Skin treatment devices, methods, programs

Abstract

It efficiently produces effects related to skin firmness, elasticity, blemishes, wrinkles, and lifting. [Solution] A skin treatment device is disclosed that generates effects on the skin related to sagging, firmness, blemishes, wrinkles, and lifting by applying AC stimulation in the range of 10 kHz to less than 200 kHz to the skin, thereby generating effects equivalent to or better than those obtained by applying AC stimulation at 1 MHz to the skin, and generating effects on the skin related to sagging, firmness, blemishes, wrinkles, and lifting.

Description

Technical Field

[0001] The present disclosure relates to a skin treatment device, method, and program.

Background Art

[0002] There is a known technique of activating fibroblasts present in the skin by stimulation with a physical stimulation generation circuit (ultrasonic oscillation circuit, low-frequency generation circuit, heat generation circuit, light wavelength oscillation circuit) to promote the production of collagen and elastin.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology as described above, various physical stimuli are targeted, and it is difficult to efficiently generate effects related to sagging, firmness, spots, wrinkles, and lifting on the skin.

[0005] Therefore, an object of the present disclosure is to efficiently generate effects related to sagging, firmness, spots, wrinkles, and lifting on the skin.

Means for Solving the Problems

[0006] On one side, a skin treatment device is provided that applies an alternating current stimulus within a range of 10 kHz or more and less than 200 kHz to the skin.

Effects of the Invention

[0007] According to the present disclosure, it becomes possible to efficiently generate effects related to sagging, firmness, spots, wrinkles, and lifting on the skin.

Brief Description of the Drawings

[0008] [Figure 1] This is a perspective view showing the appearance of the skin treatment device according to this embodiment. [Figure 2] This diagram illustrates the head section of the skin treatment device shown in Figure 1. (A) is a front view showing the arrangement of multiple electrodes and multiple outer edge electrodes. (B) is a front view of the electrodes. [Figure 3] This is a front view illustrating an example of the arrangement of multiple electrodes. [Figure 4] Figure 2(B) is a front view illustrating the linear parallel output region and the equally spaced output region of the electrodes. [Figure 5] A perspective view showing the appearance of a skin treatment device according to another embodiment. [Figure 6] This is an explanatory diagram of the control device incorporated into the skin treatment device according to this embodiment. [Figure 7] This figure shows an example of the hardware configuration of a control device. [Figure 8] These are explanatory diagrams illustrating two examples of AC waveforms. [Figure 9] This figure shows the results of cell tests that demonstrate the effect on cell viability. [Figure 10] This figure shows the results of cell tests that demonstrate the effect on collagen production. [Figure 11] This figure shows the results of a cell test demonstrating the effect on hyaluronic acid production. [Figure 12] This figure shows the results of a cell test (Experiment 1) that demonstrates the effect on cell viability. [Figure 13] This figure shows the results of a cell test (Experiment 2) that demonstrates the effect on cell viability. [Figure 14] This figure shows the results of a cell test (Experiment 3) that demonstrates the effect on cell viability. [Figure 15] This figure shows the results of a cell test (Experiment 4) that demonstrates the effect on cell viability. [Modes for carrying out the invention]

[0009] Hereinafter, each embodiment will be described in detail with reference to the accompanying drawings.

[0010] (Overall Structure of Skin Treatment Device) FIG. 1 is a perspective view showing the appearance of the skin treatment device 1 according to the present embodiment as an example of a specific configuration mode of the skin treatment device 1. FIG. 2 is a diagram for explaining the head portion 3 of the skin treatment device 1 according to the present embodiment.

[0011] The skin treatment device 1 of the present embodiment is in the form of a beauty device and is configured to impart beauty-related effects to the skin of the user's face. However, in a modified example, the skin treatment device 1 may be configured to impart similar beauty-related effects to other parts of the user's body in addition to or instead of the user's face. Further, the skin treatment device 1 may be used to impart effects different from beauty-related effects (for example, an effect of promoting transdermal absorption of pharmaceuticals).

[0012] The beauty-related effects are arbitrary and may include, for example, elimination of sagging, tightening, fat burning, lifting, face slimming, firmness and gloss of the skin, improvement of moisture, or any one or more arbitrary combinations thereof. Further, the beauty-related effects may be effects that can be quantified or effects that cannot be quantified.

[0013] The skin treatment device 1 of the present embodiment is configured to impart beauty-related effects to the user's skin by applying various outputs through a plurality of electrodes that contact the user's skin.

