Electrical stimulation catheter and preparation method thereof

Abstract

The invention provides an electrical stimulation catheter and a preparation method thereof, and belongs to the technical field of medical instruments.The electrical stimulation catheter comprises a catheter body, the outer wall of the catheter body is sequentially provided with a substrate layer, a liquid metal layer and a packaging layer from inside to outside, the liquid metal layer comprises a plurality of electrode connecting discs and wires connected with the electrode connecting discs, and the electrode connecting discs are connected with the packaging layer. The electrode terminal pad is formed by printing liquid metal, and an electrode contact covers the electrode terminal pad. The problem that the antibacterial effect of the catheter is not lasting can be solved, and catheter-related urinary tract infection is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of medical devices, and particularly relates to an electric stimulation urinary catheter and a preparation method thereof. BACKGROUND

[0002] Catheter-associated urinary tract infection (CAUTI) is one of the most common iatrogenic infections in clinical practice, which is mainly caused by the formation of bacterial biofilm on the surface of indwelling urinary catheters. The existing methods for preventing and treating CAUTI are mainly through coating antibiotic coating or silver ion coating on the outer side of the urinary catheter, wherein the coating of antibiotic coating on the outer side of the urinary catheter is easy to cause drug resistance of bacteria, and the effect decreases over time, and the coating of silver ion coating on the outer side of the urinary catheter is easy to be inactivated by protein and other substances in body fluid, and the antibacterial effect is not durable. SUMMARY

[0003] In view of the defects or deficiencies in the prior art, the present application provides an electric stimulation urinary catheter and a preparation method thereof, which can avoid the problem of short-term antibacterial effect of the urinary catheter, thereby reducing catheter-associated urinary tract infection.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: In a first aspect, an embodiment of the present application provides an electric stimulation urinary catheter, comprising a urinary catheter body, a substrate layer, a liquid metal layer and an encapsulation layer are sequentially arranged on the outer wall of the urinary catheter body from inside to outside, the liquid metal layer comprises a plurality of electrode connection pads and wires connecting the plurality of electrode connection pads, and the liquid metal layer is printed by liquid metal, and the electrode connection pads are covered with electrode contacts.

[0005] Further, the substrate layer is made of polydimethylsiloxane prepolymer, which is spin-coated on the outer wall of the urinary catheter body, and the thickness is 100-200 microns, and the substrate layer is used to isolate the urinary catheter body and the liquid metal layer.

[0006] Further, the liquid metal is gallium-indium liquid metal, which has high fluidity and conductivity, and is convenient for printing circuits on the substrate layer.

[0007] Further, the electrode connection pads are arranged at the preset stimulation and sensing positions on the urinary catheter body, and the preset positions on the urinary catheter body are electrically stimulated through the electrode connection pads, so as to interfere with bacterial metabolism and destroy the structure, thereby achieving the purposes of antibiosis and treatment.

[0008] Further, the encapsulation layer is made of polydimethylsiloxane prepolymer, and the thickness is 100-200 microns, and the encapsulation layer fully covers the liquid metal below, so as to avoid the contact between the liquid metal and human tissues, and at the same time ensure the conduction of electric signals.

[0009] Furthermore, the electrode contacts are made of a conductive composite material of platinum powder and polydimethylsiloxane, which solves the problems of mismatch between rigid electrodes and flexible catheters, as well as poor biocompatibility.

[0010] Furthermore, the liquid metal layer is also connected to leads, which are provided in multiple ways. One end of each lead is connected to the circuit formed by the liquid metal, and the other end of each lead converges to the proximal end of the catheter body for connection to an external monitoring device. The external monitoring device can be used to realize antibacterial and detection functions.

[0011] Furthermore, the external monitoring device includes an electrical stimulation module, a signal acquisition module, and a processing and display unit. The electrical stimulation module is used to apply safe and effective electrical stimulation; the signal acquisition module acquires the electrophysiological signals sensed by the electrode contacts, amplifies them, and transmits them to the processing unit; the processing and display unit is used to process the signals, assess the risk of infection, and display the results.

