Antimicrobial device based on electroporation

Abstract

This technology relates to an antimicrobial device based on electroporation. The antimicrobial device based on electroporation is powered by an energy source and includes negative and positive electrodes operably coupled to an air intake structure. When an external electric field is applied across the negative and positive electrodes, a lightning rod effect is generated that causes permanent damage to the outer structure of microorganisms passing through the air intake structure with the air, thereby achieving immediate disinfection. The energy source includes a respiration-driven triboelectric nanogenerator (R-TENG) for recovering unused biomechanical energy from the periodic motion of respiration. The R-TENG includes a pair of nanofiber membranes, including a first nanofiber membrane composed of a triboelectric positively charged material and a second nanofiber membrane composed of a triboelectric negatively charged material. The triboelectric positively charged material and the triboelectric negatively charged material have opposite polarities, and the R-TENG simultaneously functions as a filtration system.

Description

Technical Field

[0001] The present technology relates to a face mask that is disinfected in-situ. More specifically, the present technology relates to an electrospray-based antibacterial device that operates based on triboelectric power supply nanowire-assisted electrospray.

Background Art

[0002] Currently, the occurrence of Coronavirus Disease 2019 (COVID-19) has caused a global crisis and had a major impact on the international medical system. As an airborne infectious disease, COVID-19 spreads through aerosol transmission, which means that a person can be infected simply by inhaling respiratory particles containing the virus. Therefore, in order to control its spread in society, the public is recommended or even forced to wear face masks because face masks provide an effective barrier against respiratory droplets. Thus, the importance and effectiveness of wearing masks to control the spread of airborne infectious diseases are being recognized again as the memories of some past pandemics, such as the 1918 Spanish flu pandemic and the occurrence of severe acute respiratory syndrome (SARS) in 2002, gradually fade.

[0003] Controlling the spread of infection before an effective vaccine is fully developed is crucial to minimizing the impact of the emerging disease on various aspects, including health, economy, finance, and society. Furthermore, while the wearing of personal protective equipment (PPE) (especially face masks) is considered the most convenient non-medical measure to break the chain of infection, it has several limitations. First, most commercially available face masks lack antibacterial and self-disinfecting properties and can only filter respiratory particles. These droplets accumulate on the surface of the face mask, and viruses can survive for hours or even days. Therefore, frequent replacement of face masks is recommended. However, most consumers tend to discard face masks without proper disinfection, increasing the likelihood of secondary infections. In addition, the high consumption rate and low reusability of polypropylene face masks generate enormous amounts of plastic waste, negatively impacting the environment. As a result, there is a demand for face masks that offer immediate self-disinfection with a longer lifespan.

[0004] Several studies have been conducted to impart functionality to face masks through various methods in order to achieve self-disinfection. For example, a photosensitizer can be incorporated into the face mask as an antiviral agent. This photosensitizer absorbs energy from visible light and transfers it to the surrounding oxygen under sunlight irradiation. As a result, reactive oxygen species (ROS) are generated, which can rapidly inactivate bacteria and viruses by damaging their DNA and cellular proteins. In the case of photothermal materials such as graphene oxide, the increased local temperature under sunlight irradiation can cause microbial denaturation. Both photosensitizers and photothermal materials can disinfect face masks, but their performance is mainly limited by the availability of solar energy. Furthermore, an electrothermal graphene-modified mask has been proposed, which can rapidly generate temperatures exceeding 80°C under a voltage of 3V without weather constraints. However, the charging procedure requires a specific DC power supply, which limits its practical application in certain areas. Therefore, to overcome the above problems, a technology is needed that includes a weather-independent disinfection method and a portable energy harvester. [Overview of the project]

[0005] This technology relates to a technique for immediately disinfecting air by damaging the external structure of pathogens such as viruses, bacteria, and fungi on the surface of an air intake structure through nanowire-assisted electroporation. In one embodiment, an electroporation-based antimicrobial device is disclosed that functions simultaneously as an energy harvester and a filtration system, powered by a respiration-driven triboelectric nanogenerator (R-TENG). This technology is powered by a sustainable energy source, such as a respiration-driven triboelectric nanogenerator (R-TENG), which sustainably recovers unused biomechanical energy from respiration, to power the electroporation unit, while simultaneously functioning as a filtration system.