[0014] The skin treatment device 1 of the present embodiment is portable and can be held by the user's hand, but may also be applied to a movable type that is movably supported by a fixed device via an arm or the like.

[0015] The skin treatment device 1 of the present embodiment includes a grip portion 2 and a head portion 3. In this case, the user can hold the grip portion 2 and apply the head portion 3 to a desired site on his / her own face or the face of another person (for example, a patient), thereby applying various outputs from the skin treatment device 1 to the desired site.

[0016] The gripping part 2 has a shape that is easily grasped by the user's hand. The gripping part 2 may include a user interface 20 that includes various buttons such as a power on / off button, a mode switching button, and an intensity adjustment button. These buttons may be mechanical buttons or touch switches. The gripping part 2 may also be provided with a display unit (not shown) that displays the status of the skin treatment device 1, etc. The gripping part 2 may also be provided with electrodes (not shown) that come into contact with the user's hand.

[0017] The head portion 3 is provided at the end of the gripping portion 2. The head portion 3 may be fixed to the gripping portion 2, detachable, or movable relative to the gripping portion 2.

[0018] The head portion 3 is capable of contacting the user's skin and has a shape suitable for contact with the user's skin. The head portion 3 may have a contact surface 3a that is, for example, substantially planar (including a curved surface with a relatively large radius of curvature). The contact surface 3a is a plane in which the direction of extension of the contact surface 3a (basic plane) can be approximated as substantially straight when viewed from the side. The shape of the contact surface 3a when viewed from the front (i.e., the shape when viewed in a direction perpendicular to the contact surface 3a) can be arbitrary, such as a rectangle, circle, ellipse, polygon, etc. In this embodiment, the shape of the contact surface 3a when viewed from the front is, as an example, circular, as shown in Figure 2(A). With respect to the contact surface 3a of the head portion 3, the center when the contact surface 3a is viewed from the front (i.e., the centroid position when viewed in a direction perpendicular to the contact surface 3a) is referred to as the "center C of the contact surface 3a".

[0019] Multiple electrode groups are arranged in the head portion 3 according to attribute; specifically, a first electrode group and a second electrode group are arranged therein. The multiple electrode groups are provided in such a manner that they form the contact surface 3a of the head portion 3.

[0020] The first electrode group includes a plurality of electrodes 30 arranged in an array on the contact surface 3a. The second electrode group includes a plurality of outer edge electrodes 33 arranged on the contact surface 3a in a rotationally symmetrical manner around the center C of the contact surface 3a (which is also the center of the first electrode group), so as to surround the plurality of electrodes 30. These electrodes 30 and outer edge electrodes 33 are formed to easily come into contact with the user's skin and may be on the same plane as the basic surface of the contact surface 3a of the head portion 3, or they may protrude slightly from the basic surface of the contact surface 3a of the head portion 3.

[0021] In this embodiment, the head portion 3 has seven electrodes 30 as a first electrode group, but the number of electrodes 30 in the first electrode group is not limited to seven, and can be any number of two or more. In this embodiment, the head portion 3 also has three outer edge electrodes 33 as a second electrode group, but the number of outer edge electrodes 33 in the second electrode group is not limited to three, and can be any number of two or more.

[0022] Each of the multiple electrodes 30 has an inner electrode 31 and an outer electrode 32 that is spaced apart from the inner electrode 31 and surrounds it. The inner electrode 31 and outer electrode 32 of each of the multiple electrodes 30 form a pair of electrodes for applying an output waveform of a predetermined frequency that has, for example, a beauty-related effect (specifically, an effect related to sagging, firmness, blemishes, wrinkles, and lifting, as described later) to the user's skin.

[0023] In other words, in the first electrode group, the inner electrode 31 and outer electrode 32 of each of the multiple electrodes 30 form a pair to generate a desired output waveform. In this case, the output waveform is arbitrary and may be, for example, an AC waveform or a pulsed DC waveform. Preferred examples of the frequency band of the AC output waveform will be described later. Also, several examples of output waveforms realized by the pair of inner electrode 31 and outer electrode 32 will be described later.

[0024] By arranging the multiple outer edge electrodes 33 constituting the second electrode group so as to surround at least a portion of the multiple electrodes 30 constituting the first electrode group, a configuration can be achieved that produces a synergistic effect between the action provided by the first electrode group and the action provided by the second electrode group. Furthermore, by shaping and arranging the multiple outer edge electrodes 33 constituting the second electrode group in accordance with the overall shape of the collection of multiple electrodes 30 constituting the first electrode group, the contact surface 3a of the head portion 3 can be used efficiently, and an appropriate (in other words, sufficient) area can be secured for the electrodes constituting the second electrode group. This prevents discomfort caused by strong sensations when low-frequency currents are passed through electrodes with a small area.

