RU2773965C1 - Method for coating acupuncture needle - Google Patents

Abstract

FIELD: medical equipment.

SUBSTANCE: invention relates to medical equipment, namely to a method for applying iron oxide coating on acupuncture needles by atomic layer deposition. Acupuncture needles are placed in the reaction chamber, a vacuum is created inside the chamber at a pressure of 1-5 mbar, a cycle is carried out, including heating the acupuncture needles to a temperature of 220-280°C, discretely sequential supply of vapors of the precursor of bis-η⁵-cyclopentadienyl iron II ( ferrocene) with a temperature of 80-100°C for 1-3 s with a holding time of 1-3 s and an oxygen reagent gas at a pressure of 1-3 bar for 5-7 s with a holding time of 1-3 s. After the mentioned precursor has been vented and after oxygen has been vented, the reactor is purged with nitrogen and pumped out to the initial pressure.

The specified cycle is carried out until the formation of a given coating thickness of 4-32 nm with at least 600 cycles.

EFFECT: invention provides uniform coating, increased sorption properties and adhesive strength of the resulting acupuncture needles.

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Description

SUBSTANCE: invention relates to medical equipment, namely to a method of coating acupuncture needles, and can be used in practical medicine for acupuncture, which promotes the sorption and removal of heavy metal particles from the human body.

From the prior art (RU 2674985C2, 12/14/2018) a method of coating a surgical needle is known, including applying a silicone coating to a surgical needle, where this needle is installed on a carrier, by immersing the surgical needle in a silicone coating solution by moving the needle in a bath with a silicone solution coating, while the needle is mounted on the carrier so that the needle tip is directed upwards, removing the needle from the coated bath, directing the air flow to the needle along the path at an angle of about +/- 20 ° to the longitudinal central axis of the distal end section of the needle, thus that a sufficient amount of silicone coating solution is retained on the end section of the needle; and curing the silicone coating, wherein the silicone coating solution contains a vinyl-terminated polydimethylsiloxane, a methyl-terminated polymethylsiloxane, a methylhydrosiloxane crosslinker, a platinum complex with divinyltetramethyldisiloxane and ethynylcyclohexanol, and organic solvents.

Also from the prior art (KHAFIZOV A.A. et al. Sputtering of ferromagnetic powder on steel by a plasma installation with an electrolytic cathode, Socio-economic and technical systems: research, design, optimization, 2015, T. 1, N 1 (64), C . 25-33) a method of applying a coating of iron oxide (II,III) by gas-plasma spraying on metal surfaces is known. The essence of this method is that gas (argon, nitrogen, air) is passed through an arc burning between two electrodes (an electrolyte electrode and a copper nozzle). Due to the high energy of the burning arc, gas atoms lose electrons from their outer shells. The result is an ion-electron gas or plasma. The temperature of the plasma jet reaches a temperature of 3000-5000°C. The sprayed material in the form of a powder is fed into the plasma jet into the zone at the outlet of the nozzle. As a result, the sprayed material is heated to melting, accelerates and is applied to the surface of the workpiece. During the deposition process, it is necessary to control the thickness of the deposited layer, which for plasma coating is 0.1-2 mm.

The disadvantage of this method is that there is a need to control the thickness of the sprayed layer, which for a plasma coating is 0.1-2 mm.

It is also known from the prior art (RU 2761440 C2 08.12.2021) a method of coating medical devices that come into contact with tissues, in particular, injection needles by cleaning and activating the surface of the needle with accelerated ions and further ion-plasma spraying, first with a stream of gaseous accelerated particles containing an organosilicon compound, and then ion-plasma spraying with a stream of gaseous accelerated particles containing metal atoms: iron (Fe) and/or titanium (Ti).

The disadvantage of this method is the application of an additional pre-coating of organosilicon compounds, which lengthens the duration of the method, and the needles have insufficient adhesive strength.

In addition, acupuncture needles are known from the prior art (RU 2717705 C1, 03/25/2020) and RU (189268 U1, 05/17/2019), in which the iron oxide coating is applied by flame spraying. The size of Fe ₃ O ₄ nanoparticles of the coating is from 10 to 100 nm ± 20%.

The disadvantage of this method is that the granular composition of the used iron oxide powder (II,III) must be uniform for application. With a wide range of particle sizes, the quality and adhesion of coatings deteriorate significantly.

