Ionization Fluorescence Sensor for Particle Detection.

Abstract

A sensor (100) for detecting airborne substances includes an ionization chamber (110) configured to receive a fluid sample (102) containing particles (104) to be detected. An energy source (120) is configured to provide a sufficient amount of energy to the particles (104) to ionize and at least partially disintegrate the particles (104). A photodetector (130) is configured to detect a characteristic radiation signature of radiation emitted from the ionized particles. In use, the sensor (100) detects the radiation emitted from the ionized particles (104) and correlates it with known characteristic radiation signatures of target particles (104). The sensor (100) further indicates and identifies the presence of the particles (104) in the fluid sample (102).

Description

Citation of Related Applications

[0001] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 421,071, filed October 31, 2022, the disclosure of which is incorporated herein by reference. STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] This invention was made with federal support under Grant No. 2030359 awarded by the National Science Foundation, and the federal government reserves certain rights in this invention.

[0003] No applicable collaborative research agreement exists.

[0004] There is no relevant disclosure. [Background technology]

[0005] Detecting microparticles is not always easy. For example, detecting particles suspended in the air with diameters on the order of a few nanometers is quite challenging, and the difficulty increases even more when the particle concentration is low. One currently used particle detection method, laser scattering, can detect particles larger than approximately 1 micron in diameter. However, this method cannot distinguish between the materials that make up the particles and can only distinguish between large and small particle sizes. Another particle detection method currently used to detect specific chemical compounds is Raman spectroscopy. In Raman spectroscopy, photons generated by a laser or other device are irradiated onto a sample, causing interactions between the photons and excitation phenomena such as molecular vibrations and phonons in the sample. This interaction has a unique response characteristic depending on the sample's composition, and as a result of this interaction, photons are emitted with energy levels shifted upward or downward due to Raman scattering. Based on the energy levels of the emitted photons, the molecules contained in the sample can be identified. Still other spectroscopic techniques currently used for the analysis of materials include, for example, infrared spectroscopy, mass spectroscopy, and x-ray fluorescence spectroscopy. Summary of the Invention

[0006] The present invention relates to a particle detection method that utilizes ionization and fluorescence to detect particles. Particles contained in a sample are ionized by inputting a sufficient amount of energy to ionize the particles. This energy input also causes the particles to decompose. The ionized species produced by these ionization and decomposition processes emit fluorescence, which has an emission spectrum unique to the ionized species. By correlating this emission spectrum with the emission spectrum that the substance to be identified should have, various particles, such as various virus particles, toxic substance molecules, and nanoparticles, can be identified.

[0007] According to one embodiment, a particle detection sensor includes an ionization chamber into which a fluid sample containing particles to be detected can be introduced, an energy source for providing a sufficient amount of energy to the particles to ionize them and cause at least a portion of them to fragment, and a photodetector for detecting a characteristic radiation characteristic of radiation emitted from the ionized particles.

[0008] In one embodiment, a particle detection method includes providing a fluid sample containing particles to be detected with a sufficient amount of energy to ionize the particles and at least partially fragment the particles; detecting and analyzing radiation emitted from the ionized particles to identify the ionized particles; correlating radiation characteristics of the detected radiation with characteristic radiation characteristics of the particles; and further indicating the presence of the particles in the fluid sample.

[0009] The foregoing has outlined, rather broadly, some of the more important features of the present invention in order to facilitate understanding of the detailed description of the invention that follows, and to facilitate appreciation of the present contribution to the art. Other features of the present invention will be more clearly understood from the following detailed description of the invention when read in conjunction with the accompanying drawings and appended claims, or may be learned by the practice of the invention. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of an example particle detection sensor according to various embodiments of the present disclosure. [Figure 2] FIG. 2 is a schematic diagram of another embodiment of a particle detection sensor according to various embodiments of the present disclosure. [Figure 3] FIG. 2 is a schematic diagram of another embodiment of a particle detection sensor according to various embodiments of the present disclosure. [Figure 4] FIG. 1 is a schematic diagram of an exemplary plasma generating device that may be used in various embodiments of the present disclosure. [Figure 5] FIG. 2 is a schematic diagram of another exemplary plasma generating device that may be used in accordance with various embodiments of the present disclosure. [Figure 6] FIG. 2 is a schematic diagram of another exemplary plasma generating device that may be used in accordance with various embodiments of the present disclosure. [Figure 7] FIG. 2 is a schematic diagram of another exemplary plasma generating device that may be used in accordance with various embodiments of the present disclosure. [Figure 8] FIG. 2 is a schematic diagram of another embodiment of a particle detection sensor according to various embodiments of the present disclosure. [Figure 9] FIG. 2 is a schematic diagram of another embodiment of a particle detection sensor according to various embodiments of the present disclosure. [Figure 10A] FIG. 1 is a schematic diagram of a particle sample concentrator for use in various embodiments of the present disclosure. [Figure 10B] FIG. 1 is a schematic diagram of a particle sample concentrator for use in various embodiments of the present disclosure. [Figure 10C] FIG. 1 is a schematic diagram of a particle sample concentrator for use in various embodiments of the present disclosure. [Figure 11] FIG. 1 is a perspective view of another embodiment of a particle detection sensor according to various embodiments of the present disclosure. [Figure 12] FIG. 2 is a schematic diagram of electrodes connected to a capillary tube used in a particle detection sensor according to one embodiment of various embodiments of the present disclosure. [Figure 13A] FIG. 1 is a schematic diagram of an exemplary MEMS-based mass spectrometer for use in an embodiment of a particle detection sensor according to various embodiments of the present disclosure. [Figure 13B] 1 is a cross-sectional view of an exemplary MEMS-based mass spectrometer that may be used in accordance with various embodiments of the present disclosure. [Figure 14] 1 is a graph showing the normalized water contribution to the emitted light spectrum. [Figure 15] 1 is a graph showing normalized emitted light spectra of a potassium chloride solution, a sodium chloride solution, and water. [Figure 16]1 shows graphs of normalized emission spectra of guanine, adenine, cytosine, and thymine solutions, with an offset of +0.2 added to the adenine graph, +0.4 added to the cytosine graph, and +0.6 added to the thymine graph. [Figure 17] 1 is a normalized graph showing the emission spectra of adenine solutions having concentrations of 0.0025 g / ml (1x concentration), 0.005 g / ml (2x concentration), and 0.01 g / ml (4x concentration), respectively. [Figure 18] FIG. 1 is a graph showing normalized emission spectra in the wavelength range of 300 nm to 500 nm of cytosine solutions with concentrations of 0.0025 g / ml (1x concentration), 0.005 g / ml (2x concentration), and 0.01 g / ml (4x concentration). [Figure 19] 1 is a graph showing the peak heights of the emission light peak of an adenine solution at a wavelength of 439.5 nm, the emission light peaks of cytosine and thymine solutions at a wavelength of 440.5 nm, and the emission light peak of a guanine solution at a wavelength of 421.5 nm as a function of concentration. [Figure 20] FIG. 1 shows normalized synchrotron radiation spectra of saliva collected before a meal, 5 minutes after a meal, and 60 minutes after a meal immediately after collection. [Figure 21] FIG. 1 shows normalized spectra of emitted light from uninfected and infected saliva. [Figure 22] FIG. 1 shows normalized emission spectra of several types of airborne inorganic particles. [Figure 23] This figure shows the emission spectra of influenza A virus and SARS-CoV-2 virus. [Figure 24] FIG. 10 shows the spectra of emitted light when there is no liquid sample in contact with the gold electrode and when there is a saliva sample. [Figure 25] FIG. 1 shows the spectra of emitted light when acetone is present and when isopropyl alcohol is present. [Figure 26] FIG. 10 shows the emission spectra of saliva samples with different viral loads. [Figure 27] FIG. 1 shows the radiation spectra of two types of saliva samples. [Figure 28] FIG. 1 shows the emission spectra of water, isopropyl alcohol, and acetone.

[0011] The above-mentioned attached drawings are presented to explain various aspects of the present invention, and the dimensions, materials, structures, configurations, and proportions shown in the attached drawings do not constitute limitations on the scope of the present invention unless they are clearly stated in the claims. DETAILED DESCRIPTION OF THE INVENTION

[0012] Various embodiments will now be described in sufficient detail to enable those skilled in the art to practice the invention. However, it will be understood that the invention may be practiced in other ways than those described in the examples, and that various modifications of the examples may be incorporated without departing from the spirit and scope of the invention. Therefore, the following more detailed description of various embodiments of the invention is not intended to further limit the scope of the invention as defined in the claims. Rather, it is presented for illustrative purposes only, rather than limiting, and is intended to clarify the characteristics and properties of the invention, set forth the best mode for carrying out the invention, and fully enable those skilled in the art to practice the invention. Therefore, the scope of the invention is to be limited only by the scope of the claims.