[0025] Multiple outer edge electrodes 33 form pairs of electrodes for applying output waveforms of predetermined frequencies, which have, for example, cosmetic effects (specifically, muscle electrical stimulation effects), to the user's skin.

[0026] In other words, in the second electrode group, the outer edge electrodes 33 can be paired together to generate a desired output waveform. In this case, the output waveform is arbitrary and may be, for example, an AC waveform or a pulsed DC waveform. In this case, the frequency band of the output waveform is arbitrary, but may be, for example, a high frequency or low frequency that has a muscle electrical stimulation effect. Several examples of output waveforms realized by the paired outer edge electrodes 33 will be described later.

[0027] In this embodiment, each of the multiple electrodes 30 has an inner electrode 31 with a hexagonal outer edge, and an outer electrode 32 with hexagonal inner and outer edges. The outer electrode 32 is formed in a hexagonal band-like shape, spaced apart from the inner electrode 31 and surrounding it. That is, the outer electrode 32 is positioned outside the outer circumference of the inner electrode 31 (in other words, radially outward) such that the center of the inner electrode 31 (the centroid in a front view; the same applies hereafter) and the center of the outer electrode 32 (the centroid in a front view; the same applies hereafter) coincide.

[0028] In this embodiment, each of the multiple electrodes 30 is formed with a rounded hexagon shape, with the outer edge of the inner electrode 31 and the inner and outer edges of the outer electrode 32 being rounded. This ensures that the distance between the outer edge of the inner electrode 31 and the inner edge of the outer electrode 32 is constant throughout the entire space S between the inner electrode 31 and the outer electrode 32 (see Figure 2(B)). In this case, the symmetry and uniformity of the distance from the inner electrode 31 to the outer electrode 32 enables uniform electrical application with suppressed electrical bias between the inner electrode 31 and the outer electrode 32. However, the outer edge of the inner electrode 31 and the inner and outer edges of the outer electrode 32 may be formed with shapes other than rounded corners.

[0029] In this embodiment, all of the electrodes 30 have the same shape. However, some of the electrodes 30 may have different shapes (in other words, some may have the same shape), or all of the electrodes 30 may have different shapes from each other. That is, the electrodes 30 may all have the same shape, or two or more electrodes with different shapes may be arranged.

[0030] One electrode 30 (reference numeral 30c in Figure 2(A)) is positioned such that the center of the inner electrode 31 coincides with the center C of the contact surface 3a. Furthermore, six electrodes 30 (reference numeral 30a in Figure 2(A)) are arranged around the electrode 30 (reference numeral 30c in Figure 2(A)) positioned at the center C of the contact surface 3a, on a circle centered at the center C of the contact surface 3a, at equal intervals from one another.

[0031] The dimension Li between opposite sides of the outer edge of the inner electrode 31 is not limited to a specific value, but as an example, it may be set to any value within the range of approximately 2 to 5 mm.

[0032] The distance between the centers of the inner electrodes 31 of adjacent electrodes 30 is not limited to a specific value, but as an example, it may be set to a value within the range of approximately 4 to 12 mm.

[0033] In this embodiment, as described above, each of the multiple electrodes 30 is configured such that the outer peripheral edge of the inner electrode 31 is formed in the shape of a regular hexagon (more specifically, a rounded regular hexagon; the same applies hereinafter), and the inner and outer peripheral edges of the outer electrode 32 are formed in the shape of a regular hexagon, and the inner electrode 31 and the outer electrode 32 are combined so that the center of the inner electrode 31 and the center of the outer electrode 32 coincide.

[0034] Furthermore, the multiple electrodes 30 are arranged in an array such that the multiple outer electrodes 32 are adjacent to one outer electrode 32 (see Figure 3(A)), in contact with another outer electrode 32 (see Figure 3(B)), or integrated (see Figure 3(C); in this embodiment). In adjacent electrodes 30, the outer electrodes 32 may be integrated (in other words, they may overlap or be common), but they are arranged so as not to cross.

