CN115850615A - Carboxyl magnetic beads and its preparation method and application - Google Patents

Abstract

The invention relates to the field of modification of functional polymers, in particular to carboxyl magnetic beads and a preparation method and application thereof. The invention provides a carboxyl magnetic bead modified by N-(3-aminopropyl) methacrylamide, through the reaction between N-(3-aminopropyl) methacrylamide and acrylic acid, the carboxyl magnetic Beads are modified as chain-extended carboxyl magnetic beads, which increases the steric hindrance between carboxyl magnetic beads. For carboxyl magnetic beads using the modification method of the present invention, the dispersibility and stability of the magnetic beads after coating with living materials are improved. , by improving the quality of test in vitro diagnostic kits and improving user experience.

Description

Carboxyl magnetic beads and its preparation method and application

technical field

The invention relates to the field of modification of functional polymers, in particular to carboxyl magnetic beads and a preparation method and application thereof.

Background technique

Magnetic beads refer to colloidal composite materials evenly dispersed in a certain base fluid, which have superparamagnetic properties, high specific surface area, and functional groups that can be modified. Therefore, antigens/antibodies, enzymes, nucleic acids/oligonuclear Nucleic acid, small molecule drugs, etc. are immobilized on its surface, making it widely used in the field of biomedicine. Based on the modifiability of the surface groups of magnetic beads, some magnetic beads containing amino, carboxyl, tosyl, hydroxyl and other groups on the surface have been widely used in the field of in vitro diagnostics, and the application of carboxyl magnetic beads is more common. When using carboxyl magnetic beads for antigen or antibody coating, usually the coated magnetic beads will have problems such as agglutination of the magnetic loader and a decrease in the value of the thermal acceleration signal. Through comparative studies, it is found that after the carboxyl magnetic beads are activated, the coating process of antigens or antibodies is prone to multi-layer coating, and the living material itself is too much adsorbed. The antigens or antibodies on the surface are due to their own hydrophobic adsorption or magnetic beads Small space hindrance is manifested as poor dispersion and stability.

In existing patents or literature reports, polymer compounds are usually used for the modification of carboxyl magnetic beads. The synthesis of these polymer compounds usually requires iterative synthesis, and the process is relatively complicated and the cost is high.

Contents of the invention

In view of this, the present invention provides carboxyl magnetic beads and a preparation method and application thereof. The invention provides a method for modifying carboxyl magnetic beads and an application thereof. Using the carboxyl magnetic beads of the modification method of the present invention improves the dispersibility and stability of the magnetic beads after living materials.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

The invention provides the application of N-(3-aminopropyl)methacrylamide in modifying carboxyl magnetic beads.

The present invention also provides modified carboxyl magnetic beads, which are modified by N-(3-aminopropyl)methacrylamide.

The present invention also provides a method for preparing the modified carboxyl magnetic beads: take carboxyl magnetic beads, and couple them with N-(3-aminopropyl)methacrylamide solution in the presence of a coupling agent. The product is polymerized with a cross-linking agent, acrylic acid and an initiator in the presence of nitrogen to obtain the modified carboxyl magnetic beads.

In some specific embodiments of the present invention, the carboxyl content of the carboxyl magnetic beads includes 30-63 μmol/g; and/or

The particle diameter of the carboxyl magnetic beads includes 0.98-1.45 μm.

In some specific embodiments of the present invention, the concentration of the N-(3-aminopropyl)methacrylamide solution includes 2.5-10 mg/mL; and/or

The coupling agent includes an EDC solution; the concentration of the EDC solution includes 10-30 mg/mL; and/or

The coupling time of the coupling includes 1 to 3 hours.

In some specific embodiments of the present invention, the concentration of the acrylic acid comprises 6.2-24.8 mg/mL; and/or

The crosslinking agent includes N,N-methylenebisacrylamide; the concentration of the N,N-methylenebisacrylamide is 1-5 mg/mL; and/or

The initiator includes ammonium persulfate or azobisisobutyronitrile _.