[0006] According to one aspect of this technology, an antimicrobial device based on electroporation is provided. The antimicrobial device based on electroporation is powered by an energy source and includes a negative electrode and a positive electrode operably coupled to an air intake structure, wherein when an external electric field is applied between the negative electrode and the positive electrode, a lightning rod effect is generated that causes permanent damage to the outer structure of microorganisms passing through the air intake structure with the air, thereby achieving immediate disinfection.

[0007] In one embodiment, the energy source includes a respiration-driven triboelectric nanogenerator (R-TENG) for recovering unused biomechanical energy from the periodic motion of respiration. The R-TENG also functions as a filtration system.

[0008] In one embodiment, R-TENG includes a pair of nanofiber films comprising a first nanofiber film composed of a triboelectrically charged material and a second nanofiber film composed of a triboelectrically charged material. The triboelectrically charged material and the triboelectrically charged material have opposite polarities, and R-TENG functions simultaneously as a filtration system.

[0009] In one embodiment, polyvinyl alcohol (PVA) and polyvinylidene fluoride (PVDF) are selected as the triboelectrically charged material and the triboelectrically charged material.

[0010] In one embodiment, to avoid short circuits and ensure that all compartments are securely fitted together, a first O-ring structure is placed between the R-TENG and the electroporation-based antimicrobial device, a second O-ring structure is placed between the positive and negative electrodes of the electroporation unit, and a third O-ring structure is placed between the electroporation-based antimicrobial device and the air introduction structure.

[0011] In one embodiment, the R-TENG is designed to function solely through bidirectional airflow from breathing, without requiring any additional mechanical parts.

[0012] In one embodiment, an electroporation-based antimicrobial device is sustainably powered by an R-TENG, which is enclosed within an airtight structure to ensure a slow airflow through a nanofiber membrane.

[0013] In one embodiment, the positive electrode is made from a metal mesh, and metal hydroxide nanowires are grown on the surface of the copper mesh to form the negative electrode.

[0014] In one embodiment, the positive electrode is operably coupled to the triboelectrically charged material of the R-TENG, and the negative electrode is operably coupled to the triboelectrically charged material of the R-TENG.

[0015] In one embodiment, at least one of the triboelectric materials is designed in a dome shape to control the maximum displacement between nanofiber films, achieve consistent contact separation without requiring additional mechanical parts, and ensure that the air passing through the air introduction structure is completely filtered.

[0016] In one embodiment, the pressure drop across the triboelectric material is designed to be lower than that of the remaining fabric components of the air intake structure, ensuring that air passes only through the R-TENG.

[0017] In one embodiment, the negative electrode of an antimicrobial device based on electroporation is located at the inlet of an air intake structure, causing microorganisms passing through the air intake structure to become negatively charged.

[0018] In one embodiment, the air intake structure includes a face mask and an air filter.

[0019] This technology provides R-TENG made from a triboelectric material containing any organic nanofiber, where the gap between the triboelectric positively charged material and the triboelectric negatively charged material is large enough to generate a potential difference of 1 volt (V) or more. Both electrodes of the triboelectric layer contain any conductive material that can be attached to the triboelectric layer, such as aluminum or silver, while the material of the electroporation system may contain any conductive mesh having a high aspect ratio nanostructure, such as nanowires. To generate a high local electric field, the distance between the positive and negative electrodes of the electroporation-based antimicrobial device needs to be small enough to avoid short circuits during operation, but not too close. The distance is in the range of approximately 0.2 millimeters (mm) to 1 mm. To extend the lifespan of the electroporation-based antimicrobial device and reduce the waste generated, R-TENG and the electroporation-based antimicrobial device are designed to be enclosed within a single removable and replaceable valve structure, meaning that only specific parts of the air intake structure (such as a face mask) are discarded, rather than the entire product. Furthermore, multiple valves, including an electroporation-based antimicrobial device and a sustainable energy source (e.g., R-TENG), can be integrated with commercially available face masks such as silicone oxygen masks, N95 masks, gas masks, and full-face masks.

