WO2025018912A1 - Acupuncture needle capable of sorbing plastic particles - Google Patents

Abstract

The invention relates to a method for producing acupuncture needles with an aluminium oxide coating for the sorption of microplastic and/or nanoplastic particles. Cycles of atomic layer deposition of aluminium oxide from trimethylaluminium and water are carried out at a pressure of 10 mbar ± 0.1 mbar and a reactor temperature of 100°С. Anodizing is then performed to produce a coating that has a developed structure of dendritic blind pores acting as molecular sieves. The invention makes it possible to remove microplastic and/or nanoplastic particles from the human body.

Description

ACUPUNCTURE NEEDLE SORBING PLASTIC PARTICLES

METHOD OF ITS OBTAINING AND APPLICATION

This solution relates to the field of medicine and medical technology, in particular to acupuncture needles for performing acupuncture procedures that promote the sorption and removal of microplastic or nanoplastic particles from the human body.

The claimed acupuncture needle for reflexology contains a handle and a rod, and the working part of the rod is coated with a nano-sized layer of aluminum oxide 1000 nm thick.

The invention also relates to a method for producing such needles by applying an aluminum oxide coating to acupuncture needles using atomic layer deposition and the use of such needles for the sorption of microplastic and/or nanoplastic particles.

Since the invention of plastic, more than 8 billion tons of plastic products have been produced, and most of this unimaginably huge amount has long been lying in landfills, at best. A considerable part is simply lying around, slowly, very slowly decomposing, breaking down into larger and smaller pieces. Particles whose size is from 1 micrometer to 5 mm are called microplastics, less than 1 micron - nanoplastics. Such tiny, invisible pieces of plastic fly away with air currents, are washed away by water, fly with dust, settling on the bottom of reservoirs, on tree leaves and grass, mixed with soil.

Micro- and nanoplastic particles have been found in samples taken from everywhere, from the ocean floor to the snow on mountain peaks. And they are present in human tissues, too. Microplastics enter the body with food, water, air. For example, about 5 grams of plastic particles enter the digestive system every week. This is about the same as if a person ate a credit card every week.

Every year, a person drinks about 90 thousand microplastic particles with drinking water from plastic bottles.

Another portion of microplastic “crumbs” enters the body with cosmetics. One study found samples of microplastic in 90% of cosmetics produced by the most famous and popular brands.

Plastic particles, passing through the gastrointestinal tract (GIT), can disrupt the intestinal microbiome. And this, in turn, leads to metabolic disorders, which, ultimately, can cause a whole bunch of different diseases, from obesity and diabetes to liver diseases and other gastrointestinal organs. Studies conducted with laboratory animals have shown that exposure to microplastic particles promotes inflammation, causes cells to break down and die, and can even damage the DNA chain.

In early May 2022, ecotoxicologist Professor Dick Wethaak from the Free University of Amsterdam reported the astonishing results of his study. It turned out that 4 types of microplastics were found in the blood of 17 out of 22 healthy people examined by him and his colleagues [1]. A little earlier, microplastics were also found in other studies in lung tissue [2] and colon tissue [3], the placenta of pregnant women [4] and meconium of newborns [5].

The presence in the blood is a real cause for concern, says Wethaak, because it means that the particles are freely transported by the blood throughout the body [5]. The Dutchman's research was focused on the large-tonnage, most popular polymers used worldwide: polyethylene terephthalate (contained in half of the samples); polyethylene (contained in 36% of the samples); styrene polymers (found in 23% of samples); polymethyl methacrylate (5%).

Scientists found traces of polypropylene, but its concentration in the blood of the subjects was insignificant. The average value of the total concentration of plastic particles in the blood was 1.6 μg/ml.

Vethaak clarifies that the amount and type of plastic varied significantly between blood samples, which may be due to the short duration of contact with plastic before the sample was taken: for example, after touching a plastic food container or wearing a plastic face mask.

There are currently no clear dimensions for this category of plastic - Professor Vethaak focused his research on the size of the filter pores that retain particles >700 nm in size. The upper limit of the size of microplastics, named in 2004, is considered to be a length of 5 mm.