In some specific embodiments of the present invention, the polymerization temperature includes 40-60°C; and/or

The polymerization time includes 8-12 hours.

In some specific embodiments of the present invention, the preparation method specifically includes:

Wash the carboxyl magnetic beads and remove the supernatant, add EDC solution, shake for 1 to 3 hours, remove the supernatant by magnetic suction, add N-(3-aminopropyl)methacrylamide solution and continue to shake and couple to obtain N-( 3-aminopropyl)methacrylamide modified carboxyl magnetic beads. The purpose of this step is to modify N-(3-aminopropyl) methacrylamide to the surface of carboxyl magnetic beads in advance, and to prepare for the further connection of acrylic acid to the surface of carboxyl magnetic beads by free radical polymerization in the next step, which is also the present invention One of the key steps to obtain carboxyl magnetic beads with greater steric hindrance by chain extension of ordinary carboxyl magnetic beads.

The preparation method also includes:

The obtained N-(3-aminopropyl) methacrylamide-modified carboxyl magnetic beads were sucked magnetically, and the supernatant was removed, N, N-methylenebisacrylamide, acrylic acid and initiator were added, and the mixture was heated under a nitrogen atmosphere at 40 Shake polymerization at ~60°C for 8-12 hours to obtain modified chain-extended carboxyl magnetic beads. The purpose of this step is to utilize initiator, cross-linking agent to acrylic acid and the N-(3-aminopropyl) methacrylamide that the first step obtains to modify the carboxyl magnetic beads (the surface of this magnetic bead stretches out at this moment is N -(3-aminopropyl) methacryloyl) for connection, further connecting N-(3-aminopropyl) methacrylamide and acrylic acid through a cross-linking agent, so far to obtain the final modified carboxyl magnetic beads, The surface of the modified carboxyl magnetic beads is modified in two steps, and the surface carboxyl groups have certain steric hindrance, which is the main difference between the modified carboxyl magnetic beads and unmodified carboxyl magnetic beads, and also One of the key steps to modify ordinary carboxyl magnetic beads into carboxyl magnetic beads with extended chains and greater steric hindrance.

The present invention also provides a reagent, which includes any of the following items and acceptable auxiliary agents:

(1), the modified carboxyl magnetic beads; and/or

(II), the modified carboxyl magnetic beads prepared by the preparation method.

The present invention also provides the application of any of the following items in the preparation of in vitro diagnostic test kits:

(1), the modified carboxyl magnetic beads; and/or

(II), the modified carboxyl magnetic beads prepared by the preparation method; and/or

(III), said reagent.

The present invention also provides a kit, which includes any of the following items, and acceptable auxiliaries or carriers:

(1), the modified carboxyl magnetic beads; and/or

(II), the modified carboxyl magnetic beads prepared by the preparation method; and/or

(III), said reagent.

The present invention has obtained beneficial effects including but not limited to:

The use of the N-(3-aminopropyl)methacrylamide and acrylic acid-modified carboxyl magnetic beads can improve the dispersion and stability of the magnetic beads coated with antigen/antibody, thereby improving the quality of the in vitro diagnostic kit, Improve customer experience.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings that are required in the description of the embodiments or the prior art.

Fig. 1 shows the schematic diagram of N-(3-aminopropyl)methacrylamide, cross-linking agent (N,N-methylenebisacrylamide), acrylic acid and carboxyl magnetic beads;

Fig. 2 shows the schematic diagram of N-(3-aminopropyl) methacrylamide modified carboxyl magnetic beads;

Figure 3 shows N, N-methylenebisacrylamide as a crosslinking agent, a schematic diagram of N-(3-aminopropyl) methacrylamide and acrylic acid modified by free radical polymerization of magnetic beads;

Figure 4 shows the dispersibility comparison between Merck carboxyl magnetic beads and the modified carboxyl magnetic beads of the present invention in different projects;

Figure 5 shows the comparison of the dispersibility of Merck carboxyl magnetic beads, acrylamide + acrylic acid modified carboxyl magnetic beads and the modified carboxyl magnetic beads of the present invention in the PⅢNP project.