[0035] In this embodiment, multiple electrodes 30 are arranged such that at least a portion of the outer electrodes 32 of adjacent electrodes 30 are common, that is, in the manner shown in Figure 3(C). In this case, the outer electrodes 32 are formed in a mesh-like manner when viewed from the front, specifically in a honeycomb shape. Furthermore, the outer edge of the outer electrodes 32 is formed in the shape of a regular hexagon, and multiple electrodes 30 are arranged such that at least a portion of the outer electrodes 32 of adjacent electrodes 30 are integrated (in other words, overlapping, common). This allows the electrodes 30 to be arranged so as to fill the entire surface of the contact surface 3a, without any gaps between them (in other words, without wasted space), by adjusting the number and arrangement of the electrodes 30 to match the size and shape of the contact surface 3a.

[0036] Furthermore, by assembling multiple electrodes 30, each consisting of an inner electrode 31 and an outer electrode 32 surrounding it, to form an electrode assembly, the expandability and freedom of electrode placement can be increased, and the overall shape of the electrode assembly can be freely adjusted according to the area to which beauty-related effects are to be applied. Specifically, for example, the overall shape of the electrode assembly may be such that it fills an area roughly circular, as in this embodiment, or an area roughly elliptical, or an area roughly rectangular, or even an area roughly gourd-shaped.

[0037] By forming a pair of electrodes with an inner electrode 31 and an outer electrode 32 that surrounds the inner electrode 31 at a distance from it, the distance between the pair of electrodes (i.e., the dimension d between the outer peripheral edge of the inner electrode 31 and the inner peripheral edge of the outer electrode 32) can be adjusted to any value by changing the size of the inner electrode 31 or the outer electrode 32, or by changing the width of the outer electrode 32. The dimension d between the outer peripheral edge of the inner electrode 31 and the inner peripheral edge of the outer electrode 32 is not limited to a specific value, but is preferably 1.0 mm or more and 3.0 mm or less, more preferably 1.6 mm or more and 2.0 mm or less, and most preferably about 1.8 mm.

[0038] In this embodiment, it is preferable that the shape of the outer peripheral edge of the inner electrode 31 and the shape of the inner peripheral edge of the outer electrode 32 both have straight, parallel portions. By doing so, uniform electrical application with even better suppression of electrical bias can be achieved.

[0039] In this embodiment, as shown in Figure 4, both the outer peripheral edge shape of the inner electrode 31 and the inner peripheral edge shape of the outer electrode 32 of the electrode 30 have a linear, parallel portion SP. In the region between the inner electrode 31 and the outer electrode 32 in this parallel portion SP (the dark gray shaded area in Figure 4, the "linear parallel output region"), uniform electrical application with even better suppression of electrical bias is achieved. Furthermore, because the outer peripheral edge shape of the inner electrode 31 and the inner peripheral edge shape of the outer electrode 32 are formed as rounded hexagons, the dimension d between the outer peripheral edge of the inner electrode 31 and the inner peripheral edge of the outer electrode 32 is constant throughout the entire space S between the inner electrode 31 and the outer electrode 32. In the region between the inner electrode 31 and the outer electrode 32 in the rounded portion (the area between the linear parallel output regions in Figure 4, the "equally spaced output region"), uniform electrical application with suppressed electrical bias is achieved.

[0040] It is preferable that the ratio of the area of ​​the outer electrode 32 to the area of ​​the inner electrode 31 of each electrode 30 (referred to as the "ratio of inner and outer electrode areas") is within a predetermined range. Preferably, the ratio of inner and outer electrode areas is 0.8 or more and 1.2 or less, more preferably 0.9 or more and 1.1 or less, even more preferably 0.95 or more and 1.05 or less, and most preferably 1.0. By setting the ratio of inner and outer electrode areas within an appropriate range, good electrical application between the inner electrode 31 and the outer electrode 32 is achieved.

[0041] It is preferable that the ratio of the total area of ​​the space S between the inner electrode 31 and the outer electrode 32 to the sum of the areas of the inner electrode 31 and the outer electrode 32 of the multiple electrodes 30 (referred to as the "ratio of inter-electrode area to electrode area") is within a predetermined range. The ratio of inter-electrode area to electrode area is preferably 0.6 or more and 1.6 or less, more preferably 0.6 or more and 1.2 or less, even more preferably 0.7 or more and 1.1 or less, and most preferably 0.9 or more and 1.0 or less. By setting the ratio of inter-electrode area to electrode area within an appropriate range, good electrical application between the inner electrode 31 and the outer electrode 32 is achieved.

