JPH0350927Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a semiconductor ion penetration device that allows semiconductor ions to penetrate into the body of a living body through the skin surface. Living organisms are highly efficient heat engines made up of organic combinations of 20 to 30 different elements. Energy sources supplied from the outside are decomposed and purified within the body, eventually becoming organic substances with a relatively simple composition, which release thermal energy as a result of redox reactions. Living organisms take in this thermal energy and use it as a power source for each organ. If the organs responsible for the energy supply process of the biological system described above cease to function properly due to invasion by pathogenic bacteria or mechanical damage, the entire biological activity will be seriously affected. Therefore, living organisms have the ability to self-repair and restore organ function. Interferons and interleukins have recently attracted attention as substances that control autoimmunity, which detects the invasion of foreign antigens and activates the defense system (antibody reaction). Although these substances are produced by animals themselves, they are not always present in sufficient concentrations during times of war (when functional damage occurs), and their healing effects are often insufficient. As one measure to activate the autoimmune effect, in recent years, elements that do not originally exist in living tissues or exist only in very small amounts are artificially administered into living tissues, and the exclusion of these elements has been attempted. Attempts have been made to increase the proliferation of interferons and interleukins through physiologically induced processes, and these efforts are attracting attention. Elements that exhibit this effect include semiconductors such as germanium, silicon, and selenium. These semiconductors are usually inorganic;
Therefore, even if it is orally administered to the human body as it is, it is not absorbed into the tissues and is excreted, so it is often used after being converted into an organic form. However, there have been problems with organicization, such as increased manufacturing costs and high prices, and oral administration, which makes it difficult to locally administer high concentrations to affected areas. The semiconductor ion permeation device of the present invention has an extremely simple structure and combines the principles of biological batteries and semiconductor bonding to ionize and infiltrate semiconductor elements from outside the body to the necessary locations within the body tissue. This is an attempt to solve the above-mentioned problems. That is, a skin contact tool is attached to an element in which a semiconductor crystal that generates penetrating ions and a metal whose standard unipolar potential is approximately Eg/2e volt or more higher than that of the semiconductor are electrically bonded, and the skin contact tool is used to The device is used by being crimped onto the required location on the skin of the living body. Here, Eg is the energy corresponding to the forbidden band width of the semiconductor, and e is the amount of electron charge. From an electrical point of view, the biological skin surface is a type of conductive resistor, and as a result, a resistor junction (potential barrier) is created on both sides of the semiconductor crystal, and the semiconductor is ionized by the battery action and the action of this semiconductor junction. and in vivo osmotic diffusion. The principle of the present invention will be explained below using the drawings. FIG. 1a shows a state in which a semiconductor iontophoresis device (one example) according to an embodiment of the present invention is attached to a biological skin surface 4 (cross-sectional view). In the figure, the semiconductor ion penetration device is a semiconductor crystal (A) that generates ions to be penetrated.
1. Consists of a metal (B) electrically connected to the A, 2, and a leather fitting 3. In Fig. 1a, A 1 and Otsu 2 are in pressure contact with the skin surface 4 at the same time, but in order to explain the principle of the present invention using an energy band, first, only Otsu 2 is in contact with the biological skin surface 4. , consider the case where A1 is not in contact with 4. At this time, each substance (1, 2, 4) is considered to be in a state of thermal equilibrium, so the energy band diagram becomes as shown in FIG. 1b. Semiconductor crystal shell is non-doped
It was made into a single crystal with type conductivity. A so-called Schottky barrier is formed at the interface between the A1 and the A2 and the interface between the A1 and the biological skin surface 4, and a depletion layer spreads toward the A1 side. The diffusion potential φ _p of the depletion layer takes a value slightly smaller than Eg/2e in the case of an undoped semiconductor. Assuming that the standard unipolar potential of the metal Otsu 2 is larger than that of the semiconductor crystal A 1 by approximately Eg/2e, when A 1 and Otsu 2 are pressed against the skin surface 4 at the same time as shown in Figure 1a, the An energy band diagram as shown in Figure 1c is obtained. That is, since the battery action is activated, the diffusion potential φ _p formed at the interface between A 1 and Otsu 2 due to the positive electrode effect of metal Otsu 2 is biased, and the potential barrier disappears. As a result, free electrons in the conduction band of the semiconductor crystal A1 flow into the conduction band of the metal B2, which is located at a lower (stable) position in terms of energy. Since the resistance of the biological skin surface 4 is considerably higher than that of Otsu 2, the band inclination of the skin surface 4 due to the application of the battery electric field becomes considerably gentler than that of Otsu 2. on the other hand,