Detailed ways

The invention discloses a carboxyl magnetic bead and its preparation method and application. Those skilled in the art can learn from the content of this article and appropriately improve the process parameters to realize it. In particular, it should be pointed out that all similar replacements and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The method and application of the present invention have been described through preferred embodiments, and the relevant personnel can obviously make changes or appropriate changes and combinations to the method and application described herein without departing from the content, spirit and scope of the present invention to realize and Apply the technology of the present invention.

The purpose of the present invention is to provide a method for modifying carboxyl magnetic beads, which uses free radical polymerization to pass N-(3-aminopropyl)methacrylamide and acrylic acid through the cross-linking agent N,N-methylenebis Acrylamide is polymerized together, so that the carboxyl groups on the surface of ordinary carboxyl magnetic beads are extended after chemical modification, that is, the carboxyl groups on the surface of magnetic beads have a certain spatial structure. When the antigen/antibody is coated, the modified The long chain structure between magnetic beads and carboxyl groups acts as a "bridge" between antigen/antibody and magnetic beads. The carboxyl magnetic beads modified by this method have higher stability during the process of coating antigen/antibody; by improving the steric hindrance between magnetic beads after coating antigen/antibody, the coated magnetic beads have better dispersibility.

The object of the present invention is also to provide a kind of in vitro diagnostic kit, use N-(3-aminopropyl) methacrylamide and carboxyl magnetic beads modified by acrylic acid, which can improve the dispersibility and Stability, thereby improving the quality of in vitro diagnostic kits and improving customer experience.

In order to achieve the purpose of the above invention, the present invention provides the following technical scheme: remove the supernatant after washing the carboxyl magnetic beads, add EDC solution, remove the supernatant by magnetic suction after shaking for a period of time, add N-(3-aminopropyl) formazan The methacrylamide solution was continuously oscillatingly coupled to obtain N-(3-aminopropyl)methacrylamide-modified carboxyl magnetic beads. The obtained N-(3-aminopropyl) methacrylamide-modified carboxyl magnetic beads were magnetically sucked to remove the supernatant, and N,N-methylenebisacrylamide, acrylic acid and initiator were added, and in a nitrogen atmosphere, certain Vibrating and polymerizing for a period of time under temperature conditions to obtain modified chain-extended carboxyl magnetic beads.

The positive effect that the present invention produces is as follows:

In the modified carboxyl magnetic beads of the present invention, the carboxyl groups on the surface of the magnetic beads have a certain spatial structure. When the antigen/antibody is coated, the long chain structure between the modified magnetic beads and the carboxyl groups acts as an antigen/antibody and the "bridge" between magnetic beads. The carboxyl magnetic beads modified by this method can significantly reduce non-specific adsorption during the process of coating antigen/antibody, and have more chemical connection ratios and higher stability; by improving the steric hindrance between magnetic beads after coating antigen/antibody , the dispersibility of the coated magnetic beads is better. The method can obviously improve the spatial structure of the groups on the surface of the magnetic beads, and improve the dispersibility and stability during the process of coating living materials and after coating.

Unless otherwise specified, the raw materials and reagents used in the carboxyl magnetic beads provided in the present invention and their preparation methods and applications can be purchased from the market.

Below in conjunction with embodiment, further set forth the present invention:

Preparation example 1 Preparation of modified carboxyl magnetic beads of the present invention

(1) Take Merck carboxyl magnetic beads (lot number: M8998, carboxyl content: 30μmol/g, particle size: 0.98μm, concentration: 100mg/mL, 30μL), wash 3 times (0.1mol/L PBS, 300μL/time) Remove the supernatant, add EDC solution (10 mg/mL, 100 μL) and place on a shaker for 1 h after shaking evenly with a rapid mixer.

(2) Use a magnet to remove the supernatant, add N-(3-aminopropyl)methacrylamide (2.5mg/mL, 60μL) and 40μL buffer (0.1mol/L PBS buffer, pH7.4 ) placed on the shaker for 1h after shaking evenly with a fast mixer.