Thus, the creation of systems capable of retaining or extracting microplastics from the body/blood is an important and urgent task. Moreover, as the author claims, the most dangerous are particles with sizes from 700 nm.

The technical result is to provide effective sorption properties for removing plastic particles, the size of which is from 1 micrometer to 5 mm - microplastic, less than 1 micron - nanoplastic, from the human body due to the use of a coating based on aluminum oxide.

The acupuncture needles according to the invention can be used both for cleansing the body for medicinal purposes and for daily use for preventive purposes.

A method for applying a coating to a surgical needle is known from the prior art [6], which includes applying a silicone coating to a surgical needle, where this needle is mounted on a carrier, by immersing the surgical needle in a silicone coating solution by moving the needle in a bath with a silicone coating solution, wherein the needle is mounted on the carrier in such a way that the tip of the needle directed upward, removing the needle from the coating bath, directing the air flow onto the needle along a path at an angle of about +/- 20° to the longitudinal central axis of the distal end section of the needle, such 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 comprises polydimethylsiloxane with a vinyl end group, polymethylsiloxane with a methyl end group, a crosslinker - methylhydrogensiloxane, a platinum complex with divinyltetramethyldisiloxane and ethynylcyclohexanol and organic solvents.

Also, a method for applying a coating of iron oxide (II, III) by gas-plasma spraying on metal surfaces is known from the publication [7]. The essence of this method is that gas (argon, nitrogen, air) is passed through an arc burning between two electrodes (electrolyte electrode and copper nozzle). Due to the high energy of the burning arc, gas atoms lose electrons from their outer shells. The result is ion-electron gas or plasma. The temperature of the plasma jet reaches 3000-5000 °C. The sprayed material in the form of powder is fed into the zone at the exit from the nozzle into the plasma jet. As a result, the sprayed material is heated to melting, accelerated and applied to the surface of the workpiece. During the spraying process, it is necessary to control the thickness of the sprayed 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 plasma coating is 0.1-2 mm.

Also known from the prior art is [8] a method for applying a coating to medical devices that come into contact with tissues, in particular, to injection needles, by cleaning and activating the surface of the needle with accelerated ions and subsequent ion-plasma spraying, first with a flow of gaseous accelerated particles containing an organosilicon compound, and then ion-plasma spraying with a flow 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 compound, which extends the duration of the method, and the needles have insufficient adhesive strength.

In addition, the prior art [9] discloses the application of a flame spray coating of iron oxide to needles. The size of the Fe3O4 nanoparticles in the coating is from 10 to 100 nm ± 20%.

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

The closest analogue of the presented solution in terms of the method for creating acupuncture needles with sorption properties is the solution disclosed in [10]. The known solution is a method for applying an iron oxide coating to acupuncture needles using the atomic layer deposition method. The acupuncture needles are placed in a reaction chamber, a vacuum is created inside the chamber under a pressure of 1-5 mbar, a cycle is carried out that includes heating the acupuncture needles to a temperature of 220-280°C, discretely sequentially feeding the precursor vapors of bis-g|5-cyclopentadienyl iron II (ferrocene) with a temperature of 80-100°C into the reaction zone for 1-3 s with a holding time of 1-3 s and the reagent gas oxygen under a pressure of 1-3 bar for 5-7 s with a holding time of 1-3 s. After the aforementioned precursor is injected and after oxygen is injected, the reactor is purged with nitrogen and pumped down to the initial pressure. The specified cycle is carried out until the specified coating thickness of 4-32 nm is formed, with at least 600 cycles. The solution ensures uniform application of the coating, increased sorption properties and adhesive strength of the resulting acupuncture needles.

However, the prior art does not disclose a method for applying aluminum oxide to needles, including acupuncture needles, therefore, there is a need to provide a method for producing acupuncture needles with sorption properties, including with respect to plastic particles, which will be technologically simple, and, therefore, inexpensive, while allowing the production of needles with standardized parameters, in particular, the thickness of the aluminum oxide coating.