[0042] Note that the electrode configurations shown in Figures 1 to 4 are merely examples, and the electrode configuration is arbitrary as long as it is possible to apply the output waveform of the AC stimulation in the range of 10 kHz to less than 200 kHz, as described below, to the user's skin. Therefore, it is applicable to a variety of electrode configurations, such as the concentric two-annular electrode configuration shown in Figure 5, the concentric three-annular electrode configuration, the linearly arranged electrode configuration, and the electrode configuration including circumferentially separated annular electrodes.

[0043] However, in this embodiment, the electrode 30 is configured to make contact with the user's skin over a surface area. That is, the electrode 30 acts over the user's skin over a surface area and does not puncture the skin. In contrast, if the electrode has a pointed tip, it acts over the user's skin at a point and punctures the skin. From this viewpoint, the minimum external dimension of the cross-section of the electrode 30 (the cross-section viewed in a direction perpendicular to the contact surface 3a) is preferably 1 mm or more.

[0044] Figure 6 is an explanatory diagram of the control device 100 incorporated into the skin treatment device 1 according to this embodiment. Figure 7 is a diagram showing an example of the hardware configuration of the control device 100. In Figure 7, peripheral devices 160 are schematically illustrated in relation to the hardware configuration of the control device 100.

[0045] The control device 100 is electrically connected to the power supply 90 and also to the first electrode 31, the second electrode 32, and the third electrode 33. The power supply 90 may be realized by an internal battery that can be mounted in the skin treatment device 1, and / or by an external power supply that can be connected to the skin treatment device 1. The control device 100 may have a power supply circuit that generates various operating power supplies based on the power supply 90. The control device 100 may also include a general-purpose processor, a special-purpose processor, an integrated circuit, an ASIC (Application Specific Integrated Circuit), etc.

[0046] In the example shown in Figure 7, the control device 100 includes a CPU (Central Processing Unit) 111, RAM (Random Access Memory) 112, ROM (Read Only Memory) 113, auxiliary storage device 114, drive device 115, and communication interface 117 connected by a bus 119, as well as a wired transceiver 125 and a wireless transceiver 126 connected to the communication interface 117.

[0047] The auxiliary storage device 114 is, for example, an HDD (Hard Disk Drive) or an SSD (Solid State Drive), and is a storage device that stores data related to application software, etc.

[0048] The wired transceiver unit 125 includes a transceiver unit capable of communicating using a wired network. Peripheral devices 160 are connected to the wired transceiver unit 125. However, some or all of the peripheral devices 160 may be connected to the bus 119 or to the wireless transceiver unit 126. The peripheral devices 160 may include the multiple electrodes 30 described above, or a mobile terminal such as the user's smartphone. If a mobile terminal is included, the user may be able to make various settings related to the skin processing device 1 via the mobile terminal.

[0049] The wireless transceiver 126 is a transceiver capable of communicating using a wireless network. The wireless network may include a mobile phone wireless communication network, the internet, a VPN (Virtual Private Network), a WAN (Wide Area Network), etc. The wireless transceiver 126 may also include a Near Field Communication (NFC) unit, a Bluetooth (registered trademark) communication unit, a Wi-Fi (Wireless-Fidelity) transceiver unit, an infrared transceiver unit, etc.

[0050] The control device 100 may be connected to the recording medium 116. The recording medium 116 stores a predetermined program. The program stored in the recording medium 116 is installed in the auxiliary storage device 114 of the control device 100 via the drive device 115. The installed predetermined program becomes executable by the CPU 111 of the control device 100. For example, the recording medium 116 may be a recording medium that records information optically, electrically, or magnetically, such as a CD (Compact Disc)-ROM, flexible disk, or magneto-optical disk, or a semiconductor memory that records information electrically, such as a ROM or flash memory. Note that the recording medium 116 does not include a carrier wave.

[0051] The control device 100 generates one or more output waveforms that can be applied to the skin via multiple electrodes 30 based on the power supply 90.

[0052] In this embodiment, the control device 100 generates an AC waveform M0 (AC stimulus) having a frequency between AC stimuli in the range of 10 kHz to less than 200 kHz. In this case, the control device 100 generates the AC waveform M0 so that it can be applied to the user's skin via the first electrode 31 (inner electrode 31) and the second electrode 32 (outer electrode 32). That is, the generated AC waveform M0 can be applied to the user's skin with the first electrode 31 as the positive electrode (or negative electrode) and the second electrode 32 as the negative electrode (or positive electrode).

[0053] In this specification, unless otherwise specified, the term "AC waveform" is a concept that includes not only sine waves but also any waveform that has bipolarity.