(3) Use a magnet to remove the supernatant, add N,N-methylenebisacrylamide (1mg/mL, 20μL), acrylic acid (6.2mg/mL, 60μL), ammonium persulfate (10mg/mL, 20 μL) and 100 μL buffer solution (0.1 mol/L PBS buffer solution, pH 7.4), filled with nitrogen gas, sealed, and kept shaking at 40°C for 8 hours to obtain the modified carboxyl magnetic beads of the present invention.

Preparation example 2 Preparation of modified carboxyl magnetic beads of the present invention

(1) Take Merck carboxyl magnetic beads (lot number: M9163, carboxyl content: 47μmol/g, particle size: 1.25μm, concentration: 100mg/mL, 30μL), wash 3 times (0.1mol/L PBS, 300μL/time) The supernatant was removed, EDC solution (20 mg/mL, 100 μL) was added, shaken evenly with a rapid mixer, and placed on a shaker for 1 h.

(2) Use a magnet to remove the supernatant, add N-(3-aminopropyl)methacrylamide (6.5mg/mL, 60μL) and 40μL buffer (0.1mol/L PBS buffer, pH7.4 ) placed on the shaker for 2 hours after shaking evenly with a fast mixer.

(3) Use a magnet to remove the supernatant, add N,N-methylenebisacrylamide (3mg/mL, 20μL), acrylic acid (15.5mg/mL, 60μL), ammonium persulfate (10mg/mL, 20 μL) and 100 μL buffer solution (0.1 mol/L PBS buffer solution, pH 7.4), filled with nitrogen gas, sealed, and kept shaking at 50°C for 10 h to obtain the modified carboxyl magnetic beads of the present invention.

Preparation example 3 Preparation of modified carboxyl magnetic beads of the present invention

(1) Take Merck carboxyl magnetic beads (batch number: M8727, carboxyl content: 63μmol/g, particle size: 1.45μm, concentration: 100mg/mL, 30μL), wash 3 times (0.1mol/L PBS, 300μL/time) The supernatant was removed, EDC solution (30 mg/mL, 100 μL) was added, shaken evenly with a rapid mixer, and placed on a shaker for 1 h.

(2) Use a magnet to remove the supernatant, add N-(3-aminopropyl)methacrylamide (10mg/mL, 60μL) and 40μL buffer (0.1mol/L PBS buffer, pH7.4 ) placed on the shaker for 3 h after shaking evenly with a fast mixer to obtain N-(3-aminopropyl)methacrylamide-modified carboxyl magnetic beads.

(3) Use a magnet to remove the supernatant, and add N,N-methylenebisacrylamide (5mg/mL, 20μL ), acrylic acid (24.8mg/mL, 60μL), ammonium persulfate (10mg/mL, 20μL) and 100μL buffer (0.1mol/L PBS buffer, pH7.4), filled with nitrogen and sealed, at 60℃ Continue shaking for 12 hours to obtain the modified carboxyl magnetic beads of the present invention.

Preparation Example 4 Preparation of Carboxyl Magnetic Beads Modified by Acrylamide+Acrylic Acid

(1) Take Merck carboxyl magnetic beads (batch number: M8727, carboxyl content: 63μmol/g, particle size: 1.45μm, concentration: 100mg/mL, 30μL), wash 3 times (0.1mol/L PBS, 300μL/time) The supernatant was removed, EDC solution (30 mg/mL, 100 μL) was added, shaken evenly with a rapid mixer, and placed on a shaker for 1 h.

(2) Use a magnet to remove the supernatant, add acrylamide (10mg/mL, 60μL) and 40μL buffer (0.1mol/L PBS buffer, pH7.4) respectively, and place it for oscillation after shaking evenly with a fast mixer Shake on the mixer for 3 hours to obtain acrylamide-modified carboxyl magnetic beads.