[0020] These and other embodiments of the embodiments herein will be better understood in conjunction with the following description and accompanying drawings. However, the following description provides preferred embodiments and many specific details thereof, but is for illustrative purposes only and not intended to limit them. Many changes and modifications may be made within the scope of the embodiments herein, and the embodiments herein include all such modifications. [Brief explanation of the drawing]

[0021] With reference to the attached drawings, other purposes, features, and advantages of the present invention will become apparent from the following description. In the drawings, similar reference numerals indicate corresponding parts throughout multiple figures. [Figure 1A] Front view of an electro-poration-based antibacterial device operably coupled to a face mask according to one embodiment. [Figure 1B] Isometric view of an electro-poration-based antibacterial device operably coupled to a face mask according to one embodiment. [Figure 1C] Side view of an electro-poration-based antibacterial device operably coupled to a face mask according to one embodiment. [Figure 2A] Exploded view of an electro-poration-based antibacterial device according to one embodiment. [Figure 2B] Exploded view of an electro-poration-based antibacterial device operably coupled to a face mask according to one embodiment. [Figure 2C] Exploded view of an electro-poration-based antibacterial device operably coupled to a face mask according to one embodiment. [Figure 3] Diagram showing the periodic motion of a respiration-based R-TENG according to one embodiment.

Mode for Carrying Out the Invention

[0022] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, and / or components have not been described in detail so as not to obscure the present invention. Preferred embodiments of the present technology will be described in detail with reference to the examples shown in the drawings.

[0023] Various embodiments of the present technology provide a system for instantaneously disinfecting air by damaging the outer structure of pathogens such as viruses, bacteria, and fungi on the surface of an air-introduction structure by means of a nanowire-assisted electroporation system. In one embodiment, the present technology operates based on electroporation-based disinfection and provides an electroporation-based antibacterial device powered by a respiration-driven triboelectric nanogenerator (R-TENG) that functions simultaneously as an energy harvester and a filtration system. The present technology provides a respiration-driven electroporation-based antibacterial device powered by a sustainable energy source such as a respiration-driven triboelectric nanogenerator (R-TENG) for driving electroporation. This respiration-driven triboelectric nanogenerator sustainably recovers unused biomechanical energy from respiration for powering electroporation and simultaneously functions as a filtration system. In some other embodiments, other energy sources such as, for example, a battery, an energy source based on the piezoelectric effect, a solar energy source, etc. may be used.

[0024] According to various aspects, the triboelectric nanogenerator, so-called TENG, is a technology capable of converting ambient mechanical energy into useful electricity by the combined effect of triboelectrification and electrostatic induction. Triboelectrification is a process in which a material becomes electrically charged after contacting another material of opposite polarity. Generally, a chemical bond known as adhesion is formed between some regions of the contacting surfaces. The potential difference between the two surfaces serves as a driving force for charges such as free electrons or ions to move from one material to the other until the equilibrium state of their electrochemical potentials is achieved. When the two previously contacted surfaces are separated, some of the bonded atoms tend to donate or accept surplus electrons, resulting in triboelectric charges on the surfaces. This generates triboelectric charges that act as a driving force for electrons in the electrodes to flow through an external circuit to equalize the potential difference. Therefore, electricity is generated from the movement of free electrons having the ability to power an electroporation-based antibacterial device.

[0025] During breathing, the exhalation and inhalation of air can apply a periodic force to the face mask, resulting in the same motion as that of a contact isolation mode TENG. The R-TENG of this technology is designed to utilize bidirectional airflow from breathing as the driving force for the TENG. In one embodiment, unidirectional airflow is utilized when a unidirectional air valve is installed in the mask. In one embodiment, a nanofiber membrane that is breathable, flexible, and capable of filtering air is selected as the triboelectric material to integrate the R-TENG into the face mask. In one or more embodiments, the R-TENG is designed to function solely by bidirectional airflow from breathing without requiring any additional mechanical parts.