A Schottky barrier remains at the interface between the semiconductor crystal A1 and the skin surface 4, and even if the conduction band of the skin surface 4 is tilted due to the application of a battery electric field, this potential barrier prevents electrons from flowing from the skin surface 4 into the semiconductor. It does not flow into Crystal A1. By the way, unlike metals, there are two types of carriers (charge carriers) in semiconductors: free electrons and free holes. Free electron density n, free hole density p, cation density N ⁺ _D , anion density N ^- The condition of electrical neutrality n+N ^- _A = p+N ⁺ _D ...(1) is established between _A. In addition, in a semiconductor crystal in a state of thermal equilibrium, n.p = constant...(2). In the case as shown in FIG. 1c, since almost no external electric field acts on the bulk region of the semiconductor crystal A 1 (the electric field is concentrated in the depletion layer region), it can be considered to be in almost a thermal equilibrium state. In the case of n-type semiconductor,
The minority carrier (free hole) density p is conserved, so as shown in Figure 1c, n
When , decreases, in order to simultaneously satisfy equations (1) and (2), free electrons must be generated in the semiconductor to compensate for the decrease. As a result, free holes corresponding to the free electrons generated in the bulk region of the semiconductor shell are generated. No matter where free holes are generated in the semiconductor crystal, they drift and move to the electrically stable interface region with the skin surface 4. Atoms with holes (i.e., valence electron shells) are cations and are in a chemically unstable state, so in the interface area between 2 and 4, the electrolytic action of the skin of the living body causes it to move away from crystal A1. It elutes and permeates and diffuses into the living body. In this process, ionization and penetration of semiconductor ions occur one after another. If the standard monopolar potential difference between A1 and Otsu2 is greater than Eg/2e volts, the band of A1 will tilt in the opposite direction to that in Figure 1b near the interface between A1 and Otsu2, so Free electrons flow into A2 2 more quickly than in the case of FIG.
Conversely, if the standard monopolar potential difference between A1 and Otsu2 is much smaller than Eg/2e, the Schottky barrier formed at the interface between A1 and Otsu2 cannot be eliminated by the positive electrode effect of Otsu2, and A The free electrons of 1 cannot flow into 2 because they are blocked by this potential barrier.
Therefore, in this case, even if it is attached to the skin surface 4 as shown in FIG. Free electrons in a solid are supplied with thermal energy from the surrounding crystal lattice, so approximately 3KT
It has a certain amount of kinetic energy. Therefore, the potential barrier of about 0.1V at room temperature can be extremely high. The standard single-pole potential difference between A1 and Otsu2 is 0.1V from Eg/2e.
In a small range, semiconductor ions can be generated and penetrated into the body, although the effect is weak. Now, when the conductivity type of the semiconductor crystal A 1 electrically connected to the metal A 2 is p-type, the energy band diagram in the thermal equilibrium state corresponding to FIG. 1b is as shown in FIG. 2a. In this case, the majority carriers in semiconductor crystal A1 are free holes, and the Schottky barrier formed at the interfaces between A1 and A1 and the interface between A1 and the biological skin surface 4 allows the carriers to be absorbed into the filled zone of A1. Trapped. When it is pressed against the biological skin surface 4 as shown in Figure 1a, the battery action is exerted and the band tilts, but the Schottky barrier at the interface between A1 and Otsu2 is biased in the opposite direction, so the height of the barrier is reduced. The barrier at the interface between the upper 1 and the skin surface 4 is further biased and lowered. However, in general, the resistance of the body's skin surface is much greater than that of metal, so instep 1 and skin surface 4