(3) Use a magnet to remove the supernatant, and add N,N-methylenebisacrylamide (5 mg/mL, 20 μL) and acrylic acid (24.8 mg/mL, 60 μL) to the acrylamide-modified carboxyl magnetic beads respectively. , ammonium persulfate (10 mg/mL, 20 μL) and 100 μL buffer solution (0.1mol/L PBS buffer solution, pH 7.4), filled with nitrogen and sealed, and kept shaking at 60 ° C for 12 hours to obtain acrylamide + acrylic acid modified Carboxylated magnetic beads.

Example 1 Stability and dispersibility of carboxyl magnetic beads coated with Anti-SSA antigen

Take unmodified carboxyl magnetic beads (that is, Merck carboxyl magnetic beads (batch number: M8998, carboxyl content: 30 μmol/g, particle size: 0.98 μm, concentration: 100 mg/mL, 30 μL)) and the preparation prepared in Example 1. Invent modified carboxyl magnetic beads, use a magnet to remove the supernatant, wash 3 times (0.1mol/L PBS, 300μL/time) to remove the supernatant, add EDC solution (20mg/mL, 100μL) and shake in a fast mixer After uniformity, place on the shaker for 1 h; use a magnet to remove the supernatant, add Anti-SSA antigen (3mg/mL, 15μL) and 85μL buffer (0.1mol/L PBS buffer, pH7.4) in the rapid mixing After oscillating evenly with the homogenizer, place it on the shaker for 2 hours, continue to use a magnet to absorb it, remove the supernatant, seal it with sealing solution for 3 times, and then dilute to 3mL.

The Anti-SSA project uses Merck carboxyl magnetic beads (batch number: M8998) and the modified carboxyl magnetic beads of the present invention prepared in Preparation Example 1. After being coated, the dispersion comparison after the magnetic attraction is accelerated for 3 days and loaded on the machine for 30 minutes is shown in the figure 4, it can be seen that the dispersibility of the finished product coated with the carboxyl magnetic beads modified by the method of the present invention is significantly better than that of the conventional unmodified carboxyl magnetic beads, and its excellent dispersibility benefits from the carboxyl magnetic beads modified by the method of the present invention. There is a relatively large steric hindrance between the beads, which makes the beads more dispersed.

The Anti-SSA project uses Merck carboxy magnetic beads (batch number: M8998) and the modified carboxy magnetic beads of the present invention prepared in Preparation Example 1. After coating, place them in parallel at 4°C and 37°C for 10 days, and use Antu Biological A2000Plus model The instrument used to detect the stability of carboxyl magnetic beads coated with Anti-SSA antigen.

The stability results are shown in Table 1:

Table 1 Thermal acceleration stability of Anti-SSA magnetic particles (R10 is thermal acceleration for 10 days)

It can be seen from Table 1 that the luminescence value of the Anti-SSA project using unmodified carboxyl magnetic beads after coating is comparable to the luminescence value of the carboxyl magnetic beads coated by the carboxyl magnetic bead modification method provided by the present invention. Compared with the modified carboxyl magnetic beads coating titer of the present invention is slightly lower than the unmodified carboxyl magnetic beads coating titer, but the thermal acceleration stability of the modified carboxyl magnetic beads of the present invention after coating is obviously better than that without modification. We believe that the spatial structure of the surface groups of the modified carboxyl magnetic beads in the present invention inhibits a part of the adsorption, improves the chemical connection rate, and then improves the thermal acceleration stability.

Example 2 Stability and dispersibility of β2-MG antibody coated with carboxyl magnetic beads

Take unmodified carboxyl magnetic beads (that is, Merck carboxyl magnetic beads (batch number: M9163, carboxyl content: 47 μmol/g, particle size: 1.25 μm, concentration: 100 mg/mL, 30 μL)) and the preparation prepared in Preparation Example 2. Invent modified carboxyl magnetic beads, use a magnet to remove the supernatant, wash 3 times (0.1mol/L PBS, 300μL/time) to remove the supernatant, add EDC solution (20mg/mL, 100μL) and shake in a fast mixer After uniformity, place it on the shaker for 1 hour; use a magnet to remove the supernatant, add β2-MG antibody (5mg/mL, 15μL) and 85μL buffer (0.1mol/L PBS buffer, pH7.4) in the rapid mixing After oscillating evenly with the homogenizer, place it on the shaker for 2 hours, continue to use a magnet to absorb it, remove the supernatant, seal it with sealing solution for 3 times, and then dilute to 3mL.