[0013] definition In describing the present invention in the specification and claims, the following phraseology and terminology will be used.

[0014] Unless the context clearly indicates that a noun is singular, the noun may refer to either the singular or the plural. Thus, for example, a reference to a "pathogen" may mean either a single pathogen or multiple pathogens, and a reference to an "electrode" may mean either a single electrode or multiple electrodes.

[0015] The term "substantially," as used in the specification and claims with respect to a particular attribute or condition, means that the degree of deviation from the particular attribute or condition is sufficiently small that it is not readily measurable. The amount of deviation that is acceptable may vary depending on the particular circumstances.

[0016] The term "adjacent," as used in the specification and claims, means that two structures or structural elements are in close proximity to one another. Specifically, two components described as "adjacent" may abut one another or may be connected to one another. Furthermore, such two components may be in close proximity to one another but not in contact with one another. The actual proximity may vary depending on the particular situation.

[0017] The term "about" used in the specification and claims means that there is a tolerance associated with the period, amount, or numerical value to which it is attached. This tolerance can be easily determined by a person skilled in the art. However, unless otherwise specified, the tolerance expressed by the term "about" is generally 2% or less, often 1% or less, and in some cases 0.01% or less.

[0018] For convenience, the specification and claims may list multiple item elements, structural elements, components, and / or materials in a single list. In such cases, the individual elements or materials included in the same list are not related to each other and are included in the list as independent elements or materials. Therefore, multiple elements or materials included in the same list should not be construed as being effectively equivalent simply because they are listed together in the same list, but should be construed as being equivalent only if they are expressly stated to be equivalent.

[0019] The phrase "at least one of" used in the specification and claims is synonymous with "one or several of." For example, "at least one of A, B, and C" clearly indicates that it may include only A, only B, only C, or any combination of two or more of them.

[0020] In the specification and claims, numerical data may be expressed in the form of a range. Numerical data expressed in range form is intended for clarity and brevity, and its interpretation should be flexible. That is, it refers not only to the upper and lower limits of the range, but also to all values ​​within that range and all narrower ranges within that range, and therefore has the same meaning as if those values ​​and narrower ranges were explicitly stated. For example, a numerical range of about 1 to about 4.5 includes not only the explicitly stated limits of 1 and 4.5, but also other values ​​such as 2, 3, and 4, as well as narrower ranges such as 1 to 3, 2 to 4, etc. The same principle also applies when a single numerical value is explicitly stated; for example, a statement such as "less than about 4.5" should be interpreted as including all of the numerical values ​​and ranges exemplified above. Furthermore, this interpretation should apply regardless of the magnitude of the numerical range or the characteristics represented by the numerical value.

[0021] When a claim describing a method or process invention contains multiple steps, the invention is not limited to those steps being performed in the order recited in the claim; the steps may be performed in any order. Furthermore, limitations defined by "means for" and "steps for" constitute limitations because (a) the terms "means" or "steps" are clearly stated, and (b) what is "done" is clearly stated. Regarding "means for" statements, the structure, materials, operations, etc. required to "do" something are as described in the specification. Therefore, the scope of the present invention is defined by the inventions described in the claims and their legal equivalents, not by the detailed description of the specification, much less by the examples set forth in the specification.

[0022] Ionization Fluorescence Sensor for Particle Detection. The sensors described herein are capable of detecting and identifying a wide variety of particles, including, for example, virus particles, bacteria particles, pathogen particles, toxic compound particles, and various nanoparticles. The sensors provide energy to such particles sufficient to ionize and at least partially decompose the particles. Energy can be provided in a variety of ways, including, for example, using a plasma generator to provide energy, thereby partially or completely ionizing the particles. Other energy sources include radio frequency (RF), microwave, direct current (DC), alternating current (AC), high-frequency electromagnetic waves, ultraviolet (UV), x-rays, laser, flame, and electron beam energy. Various embodiments utilize multiple energy sources. In one embodiment, a high-power laser diode is used as the energy source.

[0023] As previously mentioned, particles are supplied with a sufficient amount of energy to ionize the particles and at least partially decompose them. For example, particles can be exposed to a plasma to cause a phase transition to the plasma phase, thereby ionizing at least a portion of the particles and causing the ionized particles to emit radiation. The radiation emitted from ionized particles has a unique spectral signature depending on the material from which the particles are formed. This spectral signature of the emitted radiation is called a characteristic radiation signature, and the particle can be identified based on this characteristic radiation signature. This can be used to detect the presence of, for example, a specific type of virus or bacteria. The radiation emitted from a specific type of virus contains multiple light components with predetermined wavelengths and appropriate light intensities, i.e., a combination of multiple unique light components. Therefore, detecting the characteristic radiation signature indicates the presence of a particle having the characteristic radiation signature in a sample and indicates that the particle corresponds to a specific type of particle (target particle) that was intended to be recognized when the particle detection sensor was designed. In various embodiments, the presence of target particles is indicated by the appearance of peaks at multiple predetermined wavelengths in the measured radiation spectrum, which should be contained in the radiation emitted by the target particles. Note that the intensity of the radiation emitted from the target particles increases as the concentration of target particles in the sample increases. Therefore, the concentration of target particles in the sample can be evaluated based on the heights of the peaks in the radiation.

[0024] In some embodiments, the energy provided causes at least a portion of the particle to decompose. Decomposition of a particle can include fragmentation into smaller particles, dissociation through chemical reactions, vaporization through evaporation or sublimation, or combinations thereof. Decomposition products produced by decomposition can also emit radiation at wavelengths appropriate for ionization. For some particles, the characteristic radiation signature (i.e., spectral signature) indicative of the particle's presence can include radiation emitted from the particle's decomposition products. Decomposition products can include smaller particles produced by fragmentation of the original particle, isolated molecules dissociated from the original particle, chemical reaction products produced by chemical reactions between components of the original particle, and chemical reaction products produced by chemical reactions between components of the original particle and air, and in various embodiments, additional decomposition products can be produced. Therefore, the characteristic radiation signature of radiation emitted by a particle, such as a virus, may be a composite of radiation emitted by the particle itself (which has been ionized but not decomposed) and radiation emitted by various decomposition products of the particle itself. Plasma-induced fluorescent spectra (PIFs) can vary depending on the intensity and type of plasma used. However, for a given plasma generation method (DC, RF, capacitively coupled, inductively coupled, etc.), the PIF remains roughly constant and does not fluctuate except when the current fluctuates due to the introduction of particles into the ionization chamber. Therefore, when correlating radiation spectra, it is sufficient to take into account the variables related to the intensity and type of plasma.

[0025] The measurement of an ionizing radiation spectrum (the spectrum of radiation emitted by ionization) is performed by collecting data on radiation intensity versus wavelength of the radiation. Then, by correlating the measured ionizing radiation spectrum with known ionizing radiation spectra of various reference materials, the particle that generated the ionizing radiation spectrum can be identified. Furthermore, the ionizing radiation spectrum is affected by factors such as the intensity of ionization, the motion of the particle passing through the ionization chamber, and the type of background gas in the ionization chamber (carbon dioxide, water vapor, etc.). Data processing to correlate the measured ionizing radiation spectrum with known ionizing radiation spectra of reference materials can be performed using an appropriate data processor. The data processing task can be based on various spectral analysis methods developed and widely used for various spectroscopic techniques, such as Raman spectroscopy.

[0026] The particle detection sensors described herein are highly useful for detecting various harmful particles, including, for example, viruses, bacteria, other pathogens, and toxic compounds. In various embodiments, the particle detection sensor ionizes and decomposes particles, converting harmful substances into safer substances. For example, viruses may be ionized and decomposed into non-infectious decomposition products. In various embodiments, the particle detection sensor generates oxygen plasma from ambient air, which may react with various molecules that make up the virus to produce oxides. Viruses may also be completely decomposed into harmless products, such as CO2 and HO. Thus, pathogens and viruses in a sample may be destroyed during the radiation emission and measurement process. Furthermore, the radiation emission and measurement process is not time-consuming, making it suitable for sampling air in large spaces, such as the interior spaces of large public buildings. For example, the particle detection sensors described herein are suitable for integration into the air conditioning systems of such large buildings. Particle detection sensors integrated into such air conditioning systems can provide near-real-time information about the presence and concentration of particles, such as viruses. For example, preliminary testing has shown that such particle detection sensors can distinguish between the SARS-CoV-2 virus and influenza A.