The diffusion potential φ _p ′ of the interface barrier between A1 and B2 is higher than the diffusion potential φ _p of the interface barrier between A1 and Otsu2. Therefore, when the minority carriers (free electrons) of A1 flow into the conduction band of B2 due to battery action, in order to establish equations (1) and (2), the generation of minority carriers and the corresponding freedom are determined. Although the number of holes increases, when the excess free holes flow from the shell 1 to the biological skin surface 4, the flow becomes worse than in the case of the n-type semiconductor. In other words, even if the standard unipolar potential of Otsu 2 is higher than that of Otsu 1 by Eg/2e volts, a Schottky barrier remains at the boundary between Otsu 1 and the skin surface 4. For this reason, when a p-type semiconductor is used as A1, there is a drawback that the generation of semiconductor ions is weaker than when an n-type semiconductor is used. Although the semiconductor ion penetration device of the present invention has been described above using FIGS. 1 and 2a, it is assumed that each of the n-type and p-type semiconductors is a single crystal. When semiconductor A 1 that forms a bond with metal Otsu 2 is polycrystalline,
The situation becomes quite complicated. For example, undoped n
In the case of a junction between a type semiconductor 1 and a metal 2, if the undoped n-type semiconductor 1 is a polycrystal with three grain boundaries, the thermal equilibrium state corresponding to FIG. 1b will be as shown in FIG. 2b. Depletion layers (small scale) are generated at the grain boundaries, such as at the interfaces between 1 and 2 and between 1 and 4, and high-density recombination centers are generated at the grain boundaries. Now, when A1 and Otsu2 are pressed against the skin surface 4 at the same time,
The energy band diagram corresponding to FIG. 1c is as shown in FIG. 2c. In other words, A1 and Otsu2
At the interface, the standard monopolar potential difference between A1 and A2 is Eg/
In the case of 2e, a large number of carriers (free electrons) flow from A1 to B2 as in Figure 1c. However, Fig. 1c
Unlike in the case of It is sucked into the recombination center at the grain interface, recombines with minority carrier free holes, and disappears. The energy of the recombined free electrons and free holes is released as heat. Free holes (minority carriers) annihilated by recombination are replenished by ionization to satisfy equations (1) and (2), but most of the free holes generated by ionization are returned to the grain interface. Because it is consumed by recombination with free electrons, instep 1 and biological skin surface 4
The density of free holes that flow to the interface with the semiconductor and are used to generate semiconductor ions is low, reducing its efficiency as an ion source. The situation is exactly the same when the semiconductor crystal A1 to be bonded to the A2 is a p-type semiconductor. Naturally, the suction of carriers by grain boundaries becomes more severe as the grain boundary density increases. In the case of a semiconductor ion structure, the distance between grain boundaries is approximately the diffusion distance of minority carriers (several microns), and almost no semiconductor ions are generated. Therefore, it is desirable that the semiconductor of A1 is a single crystal in both n-type and p-type cases.
If it is polycrystalline, the grain boundary size (grain
It can be said that it is desirable that the size) is sufficiently large (approximately 100 microns or more) compared to the diffusion distance of the minority carriers. As is clear from the above explanation, in the semiconductor iontophoresis device of the present invention, the degree of ionization depends on the type, conductivity type, and crystallinity of the semiconductor as well as the potential difference between A1 and Otsu2. Between the
If an external DC power source is connected in a direction that biases Otsu2 to positive and Otsu2 to negative, it can be fully agreed that the ionization of the semiconductor and its penetration into the living body will be significantly accelerated by that voltage. . Now, the principle of a metal-semiconductor junction element has been described above, but what kind of effect can be expected if A1 and Otsu2 are both metals (if the standard unipolar potential of Otsu2 is higher)? I wonder if there is. By attaching it to the skin surface 4 as shown in FIG. 1a, the energy band diagram becomes as shown in FIG. 3. The carriers are essentially only free electrons, and there is no potential barrier because the bottom of the conduction band (energy E _c ) is continuous at the interface of different materials. The source of electrons is A1, and the electron flow is A1 → Otsu2 → skin surface 4 → (in the living body)
→ Skin surface 4 → Flows like instep 1. When free electrons are generated in A1, in principle metal ions corresponding to the generation should be generated, but metals inherently have a high density of free electrons at room temperature, and as shown in Figure 3. Since free electrons are supplied from the biological system to A1 by the potential gradient, ionization of A1 is difficult to attract. Ionization is promoted when A1 is ionized and dissolved by the strong electrolytic action of biological systems, but this phenomenon usually does not occur on the surface of living skin, and also does not occur with metals that have a relatively small tendency to ionize. Therefore, if both A1 and B2 are metal, the element configuration shown in FIG. A "therapeutic device" that utilizes the bonding of two types of metals with different ionization tendencies has already been published (Utility Model Publication No. 57-103743).