However, to date, the state of the art has not revealed the use of atomic layer deposition (ALD) or, in other words, atomic layer deposition (APO) as a method of coating a nanosized film of iron oxide (II,III) of a given thickness on acupuncture needles. Needles are used in the medical field to carry out acupuncture procedures.

ALD is a technology that uses the principle of molecular assembly of materials from the gas phase. The process of applying a film with a thickness of the order of 1 angstrom consists of several steps - gas-phase reactions occurring impulsively in a very short period of time (about 200 μs). The total duration of the cycle (1-2 s) depends on the time of each stage, which are selected experimentally. The size of the reactor is one of the main factors determining the duration of the stages. By programmatically setting a certain number of cycles, we obtain the film thickness we need.

In this connection, it is relevant to develop a method for applying iron oxide coating by the ALD method on acupuncture needles to ensure their high sorption, strength and adhesion properties. Since one of the main advantages of the ALD method is the uniform thickness of film deposition on a complex surface, which cannot be achieved by other common technological methods.

Therefore, the technical result of the claimed invention is to provide a uniform coating, as well as its increased sorption properties and adhesive strength.

The specified technical result is achieved due to the method of coating acupuncture needles, characterized by the fact that the needles are placed in the reaction chamber, a vacuum is created inside the chamber at a pressure of 1-5 mbar, the needles are heated to a temperature of 220-280 ° C, discretely sequentially fed into the reaction zone pairs of a precursor of bis-η ⁵ -cyclopentadienyl iron II (ferrocene) with a temperature of 80-100 ° C for 1-3 s and a reagent gas oxygen at a pressure of 1-2 bar for 5-7 s, withstand each of the reagents for 1-3 s, after the inlet of each precursor, the reactor is purged with nitrogen and pumped out to the initial pressure, the process is repeated in a pulsed mode cycle by cycle until a given coating thickness of 4-32 nm is formed, but not less than 600 cycles.

For this method, any acupuncture needles known from the prior art are used, consisting of a handle and a shaft, made of a metal material, for example, (MOLCHANOVA E.E., MIRONOVA N.V. Methods of treatment of traditional oriental medicine in the clinic of internal diseases, Tutorial , Part I, Blagoveshchensk, Amur State Medical Academy, 2015, pp. 12-17). The needles are individually wrapped, eliminating the need for additional surface preparation prior to the coating process.

The method can be carried out in a reaction chamber of the longitudinal flow of gases, for example, in the equipment of Cambridge NanoTech companies. Inc., Oxford Instruments, Beneq Oy, ASM Microsystem.

For our experiments, we used the reactor of a high-tech facility TFS 200 from Beneq (Finland). The reactor is a round closed container with a diameter of 200 mm and a height of 3 mm.

The volumes of oxygen and nitrogen reagent gases used are set depending on the amount of ferrocene precursor introduced into the reactor and the desired final coating thickness.

At temperatures in the needle reactor below 220° C., the rate of the process is greatly slowed down due to the decrease in the reactivity of the iron precursor. Also, the temperature of the heated precursor below 80°C contributes to the slow reaction rate of the formation of iron oxide films (II,III).

The need to use a "pause" (precursor and reagent gas exposure) in the process became apparent after several experiments. Due to the peculiarities of the APO process and the precursor and reagent gas used, their interaction with each other and with the substrate surface is difficult and occurs slowly. Pauses provide a temporary opportunity for chemical reactions to take place in the reaction chamber.

It is concluded that the number of cycles is of fundamental importance in this process. According to the results of the experiment, only if all the above parameters are observed, a high-quality film of a given thickness is formed at 600 cycles and more.

The general scheme of the process for the synthesis of a coating on acupuncture needles according to the method of the invention is shown in FIG. one.

Based on the foregoing, only if all of the above parameters are observed, the specified technical effect is achieved, which is confirmed by the following examples of the claimed invention.

Example 1. Acupuncture needles are placed in a reactor, which is pumped out to ~1.5 mbar, heated to a temperature of 200°C and the vapor obtained by evaporation of the precursor (η ⁵ -C ₅ H ₅ ) ₂ Fe (ferrocene), heated to 80°C for 500 ms, oxygen reagent gas supplied at a pressure of 1.5 bar for 5 s. The precursors are kept in the reactor for 1 s and 3 s, respectively. After each precursor has been vented, the reactor is purged with nitrogen for 1 s and the reactor is evacuated to the initial pressure. The process is repeated in pulse mode cycle by cycle, the time of one cycle is 13.1 seconds. The number of cycles is 100. As a result, a coating with a thickness of 8 nm is obtained.