[0027] With the above in mind, we will now continue our discussion. FIG. 1 is a schematic diagram of a particle detection sensor 100 according to one embodiment. The particle detection sensor includes an ionization chamber 110 into which a fluid sample 102 containing particles 104 to be detected can be introduced. The particle detection sensor further includes an energy source 120 for providing energy to the particles 104 within the ionization chamber 110, the energy source 120 providing energy to the particles 104 in an amount sufficient to ionize the particles 104 and cause at least a portion of the particles 104 to decompose. In this embodiment, the energy source 120 is an RF plasma generator connected to two electrodes 122, which are positioned to generate a plasma within the ionization chamber 110. The ionized particles emit radiation containing optical components of appropriate wavelengths. The particle detection sensor further includes a photodetector 130 for detecting the radiation emitted from the ionized particles. In this embodiment, the photodetector 130 is a spectrometer capable of measuring the intensity of light components contained in the radiation. The radiation emitted by a particle has a characteristic spectral signature (i.e., a characteristic radiation characteristic) that allows the particle to be identified. This characteristic radiation characteristic is detected by the photodetector 130, and the particle that emitted the radiation is identified by correlating the characteristic radiation characteristic with known characteristic radiation characteristics of the particle being detected.

[0028] FIG. 2 is a schematic diagram of a particle detection sensor 100 according to another embodiment. In this embodiment, an ionization chamber 110 is larger than that of the embodiment of FIG. 1, and all components of the particle detection sensor other than the ionization chamber 110 are housed within the ionization chamber 110. A fluid sample 102 (in this embodiment, the fluid sample is an air stream) flows into the particle detection sensor. An energy source 120 is connected to two electrodes 122, which are positioned to generate plasma in a plasma space 108, indicated by a dotted circle. The photodetector 130 is composed of a detector array 131 and a lens 133, and radiation emitted from the ionized particles 104 is detected by the detector array 131.

[0029] The particle detection sensors described herein include at least one energy source for inputting a sufficient amount of energy to ionize and at least partially decompose particles contained in a sample. A variety of energy sources can be used to ionize and decompose particles in the particle detection sensors described herein. Any energy source or combination of energy sources can be used, as long as it is capable of inputting a sufficient amount of energy to ionize and at least partially decompose particles. Energy sources used in various embodiments include radio frequency (RF) power supplies, microwave generators, direct current (DC) power supplies, alternating current (AC) power supplies, plasma generators, high frequency electromagnetic wave generators, ultraviolet (UV) irradiators, x-ray irradiators, laser irradiators, flame blasters, and electron beam irradiators, as well as combinations thereof. In various embodiments, the energy source is an electromagnetic wave irradiator that irradiates electromagnetic waves at energy levels equal to or greater than infrared (i.e., wavelengths shorter than infrared). Furthermore, among such electromagnetic wave irradiation devices, there are those that irradiate electromagnetic waves with wavelengths of about 1 mm to about 0.03 nm, about 3,000 nm to about 0.03 nm, about 750 nm to about 0.03 nm, about 700 nm to about 0.03 nm, about 700 nm to about 1 nm, about 700 nm to about 100 nm, and about 700 nm to about 400 nm.

[0030] In various embodiments, an energy source generates a plasma in an ionization chamber. The plasma may contain oxygen and nitrogen generated from ambient air, as well as plasma generated by ionizing particles contained in the ambient air. Energy sources for generating the plasma include, for example, capacitively coupled plasma generators, inductively coupled plasma generators, dielectric barrier discharge plasma generators, alternating current (AC) plasma generators, direct current (DC) plasma generators, and radio frequency (RF) plasma generators, as well as combinations thereof. In various embodiments, the energy source is a capacitively coupled plasma generator, which includes two electrodes separated by a gap, and a sufficiently high voltage is applied between the electrodes to generate the plasma. In such embodiments, at least a portion of the gap is located within the ionization chamber of the particle detection sensor. In various other embodiments, the energy source is an inductively coupled plasma generator, which includes a coil, such as a planar spiral coil, a helical coil, or a toroidal coil.

[0031] In one embodiment, a dielectric barrier RF resonance ionizer with an operating frequency of 13.56 MHz is used to generate oxygen and nitrogen plasmas. The power level of the ionizer is set within a range of approximately 10 mW to several hundred watts depending on the air volume. In another embodiment, an ionizer with an operating frequency of 600 MHz is used with an RF power level set within a range of 10 mW to 20 mW. In various embodiments, the power level of the plasma generator used in the particle detection sensor is set within the range of about 10 mW to about 100 W, about 1 mW to about 10 W, about 10 mW to about 1 W, about 10 mW to about 1 W, about 10 mW to about 500 mW, about 10 mW to about 100 mW, about 10 mW to about 50 mW, about 1 W to about 1,000 W, about 10 W to about 1,000 W, and about 100 W to about 1,000 W, depending on the plasma generation method, the volume of the ionization chamber where the plasma is generated, the air flow rate, the particle concentration, and the type of background gas (carbon dioxide, water vapor, etc.). Still other embodiments include using other types of energy sources as described above, with the power level of the energy source set within the ranges listed above.

[0032] In various embodiments, a combination of multiple energy sources is used. In one embodiment, in addition to a DC electric field generator as an energy source for generating a DC electric field to extend the binding distance, an AC electric field generator (e.g., an RF electric field generator) is used as an energy source for generating an AC electric field to introduce sufficient vibration into the binding distance to cause decomposition. While a field strength of, for example, about 1,000 V is required to perform decomposition using a DC electric field alone, the use of an AC electric field in combination can sometimes reduce the required field strength to, for example, about 100 V to about 200 V. Furthermore, other energy sources may also be used in combination, such as a laser device (e.g., a green laser device or a blue laser device) capable of emitting a laser with a wavelength matching the resonant frequency of the target substance (the substance intended to be detected). In various embodiments, the field strength may be increased to about 10 5 In some embodiments, the field strength of the electric field generated by the energy source is set to about 10 V / cm or more, so that the target particles (particles to be detected) can be sufficiently ionized by the application of the electric field. 3 V / cm ~ approx. 10 8 V / cm, about 10 4 V / cm ~ approx. 10 8 V / cm, about 10 5 V / cm ~ approx. 10 8 V / cm, about 10 5 V / cm ~ approx. 10 7 V / cm, and about 10 5 V / cm ~ approx. 10 6 Some sources use V / cm.

[0033] 3 is a schematic diagram of a particle detection sensor 100 according to one embodiment. This particle detection sensor 100 is equipped with multiple energy sources, which can be used in any combination. These energy sources include an RF power supply 120, an electrode 122 of a capacitively coupled plasma generator, a coil 124 of an inductively coupled plasma generator, a flame blower 126 for flame-heating particles contained in the sample 102, a laser 128, an X-ray irradiation device 132, and an electron beam (E-beam) irradiation device 134. These energy sources can be used alone or in any combination. The particle detection sensor further includes a spectrometer 130 arranged to receive radiation 136 emitted from the ionized particles.

[0034] Various embodiments include a plasma generator, and various types of plasma generators are used. Figure 4 shows a schematic diagram of a plasma generator according to another embodiment. This plasma generator includes a power supply 122 connected to an electrode 122. It also includes a barrier 121, which is tubular and shaped like a nozzle. One electrode 122 is disposed inside the nozzle, and the other electrode 122 is ring-shaped and disposed around the nozzle. The sampled air flows through the nozzle, and plasma is generated from the air, creating a plasma in the plasma space 108. Target particles 104 are then ionized within the plasma space 108. The ionized particles emit light, which is detected by a photodetector 130.

[0035] FIG. 5 shows another example of a plasma generator. The plasma generator shown in FIG. 5 is a dielectric barrier type plasma generator. In this example, the plasma generator also includes multiple electrodes connected to a power source 120. In this example, the electrodes are housed within two rows of cylindrical dielectric barriers 123. Furthermore, the dielectric barriers 123 are housed within a vessel-shaped ionization chamber 110, which includes an inlet 111 and an outlet 113. A fluid sample containing target particles 104 flows in through the inlet 111, passes through the space between the two rows of dielectric barriers, and exits through the outlet 113. Plasma is generated in the space between the rows of dielectric barriers, and the target particles 104 are ionized within this space. A photodetector 130 is positioned to detect the radiation emitted from the ionized particles.