The β2-MG project uses Merck carboxyl magnetic beads (batch number: M9163) carboxyl magnetic beads and the modified carboxyl magnetic beads of the present invention prepared in Preparation Example 2. After being coated, the magnetic absorption is accelerated for 3 days and the dispersibility of the machine is loaded for 30 minutes. As shown in Figure 4, it can be seen that the dispersibility of the finished product coated with the carboxyl magnetic beads modified by the method of the present invention is significantly better than that of conventional unmodified carboxyl magnetic beads, and its excellent dispersibility benefits from the modification of the method of the present invention. The carboxyl magnetic beads have relatively large steric hindrance, which makes the magnetic beads more dispersed.

β2-MG antibody project Merck carboxyl magnetic beads (batch number: M9163) and the modified carboxyl magnetic beads of the present invention prepared in Preparation Example 2 were coated, placed in parallel at 4°C and 37°C for 10 days, and then used Antu Biological A2000Plus model The instrument used to test the stability of carboxyl magnetic beads after coating with β2-MG antibody.

The stability results are shown in Table 2:

Table 2 Thermally accelerated stability of β2-MG magnetic particles (R10 is thermally accelerated for 10 days)

It can be seen from Table 2 that the luminescence value of the β2-MG project coated with unmodified carboxyl magnetic beads is comparable to the luminescence value of the coated carboxyl magnetic beads obtained after modification by the carboxyl magnetic bead modification method provided by the present invention. Compared with the modified carboxyl magnetic beads coating titer of the present invention is slightly lower than the unmodified carboxyl magnetic beads coating titer, but the thermal acceleration stability of the modified carboxyl magnetic beads of the present invention after coating is obviously better than that without modification. We believe that the spatial structure of the surface groups of the modified carboxyl magnetic beads in the present invention inhibits a part of the adsorption, improves the chemical connection rate, and then improves the thermal acceleration stability.

Example 3 Stability and dispersibility of carboxyl magnetic beads coated with PⅢNP antigen

Take Merck carboxyl magnetic beads (batch number: M8727, carboxyl content: 63 μmol/g, particle size: 1.45 μm, concentration: 100 mg/mL, 30 μL), the modified carboxyl magnetic beads of the present invention prepared in Preparation Example 3 and the preparation The acrylamide + acrylic acid modified carboxyl magnetic beads prepared in Example 4 were magnetically attracted to remove the supernatant, washed 3 times (0.1mol/L PBS, 300μL/time) to remove the supernatant, and added EDC solution (20mg/mL , 100 μL) placed on the shaker for 1 h after shaking evenly with a fast mixer. Use a magnet to remove the supernatant, add PⅢNP antigen (5mg/mL, 5μL) and 95μL buffer (0.1mol/LPBS buffer, pH7.4), shake evenly with a fast mixer, and place on a shaker for 2h. Continue to use the magnet to remove the supernatant, seal with the sealing solution for 3 times, and then dilute to 3mL.

The PⅢNP project uses Merck carboxyl magnetic beads (batch number: M8727), the acrylamide+acrylic acid modified carboxyl magnetic beads prepared in Preparation Example 4, and the modified carboxyl magnetic beads of the present invention prepared in Preparation Example 3. After coating, the magnetic The comparison chart after 3 days of suction acceleration and 30 minutes of loading on the machine is shown in Figure 5. It can be seen that the N-(3-aminopropyl)methacrylamide used in the modification of the present invention benefits from its relatively extended spatial structure. Finally, the dispersibility of the modified carboxyl magnetic beads of the present invention is significantly better than that of acrylamide+acrylic acid modified carboxyl magnetic beads and Merck carboxyl magnetic beads (batch number: M8727), which is a larger space between the modified carboxyl magnetic beads of the present invention. Advantages brought about by resistance.