[0054] In this embodiment, the AC waveform M0 may be a square wave, but preferably it has a sinusoidal shape, that is, a shape that gradually changes toward a peak value. In this case, the inconveniences that may occur when it is a square wave (for example, user discomfort due to a sudden increase in current) can be eliminated or reduced.

[0055] For example, the AC waveform M0 may have waveforms like those shown in the two examples in Figure 8. Figure 8 shows the output waveform (time-series waveform) of the AC waveform M0 when time is plotted on the horizontal axis and voltage value on the vertical axis. In Figure 8, ΔT1 and ΔT3 represent intervals (ranges) corresponding to one period of the output waveform.

[0056] In the upper embodiment of Figure 8, the AC waveform M0 has multiple peak voltage values ​​during half a period (ΔT1 / 2). In this case, the multiple peak voltage values ​​include a first peak voltage value Vp1 and one or more second peak voltage values ​​Vp2.

[0057] The first peak voltage value Vp1 is the peak voltage value that appears at the beginning of a half-cycle, and the second peak voltage value Vp2 appears after the first peak voltage value Vp1 and is smaller in magnitude than the first peak voltage value Vp1. Multiple second peak voltage values ​​Vp2 may occur in a manner that gradually decreases, as shown in Figure 8. Preferably, the second peak voltage value Vp2 is smaller than half the magnitude of the first peak voltage value Vp1.

[0058] Here, the AC waveform M0 has frequencies between AC stimuli in the range of 10 kHz to less than 200 kHz, which allows it to provide the following excellent effects to the applied skin.

[0059] In this embodiment, the voltage value of the AC waveform M0 is preferably 300V or less on a peak-to-peak basis. For example, in the example shown in Figure 8, the first peak voltage value Vp1 and the second peak voltage value Vp2 are 150V or less.

[0060] Figures 9 to 12 show some test results demonstrating the superiority of AC stimulation in the range of 10 kHz to less than 200 kHz.

[0061] Figures 9 to 11 show test results demonstrating the effect at 165 kHz within the range of AC stimulation between 10 kHz and less than 200 kHz, with comparison to a control and 1 MHz. The "control" corresponds to the results when the head unit 3 of the skin treatment device 1 is applied to the skin, but no output waveform is applied to the skin from the head unit 3.

[0062] The testing method is as follows:

[0063] (Step S1) NB1RGB fibroblasts derived from normal human neonatal cells were seeded in a 60 mm dish at a density of 2.0 × 10⁵ cells / dish and cultured in a CO₂ incubator (CO₂ concentration = 5%, 37°C) for 24 hours. NHDF(NB) cells may be used instead of NB1RGB cells.

[0064] (Step S2) The test medium (EMEM 8 mL) containing 0.5% FBS was replaced, and the facial device was applied every 24 hours for 3 days according to the test conditions. The temperature of the medium level and the temperature of the liquid were measured before and after application of the facial device.

[0065] (Step S3) The culture supernatant was collected in a 15 mL tube (Cat No. 23-2265, Crystalgen, USA) and stored frozen (-20°C). The collagen and hyaluronic acid production-promoting effects of the collected culture supernatant were evaluated using an Enzyme-Linked Immuno Sorbent Assay (ELISA). The cell count in the 60 mm dish from which the culture supernatant was removed was also evaluated by an MTT assay.

[0066] The method for measuring collagen using the ELISA method is as follows:

[0067] (Step S1) 150 μL of PBS was placed in a high-adsorption 96-well plate (Cat No. 3855, Thermo Scientific, USA), and then 50 μL of the culture supernatant sample was added. The plate was left to stand overnight at 4°C. Type I collagen solution (Cat No. 009-001-103, RCK, USA) was used as the standard substance.

[0068] (Step S2) The microplate was washed with 200 μL of PBS(-) containing 0.05% Tween20 (PBS-T, Tween20: CAS No. 9005-64-5, Sigma-Aldrich, USA), and 150 μL of 1% Bovine Serum Albumin (BSA, Cat No. PRL68700-50G, Proliant, USA) solution was added. The mixture was then allowed to stand at 37°C for 1 hour.

[0069] (Step S3) After washing with 200 μL of PBS-T, 100 μL of a 100 ng / mL solution of biotin-labeled anti-type I collagen antibody (Cat No. 600-406-103, ROCKLAND, USA) was added and the mixture was allowed to stand at 37°C for 1 hour.