[0026] Figure 1A shows a front view of an electroporation-based antimicrobial device operably coupled to a face mask 100 according to one embodiment. Figure 1B shows an isometric projection of the electroporation-based antimicrobial device 100 according to one embodiment. Figure 1C shows a side view of the electroporation-based antimicrobial device 100 according to one embodiment.

[0027] Figure 2A shows an exploded view of an electroporation-based antimicrobial device 100 according to one embodiment. Figures 2B-2C show exploded views of the electroporation-based antimicrobial device 100 operably coupled to a face mask 203 according to one example scenario. In one embodiment, the electroporation-based antimicrobial device 100 is powered by an energy source 202 operably coupled to an air intake structure 208. The electroporation-based antimicrobial device 100 includes a negative electrode 204a and a positive electrode 204b powered by the energy source 202. When an external electric field is applied to the negative electrode 204a and the positive electrode 204b, a lightning rod effect is generated that causes permanent damage to the outer structure of microorganisms in the air passing through the air intake structure 208, thereby achieving immediate disinfection.

[0028] In one embodiment, the energy source 202 includes a respiration-driven triboelectric nanogenerator (R-TENG) for recovering unused biomechanical energy from the periodic motion of respiration, and the air introduction structure is a face mask in which the R-TENG 202 also functions as a filtration system. In one embodiment, the R-TENG 202 includes a pair of nanofiber membranes comprising a first nanofiber membrane 202a composed of a triboelectrically charged material and a second nanofiber membrane 202b composed of a triboelectrically charged material, wherein the triboelectrically charged and triboelectrically charged materials have opposite polarities. The R-TENG 202 also functions as a filtration system.

[0029] In one embodiment, polyvinyl alcohol (PVA) and polyvinylidene fluoride (PVDF) are selected as the triboelectrically charged and triboelectrically negative materials. In several other embodiments, any other known triboelectrically charged and triboelectrically negative materials can be used. In one embodiment, the R-TENG 202 is designed to function solely by bidirectional airflow from breathing without requiring any additional mechanical parts. In one embodiment, to avoid short circuits and ensure that all compartments are hermetically fitted, a first O-ring structure 210a is placed between the R-TENG and the electroporation-based antimicrobial device 100, a second O-ring structure 210b is placed between the positive and negative electrodes of the electroporation-based antimicrobial device 100, and a third O-ring structure 210c is placed between the electroporation-based antimicrobial device 100 and an air introduction structure 208 (e.g., a face mask).

[0030] In one embodiment, the electroporation-based antimicrobial device 100 is sustainably powered by R-TENG 202, which is housed in an airtight structure to ensure a slow airflow through a nanofiber membrane. In one embodiment, the positive electrode 204b is made from a metal mesh (e.g., copper) having a pore size of approximately 50-200 μm, and metal hydroxide nanowires (e.g., copper hydroxide nanowires) are grown on the surface of the metal mesh to form the negative electrode 204a. The positive electrode 204b is operably connected to the triboelectrically charged material 202a of R-TENG, and the negative electrode 204a is operably connected to the triboelectrically charged material 202b of R-TENG 202.

[0031] In one embodiment, at least one of the triboelectric materials (202a and 202b) is designed in a dome shape to control the maximum displacement between the nanofiber films 202a / b, achieve consistent contact separation without requiring additional mechanical parts, and ensure that the air is completely filtered. In one embodiment, the pressure drop across the triboelectric materials 202a / b is designed to be lower than that of the remaining fabric parts of the face mask to ensure that air passes only through the R-TENG 202. The triboelectric materials 202a / b are arranged in parallel with each other. In some other embodiments, at least one of the triboelectric materials (202a and 202b) is designed in a shape other than a dome shape.