The PⅢNP project uses Merck carboxyl magnetic beads (batch number: M8727), the acrylamide+acrylic acid modified carboxyl magnetic beads prepared in Preparation Example 4, and the modified carboxyl magnetic beads of the present invention prepared in Preparation Example 3. After coating, parallel After being placed at 4°C and 37°C for 10 days, the stability of carboxyl magnetic beads coated with PⅢNP antigen was detected by using Antu Biological A2000Plus instrument.

The stability results are shown in Table 3:

Table 3 Thermal acceleration stability of PⅢNP magnetic particles (R10 is thermal acceleration for 10 days)

It can be seen from Table 3 that the PⅢNP project uses Merck carboxyl magnetic beads (batch number: M8727), the acrylamide+acrylic acid modified carboxyl magnetic beads prepared in Preparation Example 4, and the modified carboxyl magnetic beads of the present invention prepared in Preparation Example 3. The thermally accelerated stability of the magnetic bead coating becomes better in turn, and the thermally accelerated stability of the carboxyl magnetic beads modified by acrylamide + acrylic acid is still far behind the thermally accelerated stability of the carboxyl magnetic beads modified in the present invention. After the N-(3-aminopropyl) methacrylamide used in the invention is modified on the surface of the magnetic beads, because its carbon chain length is longer than that of acrylamide, the carboxyl group on the surface of the carboxyl magnetic beads modified by the two The steric hindrance between them is inconsistent, and the modified carboxyl magnetic beads of the present invention have a higher chemical connection rate and thus are more stable.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1.N- (3-aminopropyl) methacrylamide is used in modification of carboxyl magnetic beads.

2. A modified carboxyl magnetic bead, characterized in that it is modified with N- (3-aminopropyl) methacrylamide.

3. The method of claim 2, wherein the modified magnetic beads have a carboxyl group,

and (2) coupling the carboxyl magnetic beads with the N- (3-aminopropyl) methacrylamide solution in the presence of a coupling agent, and polymerizing a coupling product with a cross-linking agent, acrylic acid and an initiator in the presence of nitrogen to obtain modified carboxyl magnetic beads.

4. The method according to claim 3, wherein the carboxyl content of the carboxyl magnetic beads is 30 to 63 μmol/g; and/or

The particle size of the carboxyl magnetic beads is 0.98-1.45 mu m.

5. The method according to claim 3 or 4, wherein the concentration of the N- (3-aminopropyl) methacrylamide solution is comprised between 2.5 and 10mg/mL; and/or

The coupling agent comprises an EDC solution; the concentration of the EDC solution comprises 10-30 mg/mL; and/or

The coupling time of the coupling comprises 1-3 h.

6. The production method according to any one of claims 3 to 5, wherein the concentration of acrylic acid comprises 6.2 to 24.8mg/mL; and/or

The cross-linking agent comprises N, N-methylene bisacrylamide; the concentration of the N, N-methylene bisacrylamide is 1-5 mg/mL; and/or

The initiator comprises ammonium persulfate or azobisisobutyronitrile _。

7. The method of any one of claims 3 to 6, wherein the temperature of the polymerization comprises 40 to 60 ℃; and/or

The polymerization time is 8-12 h.

8. An agent, characterized in that it comprises any of the following and acceptable auxiliaries:

(I) The modified magnetic carboxyl bead of claim 2; and/or

(II) the modified magnetic carboxyl bead produced by the production method according to any one of claims 3 to 7.

9. Use of any of the following in the preparation of an in vitro diagnostic test kit:

(I) The modified magnetic carboxyl bead of claim 2; and/or

(II) the modified magnetic beads having carboxyl groups prepared by the method according to any one of claims 3 to 7; and/or

(III) the reagent according to claim 8.

10. A kit, characterized in that it comprises any of the following, together with acceptable adjuvants or carriers:

(I) The modified magnetic carboxyl bead of claim 2; and/or

(II) the modified magnetic beads having carboxyl groups prepared by the method according to any one of claims 3 to 7; and/or

(III) the reagent according to claim 8.

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