[0070] (Step S4) After washing with 200 μL of PBS-T, 100 μL of Streptavidin-HRP (Cat No. CJ30H-1, Agilent Technologies, USA, 1:10000 dilution) solution was added and the mixture was allowed to stand at room temperature for 30 minutes.

[0071] (Step S5) After washing with 200 μL of PBS-T, 100 μL of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS, Cat No. 5110-0010, KPL, USA) solution was added and the color development was confirmed.

[0072] (Step S6) After homogenizing the dye in the 96-well plate, the absorbance at 405 nm (OD405) was measured using a microplate reader.

[0073] (Step S7) The collagen production rate of the facial device application group was calculated using the control group's OD405 as 100%. In addition, the collagen production rate per cell was calculated by dividing the OD405 of the facial device application group by the OD570 measured by the MTT assay.

[0074] The method for measuring hyaluronic acid using the ELISA method is as follows:

[0075] (Step S1) Add 100 μL of Hyaluronan Binding Protein (HABP, Cat No. BC40, Hokudo, Japan, 1:5500) solution prepared in PBS to a high-adsorption 96-well plate and incubate overnight at 4°C.

[0076] (Step S2) The immobilized HABP solution was removed, washed with 200 μL of PBS-T solution, then 150 μL of 1% BSA solution was added and incubated at room temperature for 1 hour.

[0077] (Step S3) Remove the BSA solution, wash with 200 μL of PBS-T, add 100 μL of culture supernatant diluted 100-fold with PBS(-), and incubate at room temperature for 1 hour. Sodium hyaluronate (Cat No. 087-04511, Wako, Japan) was used as the standard.

[0078] (Step S4) Remove the culture supernatant, wash with 200 μL of PBS-T, add 100 μL of biotin-labeled HABP (Cat No. BC41, Hokudo, Japan, 1:2000 dilution) solution prepared with 0.5% BSA-containing PBS(-), and let stand overnight at 4°C.

[0079] (Step S5) Remove the biotin-labeled HABP solution, wash with 200 μL of PBS-T, add 100 μL of Streptavidin-HRP solution (1:10000) prepared in 0.5% BSA-containing PBS(-), and let stand at room temperature for 30 minutes.

[0080] (Step S6) Remove the Streptavidin-HRP solution, wash with 200 μL of PBS-T, add 100 μL of ABTS solution, and check for color development.

[0081] (Step S7) After homogenizing the dye in the 96-well plate, the absorbance at 405 nm (OD405) was measured using a microplate reader.

[0082] (Step S8) The hyaluronic acid production rate of the facial device application group was calculated using the OD405 of the control group as 100%. In addition, the hyaluronic acid production rate per cell was calculated by dividing the OD405 of the facial device application group by the OD570 measured by the MTT assay.

[0083] The inventors of this application discovered, by repeatedly performing the above tests while varying the frequency, that applying AC stimulation in the range of 10 kHz to less than 200 kHz produces effects on skin sagging, firmness, blemishes, wrinkles, and lifting that are equivalent to or better than RF of 1 MHz or higher, which is also used in medical devices. Furthermore, this method is fundamentally different from microchannels (i.e., ablation, which creates physical pores in the epidermis (surface dermis)), and these effects can be obtained without forming pores in the skin. The test results are described in detail below.

[0084] It is widely known that an increase in fibroblasts promotes collagen and hyaluronic acid production. Furthermore, it is known that increased collagen and hyaluronic acid production rates can enhance skin firmness, elasticity, wrinkle reduction, and lifting effects (see, for example, the following paper). Paper 1: “Radiofrequency facial rejuvenation: Evidence-based effect” by Moetaz El-Domyati et al., J Am Acad Dermatol. 2011 March; 64(3): 524·535. doi:10.1016 / j.jaad.2010.06.045 Paper 2: "IF-06 RF Opens Up New Limits in Cosmetic Skin Whitening" by Saya Koike et al., 1st Japan Society of Cosmetic Chemists Program, Conference Theme: What's next for SCCJ? Diverse Cosmetic Technologies for the Future Figures 9 to 11 show the test results, illustrating the effect of applying a 165 kHz AC stimulus on cell viability, comparing the control group with the group that applied a 1 MHz AC stimulus. In each figure, "*" indicates a statistically significant difference based on a t-test, and "*" indicates a p-value of 0.05 or less.