The closest analogue of the presented solution in terms of acupuncture needles with sorption properties is the solution disclosed in [I]. The known acupuncture needle for reflexology contains a handle and a rod, and a coating is applied to the working part of the rod. The needle provides sorption and removal of heavy metal particles from the human body due to the use of a coating based on magnetic nanoparticles of iron oxides magnetite (Fe3O4) and/or maghemite (y-Fe2O3). However, in the state of the art, there is a need for acupuncture needles with expanded sorption properties.

The prior art does not contain needles with sorption properties for micro- and nanoparticles of plastic.

Thus, there is a need to create such needles.

Disclosure of the essence of the invention

The objective of the present invention is to create a unique separation coating made of aluminum oxide in the form of molecular sieves.

The technical result is to provide effective sorption properties for removing plastic particles, the size of which is from 1 micrometer to 5 mm - microplastic, less than 1 micron - nanoplastic, from the human body due to the use of a coating based on aluminum oxide.

The problem of the invention is solved, and the technical result is achieved by means of needles with a 1000 nm thick aluminum oxide coating applied by the atomic layer deposition (ALD) method.

The present invention relates to a method for producing acupuncture needles with sorption properties with respect to microplastic and/or nanoplastic particles having an aluminum oxide coating on the surface. Where the method includes applying a nano-sized oxide layer to the surface of the needles by atomic layer deposition aluminum 1000 nm. Then they are anodized in oxalic acid with the formation on the surface of the needles of a developed structure of tree-like blind pores - molecular sieves, with sizes sufficient for the passage of nano-plastic, larger than 700 nm.

The deposition process is based on the chemical interaction between the substrate surface and the reagents. Two or more reagents sequentially react with the active groups of the surface, depositing as a single monolayer of material. And multiple processing allows depositing a thin film of the target material of the required thickness with high accuracy. Most ALD reactors use a flow scheme, when an inert gas is continuously passed through the reactor, and the reagents are added in small doses to the carrier gas. The carrier gas delivers the reagent to the reaction chamber and then through the filtration and neutralization system to the vacuum pump.

Fig. 1 - Scheme of formation of thin film of aluminum oxide using ALD method.

Fig. 2 - first sample of the needle. 1000 nm image obtained using a scanning electron microscope (SEM).

Fig.3 - Second needle sample. 1000 nm image obtained using a scanning electron microscope (SEM).

Fig.4 - Third needle sample. 1000 nm image obtained using a scanning electron microscope (SEM). Example 1. Production of needles with a coating and aluminum oxide

The application of an aluminum oxide film to the surface of the samples was carried out using equipment for carrying out the ASO process Beneq TFS 200 (manufactured in Finland).

The ASO cycle for the precipitation of aluminum oxide from trimethylaluminum (TMA) and water consisted of the following steps: 1. Injecting TMA into the reaction chamber, where the molecules react and attach to the substrate surface. The process continues until all active surface groups have reacted with the TMA molecules.

2. An inert gas, nitrogen, was passed through the chamber, which removes gaseous reaction products and remaining reagents.

3. Introducing water vapor into the reaction chamber, where water molecules reacted with the substrate surface, forming a layer of aluminum oxide.

4. An inert gas was passed through the chamber.

The process of applying aluminum oxide to the surface of the needle samples was carried out under the following parameters: pressure 10 mbar ± 0.1 mbar, reactor temperature 100 °C, the required number of cycles, in this case 1300 cycles, since the thickness of the aluminum oxide film per cycle is ~ 0.8 nm. The time of one cycle is 20 seconds. The total time for obtaining a film with a thickness of 1000 nm is about 7-8 hours.

Example 2. Obtaining needles with a developed structure of tree-like blind pores - molecular sieves

Electrolytic anodization of the obtained needles, obtained according to example 1, was carried out.

Example 2A. First option

Anodizing was performed once for two hours in a 0.3M oxalic acid solution at a voltage of 300 V, followed by boiling in a solution of H3PO4 + Cr3O3 at 80°C. SEM images for this sample are shown in Fig. 2. The pores have an average depth of 180 nm and a diameter of 560 nm.

Example 2B. Second option

The first anodization was carried out at a voltage of 300 V in a solution of 0.3 M oxalic acid for one hour, followed by boiling in a solution of H3PO4 + Cr3O4 for five minutes at a temperature of 80 °C. Repeated anodization was also carried out 3 hours in oxalic acid at a voltage of ZOV. In the breaks of the tree-like structure, a porous self-ordered nanostructure is observed (Fig. 3), where the average pore depth is 1 micrometer, and the pore diameter is 850 nm.