[0012] Secondly, embodiments of the present invention provide a method for preparing an electrically stimulated urinary catheter, which, using the electrically stimulated urinary catheter described above, includes the following steps: The polydimethylsiloxane prepolymer and curing agent are mixed at a weight ratio of 10:1. After removing air bubbles, the mixture is evenly spin-coated onto the outer wall of the catheter body. After curing in an oven, a transparent flexible layer is formed. The prefabricated conductive template is attached tightly to the substrate layer, gallium indium liquid metal is scraped to form a circuit, and then one end of the lead is embedded and fixed in the circuit formed by the liquid metal. Platinum powder and silicone elastomer are mixed evenly by weight at a ratio of 80:20. Using a dispensing device, the composite is precisely applied to the electrode connection pad to form a circular contact, which completely covers the electrode connection pad. After curing, the electrode contact is formed. Polydimethylsiloxane prepolymer is then applied to the remaining parts of the liquid metal layer to form an encapsulation layer.

[0013] Furthermore, the other end of the lead wire is led out to the proximal end of the conduit and connected to an external control device to test the continuity of each circuit.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a base layer, a liquid metal layer, and an encapsulation layer on the outside of a urinary catheter. The liquid metal layer is formed by printing multiple electrode connection pads and wires connecting the multiple electrode connection pads with liquid metal. The liquid metal layer can be connected to an external monitoring device. During the use of the urinary catheter, electrical stimulation is applied to destroy the bacterial biofilm on the surface of the urinary catheter, which can prevent the antibacterial effect of the urinary catheter from decreasing during long-term use and reduce catheter-related urinary tract infections.

[0015] 2、The liquid metal is set, so that the whole system is as soft as the catheter body, is closely attached, does not cause mechanical damage to the urethral tissue, and the comfort of the patient is improved while realizing electric stimulation.

[0016] 3、The packaging structure of the PDMS substrate+platinum-silicon electrode is used at the electrode connecting pad, the biocompatibility risk of the liquid metal is solved, the contact interface impedance of the platinum-silicon composite electrode and the tissue is lower than that of the traditional rigid metal electrode, weak bioelectric signals can be more effectively collected, and the monitoring sensitivity is higher. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a catheter body structure schematic diagram in the embodiment one of the application; Figure 2 It is a base layer, liquid metal layer and packaging layer position relation diagram in the embodiment one of the application; 1, catheter body; 2, base layer; 3, liquid metal layer; 4, packaging layer; 5, electrode connecting pad; 6, wire; 7, electrode contact. DETAILED DESCRIPTION

[0018] The application will be further described below in combination with the drawings and embodiments.

[0019] Embodiment one A typical embodiment of the application is shown in Figure 1 and Figure 2 An electric stimulation catheter, including a catheter body 1, a base layer 2, a liquid metal layer 3 and a packaging layer 4 are sequentially arranged on the outer wall of the catheter body 1 from inside to outside, the base layer 2 adopts polydimethylsiloxane (PDMS) prepolymer, is spin-coated on the outer wall of the catheter body 1, and after solidification, a flexible insulating layer with a thickness of 100-200 μm is formed.

[0020] The base layer 2 is arranged to isolate the catheter body 1 and the liquid metal layer 3, so as to protect the liquid metal layer 3.

[0021] The liquid metal layer 3 adopts a gallium-indium (Galinstan) liquid metal composite material, is printed on the base layer 2 which is not completely solidified, forms a preset circuit, the circuit includes a plurality of electrode connecting pads 5 and wires 6 connecting the plurality of electrode connecting pads 5, and the electrode connecting pads 5 are arranged at the preset stimulation and sensing positions on the catheter body 1.

[0022] The gallium-indium liquid metal has high fluidity, can be printed on the PDMS substrate which is not completely solidified by using a template printing method, and the gallium-indium liquid metal has high directivity, so that the conduction of electric signals is facilitated.

[0023] The liquid metal layer 3 is also connected with a plurality of leads, one end of the plurality of leads is connected to the circuit formed by the liquid metal, and the other end of the plurality of leads is gathered to the proximal end of the catheter body 1, which is used to connect an external monitoring device. The external monitoring device can transmit a current to the circuit through the leads, the current is gathered on the electrode connection pad 5 through the lead wire 6, and the preset position on the catheter body 1 is electrically stimulated, so that the electric field can effectively penetrate the biological membrane, interfere with the metabolism of bacteria and destroy the structure of the bacteria.

