portion  270  (for example, ZigBee, Bluetooth, LAN, etc.) 
       FIG. 2A  is a front view of a stent according to a first exemplary embodiment of the present invention, wherein a circuit portion  200  may be placed in the interior thereof.  FIG. 3  is a cross-sectional view of an A-A part in  FIG. 2A . As shown in  FIG. 2A  and  FIG. 3 , the circuit portion  200  may be placed on the inner surface of one side of the stent  250 . The circuit portion  200  may be embodied into an Application Specific Integrated Circuit (ASIC), a Micro Electro Mechanical System (MEMS), a One Chip or etc. A silicone layer  280  may be a coating layer which surrounds the circuit portion  200 , allowing protecting the circuit portion  200  from electric short or corrosion and preventing the outflow of harmful substances from the circuit portion  200 . Further, the silicone layer  280  may fix the circuit portion  200  and the stent  250  firmly, allowing preventing detachment of the circuit portion  200 . The power receiving portion  230  may be a plurality of induction coils (having a diameter of 1 cm-2 cm) which are connected parallel. The LED  220  may exposed to the exterior of the silicone layer  280 , so as to emit light. The sensor  260  may be slightly exposed to the exterior of the silicone layer  280  and/or the stent  250 , so as to detect an accurate signal. The silicone layer  280  may be replaced with other materials which are capable of protecting the circuit portion  200  and maintaining the fixability. Such materials may include, as an example, Teflon, Polyimide (PI), polytetrafluoroethylene (PTFE), zwitterionic polymers, siloxanes, polystyrene, polyolefins, fluoropolymers, polyaramid, polycarbonates, acrylic polymers, methacrylates, styrenes and substituted styrenes, polysulfones, epoxies, polyacrylonitriles, polyamides, polyimides, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetals, polyesters, polyvinyl esters, polyesters, polyvinyl ethers, polydiacetylenes, polyvinyl acetate, polyethylene terephthalate and polyethylene oxide, optionally copolymerized with other polymerizable monomers or cross-linkers, covalently crosslinked PEG or acrylamide combined with ionically crosslinked alginate, etc. 
       FIG. 2B  is a front view of a stent according to a second example embodiment of the present invention, wherein a circuit portion  200  may be placed in the exterior thereof.  FIG. 4  is a cross-sectional view of a B-B part in  FIG. 2B . As shown in  FIG. 2B  and  FIG. 4 , the circuit portion  200  may be placed on the outer surface of one side of the stent  250 . Since other configurations thereof are the same as the aforementioned first example embodiment, description therefor is omitted herein. 
       FIG. 5  is a cross-sectional view of a stent according to a third example embodiment of the present invention, wherein a circuit portion  200  may be placed in a mid-point of a cross-sectional surface thereof. As shown in  FIG. 5 , the circuit portion  200  may be placed between an outer stent  252  and an inner stent  254 . A double concentric structure of  FIG. 5  may be applied to either the whole length of the stent  250  or the only region where the circuit portion  200  is placed. The circuit portion  200  may be embodied by using ASIC, MEMS or a One Chipped IC chip together with a Flexible Printed Circuit Board (FPCB) in a manner of bending to be round. A plurality of the LEDs  220  may be exposed to the surroundings of the circuit portion  200 , and the sensor  260  may be exposed to a desired position (for example: the inner or outer side of the stent). Even though not shown in  FIG. 5 , the circuit portion  200  may be coated with a silicone layer  280 . 
       FIGS. 6A-6F  show photographs of a heating stent according to one example embodiment of the present invention and of various heating experiments.  FIG. 6A  shows a mono layered heating stent and  FIG. 6B  shows a double layered heating stent.  FIG. 6C  is the photograph of a heating stent in a heated state, taken using an infrared camera, in which the heating stent is heated by coupling electrodes to both ends thereof and applying an electric current thereto.  FIGS. 6D-6F  are infrared photographs showing a heating process in which a stent is inserted into a variety of tissues and generates heat. 
     Further,  FIGS. 7A-7E  show graphs which indicate correlation between power and temperature obtained through the heating experiments according to  FIGS. 6A-6F . The horizontal axis on the graph indicates power (W) and the vertical axis thereon indicates average temperature (° C.). As shown in  FIGS. 7A-7E , the temperature and the power are in the linear relationship which is capable of being represented by the liner function. 
     More particularly,  FIG. 7A  is the graph of an experiment for a mono layered heating stent.  FIG. 7B  is the graph of an experiment for a double layered heating stent.  FIG. 7C  is the graph of an experiment for a double layered heating stent inserted into a tissue.  FIG. 7D  is the graph of an experiment for a mono layered mesh heating stent (the negative is coupled to the center).  FIG. 7E  is the graph of an experiment for a mono layered mesh heating stent (the negative is coupled to center with a thicker wire). 
     The first control portion  100  may amplify an RE signal to corresponding power to generate desired temperature heat, based on such graphs. For example, the mono layered stent of  FIG. 6A  may need 4-5W of power for 3-5 seconds in order to reach 45° C.-50° C. of temperatures which are adapted for necrosis of the cancer cell. The double layered stent of  FIG. 6B  may need 6-7W of power. 
     Even though the present invention is described in connection with the aforementioned exemplary embodiments, it would be understood by those skilled in the art that various modifications and alternations may be made within the purport and scope of the present invention. Further, it is obvious that such modifications and alternations belong the scope of the claimed invention.