Example 2C. Third option

The first anodization was carried out in sulfuric acid at a voltage of 20 V for one hour. Then the sample was boiled in a solution of H3PO4 + Cr3O4 for five minutes at a temperature of 80 °C. Then the anodization process was repeated for 2 hours and 20 minutes. The first 50 minutes of anodization were carried out at a voltage of 25 V, after which the voltage was reduced to 20 V. SEM images of the sample microstructure are shown in Fig. 4. Ordered pores are observed in the breaks of the tree-like structure. The pore depth was 150 nm and the average pore diameter was 550 nm.

As can be seen, the indicated variants of electrolytic anodizing allow obtaining needles with a coating in which blind channels are formed with a depth and average pore diameter that allows the sorption of macro- and/or microplastics.

Example 3. Sorption of plastic particles The most common plastic, polyethylene, was chosen as the plastic.

The content of plastic particles after the sorption process was determined gravimetrically.

To study the sorption properties, 10 ml of a solution of micro- and nanoplastics in water with a concentration of 16 μg/ml were prepared. Then we placed there the needles according to the invention, obtained according to example 2 with a thickness of 1000 nm. The solution was stirred on a magnetic stirrer. Then the needles were removed, and the solution was evaporated to dryness and weighed. Based on the difference in the content of microplastics before sorption and after drying, we determined the percentage of absorbed (sorbed) microplastics.

The microplastic sorption value was 0.5%, meaning that one needle can sorb 0.08 μg of micro- and/or nanoparticles of plastic. Bibliography:

1. Heather A Leslie et al., Discovery and quantification of plastic particle pollution in human blood, ScienceDirect, Environ Int. May 2022; 163:107199. doi:10.1016/j.envint.2022.107199. Epub 2022 Mar 24.

2. Lauren C Jenner et al., Detection of microplastics in human lung tissue using pFTIR spectroscopy, ScienceDirect, Sci Total Environ, 2022 Jul 20; 831:154907. doi:

10.1016/j.scitotenv.2022.154907. Epub 2022 Mar 29.

3. Elisabeth S. Gruber et al., To Waste or Not to Waste, Springerlink, 2023, volume 15, pages 33-51.

4. Antonio Ragusa et al., Plasticenta: First evidence of microplastics in human placenta, ScienceDirect, Environ Int. 2021 Jan; 146:106274. doi: 10.1016/j.envint.2020.106274. Epub 2020 Dec 2.

5. Fiona Harvey and Jonathan Watts, Microplastics found in human stools for the first time, The Guardian, Mon 22 Oct 2018 23.00 BST

6. RU 2674985C2, 14.12.2018.

7. KHAFIZOV A.A. et al. Spraying of ferromagnetic powder on steel using a plasma installation with an electrolytic cathode, Socio-economic and technical systems: research, design, optimization, 2015, Vol. 1, No. 1 (64), pp. 25-33.

8. RU 2761440 C2 12/08/2021.

9. RU 2717705 C1, 03/25/2020.

10. RU 2773965 C1, 06/14/2022.

11. RU 189268 U1, 05/17/2019

Claims

Invention formula 1. A method for producing acupuncture needles with an aluminum oxide coating, including carrying out atomic layer deposition (ALD) cycles under the following parameters: pressure 10 mbar ± 0.1 mbar, reactor temperature 100 °C, each ALD cycle for depositing aluminum oxide from trimethylaluminum (TMA) and water consists of the following stages: - admission of TMA into the reaction chamber; - an inert gas is passed through the chamber; - introducing water vapor into the reaction chamber; - an inert gas is passed through the chamber. 2. An acupuncture needle for sorption of micro- and/or nanoparticles of plastic, obtained by the method according to item 1, having a coating of an aluminum oxide film, wherein the film, after anodization, has a developed structure of tree-like blind pores - molecular sieves. 3. Use of an acupuncture needle according to paragraph 2 for the sorption of micro- and/or nanoparticles of plastic.