issue). As explained using FIG. 3, this therapeutic device was developed for the purpose of passing a circular current through a living body. In contrast, the "semiconductor ion penetration device" of this invention
As explained in Figures 1 and 2, _the semiconductor By selecting an appropriate combination of ions and metals, semiconductor ions can be efficiently generated and penetrated into biological systems to serve the intended therapeutic purpose. That is, the device of the present invention effectively acts as an ion source. The present invention will be explained below using examples. (Example 1) An undoped n-type germanium single crystal with a purity of 99.99% was selected as the semiconductor crystal A1, and a noble metal was selected as the metal B2 to form a semiconductor ion penetration tool having the structure as shown in FIG. 1a. Precious metals have excellent corrosion resistance and can be used for long periods of time. Both A1 and B2 have a spherical shape with a diameter of 5 mm, and while both spheres are pressed together in an inert gas atmosphere, the pressure contact points are slightly welded by heating to an appropriate temperature of 50° to 650°C for a short time. This connecting ball was applied to the adhesive surface of Bansouko 3, and the semiconductor ion permeation device was applied by pressure to a semi-ripened tomato fruit. The surface of the tomato was washed in advance with alcohol, dried, and then pasted. Removed after 120 hours,
After cutting the specimen from the branch, the area directly below the attachment point (approximately 1 cm deep) was cut out and ground, and the concentration of Ge contained was examined by physical analysis. Gold, silver, and platinum were used as Otsu 2, and copper was also used for comparison.
Three samples were prepared for each case, and the results obtained are shown in Table 1 as an average value.

[Table] Since the Ge concentration contained in the sample to which the semiconductor ion penetration device was not attached was around the detection limit (1 ppm), the results in Table 1 clearly show the effect of the penetration device being applied. It is thought that The forbidden band width in the semiconductor Ge theorem is 0.66 (eV)
It is. In addition, the standard single-pole potential difference between Otsu 2 and A (Ge) 1 is 1.4 volts for Ag, approximately 1.0 volts for Pt, 0.8 volts for Au, and approximately 0.2 volts for Cu, and Eg/2e0.33 (V) In the case of a noble metal anode, it is sufficiently large. However, in the case of a copper anode, it is found that Ge ionization is difficult to occur because it is more than 0.1 volt lower than Eg/2e. On the other hand, the same semiconductor ion penetration device as above was constructed using a p-type Ge single crystal doped with 10 ¹⁷ atoms/cm ³ of indium as A1 and Au as A2. This was applied to tomato seeds as described above, and a penetration experiment was conducted for 120 hours.
Analysis of the contained Ge concentration shows that it is 300 to 500 ppm,
It was found that this was less than half that of the n-type Ge cathode. Now, in Table 1, Otsu 2, which was also very effective,
Ag was used as the anode metal, and the electrical connection with A1 Ge was made of a sintered body of small particles. That is, undoped n
The type Ge single crystal is crushed into small particles with a size of approximately 7 to 10 μm, mixed with Ag powder of approximately the same particle size at a 1:1 molar ratio, and pressed into a disk shape with a diameter of 10 mm and a thickness of 2 mm. A sintered body containing a high density of Ag-Ge bonds was obtained by heating to 500°C in an inert gas atmosphere for a short time. Furthermore, 95 mol% of Ge powder was added using the same method.
A sintered body was obtained in which Ag powder was mixed at a ratio of 5 mol %. These were pressed onto the surface of the tomato fruit using Bansoukou 4, and the state of Ge ion penetration was examined after 120 hours had elapsed. When physically analyzed using the same method as above,
The concentration of Ge contained in tomatoes is 10 to 50 ppm in the case of Ge:Ag=1:1 sample, and 5 in the case of Ge:Ag=95:5.
It was found to be ~10ppm. Single crystals in Table 1
Compared to the case using Ge, the ion penetration effect is 2
It can be seen that it has decreased by ~3 orders of magnitude. This result is the value obtained by dividing the bonding interface area between semiconductor crystal A1 and metal B2 by the semiconductor bulk volume (junction specific surface area).
is extremely high compared to the case using single-crystal Ge (Ge:Ag=1:1), and when the Ge grain boundary density is high and the grain boundary size is about the minority carrier diffusion distance (Ge:Ae = 95:5), the ionization of the semiconductor is hindered by the influence of the interfacial recombination centers explained in Figure 2 b and c, indicating that the ion source, which is the purpose of this invention, is invincible. There is. (Example 2) An undoped n-type copper selenide (Cu ₂ Se) 1 polycrystal with an average grain boundary size of about 2 mm is 5 mm in diameter and 5 mm in height.
