Method for synthesizing bionic magnetosome nano chain in vitro
By synthesizing biomimetic magnetosome nanochains in vitro, the assembly problem of magnetosome chains has been solved, achieving excellent magnetocaloric properties and biocompatibility, thus enhancing the clinical application potential of magnetosomes.
Patent Information
- Application Number
- CN202511306598.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-12
- Publication Date
- 2025-12-19
AI Technical Summary
Existing technologies make it difficult to effectively assemble magnetosome chains in vitro, resulting in a decrease in their magnetocaloric properties, and chemically synthesized materials are unlikely to achieve the same effect as natural magnetosome chains.
Magnetosomes were isolated by culturing magnetotactic bacteria, washed with isopropanol and arranged under an external magnetic field, and then coated with silica by reacting with tetraethyl orthosilicate and ammonia to prepare biomimetic magnetosome nanochains.
The prepared biomimetic magnetic nanochains retain the natural chain structure, have ultra-long length and unidirectional alignment characteristics, significantly improve magnetocaloric performance and biocompatibility, and significantly increase coercivity and specific absorption rate.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of nanomaterials, and particularly relates to a method for synthesizing a biomimetic magnetosome nanochain in vitro. BACKGROUND
[0002] As an effective tumor treatment method, magnetic hyperthermia has been widely used in clinical practice. Magnetic materials play a crucial role in magnetic hyperthermia, especially the biological magnetosomes produced by magnetotactic bacteria. Compared with traditional chemically synthesized magnetic nanomaterials, magnetosomes have a single magnetic domain structure and perfect crystalline characteristics, which make them show significant advantages in magnetic hyperthermic effect. Existing researches show that when magnetosomes are arranged in chains in the body of magnetotactic bacteria, their magnetic hyperthermic performance is much better than other materials. However, for the consideration of biological safety, magnetosomes are usually extracted from the body of magnetotactic bacteria for use. Unfortunately, the extraction process will cause the collapse of the chain structure of magnetosomes, thereby significantly reducing their magnetic hyperthermic performance. Although some researches have tried to assemble chemically synthesized magnetic particles into magnetic rods by simulating the chain structure of magnetosomes, the magnetic hyperthermic effect of these synthetic materials is still inferior to that of the magnetosome chains in the body of magnetotactic bacteria. When magnetosomes are directly assembled into chains by this method, a large amount of aggregation will be generated, and it is difficult to obtain a monodisperse chain structure. Therefore, a new method is urgently needed to effectively assemble magnetosome chains in vitro to obtain magnetic hyperthermic materials with excellent magnetic hyperthermic performance. SUMMARY
[0003] To solve the above technical problems, the purpose of the present application is to provide a method for synthesizing a biomimetic magnetosome nanochain in vitro, which realizes the in-vitro assembly of magnetosomes biologically synthesized by magnetotactic bacteria while retaining the natural chain structure, and the obtained biomimetic magnetosome nanochain has an ultra-long length and a one-way arrangement characteristic, thereby significantly improving the magnetic hyperthermic performance and biocompatibility of magnetosomes.
[0004] The technical solution of the present application to solve the above technical problems is as follows: a method for synthesizing a biomimetic magnetosome nanochain in vitro is provided, which comprises the following steps in sequence: (1) culturing magnetotactic bacteria and separating magnetosomes, and then ultrasonically dispersing the magnetosomes into single or short-chain magnetosomes; (2) washing the magnetosomes with deionized water or a PBS solution, and then dispersing the magnetosomes in a solvent; (3) linearly arranging the magnetosomes under the action of an external magnetic field, and then adding tetraethyl orthosilicate and ammonia to react to form a silica coating, thereby obtaining a biomimetic magnetosome nanochain.
[0005] Further, in step (1), the magnetotactic bacteria are MSR-1 strains.
[0006] Further, in step (1), the ultrasonic frequency is 20 kHz, and the ultrasonic time is 0.5-1.5 h.
[0007] Further, in step (2), the solvent is 50-80 vt% isopropanol aqueous solution.
[0008] Further, in step (3), the magnetic field strength of the external magnetic field is 20-400 mT, and the action time is 10-60 min.
[0009] Further, in step (3), the external magnetic field is applied by placing a magnet on one side of the solution.
[0010] Further, in step (3), the external magnetic field is applied by placing a magnet on both sides or multiple directions of the solution.