[0036] FIG. 6 shows another example of a plasma generator, which is an inductively coupled plasma generator (ICP generator). In this example, sample air 102 containing sampled target particles 104 flows through a central passage 125. An exhaust guide gas 127 flows through a circular passage 129 outside the central passage. A cooling gas 141 passes through an inlet 143 and flows through the outermost passage. The sample air 102, exhaust guide gas 127, and cooling gas 141 flow out through a nozzle. A winding coil 124 is disposed around the nozzle and connected to a power supply 120. An inductively coupled plasma is generated in a plasma space 108 by the winding coil 124. Although not shown, a photodetector and an ionization chamber are attached to the plasma generator of this example.

[0037] 7 shows one specific example of a plasma generator, which is a micro RF plasma generator. It has a cloverleaf-shaped antenna formed by four electrodes 122, which is connected to an RF power supply 120. In this plasma generator, plasma is generated in a plasma space located at the center of the antenna. In various embodiments, the plasma generator is disposed in a sample air flow path so that target particles 104 contained in the sample air are ionized.

[0038] In various embodiments, sample air containing target particles is passed through a nozzle into an ionization chamber, generating an electric field within the ionization chamber. The electric field can be generated by an RF power supply, a microwave generator, or a high-frequency electromagnetic wave generator that generates electromagnetic waves in the infrared or higher frequency range. One embodiment of a particle detection sensor 100, shown in FIG. 8, is configured to monitor target particles contained in air while continuously flowing through the particle detection sensor. The particle detection sensor includes a housing 112 having an air inlet 114. The air in the surrounding environment of the particle detection sensor contains particles 104. The particle detection sensor further includes a blower fan 116, which draws air through the air inlet 114 into the housing 112. A filter 118 is provided adjacent to the blower fan 116, and the air is filtered to remove particles before being blown back into the environment by the blower fan 116. As air is drawn into the housing 112, it flows into the ionization chamber 110, where a plasma is generated by an electrode 122 connected to an RF plasma generator. If the air contains particles, the particles are ionized and at least partially decomposed. The emitted light from the ionized particles is measured by a photodetector 130 positioned to receive the emitted light from the ionization chamber.

[0039] When electrodes are used to generate plasma for ionizing target particles, the spectrum of radiation measured by the photodetector may include radiation emitted from the material of the electrodes. Therefore, in various embodiments, electrodes are made of a material whose radiation emission is known, allowing the spectrum of radiation emitted from the electrode to be subtracted from the spectrum of radiation measured by the photodetector, thereby eliminating the influence of the electrodes. In various embodiments, gold electrodes are used. Gold has characteristic radiation peaks near 669 nm, 439.5 nm, and 421.5 nm. In other embodiments, the electrodes are made of metals such as copper or iron. Copper has characteristic radiation peaks near 668.5 nm, 439.5 nm, and 418.5 nm. Iron has characteristic radiation peaks near 440.5 nm, 387 nm, and 537 nm. When a gold electrode and a copper electrode are used together, emission peaks appear at around 668.5 nm, 439.5 nm, and 418.5 nm, while when a copper electrode and an iron electrode are used together, emission peaks appear at around 441 nm, 388.5 nm, and 538 nm.

[0040] In various embodiments, the surface of the electrode used to generate the plasma is nanotextured to increase the effective surface area of ​​the electrode, thereby increasing the strength and efficiency of ionization.

[0041] In various embodiments, the spectra of the radiation emitted by various known undetected substances present in the ionization chamber, each with its own characteristic spectrum, are subtracted from the spectrum of the radiation measured by the photodetector in the same manner as the spectrum of the radiation emitted by the electrode is subtracted from the spectrum of the radiation emitted by the known undetected substances, such as oxygen, nitrogen, and water vapor.

[0042] The radiation emitted by the ionization and decomposition of particles can be measured and analyzed using an appropriate photodetector. The measurement and analysis can also be performed using various spectroscopic techniques, including Raman spectroscopy. For example, once particles enter the ionization chamber, they can scatter the laser light. This scattering can be achieved through various scattering phenomena, such as Rayleigh scattering, Mie scattering, and inelastic Raman scattering (Stokes scattering / anti-Stokes scattering). In the case of Raman scattering, the spectrum of the scattered light can be captured using a high-speed camera connected to a spectrometer. As the laser power is increased, the particles are ionized and begin to emit radiation, eventually resulting in decomposition of the particles. The spectrum of the radiation is unique to the material that constitutes the ionized particles. In various embodiments, as described above, a laser is used in addition to a plasma generator. In other embodiments, a laser is used in addition to an electric field generator because the energy provided by the electric field generator alone is insufficient to generate plasma. That is, the laser device and the electric field generator work together to provide a sufficient amount of energy to ionize the particles.

[0043] In various embodiments, the photodetector used is a spectrometer. In various embodiments, the spectrometer is a commercially available spectrometer with a wavelength resolution of 0.1 nm. In various embodiments, the spectrometer has a wavelength resolution of about 0.1 nm to about 5 nm, about 0.1 nm to about 1 nm, or about 0.1 nm to about 0.5 nm. In still other embodiments, the photodetector used is a microelectromechanical (MEMS) spectrometer.

[0044] In various embodiments, the photodetector used is a silicon photodiode array capable of detecting light with a wavelength of about 400 nm to about 1100 nm. 10pieces / cm 2 In some embodiments, the silicon photodiode array is designed to be capable of detecting extremely low intensity light of about 0.2 A / W to about 0.7 A / W.

[0045] In various embodiments, the photodetector used is not a spectrometer, but a photodiode equipped with an interference filter that transmits light in a predetermined wavelength range. A photodetector configured with an array of multiple photodiodes, each equipped with an interference filter, is faster and consumes less power than a spectrometer. Such a simple repeating photodetector can also be configured by simply combining a single detection CCD with a single interference filter (the transmission wavelength of which is set to match the characteristic wavelength of radiation emitted by, for example, virus particles).

[0046] The optical filter is configured to selectively pass light of specific wavelengths. The specific wavelengths are wavelengths of optical components contained in the characteristic radiation characteristics of the radiation emitted from the target particle when the particle is ionized. For example, when a given virus particle is ionized, the radiation emitted from the virus particle contains several specific wavelengths. In other words, the spectrum of the radiation has peaks at several specific wavelengths, and the presence of the virus particle is indicated by the peaks in the measured spectrum. In various embodiments, the optical filter is configured to pass light of specific wavelengths and block or reflect light of other wavelengths. By configuring a photodetector behind the optical filter, the radiation emitted from the ionized particle can pass through the filter and be detected by the photodetector. In this configuration, the photodetector can simply be a photodiode that converts the light intensity into an electrical signal. Alternatively, by configuring multiple photodiodes behind multiple optical filters, light of multiple specific wavelengths can be detected. Furthermore, with this configuration, the cost of the particle detection sensor can be further reduced compared to when the spectroscope itself is used as the light detector.

[0047] In various embodiments, the optical filter described above is an interference filter. An interference filter reflects light in a specific band of the spectrum and transmits light in other bands. An interference filter can be fabricated by stacking multiple optical thin film layers with different refractive indices. Multiple reflected light beams with different phases generated at the interfaces between the thin film layers act to constructively interfere with each other at some wavelengths and to destructively interfere with each other at other wavelengths. The wavelength band of light passing through the interference filter can be adjusted by appropriately determining the number and thickness of the thin film layers. In various embodiments, a bandpass interference filter is used to transmit light in a specific wavelength band and reflect light in other wavelength bands. In various other embodiments, the optical filter described above is a type of filter other than an interference filter, such as an absorption filter.

[0048] FIG. 9 is a schematic diagram of an embodiment of the particle detection sensor 100 equipped with three optical filters 140. The three optical filters are disposed between the sample and each of the three photodetectors 130a to 130c. The three photodetectors are photodiodes that simply emit an electrical signal when they detect light. The three optical filters are narrow-band filters that pass narrow-band light corresponding to each of multiple peak wavelengths that should be included in the characteristic spectrum of radiation emitted from the target particle 104 to be detected. If any of the three photodiodes detects light with an intensity sufficiently exceeding a threshold, this indicates the presence of the target particle in the sample.