The film surface morphology was studied using an SPM 9600 scanning probe microscope (SPM) from SHIMADZU.

Based on FIG. 1, the quality and performance properties of the coating of the nanoscale film of iron oxide (II,III) on acupuncture needles obtained by the claimed method are unsatisfactory, since the surface of the coating is uneven even at a given coating thickness.

Example 2

Acupuncture needles are placed in a reactor, which is pumped out to ~1.5 mbar, heated to a temperature of 280°C, and the vapor obtained by evaporation of the precursor (η ⁵ -C ₅ H ₅ )Fe (ferrocene), heated to 100°C in for 500 ms, oxygen reagent gas supplied at a pressure of 1.5 bar for 7 s. The precursors are kept in the reactor for 1 s and 3 s, respectively. After each precursor has been vented, the reactor is purged with nitrogen for 1 s and the reactor is evacuated to the initial pressure. The process is repeated in pulse mode cycle by cycle, the time of one cycle is 13.1 seconds. The number of cycles is 500. As a result, a coating with a thickness of 32 nm is obtained.

The analysis obtained in example 2 sample (Fig. 2) was performed on a scanning electron microscope Quanta TM 3D 200i systems: microanalysis (EDS), EBSD, focused ion beam (FIB).

At a temperature of 280°C, ferrocene is easily oxidized to a ferrocenium radical cation, which is highly reactive, which leads to the nucleation and formation of an iron (II, III) oxide film. High temperature (η ⁵ -C ₅ H ₅ ) ₂ Fe (above 100°C) leads to boiling of the precursor, with further decomposition without reaching the reaction chamber.

Based on FIG. 2, the quality and performance properties of the coating of the nanoscale film of iron oxide (II,III) according to example 2 on acupuncture needles obtained by the claimed method are satisfactory. However, the coating surface is still not uniform enough.

Examples 1 and 2 indicate that the insufficient temperature of the process and the precursor (η ⁵ -C ₅ H ₅ ) ₂ Fe, the time of puffing precursors, as well as the number of process cycles affect the quality and performance properties of the coating of a nanosized film of iron oxide (II, III ) on acupuncture needles obtained by the APO method.

Precursor inlet time up to 1 s is not enough for (η ⁵ -C ₅ H ₅ ) ₂ Fe to interact with the substrate surface due to the low rate of formation of iron oxide (II, III). Increasing the time to 3 s increases the concentration of the precursor (η ⁵ -C ₅ H ₅ ) ₂ Fe, which increases the rate of the reaction for the formation of iron oxide (II, III), but a further increase in the puff time seems to be economically inexpedient.

Example 3

Acupuncture needles are placed in a reactor, which is pumped out to ~1.5 mbar, heated to a temperature of 280°C, and the vapor obtained by evaporation of the precursor (η ⁵ -C ₅ H ₅ ) ₂ Fe (ferrocene) heated to 100°C is sequentially fed for 1 s, oxygen reagent gas supplied at a pressure of 3 bar for 1 s. The precursors are kept in the reactor for 1 s and 3 s, respectively. After each precursor has been vented, the reactor is purged with nitrogen for 1 s and the reactor is evacuated to the initial pressure. The process is repeated in pulse mode cycle after cycle, the time of one cycle is 11.6 seconds. The number of cycles is 700. As a result, a coating with a thickness of 16 nm is obtained.

Example 4

Acupuncture needles are placed in a reactor, which is pumped out to ~3 mbar, heated to a temperature of 220°C, and the vapor obtained by evaporation of the precursor (η ⁵ -C ₅ H ₅ ) ₂ Fe (ferrocene), heated to 80°C for 3 s, oxygen reagent gas supplied at a pressure of 1.5 bar for 1 s. The precursors are kept in the reactor for 1 s and 3 s, respectively. After each precursor has been vented, the reactor is purged with nitrogen for 1 s and the reactor is evacuated to the initial pressure. The process is repeated in pulse mode cycle after cycle, the time of one cycle is 11.6 seconds. The number of cycles is 600. As a result, a coating with a thickness of 16 nm is obtained.