[0024] In addition, the circuit is connected to the external monitoring device through the leads, and the urethral electrophysiological signal can be monitored in real time. The electrophysiological signal is transmitted to the external monitoring device through the electrode connection pad 5 and the lead wire, and the change of the electrical signal of the local tissue is detected, so as to provide real-time data for the clinic.

[0025] The encapsulation layer 4 adopts a polydimethylsiloxane (PDMS) prepolymer, which is covered on the liquid metal layer 3, and the thickness is 100-200 μm. At the same time, the electrode contact 7 formed by the conductive composite material mixed with platinum powder and polydimethylsiloxane (PDMS) is coated at the position of the electrode connection pad 5, and the thickness after solidification is 100-200 μm. The encapsulation layer 4 completely covers the liquid metal below, avoids the contact between the liquid metal and the human tissue, and ensures the conduction of the electrical signal.

[0026] By adopting the encapsulation structure of "PDMS substrate + platinum-silicon electrode", the biocompatibility risk of the liquid metal is solved, and the whole system is as soft as the catheter body 1, which is closely attached and does not cause mechanical damage to the urethral tissue, thereby improving the comfort of the patient.

[0027] At the same time, the contact interface impedance between the electrode contact 7 in the application and the tissue is lower than that of the traditional rigid metal electrode, which can more effectively collect weak bioelectric signals and improve the detection sensitivity.

[0028] Further, the external monitoring device includes an electrical stimulation module, a signal acquisition module, and a processing and display unit. The electrical stimulation module can generate a direct current with an amplitude of 0.1-5V, which is used to apply a safe and effective electrical stimulation to destroy the bacterial biofilm. The signal acquisition module can collect the urethral impedance, electromyogram and other electrophysiological signals sensed by the electrode contact 7, amplify and transmit to the processing unit. The processing and display unit is used to process the signal, evaluate the infection risk (such as judging the thickness of the biofilm by the impedance change) and display the result.

[0029] In the embodiment, the external monitoring device is an existing medical device, and the function and use method thereof are prior art, which will not be described in detail here.

[0030] In use, after the indwelling catheter body 1 is placed, the electric field can effectively penetrate the biological membrane, interfere with bacterial metabolism and destroy its structure by the external device applying electric stimulation regularly or continuously, thereby achieving the purposes of antibiosis and treatment. During the intermittent period of stimulation, the external control device can be switched to a sensing mode to detect the changes in the electrical signals of the local tissue and provide real-time data for the clinic.

[0031] By arranging the base layer 2, the liquid metal layer 3 and the encapsulation layer 4 on the outside of the catheter, and printing the liquid metal layer 3 into a plurality of electrode connecting pads 5 and wires 6 connecting the plurality of electrode connecting pads 5, electric stimulation can be applied during the use of the catheter to destroy the bacterial biofilm on the surface of the catheter, which can avoid the problem that the long-term use effect decreases due to the drug resistance of bacteria caused by the antibiotic coating on the outside of the catheter, and can also avoid the problem that the silver ion coating on the outside of the catheter is easily inactivated by proteins and other substances in the body fluid, the antibacterial effect is not long-lasting, and the catheter-associated urinary tract infection is reduced.

[0032] Embodiment Two The embodiment provides a preparation method of an electrically stimulated catheter, which uses the electrically stimulated catheter as described in Embodiment One and comprises the following steps: The polydimethylsiloxane (PDMS) prepolymer and the curing agent are mixed at a weight ratio of 10:1, and after the bubbles are removed, the catheter is fixed on a spin coater, and spin coating is performed at a speed of 1000 rpm for 10 seconds to make the catheter uniformly covered, and then the catheter is cured in a 60°C oven for 1 hour to form a transparent flexible layer with a thickness of about 150 μm.

[0033] The pre-prepared conductive template is tightly attached to the base layer 2, the Galinstan liquid metal is scraped to form a circuit, and then one end of the lead wire is pre-embedded and fixed in the circuit formed by the liquid metal.

[0034] The platinum powder with a particle size of 5 μm and the silicone elastomer (NuSil Technology) are uniformly mixed at a weight ratio of 80:20, the compound is accurately and locally coated at the electrode connecting pad 5 using a dispensing device to form a circular contact with a diameter of 1 mm, the electrode connecting pad 5 is completely covered, and the electrode contact 7 is formed by curing at 90°C for 1.5 hours. The polydimethylsiloxane (PDMS) prepolymer is used to cover the rest of the liquid metal layer 3 to form the encapsulation layer 4.