[0049] The particle detection sensors described herein can be used to detect and identify a variety of particles, ranging in size from a few nanometers to hundreds of micrometers. In various embodiments, detectable particle sizes range from about 3 nm to about 500 micrometers, about 5 nm to about 500 micrometers, about 10 nm to about 500 micrometers, about 20 nm to about 500 micrometers, about 50 nm to about 500 micrometers, about 100 nm to about 500 micrometers, about 200 nm to about 500 micrometers, about 500 nm to about 500 micrometers, about 1 micrometer to about 500 micrometers, about 10 micrometers to about 500 micrometers, about 5 nm to about 1 micrometer, about 5 nm to about 500 nm, about 5 nm to about 200 nm, and about 5 nm to about 200 nm.

[0050] Various embodiments include a particle detection sensor that can be incorporated into air filtration systems, such as HEPA air filters. Such particle detection sensors are particularly useful for monitoring hazardous substances, such as virus particles. One embodiment is a particle detection sensor that can distinguish between at least four types of virus particles. Particles that can be distinguished by such a particle detection sensor include COVID-19 virus particles, SARS virus particles, Mycobacterium tuberculosis particles, and influenza virus particles, as well as other particles. Another embodiment is a particle detection sensor that can detect bacterial particles with diameters ranging from one micrometer to several tens of micrometers.

[0051] The detection method using ionization fluorescence described herein is capable of detecting extremely small particles on the order of nanometers. Nanometer-order particles are much smaller than the wavelength of laser light (e.g., 500 nm to 1000 nm). Such particles are ionized, and the resulting emitted light, which is specific to the particle, is detected using a spectrometer. This detection method can detect particles suspended in air at low concentrations, and the detection can be performed without using an enhancement structure, such as a bowtie antenna or a sharp tip, which are used to improve the signal-to-noise ratio in techniques such as tip-enhanced Raman spectroscopy and surface-enhanced Raman spectroscopy.

[0052] In various embodiments, the particle detection sensor can detect particles in a sample in a concentration range of about 1 particle / cm. 3 ~Approximately 1,000,000 particles / cm 3 The limit of detection (LOD) is the lower limit of the particle concentration range that a particle detection sensor can detect, and this detection limit is approximately 1 particle / cm 3 ~About 100 particles / cm 3 Here, the lowest detection limit is 1 particle / cm 3 This value is determined by the minimum detectable signal of the photodetector. 3 This value is determined by the saturation limit of the photodetector, and can be adjusted by changing the ionization parameters. In various embodiments, the detection limit is set to approximately 2 particles / cm. 3 ~About 100 particles / cm 3 Set at approximately 5 particles / cm 3 ~About 100 particles / cm 3 Set to approximately 10 particles / cm 3 ~About 100 particles / cm 3 Set at approximately 2 particles / cm 3 ~About 10 particles / cm 3 and about 5 particles / cm 3 ~About 50 particles / cm 3There is something set to.

[0053] As target particles pass through the ionization chamber of the particle detection sensor described above, it is possible that only some of the target particles are ionized, while the remaining target particles are not. In this case, the ratio of the number of ionized particles to the total number of target particles passing through the ionization chamber is referred to as the ionization efficiency. In various embodiments, the ionization efficiency value is about 0.3 to about 0.99, about 0.4 to about 0.99, about 0.5 to about 0.99, about 0.5 to about 0.8, about 0.5 to about 0.7, and about 0.4 to about 0.6.

[0054] The particles to be detected are particles contained in a fluid sample, which may be a gas, a liquid, or a mixture of both. In various embodiments, the fluid may be water, saliva, air, or a mixture thereof.

[0055] The concentration of particles in a fluid sample may be low enough that they are beyond the detection limit of a particle detection sensor. Even such low concentrations of viral particles in air or water can be dangerous. Various embodiments of particle detection sensors described herein include a concentrator that allows the fluid sample to be concentrated before the particles are ionized. Concentrating a fluid sample refers to increasing the number of target particles in a given volume of the fluid sample to a level where the particles can be easily detected. The in-line particle concentrator can be used to increase the particle concentration to a detectable concentration level, e.g., 10 micrograms / m. 3 ~1,000 micrograms / m 3The concentration can be reduced to 10 to 20 seconds. The time required to complete the concentration process depends on the processing capacity of the air treatment device, but it can take anywhere from 10 to 20 seconds. After concentration is complete, the air is sent to an ionization chamber, where particles are partially or completely ionized. The radiation emitted from the ionized particles is analyzed, and the particles are identified based on the radiation intensity in multiple radiation bands. It is also possible to estimate the particle concentration based on the radiation intensity in these radiation bands.

[0056] Various types of concentrators can be used, including any type capable of increasing the number of solid particles contained in a unit volume of air, water, or other fluid. In various embodiments, the concentrator used is a spiral concentrator. Other exemplary concentrators include concentrator 160, the configuration of which is shown in Figures 10A, 10B, and 10C. These concentrators extract particles from air by utilizing the momentum of the particles and appropriately deflecting their direction of motion. Once a sufficiently high concentration of particles is obtained using the concentrator, the highly concentrated particles can be ionized as described above to detect the target particles. Concentrators for increasing particle concentration include various concentrating methods, such as cyclone, electrostatic / magnetic, and filter concentrators, which can be used to concentrate particles within a particle detection sensor before particle detection.

[0057] In various other embodiments, particle detection sensors are equipped with filters to remove particles within a specific size range from a fluid sample, such as air. This allows for the rejection of particles significantly smaller or larger than the target particle size. After the filter removes particles with sizes that are unlikely to be target particles, the remaining particles are more likely to be target particles, while many of the non-target particles that would otherwise make target particle detection difficult are removed. For example, SARS-CoV-2 virus particles range in size from 70 nm to 150 nm, while dust particles can be hundreds of micrometers in size. In this case, filtering particles 0.5 micrometers or larger in size can prevent the emitted radiation from ionizing such large particles from saturating the spectrometer, which is a photodetector.

[0058] As described above, the particle detection sensor includes an ionization chamber. The ionization chamber is configured to accept a fluid sample, which is then tested for the presence of target particles. The ionization chamber includes a containment space for the fluid sample. In various embodiments, the containment space is fully enclosed or partially enclosed. In various embodiments, the fluid sample introduced into the ionization chamber is held stationary within the ionization chamber, while in other embodiments, the fluid sample introduced into the ionization chamber flows through the ionization chamber. For example, the ionization chamber of the particle detection sensor may be tubular, with a continuous flow of air passing through it. This configuration allows for continuous flow of air through the ionization chamber, allowing for large volumes of air to be tested. In various other embodiments, the ionization chamber is a liquid container that can contain a liquid sample, such as water or saliva. Analysis of the liquid sample contained in the liquid container may be performed in a batch process rather than a continuous flow process. Among the batch processing embodiments, there are particle detection sensors that test whether the liquid sample contains target particles while maintaining the liquid sample in a stationary state in the ionization chamber, and there are particle detection sensors that test whether the liquid sample contains target particles while maintaining the liquid sample in an agitated state in the ionization chamber.

[0059] In embodiments where detection is performed while a fluid sample, such as air, is continuously flowing, the particles are in motion when ionized and detected. The velocity of the particles is determined by the velocity of the fluid, such as air, that contains and carries the particles. In various embodiments, the velocity of the particles when detection is performed is between about 1 cm / s and about 1,000 cm / s. In various other embodiments, the velocity of the particles when detection is performed is between about 10 cm / s and about 1,000 cm / s, between about 100 cm / s and about 1,000 cm / s, between about 10 cm / s and about 500 cm / s, and between about 10 cm / s and about 100 cm / s.

[0060] FIG. 11 shows a perspective view of one embodiment of a particle detection sensor 100. The particle detection sensor includes an ionization chamber 110 configured as a liquid container. The liquid container is configured to contain a liquid sample 102, such as water or saliva, which may contain target particles. Two electrodes 122 are disposed within the liquid container and contact the liquid sample. The two electrodes are connected to a power source (not shown), such as an RF power supply. The assembly consisting of the liquid container, electrodes, and liquid sample can be lowered into the housing 112, and once the assembly is moved there, a laser device 128 is aimed at the liquid sample. Additional energy is supplied from the laser device 128 to the liquid sample, thereby ionizing the target particles. Furthermore, an optical fiber-input spectrometer 130 is also aimed at the liquid sample, allowing the spectrometer 130 to measure the radiation emitted from the ionized liquid sample.