Examples 3 and 4 characterize the optimal combination of all parameters of the ASO process to obtain a high-quality nanosized film of iron oxide (II, III) for the use of this coating on acupuncture needles in the acupuncture procedure (Fig. 3).

The X-ray diffraction pattern of the film obtained according to example 4 is shown in Fig. four.

Next, tests were carried out to compare the sorption properties of acupuncture needles coated with iron oxide (II, III), obtained by the claimed method according to example 3 and 4, in comparison with needles without coating (Control I) and needles coated with iron oxide (II, III), obtained using a gas-plasma method with a thickness of 16 nm (Control II).

Sorption of aluminum ions was carried out with the indicated acupuncture needles coated with iron oxide (II, III) with a thickness of 16, 8, 4 nm, for 1 hour from a solution with a concentration of aluminum ions = 13.18 µg/l.

After sorption, the concentration of ions in the solution was measured using a SHIMADZU AA-7000 atomic absorption spectrophotometer. The measured sorption capacity is presented in Table 1.

Similarly, experiments were carried out on the sorption of mercury (II) ions by needles obtained by the claimed method with a coating of iron oxide (II, III) with a thickness of 32.16, 8.4 nm, for 1 hour from a solution with a concentration of mercury (II) ions = 0 .5 µg/l, as well as the control samples indicated above. After sorption, the concentration of ions in the solution was measured using a SHIMADZU AA-7000 atomic absorption spectrophotometer. The measured sorption capacity is presented in Table 2.

Similarly, experiments were carried out on the sorption of cesium ions by needles obtained by the claimed method with a coating of iron oxide (OPC) with a thickness of 32, 16, 8, 4 nm, for 1 hour from a solution with a concentration of cesium ions = 0.5 μg/l, as well as control samples mentioned above. After sorption, the concentration of ions in the solution was measured using a SHIMADZU AA-7000 atomic absorption spectrophotometer. The measured sorption capacity is presented in Table 3.

It can be seen from the experimental results that needles without Fe ₃ O ₄ coating and Fe ₃ O ₄ coated needles obtained by gas-plasma spraying either do not sorb metal ions or have a significantly low sorption capacity, respectively, compared with needles obtained by the claimed method.

It is also seen that the highest sorption capacity is observed for needles coated with Fe ₃ O ₄ with a thickness of 16 nm.

Modified needles also absorb the following metal ions: copper, iron, cobalt, manganese, nickel, cesium, pigs, aluminum, mercury (I), mercury (II), beryllium, antimony, cadmium, thallium, bismuth, osmium, chromium, zinc, tin, molybdenum, vanadium, gallium, zirconium.

Next, control and test samples with a thickness of 16 nm were studied according to examples 3, 4 (experiment 1, experiment 2, respectively) for measuring adhesive strength, which was carried out in the same way as in A. A. Khafizov. Sputtering of ferromagnetic powder on steel by a plasma installation with an electrolytic cathode, Socio-economic and technical systems: research, design, optimization, 2015, vol. 1, no. 1 (64), pp. 25-33. The data obtained are shown in Table 4.

Based on the data obtained, it can be concluded that the prototypes obtained by the claimed method have an increased adhesive strength of the coating even with a thickness in nm compared to the control sample with the minimum possible thickness of 0.1 mm, obtained by the gas-plasma coating method.

Thus, according to the claimed method, acupuncture needles are obtained with a unique Fe ₃ O ₄ sputtering layer, which ensures uniform coating, and also increases the sorption properties and adhesive strength of the resulting needles.

Claims (1)

A method for applying a coating of iron oxide on acupuncture needles by atomic layer deposition, characterized in that the acupuncture needles are placed in the reaction chamber, a vacuum is created inside the chamber at a pressure of 1-5 mbar, a cycle is carried out, including heating the acupuncture needles to a temperature of 220-280 ° C, discretely sequential supply of vapors of the precursor bis-η ⁵ -cyclopentadienyl iron II (ferrocene) to the reaction zone at a temperature of 80-100 ° C for 1-3 s with exposure for 1-3 s and oxygen reagent gas under pressure 1 -3 bar for 5-7 s with a holding time of 1-3 s, while after the inlet of the mentioned precursor and after the inlet of oxygen, the reactor is purged with nitrogen and pumped out to the initial pressure, while the specified cycle is carried out until the specified coating thickness is formed 4-32 nm with at least 600 cycles.

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