[0085] When a 165kHz AC stimulus was applied, as shown in Figure 9, cell viability (fibroblast viability) increased by 31% compared to the control, which was a more significant increase than the 20.9% increase when a 1MHz AC stimulus was applied. Furthermore, when a 165kHz AC stimulus was applied, as shown in Figure 10, collagen production increased by 8.3% compared to the control, which was a more significant increase than the 7.5% increase when a 1MHz AC stimulus was applied. Also, when a 165kHz AC stimulus was applied, as shown in Figure 11, hyaluronic acid production increased by 16.3% compared to the control, which was a more significant increase than the 9.6% increase when a 1MHz AC stimulus was applied.

[0086] Figure 12 is a graph showing the results of Experiment 1, a new experiment conducted on a different occasion than the tests in Figures 9 to 11. Experiment 1 compared the control, 165 kHz, 1 MHz, and 500 kHz. Cell viability at 165 kHz increased by 19.7% compared to the control, and was equal to or greater than the increase at 1 MHz (10% increase) or 500 kHz (9.4% increase). The results in Figure 12 confirm the same effect as in Figure 9. Furthermore, the results in Figure 12 show that 1 MHz and 500 kHz have almost equivalent effects. In addition, as can be seen from Table 1 below, cell viability at 165 kHz increased significantly and remarkably compared to 500 kHz or 1 MHz.

[0087] [Table 1] Figure 13 is a graph showing the results of the new Experiment 2. In Experiment 2, the control, 1 MHz, 40 kHz, 199 kHz, and 1 kHz were compared. The cell viability at 40 kHz and 199 kHz increased by 15.3% and 13.3% respectively compared to the control, and increased to or greater than that of 1 MHz (2.0%). Furthermore, the cell viability at 1 kHz did not increase compared to the control, and no increase equivalent to or greater than that of 500 kHz or 1 MHz was observed. In addition, the cell viability at 40 kHz and 199 kHz increased significantly compared to 500 kHz or 1 MHz, showing a remarkable increase. Furthermore, the cell viability at 40 kHz and 199 kHz increased significantly compared to 1 kHz, showing a remarkable increase. Table 2 below is a table showing the results of Experiment 2.

[0088] [Table 2] Figure 14 is a graph showing the results of a new experiment, Experiment 3. In Experiment 3, instead of 1 MHz, a comparison was made with 500 kHz, which showed equivalent cell viability in Experiment 1. The cell viability at 40 kHz increased by 10.9% compared to the control, and increased to or greater than that of 500 kHz (2.3%). Furthermore, the cell viability at 40 kHz also increased significantly compared to 500 kHz and 300 kHz, showing a remarkable increase. Table 3 below is a table showing the results of Experiment 3.

[0089] [Table 3] Figure 15 is a graph showing the results of the new Experiment 4. In Experiment 4, the cell viability was compared between 1 MHz and 90 kHz, 70 kHz, 20 kHz, and 10 kHz. It was found that cell proliferation was significantly higher at 90 kHz, 70 kHz, 20 kHz, and 10 kHz compared to 1 MHz. Table 4 below is a table showing the results of Experiment 4.

[0090] [Table 4] From the above, it was found that frequencies between 10 kHz and 200 kHz significantly stimulate fibroblast proliferation to an extent equivalent to or greater than that of 1 MHz. Therefore, it can be seen that applying AC stimulation within the range of 10 kHz to 200 kHz to the skin can produce beauty-related effects equivalent to or greater than those of 1 MHz (effects caused by fibroblast proliferation, such as effects related to skin firmness, elasticity, blemishes, wrinkles, and lifting).

[0091] Incidentally, when using the frequency range known as RF or 500kHz, effects related to fibroblast proliferation, such as skin tightening, firmness, blemishes, wrinkles, and lifting, can be expected. However, there are disadvantages due to the relatively high frequency. For example, these include high power consumption and the risk of burns.

[0092] In this respect, according to this embodiment, effects equivalent to or better than those of RF can be obtained without using the frequency range known as RF. That is, according to this embodiment, AC stimulation at a frequency significantly lower than the frequency range known as RF (within the range of 10kHz to less than 200kHz) is applied to the skin, thereby increasing safety and making it suitable for home use while obtaining beauty-related effects equivalent to or better than those of RF.

[0093] Although each embodiment has been described in detail above, the invention is not limited to any particular embodiment, and various modifications and changes are possible within the scope described in the claims. Furthermore, it is possible to combine all or more of the components of the embodiments described above. [Explanation of Symbols]

[0094] 1 Skin treatment device 2 Grip part 3. Head section

Claims

[Claim 1] A skin treatment device that applies alternating current stimulation within the range of 10 kHz to less than 200 kHz to the skin.

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