[0061] Another example of an ionization chamber includes one or more capillaries capable of holding a liquid sample. In one such example, the liquid sample is held in two capillaries, each connected to an electrode, defining a gap between the two capillaries. By applying a voltage between the two electrodes, a plasma can be generated in the gap between the two capillaries. The plasma ionizes particles present in the liquid sample. FIG. 12 shows one example of such a configuration, including two capillaries 150 connected to two electrodes 122. The two capillaries each contain a liquid sample 102, defining a gap 152 between the two capillaries. By applying a voltage between the two electrodes, a plasma can be generated in the gap.

[0062] In various other embodiments, the sensitivity, resolution (ability to distinguish different particle species), and dynamic range of the particle detection sensor are enhanced by combining the measurement of emitted light using a photodetector such as a spectrometer with mass spectrometry using a microelectromechanical (MEMS) ion trap mass spectrometer. The MEMS mass spectrometer is used in combination with the ionization chamber and photodetector described above. FIG. 13A shows a schematic diagram of one example of a MEMS mass spectrometer 170. Particles 104 are charged in the ionization chamber 110 by two electrodes 122 connected to a power supply 120 for generating an electric field. The ionized particle 106, which is the charged and ionized particle species produced in the ionization chamber, is deflected as it passes through a constant magnetic field region 172 (the magnetic field direction of which is perpendicular to the plane of the drawing, as indicated by the circle with an X inside it). The ionized particle species 106 include particles with different speeds and charges. These particles are deflected by different amounts by the Lorentz force (≒qv × B). As a result, particles with different speeds and charges are separated and arrive at different bins 174. Each bin is equipped with a separate charge detector and mass detector, and particles are identified based on the outputs of these detectors. Thus, particles with the same charge-to-mass ratio (q / m) arrive at the same bin. However, it should be noted that if the resolution determined by the bin size is coarse, particles with only slight differences in charge-to-mass ratio may arrive at the same bin. Therefore, it is desirable to determine the bin size according to the target resolution, which is the ability to distinguish particles with only slight differences in charge-to-mass ratio (smaller bin sizes can improve resolution).

[0063] Using a MEMS microbalance sensor, it is possible to measure the mass and charge of particles. For example, using an N57 rare earth magnet, a particle with an area of ​​1 cm is placed in a gap region with a separation width of 5 mm. 2The plasma ionization process creates a uniform magnetic field with a magnetic flux density of 500 mT to 900 mT. When the target particle is a SARS-CoV-2 virus particle, the spike protein of the virus is cleaved smoothly during plasma ionization, resulting in the formation of segments of the S1 and S2 regions, each approximately 5 nm to 12 nm in length. The mass of these segments is m ≈ 1.6 × 10 -20 g, and the charge of each segment is 1 positive elementary charge (q ≒ 1.6 × 10 -19 If the magnetic field is a magnetic field with a magnetic flux density B = 1 T and an initial velocity V = 0.1 m / s, the radius of the flight path of the segments is approximately r = (m / q)V / B = 10 mm. Therefore, by appropriately setting the initial velocity and the magnetic flux density of the magnetic field, a compact system can be realized. Figure 13B shows a specific example of a MEMS-type microbalance array 170 configured in this way. In this example, multiple bins 174 each have an individual end-supported beam. These end-supported beams are equipped with thin-film piezoelectric actuators 176 made of aluminum nitride (AlN) layers. By actuating these thin-film piezoelectric actuators, the end-supported beams can be vibrated at a vibration frequency of approximately 15 kHz. Platinum layers 178 are formed on the top and bottom surfaces of the AlN layer. A silicon nitride (Si3N4) layer 180 is formed on the top platinum layer, and a gold layer 182 is further formed on top of that. The upper platinum layer 178 and the lower platinum layer 178 are electrically connected to a power supply 184, which supplies power to the AlN piezoelectric layer. In this example, each gold layer 182 of the multiple vials 174 is electrically connected to an electrometer 186, which measures the total charge of all particles adsorbed in one vial.

[0064] In a particle detection sensor that uses plasma for ionization and a spectrometer for measurement, if the spectrometer has a wavelength resolution of 0.1 nm, when the particle detection sensor detects the above-mentioned virus, all mutant strains of the virus will be detected simultaneously because the emission bands of the various mutant strains are very similar to each other. However, if such a particle detection sensor is combined with mass spectroscopy using a MEMS-type ion trap mass spectrometer, it becomes possible to distinguish and detect different mutant strains separately. However, in many cases, it is preferable to detect all mutant strains simultaneously as a single virus species. Both methods, with and without mass spectroscopy, can be performed without the use of molecular tags such as aptamers or antibodies / antigens. Furthermore, the particle detection sensor described herein can be quickly and easily reprogrammed to enable mutant detection. Furthermore, the method described herein can be label-free and can eliminate the need for an analyte.

[0065] Among other various embodiments, particle detection sensors can be programmed in real time to adapt to the detection of newly emerging viruses, and the system output can be displayed on an OLED (organic light-emitting diode) display. Additionally, the particle detection sensors can wirelessly transmit the system output to a smartphone or centralized monitoring system, allowing for real-time monitoring of virus particles in homes, other buildings, and various locations across a city. [Example]

[0066] Example 1 The detection capabilities of a plasma-based ionization method for detecting various liquids were demonstrated by testing the liquids: acetone, isopropyl alcohol, water, uninfected saliva, and infected saliva infected with the COVID-19 virus. This method uses an ionization source (a source of energy for ionization) to electrophoretically extract and ionize molecules or other particles near the liquid's surface. Alternatively, ultrasonic or nebulizers can be used to generate a mist containing the liquid, which is then introduced into an ionization chamber for ionization. Other methods for ionizing liquids include x-rays, ultraviolet (UV), electron beams, high-voltage DC fields, RF fields, flames, and frictional contact.

[0067] Ionization excites a substance, and oxidation / reduction reactions occur between the excited particle and the surrounding objects or gases (molecules). If the particle is a virus or a virus-derived particle, the process by which the particle becomes excited can include: 1) evaporation of the liquid adhering to the particle's surface; 2) degradation of the particle's surface proteins, particularly in the case of COVID-19 virus particles, removal of the spike protein; 3) degradation of the virus's internal macromolecules, such as DNA and RNA; and 4) ionization of the various components of the particle. Some of these ionization and degradation processes involve the emission of fluorescence, and detecting this fluorescence can identify the process by which the particle becomes excited or decomposes.

[0068] An experiment was carried out using a particle detection sensor. The particle detection sensor had an ionization chamber configured as a liquid container, a lower electrode disposed at the bottom of the liquid container, and an upper electrode disposed at a position corresponding to above the liquid surface of the liquid sample contained in the liquid container. A high voltage (1000 V to 5000 V) was applied between the upper and lower electrodes so that molecules located at the liquid surface of the liquid sample were exposed to a high-intensity electric field capable of inducing polarization. The electric field strength was set to a sufficiently high strength (for example, about 10 4 V / cm ~ approx. 10 5 V / cm), the molecules at the liquid surface of the liquid sample are ionized. When the liquid sample is an aqueous solution, water molecules are dominant, and the binding energy of the H-O bond of water molecules is 5.15 eV. Water vaporizes when exposed to a high-intensity electric field, which increases the effective dielectric constant of air. Ionization occurs when Na contained in the liquid sample is ionized. + and Cl - This also extends to other ions such as β- and β-glucan ions, and they can be detected by the emitted radiation. Larger molecules, such as proteins and DNA molecules, are electrostatically driven close enough to the liquid surface to be exposed to a strong electric field, which causes dissociation and ionization. In the case of COVID-19 virus particles, dissociation involves the detachment of spike proteins from the virus particle and subsequent fragmentation. Most of the atomic bonds involved in the excited states described above are covalent bonds between carbon, hydrogen, and oxygen atoms. Both the ionization of molecules and the fragmentation and subsequent ionization of virus particles and their derivatives, both of which are induced by electric fields, are primarily driven by interactions between polar molecules. While polar molecules rapidly reorient in response to an external electric field, nonpolar molecules are primarily polarized due to the rapid response of their electron orbitals to the external electric field. Furthermore, the particles and their derivatives can acquire residual charges, which can cause polarization, followed by fragmentation and ionization. The electrodes can also have nanotextured surfaces, which can improve spectral line definition.