[0011] Further, in step (3), the concentration ratio of the magnetic corpuscle, tetraethyl orthosilicate and ammonia water is 0.0067-0.08 mg / mL: 0.003-0.04 M: 0.1-0.5 M, and the reaction time is 0.5-12 h.
[0012] Further, in step (3), the biomimetic magnetic corpuscle nanochain is further surface-modified by polyethylene glycol carboxylic acid (mPEG-COOH) to improve the biocompatibility.
[0013] The application also provides the biomimetic magnetic corpuscle nanochain prepared by the method for synthesizing the biomimetic magnetic corpuscle nanochain in vitro.
[0014] Further, the length of the biomimetic magnetic corpuscle nanochain is 10.70±4.47 μm, and the width is 160 nm.
[0015] The application also provides the application of the biomimetic magnetic corpuscle nanochain in preparing a product for magnetic heat treatment.
[0016] The application has the following beneficial effects: 1. The method of the application uses isopropanol to wash the magnetic corpuscle, removes surface impurities, facilitates the dispersion of the magnetic corpuscle, and improves the assembly effect of the biomimetic magnetic corpuscle nanochain.
[0017] 2、Magnetosome chains biosynthesized by magnetotactic bacteria have excellent magnetic properties and tumor targeting potential, but their clinical application is limited due to structural damage during extraction and biosecurity issues. In this study, a biomimetic strategy was developed to assemble magnetosomes into silica-coated magnetic nanochains (B-MNC) using an improved Stöber method, which preserves the natural chain structure while improving biosecurity. The prepared B-MNC have an ultra-long length (10.70±4.47 μm) and a single-directional arrangement characteristic, with a coercivity of 33.55 mT, which is about 5 times that of bare magnetosomes, 1.4 times that of magnetotactic bacteria, and 2.2 times that of chemically synthesized magnetic nanochains (C-MNC22). They exhibit nearly ideal single-domain magnetic behavior, with a Mrs / Ms ratio of 0.5, which is superior to that of magnetosomes (0.35), magnetotactic bacteria (0.46), and C-MNC22 (0.27). Under an alternating magnetic field, their specific absorption rate (SAR) reaches 903.19 W / g, which is 2.3 times that of bare magnetosomes. In vitro experiments confirmed that their biocompatibility and therapeutic effect are significantly improved, with a killing efficiency of 71.4% for MB49 bladder cancer cells after 20 minutes of hyperthermia at 42°C, compared to 12.4% for magnetosomes. BRIEF DESCRIPTION OF DRAWINGS
[0018] Figure 1 Transmission electron microscopy images of biomimetic magnetosome nanochains assembled with or without isopropanol washing; Figure 2 Scanning electron microscopy and transmission electron microscopy images of biomimetic magnetosome nanochains assembled by magnetic attraction after ultrasonic washing with deionized water; Figure 3 Scanning electron microscopy images of biomimetic magnetosome nanochains assembled by magnetic attraction after ultrasonic washing with 1×PBS; Figure 4 Scanning electron microscopy images of biomimetic magnetosome nanochains assembled under different external magnetic field strengths; Figure 5 Schematic diagram of two magnetic attraction assembly methods; Figure 6 Scanning electron microscopy images of biomimetic magnetosome nanochains assembled by two magnetic attraction methods; Figure 7 Scanning electron microscopy images of biomimetic magnetosome nanochains before assembly by magnetic attraction; Figure 8 Transmission electron microscopy images of biomimetic magnetosome nanochains assembled under different reaction times; Figure 9 Transmission electron microscopy images of biomimetic magnetosome nanochains assembled by mixing magnetosomes with chemically synthesized magnetic particles in proportion; Figure 10 Scanning electron microscopy images of biomimetic magnetosome nanochains assembled after scaling up the reagents in proportion; Figure 11 Transmission electron microscope images of biomimetic magnetosome nanochains assembled for different concentrations of tetraethyl orthosilicate; Figure 12 Transmission electron microscope images of magnetosome, chemically synthesized magnetic particles, magnetotactic bacteria, biomimetic magnetosome nanochains and chemically synthesized magnetic particles assembled magnetic chains; Figure 13 A comparison chart of magnetic heating performance of chemically synthesized magnetic rods and biomimetic magnetosome nanochains of Example 1; Figure 14 A comparison chart of magnetic heating treatment effects of MB49 bladder cancer cells by naked magnetosomes and biomimetic magnetosome nanochains of Example 3. DETAILED DESCRIPTION
[0019] The principles and features of the present application are described below, and the examples are only used to explain the present application, and are not used to limit the scope of the present application. If the specific conditions are not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.