[0032] When an external electric field is applied, the electric field strength at the tip of the copper nanowire is amplified several times with a very low drive voltage of about 1V due to the lightning rod effect, which is sufficient to cause permanent damage to the outer structure of microorganisms, thereby achieving immediate disinfection within 1 second. As shown in Figure 2B, the negative electrode 204a is located at the entrance of the face mask 203 and negatively charges microorganisms that pass through the face mask 203. By charging the incoming microorganisms, more microorganisms are attracted to the positive electrode 204b where the copper nanowire is growing, thus further improving disinfection efficiency.

[0033] In one embodiment, the R-TENG202 can recover unused biomechanical energy from the periodic motion of respiration to sustainably power the electroporation unit 204, while simultaneously functioning as a filter to purify the air around the user. In one embodiment, the frictionally positively charged and frictionally negatively charged materials of the R-TENG202 are manufactured by an electrospinning process to obtain a nanofiber membrane that is breathable, flexible, and capable of filtering air. The extremely small diameter on the nanoscale and the surface charge generated from periodic contact separation motion provide superior filtration efficiency compared to microfibers, and the increased surface area due to the nanofibers further improves the electrical output of the R-TENG202, as well as the disinfection performance of the electroporation-based antimicrobial device 100. This technology can achieve immediate self-disinfection by damaging the external structure of pathogens such as viruses, bacteria, and fungi on the filter surface by nanowire-assisted electroporation, while simultaneously filtering the surrounding air.

[0034] Figure 3 shows the periodic motion of the R-TENG202 through respiration according to one embodiment. During respiration, as shown in Figure 3, a periodic force is applied to the face mask 203 through exhaled air 306 and inhaled air 304, which results in the same motion of the contact separation mode of the R-TENG202. In this technology, the R-TENG202 is designed to utilize the bidirectional airflow 302 from respiration as the driving force for the R-TENG202. To integrate the R-TENG202 into the face mask 203, a breathable, flexible, and air-filtering nanofiber membrane is selected as the triboelectric material. In one or more embodiments, the R-TENG202 is designed to function solely by the bidirectional airflow 302 from respiration without requiring any additional mechanical parts.

[0035] Consistent contact separation is required because the separation and maximum displacement of both triboelectric layers are crucial for achieving a stable electrical output. Furthermore, the R-TENG202 also functions as a filtration system, requiring an airtight seal around it to ensure that air passes only through the nanofiber membrane. To achieve the above specifications, one of the nanofiber membranes is designed in a dome shape to control the maximum displacement between the nanofiber membranes, enabling consistent contact separation without the need for additional mechanical parts and ensuring complete air filtration. Additionally, the pressure drop across the nanofiber membrane is designed to be lower than that of the remaining fabric components of the face mask 100 to further ensure that air passes only through the R-TENG202.

[0036] According to one embodiment, face masks can be effectively disinfected by incorporating antiviral agents such as nanoscale metals, salts, photosensitizers, and photothermal materials. However, immediate disinfection within seconds cannot be achieved because the reaction between ROS and microorganisms takes several minutes, and several minutes are also required to generate sufficient heat under sunlight irradiation. If immediate disinfection is not performed, microorganisms trapped inside the face mask can become a potential source of secondary infection if proper disposal procedures are not followed. Therefore, this technology utilizes electroporation as a novel disinfection method that can rapidly eliminate microorganisms. Instead of chemically inhibiting microorganisms, electroporation provides physical disinfection by instantaneously damaging the outer structure of microorganisms via a strong local electric field. High aspect ratio nanostructures such as nanowires or nanorods are required with the intention of generating an extremely high local electric field of about 10 MV / m by supplying a low voltage. When a specific voltage is supplied, an enhanced local electric field is generated at the tip of the nanostructure by the lightning rod effect. Therefore, when microorganisms come into contact with the surface, immediate disinfection can be achieved by electroporation. Furthermore, the low airflow velocity produced by breathing with a face mask further increases the probability of microorganisms approaching the tip structure, thus further enhancing the feasibility of this disinfection method.