[0069] Detection methods that use electric fields to generate ionization can also be used to detect airborne particles, such as airborne virus particles. The concentration of airborne particles is lower than that of particles suspended in a liquid phase. Therefore, concentrators and photomultipliers are often used to detect the electroluminescent, fluorescent, or radiated light spectrum generated by the electric field.

[0070] The contribution of the radiation from the gold electrode to the radiation spectrum was determined. To do this, we first measured the radiation emitted from gold itself. The radiation spectrum of gold (24K) shows a prominent peak at 669 nm, which also appears in the radiation spectrum of the liquid sample described below. The data listed in Table 1 show prominent peaks that appear in the radiation spectra of various commonly used electrode materials, including gold. The radiation spectrum of iron shows a prominent peak at 440.5 nm. The radiation spectrum of copper is similar to that of gold, with a prominent peak at 668.5 nm, but the radiation intensity is higher at 418.5 nm and lower at 537.5 nm compared to that of gold.

[0071] [Table 1]

[0072] The emission spectrum of the electrode is added to the emission spectrum of the analyte that has been ionized to identify the substance, and the sum of these spectra is measured. When identifying the analyte, the emission spectrum of the electrode must be taken into consideration. Another important substance contained in the majority of the analytes is water. Figure 14 shows the emission spectrum of water that has been ionized by a gold electrode. The peak that appears at a wavelength of around 669 nm is a direct manifestation of the characteristic peak of gold, while the spectral components resulting from the emission light of water appear in the wavelength range of 400 nm to 600 nm.

[0073] The radiation spectra of a potassium chloride solution, a sodium chloride solution, and water, all of which have been ionized using a gold electrode, are shown in Figure 15. As is clear from Figure 15, there is a difference between the radiation spectrum of pure water and the radiation spectrum of the sodium chloride solution in the wavelength region of 400 nm to 500 nm.

[0074] Even when the substance to be analyzed is an organic substance such as a deoxyribonucleic acid base (DNA base), it is possible to identify the substance based on the spectrum of radiation emitted from the ionized substance. Figure 16 shows the radiation spectrum of aqueous solutions of adenine, guanine, cytosine, and thymine, all of which are DNA bases. In this experiment, 1 mm 3 The ionization chamber was equipped with a gold electrode.

[0075] Although the synchrotron radiation spectrum shown in Figure 16 contains a significant contribution from the gold synchrotron radiation spectrum, it is still possible to distinguish between different DNA bases. Figure 17 shows how the synchrotron radiation spectrum differs depending on the concentration of an aqueous adenine solution, and Figure 18 shows how the spectrum differs for an aqueous cytosine solution.

[0076] Figure 19 shows the peak heights of the emitted light at various solution concentrations for the adenine solution (at 439.5 nm), the cytosine and thymine solutions (at 440.5 nm), and the guanine solution (at 421.5 nm). The average sensitivity was 20% / g. Figure 20 shows the spectral response of saliva collected from the same subject immediately after pre- and post-prandial sampling, which is a highly significant figure.

[0077] Figure 21 shows the emission spectra of uninfected saliva and infected saliva infected with the SARS-CoV-2 virus. The emission spectrum of the uninfected saliva in this figure is similar to the emission spectrum of uninfected saliva from another individual shown in Figure 20. There are two peaks that are only observed in the infected saliva, one at a wavelength of 425 nm and the other at a wavelength of 460 nm.

[0078] These experimental results demonstrate that the particle detection sensor described herein, which can be configured as a small device, can detect SARS-CoV-2 viral particles contained in saliva, and also provide strong evidence that the particle detection sensor described herein can detect various other viral particles.

[0079] The particle detection sensor used as the experimental device in the experiments disclosed above can be made into a small device. The device used as the ionization source can be an ultra-small plasma generation device with dimensions of 1 mm to 100 mm. The spectrum analyzer (spectroscope) can be made into a MEMS-type device to make it smaller. The interference filter can easily be a waveguide interference filter or a free-space interference filter. The photodetector can be a silicon device with a sensitive wavelength range of 300 nm to 900 nm. It can be configured as a small particle detection sensor that performs detection by ionizing using plasma.

[0080] The plasma-based ionization and detection method described above can be used as a stand-alone detection sensor or as an integrated system in combination with a fan, concentrator, outlet HEPA filter, and / or other components. A nebulizer can be used to introduce the virus-containing sample, bringing the virus-containing sample into proximity with the detection sensor at a known, quantifiable concentration. Emission spectra with characteristic emission characteristics of the virus can also be recorded, allowing the recorded spectra to be used to correlate characteristic emission characteristics with future detection of the virus.

[0081] Example 2 A particle detection sensor with the configuration shown in Figure 11 was fabricated. The ionization chamber had two gold electrodes attached to a vial, with the saliva sample coming into contact with the two gold electrodes. A laser diode with a wavelength of 780 nm was used to decompose and ionize the components of the saliva. An optical fiber input spectrometer was used to collect spectral information on the components of the decomposition products.

[0082] Figure 22 shows the radiation spectrum measured after ionizing inorganic particles suspended in the air. The inorganic particles were three types: carbon black (CB), zeolite, and a mixture of CB and zeolite. Figure 22 also shows the radiation spectrum measured by a particle detection sensor when no particles were present in the air.

[0083] Figure 23 shows the emission spectra measured after ionizing influenza A virus particles and SARS-CoV-2 virus particles. The peaks that appear in the emission spectra are different from each other. This indicates that the particle detection sensor described herein can distinguish between these two types of viruses.

[0084] Figures 24 to 28 show the emitted light spectra due to electroluminescence, and are figures comparing the emitted light spectra when there is no liquid sample in contact with the electrode, when a saliva sample is present, when acetone is present, and when isopropyl alcohol is present.

[0085] Embodiment Items For the sake of clarity, further aspects of particle detection sensors and particle detection methods are described in the following sections.

[0086] Item 1 an ionization chamber into which a fluid sample containing particles to be detected can be introduced; an energy source for supplying the particles with a sufficient amount of energy to ionize and disintegrate at least a portion of the particles; a photodetector for detecting a characteristic radiation characteristic of radiation emitted from the ionized particles; A sensor for particle detection comprising:

[0087] Item 2 3. The sensor according to claim 1, wherein the energy is sufficient to cause decomposition of the entire particle.

[0088] Item 3 The sensor according to any one of the preceding claims, wherein the particle is a virus, a bacterium, a pathogen, or a combination thereof.

[0089] Item 4 The sensor according to any one of the items, wherein the energy source is a radio frequency (RF) power supply, a microwave generator, a direct current (DC) power supply, an alternating current (AC) power supply, a plasma generator, a high frequency electromagnetic wave generator, an ultraviolet (UV) irradiation device, an X-ray irradiation device, a laser device, a flame spray device, an electron beam irradiation device, or a combination thereof.

[0090] Item 5 4. The sensor according to any one of the preceding claims, wherein the energy source is a plasma generator.

[0091] Item 6 4. The sensor according to any one of the preceding claims, wherein the plasma generator is configured to generate oxygen plasma, nitrogen plasma, or a combination thereof.

[0092] Item 7 The energy source is located within the ionization chamber. 5 4. The sensor according to any one of the items, characterized in that it is configured to generate an electric field density of 100 V / cm or more.

[0093] Item 8 The sensor according to any one of the preceding claims, wherein the energy source comprises an electrode having a nano-textured surface.

[0094] Item 9 3. The sensor according to any one of the preceding claims, wherein the photodetector comprises a spectrometer.

[0095] Item 10 The sensor according to any one of the items, wherein the spectrometer has a sensitive wavelength range of about 300 nm to about 900 nm.

[0096] Item 11 The sensor described in any one of the items is characterized in that the photodetector is provided with one or more optical filters that selectively pass light of specific wavelengths, the specific wavelengths being wavelengths that are included in the characteristic radiation characteristics of the radiation emitted from the ionized particles.

[0097] Item 12 3. The sensor of claim 1, further comprising a concentrator for concentrating the fluid sample prior to subjecting the fluid sample to ionization.

[0098] Item 13 The sensor according to any one of the items, characterized in that the fluid sample is a sample containing air and airborne solids, a sample containing water and waterborne solids, a sample containing saliva, a sample containing body fluids, or a sample containing a combination thereof.

[0099] Item 14 The sensor described in any one of the items further comprises a microelectromechanical mass spectrometer configured to separate and extract components produced by ionizing the decomposed particles based on their charge-to-mass ratio.