[0020] Example 1 A biomimetic magnetosome nanochain, the synthesis method thereof comprises the following steps in sequence: (1) Culturing magnetotactic bacteria MSR-1 and separating magnetosomes, and then dispersing the magnetosomes into single or short-chain magnetosomes under 20 kHz ultrasonic for 0.5 h; (2) Washing the magnetosomes with deionized water, and then dispersing the magnetosomes in a 60 vt% isopropanol aqueous solution; (3) Linearly arranging 0.0067 mg / mL magnetosomes under the action of an external magnetic field of 200 mT, and then adding 0.003 M tetraethyl orthosilicate and 0.1 M ammonia water to react to form a silica coating, and magnetically attracting for 0.5 h, then removing the magnetic field and standing for 11.5 h to obtain the biomimetic magnetosome nanochain.
[0021] Example 2 A biomimetic magnetosome nanochain, the synthesis method thereof comprises the following steps in sequence: (1) Culturing magnetotactic bacteria MSR-1 and separating magnetosomes, and then dispersing the magnetosomes into single or short-chain magnetosomes under 20 kHz ultrasonic for 1 h; (2) Washing the magnetosomes with deionized water, and then dispersing the magnetosomes in a 50 vt% isopropanol aqueous solution; (3) Linearly arrange 0.04 mg / mL magnetosomes under the action of an external magnetic field of 20 mT, then add 0.02 M tetraethyl orthosilicate and 0.3 M ammonia water to form a silica coating, and magnetically attract for 0.5 h, then remove the magnetic field and stand for 11.5 h to obtain the biomimetic magnetosome nanochain.
[0022] Example 3 A biomimetic magnetosome nanochain, the synthesis method of which comprises the following steps in sequence: (1) Cultivate magnetotactic bacteria MSR-1 and separate the magnetosomes, then disperse the magnetosomes into single or short-chain magnetosomes by ultrasonic treatment at 20 kHz for 1.5 h; (2) Wash the magnetosomes with deionized water, and then disperse the magnetosomes in 80 vt% isopropyl alcohol aqueous solution; (3) Linearly arrange 0.08 mg / mL magnetosomes under the action of an external magnetic field of 400 mT, then add 0.04 M tetraethyl orthosilicate and 0.5 M ammonia water to form a silica coating, and magnetically attract for 0.5 h, then remove the magnetic field and stand for 11.5 h to obtain the biomimetic magnetosome nanochain; further modify the biomimetic magnetosome nanochain with polyethylene glycol carboxylic acid (mPEG-COOH) to improve the biocompatibility.
[0023] Test Example 1 Reference Example 1 synthesis method, without adding an external magnetic field, to compare whether the deionized water ultrasonic washing assembly biomimetic magnetosome nanochain, transmission electron microscopy results as shown in Figure 1 , wherein a and b are biomimetic magnetosome nanochains assembled without deionized water ultrasonic washing, and c and d are biomimetic magnetosome nanochains assembled with deionized water ultrasonic washing.
[0024] It can be seen from Figure 1 that washing the magnetosomes with deionized water ultrasonic treatment is beneficial to the dispersion of the magnetosomes and has a great influence on the assembly of the biomimetic magnetosome nanochain.
[0025] Under the condition of an external magnetic field, after deionized water ultrasonic washing, the electron microscopy results are shown in Figure 2 , wherein a is a scanning electron microscopy image, and b is a transmission electron microscopy image.
[0026] It can be seen from Figure 2 that ultrasonic treatment can break the long-chain structure of the magnetosomes. By the methods of washing and ultrasonic dispersion, the large cross-linked biological membrane is reduced, the magnetosome chains are relatively dispersed, the magnetosomes become short chains wrapped with lipids and proteins, and the distance between the magnetosomes is significantly increased. The use of high-purity isopropyl alcohol and other chemical reagents in the assembly process can also induce protein deformation, destroy part of the lipids, and increase the dispersibility of the magnetosomes.
[0027] Test Example 2 Reference to the synthesis method of Example 1, the assembled magnetosomes were washed with deionized water instead of 1xPBS. Fresh magnetosomes were used, i.e. used within a week after the magnetotactic bacteria were crushed. The scanning electron microscope images of the synthetic biomimetic magnetosome nanochains are shown in Figure 3 .