[0035] The other end of the lead wire is led out to the proximal end of the catheter and connected to the external control device, and a multimeter is used to test that each loop is good, and the insulation resistance between the electrodes is greater than 10 MΩ.

[0036] The catheter prepared in this embodiment is sampled for in vitro antibacterial testing: the sample is immersed in a 1×10 8The experimental group is applied with 1.5V direct current stimulation, and the control group is not applied with stimulation. After 24 hours of culture at 37°C, the number of bacteria is counted by plate counting method. The number of bacteria in the experimental group is reduced by 90% compared with the control group, which shows that the antibacterial effect is extremely significant.

[0037] The application realizes active electric stimulation treatment of catheter-associated urinary tract infection (CAUTI) and real-time monitoring of urethral electrophysiological signals on the same catheter, and realizes "treatment and prevention integration, diagnosis and monitoring synchronization".

[0038] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An electro-stimulation urinary catheter, characterized in that, The urinary catheter comprises a catheter body, a base layer, a liquid metal layer and a packaging layer arranged on the outer wall of the catheter body from inside to outside, the liquid metal layer comprises a plurality of electrode connecting pads and wires connecting the electrode connecting pads, and the electrode connecting pads are covered with electrode contacts.

2. An electro-stimulation urinary catheter as claimed in claim 1, wherein, The base layer is made of polydimethylsiloxane prepolymer, which is spin-coated on the outer wall of the catheter body, and the thickness is 100-200 μm.

3. An electro-stimulation urinary catheter as defined in claim 1, wherein, The liquid metal is gallium-indium liquid metal.

4. An electro-stimulation urinary catheter as defined in claim 1, wherein, The electrode connecting pads are arranged at the preset stimulation and sensing positions on the catheter body.

5. An electro-stimulation urinary catheter as defined in claim 1, wherein, The packaging layer is made of polydimethylsiloxane prepolymer, and the thickness is 100-200 μm.

6. An electro-stimulation urinary catheter as defined in claim 1, wherein, The electrode contacts are made of a conductive composite material mixed with platinum powder and polydimethylsiloxane.

7. An electro-stimulation urinary catheter as defined in claim 1, wherein, The liquid metal layer is also connected to the lead, the lead is provided with a plurality of leads, one end of the plurality of leads is connected to the circuit formed by the liquid metal, and the other end of the plurality of leads is gathered to the proximal end of the catheter body for connecting to the external monitoring device.

8. An electro-stimulation urinary catheter as defined in claim 7, wherein, The external monitoring device comprises an electric stimulation module, a signal acquisition module and a processing and display unit, the electric stimulation module is used for applying safe and effective electric stimulation, the signal acquisition module acquires the electrophysiological signals sensed by the electrode contacts, amplifies and transmits to the processing unit, and the processing and display unit is used for processing signals, evaluating infection risk and displaying results.

9. A method for preparing an electric stimulation urinary catheter, using the electric stimulation urinary catheter according to any one of claims 1-8, characterized in that: The polydimethylsiloxane prepolymer and the curing agent are mixed in a weight ratio of 10:1, the mixture is uniformly spin-coated on the outer wall of the catheter body after removing bubbles, and a transparent flexible layer is formed after curing in an oven; The pre-prepared conductive template is tightly attached to the base layer, the gallium-indium liquid metal is scraped to form a circuit, and then one end of the lead is pre-embedded and fixed in the circuit formed by the liquid metal; The platinum powder and the silicone elastomer are uniformly mixed in a weight ratio of 80:20, the composite is accurately and precisely coated at the electrode connecting pad using a dispensing device to form a circular contact, which completely covers the electrode connecting pad, and the electrode contact is formed after curing, and the polydimethylsiloxane prepolymer is covered on the rest of the liquid metal layer to form a packaging layer.

10. A method of making an electro-stimulating urinary catheter as claimed in claim 9, wherein, Further comprising: The other end of the lead is led out to the proximal end of the catheter and connected to the external control device, and each circuit is tested to be good.

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