[0037] This technology provides an electroporation-based antimicrobial device powered by R-TENG, which is made of triboelectric material, where the gap between the triboelectric positively charged material and the triboelectric negatively charged material is large enough to generate a potential difference of 1 volt (V) or more. The electrodes of both triboelectric layers include any conductive material that can be attached to the triboelectric layer, such as aluminum or silver, and the material of the electroporation-based antimicrobial device may include any conductive mesh having a high aspect ratio nanostructure, such as nanowires. To generate a high local electric field, the distance between the positive and negative electrodes of the electroporation-based antimicrobial device needs to be small enough to avoid short circuits during operation, but not too close, and the distance is in the range of approximately 0.2 millimeters (mm) to 1 mm. To extend the lifespan of the electroporation-based antimicrobial device and reduce the waste generated, the R-TENG and the electroporation-based antimicrobial device are designed to be enclosed in a single removable and replaceable valve structure, meaning that only specific parts, rather than the entire face mask product, are discarded. Furthermore, multiple valves (including electroporation systems and sustainable energy sources such as R-TENG) can be integrated with commercially available face masks such as silicon oxygen masks, N95 masks, gas masks, and full-face masks.

[0038] It will be readily apparent to those skilled in the art that this technology can be readily produced in other specific forms without departing from its essential characteristics. Therefore, this embodiment should be considered merely illustrative and not restrictive, and the scope of the invention is indicated by the claims rather than the foregoing, with all modifications falling within that scope intended to be included within the scope of the invention.

Claims

1. The air intake structure is powered by an energy source and comprises negative and positive electrodes operably coupled to it. When an external electric field is applied across the negative and positive electrodes, a lightning rod effect is generated that causes permanent damage to the outer structure of microorganisms passing through the air intake structure with the air, thereby achieving immediate disinfection of the air passing through the air intake structure. Antimicrobial device based on electroporation.

2. The energy source includes a respiration-driven triboelectric nano-generator (R-TENG) that recovers unused biomechanical energy from the periodic motion of respiration, and the R-TENG also functions as a filtration system. An antimicrobial device based on electroporation as described in claim 1.

3. The R-TENG comprises a pair of nanofiber films, each including a first nanofiber film made of a triboelectrically charged material and a second nanofiber film made of a triboelectrically charged material, wherein the triboelectrically charged material and the triboelectrically charged material have opposite polarities, and the R-TENG also functions as a filtration system. An antimicrobial device based on electroporation as described in claim 1.

4. Polyvinyl alcohol (PVA) and polyvinylidene fluoride (PVDF) are selected as the frictionally positively charged material and the frictionally negatively charged material. The antimicrobial device based on electroporation as described in claim 3.

5. To avoid short circuits and ensure that all compartments are securely and airtightly fitted, a first O-ring structure is positioned between the R-TENG and the electroporation unit, a second O-ring structure is positioned between the positive electrode and the negative electrode of the electroporation unit, and a third O-ring structure is positioned between the electroporation unit and the face mask cover. The antimicrobial device based on electroporation as described in claim 3.

6. The R-TENG is enclosed within an airtight structure to ensure a low-speed airflow through the nanofiber membrane. The antimicrobial device based on electroporation as described in claim 3.

7. The positive electrode is made from a metal mesh. Metal nanowires grow on the surface of the metal mesh to form the negative electrode. An antimicrobial device based on electroporation as described in claim 1.

8. The positive electrode is operably coupled to the R-TENG's triboelectrically charged material, and the negative electrode is operably coupled to the R-TENG's triboelectrically charged material. The antimicrobial device based on electroporation as described in claim 2.

9. At least one of the triboelectric materials is designed in a dome shape to control the maximum displacement between the nanofiber films, achieve consistent contact separation without additional mechanical parts, and ensure that the air is completely filtered. The antimicrobial device based on electroporation as described in claim 2.

10. The pressure drop across the triboelectric material is designed to be lower than that of the rest of the face mask's fabric components to ensure that air flows only through the R-TENG. An antimicrobial device based on electroporation as described in claim 1.

11. The negative electrode is located at the entrance of the face mask and negatively charges microorganisms passing through the face mask. An antimicrobial device based on electroporation as described in claim 1.

12. The aforementioned air intake structure includes a face mask and an air filter. An antimicrobial device based on electroporation as described in claim 1.

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