[0100] Item 15 The sensor described in any one of the items further comprising one or more filters for filtering out particles within a specific size range prior to subjecting the fluid sample to ionization.

[0101] Item 16 providing a fluid sample containing particles to be detected with a sufficient amount of energy to ionize said particles and to fragment at least a portion of said particles; detecting radiation emitted from the ionized particles; correlating the radiation characteristics of the detected radiation with the characteristic radiation characteristics of the particle; indicating the presence of the particle in the fluid sample; 1. A method for particle detection comprising:

[0102] Item 17 The method according to any one of the items, wherein the energy supply is achieved by exposure to plasma, application of an electric field, supply of radio frequency (RF) energy, irradiation with microwaves, supply of direct current (DC), supply of alternating current (AC), supply of high frequency electromagnetic energy, supply of ultraviolet (UV) energy, irradiation with X-rays, supply of laser energy, spraying with a flame, irradiation with an electron beam, or a combination thereof.

[0103] Item 18 4. The method according to any one of the preceding claims, wherein the whole of the particles is subjected to decomposition.

[0104] Item 19 10. The method of any one of the items, wherein the particle is a virus, a bacterium, a pathogen, or a combination thereof.

[0105] Item 20 10. The method of any one of the preceding claims, further comprising concentrating the fluid sample prior to supplying energy to the fluid sample.

[0106] Item 21 10. The method according to any one of the items, wherein the fluid sample is a sample containing air and airborne solids, a sample containing water and waterborne solids, a sample containing saliva, a sample containing a body fluid, or a sample containing a combination thereof.

[0107] Item 22 The method according to any one of the items, wherein the detection of the radiation emitted from the ionized particles is carried out by filtering the radiation emitted from the ionized particles using one or more optical filters that selectively pass light of specific wavelengths, and then detecting the light of the specific wavelengths, wherein the specific wavelengths are wavelengths that are included in the characteristic radiation characteristics of the radiation light of the particles.

[0108] Item 23 10. The method of any one of the preceding claims, further comprising using a filter to filter out particles within a particular size range prior to applying energy to the fluid sample.

[0109] Although the flowcharts presented to illustrate the present technology depict a particular order of execution, they may be executed in a different order than depicted. For example, the order of execution of two or more blocks may be changed from that depicted. Furthermore, even though two or more blocks are depicted as being executed sequentially, they may be executed concurrently or with partial concurrence. Furthermore, embodiments may omit one or more of the blocks depicted in the flowcharts. Additionally, any number of counters, state variables, alert semaphores, messages, and the like may be added to the logic flow of the flowcharts for enhanced utility, accounting, performance measurement, and troubleshooting.

[0110] The devices described herein may be equipped with communication connections or networking equipment and network connections for communicating with other devices. Communication connections are also an example of a communication medium. Typical examples of communication media include computer-readable instructions, data structures, and program modules, as well as various data contained in data signals modulated onto a carrier wave or other transmission medium. Communication media also include various information distribution media. A "modulated data signal" as used herein refers to a signal in which information is encoded by modifying one or more of its characteristics. Examples of communication media include, but are not limited to, wired communication media, such as wired networks and direct-attached lines, and wireless communication media, such as acoustic, radio wave, and infrared. Communication media are also included in computer-readable media.

[0111] In describing the various embodiments shown in the drawings, specific language has been used to provide a detailed description. However, such specific language is not intended to limit the scope of the present technology. Modifications or further variations of the various features detailed herein, as well as further uses of the embodiments shown in the drawings, are all deemed to be within the scope of the present description.

[0112] Furthermore, various features, configurations, or characteristics described above can be combined in various ways to form embodiments. Although numerous specific details have been presented in the above description, including various embodiments with various configurations, these details have been presented to provide a thorough understanding of the embodiments of the technology described herein. However, it will be readily understood that the technology can be implemented without one or more of the specific details, and that the technology can be implemented using methods, configurations, devices, etc. that are different from those described above. Furthermore, well-known structures and processes have not been shown or described in detail to avoid obscuring various aspects of the technology.

[0113] Although the subject matter has been described above using specific expressions depicting structural features and / or steps, the subject matter defined by the claims is not necessarily limited to the specific features and steps described above. Rather, the specific features and steps described above are disclosed as exemplary forms for implementing the subject matter described in the claims. Numerous modifications and variations may be made without departing from the concept and scope of the technology described above.

Claims

1. an ionization chamber into which a fluid sample containing particles to be detected can be introduced; an energy source for supplying the particles with a sufficient amount of energy to ionize and disintegrate at least a portion of the particles; a photodetector for detecting a characteristic radiation characteristic of radiation emitted from the ionized particles; A sensor for particle detection comprising:

2. 2. The sensor of claim 1, wherein the energy is sufficient to cause disintegration of the entire particle.

3. 10. The sensor of claim 1, wherein the particle is a virus, a bacterium, a pathogen, or a combination thereof.

4. 2. The sensor of claim 1, wherein the energy source is a radio frequency (RF) power supply, a microwave generator, a direct current (DC) power supply, an alternating current (AC) power supply, a plasma generator, a high frequency electromagnetic wave generator, an ultraviolet (UV) irradiator, an X-ray irradiator, a laser device, a flame spray device, an electron beam irradiator, or a combination thereof.

5. 2. The sensor of claim 1, wherein the energy source is a plasma generator.

6. 6. The sensor of claim 5, wherein the plasma generator is configured to generate an oxygen plasma, a nitrogen plasma, or a combination thereof.

7. The energy source is located within the ionization chamber. 5 2. The sensor of claim 1, wherein the sensor is configured to generate an electric field density of at least 100 volts / cm.

8. 10. The sensor of claim 1, wherein the energy source comprises an electrode having a nano-textured surface.

9. 2. The sensor of claim 1, wherein said photodetector comprises a spectrometer.

10. 10. The sensor of claim 9, wherein the spectrometer has a sensitive wavelength range of about 300 nm to about 900 nm.

11. 2. The sensor according to claim 1, wherein the photodetector includes one or more optical filters that selectively pass light of specific wavelengths, the specific wavelengths being wavelengths included in the characteristic radiation characteristics of radiation emitted from the ionized particles.

12. 10. The sensor of claim 1, further comprising a concentrator for concentrating the fluid sample prior to subjecting the fluid sample to ionization.

13. 2. The sensor of claim 1, wherein the fluid sample is a sample containing air and airborne solids, a sample containing water and waterborne solids, a sample containing saliva, a sample containing body fluids, or a sample containing a combination thereof.

14. 2. The sensor according to claim 1, further comprising a microelectromechanical mass spectrometer configured to separate and extract components produced by ionizing the decomposed particles based on their charge-to-mass ratios.

15. 10. The sensor of claim 1, further comprising one or more filters for filtering out particles within a particular size range prior to subjecting the fluid sample to ionization.

16. providing a fluid sample containing particles to be detected with a sufficient amount of energy to ionize said particles and to fragment at least a portion of said particles; detecting radiation emitted from the ionized particles; correlating the radiation characteristics of the detected radiation with the characteristic radiation characteristics of the particle; indicating the presence of the particle in the fluid sample; 1. A method for particle detection comprising:

17. 17. The method of claim 16, wherein the energy is applied by exposure to a plasma, application of an electric field, application of radio frequency (RF) energy, application of microwave radiation, application of direct current (DC), application of alternating current (AC), application of high frequency electromagnetic energy, application of ultraviolet (UV) energy, application of x-ray radiation, application of laser energy, application of a flame, application of an electron beam, or a combination thereof.

18. 17. The method of claim 16, wherein the entire particle is subjected to decomposition.

19. 17. The method of claim 16, wherein the particle is a virus, a bacterium, a pathogen, or a combination thereof.

20. 17. The method of claim 16, further comprising concentrating the fluid sample prior to providing energy to the fluid sample.

21. 17. The method of claim 16, wherein the fluid sample is a sample comprising air and airborne solids, a sample comprising water and waterborne solids, a sample comprising saliva, a sample comprising a bodily fluid, or a sample comprising a combination thereof.

22. 17. The method of claim 16, wherein the detection of radiation emitted from the ionized particles is performed by filtering the radiation emitted from the ionized particles using one or more optical filters that selectively pass light of specific wavelengths, and then detecting the light of the specific wavelengths, wherein the specific wavelengths are within the characteristic radiation signature of the radiation emitted by the particles.

23. 17. The method of claim 16, further comprising using a filter to filter out particles within a particular size range prior to applying energy to the fluid sample.

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