After processing the pellet into a cylindrical pellet, plating the entire surface with gold 2 with a thickness of about 3 μm, polishing only the bottom surface of one side, pasting adhesive tape 3 on the bottom surface to be polished, and attaching a semiconductor ion penetration tool as shown in Figure 4. It was formed and adhered to the living body 4. After cleaning the outside of the right lower limb of a nude mouse with alcohol, the penetrant was attached to it and a penetration experiment was conducted. After 120 hours, remove the penetration tool,
The lower leg meat (5 mm in depth) was cut out and ground directly below, and the selenium concentration was examined by physical analysis. For comparison, the shape and dimensions are the same, 1 is zinc, 2 is
They created a device using gold and attached it to the outside of the right lower limb of another nude mouse specimen in an attempt to infiltrate zinc.
After 120 hours, the concentration of Se is 500~
800 ppm, and Zn was 5 to 10 ppm. The Se concentration and Zn concentration of nude mice that do not stick to the device are
Since it was about 1 ppm, the ion penetration effect due to device adhesion was observed in both cases, but compared to the ion penetration effect in the metal bonding element, the metal-semiconductor bonding element of the present invention has an effect that is two orders of magnitude higher.
This is considered to be because the standard unipolar potential difference between Au2 and Cu ₂ Se1 was sufficiently larger than the depletion layer diffusion potential of Cu ₂ Se1, and the ionization of Cu ₂ Se1 was promoted. On the other hand, the above undoped n-type copper selenide polycrystal 1 and gold 2 are each processed into a disk shape with a diameter of 5 mm and a thickness of 1 mm, and both are connected with a copper wire as shown in Fig. 5, and a variable resistor is connected between them. The battery was connected to the battery, and biased so that the copper selenide 1 side was positive and the gold 2 side was negative.
Similar to the above, this device was attached to the skin surface 4 of the right lower limb of a nude mouse using a band 3 with an electrode spacing of 2 mm, and the variable resistance was adjusted so that a direct current of about 1 mA would flow. 4 hours after application, this device was removed, a piece of flesh was taken from the area directly below the application surface (depth 5 mm), and the concentration of Se was found to be 100 to 200 ppm. It was found that the penetration effect was significantly enhanced. As described in detail using the examples above, the semiconductor ion penetration device of the present invention differs from conventionally known current generating batteries using metal cathodes and anodes; Metal-semiconductor,
Alternatively, it has the function of generating semiconductor ions by skillfully controlling the potential barrier caused at the semiconductor-living skin interface using battery electromotive force, and causing them to diffuse and permeate into the living system. The semiconductor cathode that generates penetrating ions is p
An n-type semiconductor (preferably a type that does not contain a large amount of easily ionized donors) is preferable to a type semiconductor. Further, the metal anode is preferably a noble metal from the viewpoint of standard single electrode potential and corrosion resistance. Furthermore, the semiconductor crystal is preferably a single crystal or a polycrystal with a large grain boundary size, and a sintered body with small particles (a polycrystal with a large specific surface area).
should be avoided. By means of the semiconductor iontophoresis device of the present invention, semiconductor ions useful to the living body can be easily and selectively and continuously supplied to necessary locations from outside the living body.

[Brief explanation of the drawing]

1 to 3 are diagrams showing embodiments of the present invention and diagrams for explaining the principle, and FIGS. 4 and 5 are diagrams showing different embodiments of the present invention. In the figure, 1... semiconductor crystal, 2... metal anode, 3... skin fitting, 4... biological skin surface.

Claims (1)

[Scope of claim for utility model registration] 1. Semiconductor crystal with a grain boundary size of 100 μm or more that generates penetrating ions (hereinafter referred to as A), and a standard monopolar potential of approximately Eg/2e than A (however, Eg is prohibited in A). It consists of an element made by electrically bonding a metal (hereinafter referred to as ``B'') that has a higher band width than the electronic charge amount (e is the amount of electronic charge), and a skin bonding tool for pasting the element and simultaneously contacting ``A'' and ``B'' with the skin. Semiconductor ion penetration device. 2. A semiconductor iontophoresis device in which an external DC power source is connected between Party A and Party B described in Paragraph 1 of Claims for Utility Model Registration so that Party A is biased in a positive direction and Party B is biased in a negative direction.