[0028] As can be seen from Figure 3 , the proportion of straight chains of assembled biomimetic magnetosome nanochains decreases, and the magnetosome rings increase, forming a new structure of chain-ring. It is proved that PBS washing weakens the damage to the outer biological membrane of magnetosomes, and fresh magnetosomes also guarantee the integrity of the biological membrane, so that the ring structure of the magnetosomes of the magnetotactic bacteria in vitro is preserved.
[0029] Test Example 3 Reference to the synthesis method of Example 1, different sizes of external magnetic fields were applied during assembly to synthesize biomimetic magnetosome nanochains with different degrees of bending. The applied magnetic fields were 0 mT, 20 mT, 40 mT, 100 mT, 200 mT and 400 mT. The scanning electron microscope images of the biomimetic magnetosome nanochains synthesized under different magnetic field strengths are shown in Figure 4 .
[0030] As can be seen from Figure 4 , as the strength of the applied external magnetic field increases, the degree of bending of the biomimetic magnetosome nanochains gradually decreases, and when the applied magnetic field is 200 mT, the biomimetic magnetosome nanochains basically reach the ideal straight chain state. Assembly is a process of rearranging magnetosomes induced by an external magnetic field, and when the constant magnetic field is large enough, it can "straighten" the original curved magnetosome chain. On the contrary, if the magnetic field strength is too low, there is not enough magnetic field force to make the magnetosomes distribute along the magnetic force lines, and the induction effect is weakened.
[0031] Test Example 4 Reference to the synthesis method of Example 1, the way of applying an external magnetic field during assembly was changed, and the magnetic attraction was induced by one magnet and two magnets respectively, and the magnetic field strength was 200 mT. The magnetic field induction schematic diagram is shown in Figure 5 . Figure 6 The scanning electron microscope images of the biomimetic magnetosome nanochains assembled under the two kinds of magnetic attraction are shown, wherein a is the assembly under way 1, and b is the assembly under way 2.
[0032] As can be seen from Figure 6 , there are obvious differences between the biomimetic magnetosome nanochains assembled by the two kinds of magnetic induction. The biomimetic magnetosome nanochains assembled by way 1 have a higher degree of bending than those assembled by way 2, and some small-scale aggregation, in other words, the biomimetic magnetosome nanochains assembled by way 2 have relatively good dispersibility, and it is a more suitable magnetic induction way.
[0033] Test Example 5 With reference to the synthesis method of Reference Example 1, during the assembly process, a double-sided 400 mT external magnetic field was applied, and by controlling the application time of the external magnetic field during assembly, biomimetic magnetosome nanochains of different lengths were synthesized. The magnetic attraction time was 1 min, 3 min, 5 min, 10 min, 30 min and 60 min, respectively. The sizes of the biomimetic magnetosome nanochains synthesized under different magnetic attraction times are shown in Table 1.
[0034] Table 1 Size of biomimetic magnetosome nanochains synthesized under different magnetic attraction times
[0035] As can be seen from Table 1, the average length of the biomimetic magnetosome nanochains decreases first and then increases with the magnetic attraction time. The magnetosomes were washed and ultrasonicated before assembly, which destroyed the biological membrane. However, during the assembly process, the magnetosomes inevitably connected into long chains due to their own magnetism. Within 10 min of assembly, most of the magnetic chains had not yet completed fixation, so long curved chains were first obtained. With the extension of the magnetic attraction time, the original long curved chain structure was destroyed, the magnetosomes reorganized, and the chain length decreased. With the extension of the magnetic attraction time, the number of magnetosomes assembled into a chain increased, and eventually fixed.
[0036] Test Example 6 With reference to the synthesis method of Reference Example 1, the magnetic attraction during assembly was changed to magnetic attraction before assembly. After adding ammonia, the magnetic field was applied according to Method One, the magnetic field was removed after 15 min of magnetic attraction, and tetraethyl orthosilicate was added for reaction. The scanning electron microscope image of the biomimetic magnetosome nanochains synthesized is shown in Figure 7 .
[0037] As can be seen from Figure 7 , the biomimetic magnetosome nanochains obtained by magnetic attraction before assembly have good dispersity, and the whole is in the shape of a "crescent" curved chain, which is different from the biomimetic magnetosome nanochains without a magnetic field, and there is basically no bending on the chain. The bending may be due to slight oscillation and molecular thermal motion after losing the magnetic field induction, and also due to the action of gravity.
[0038] Test Example 7 With reference to the synthesis method of Reference Example 1, during the assembly process, a double-sided 400 mT external magnetic field was applied, and by controlling the reaction time, biomimetic magnetosome nanochains of different morphologies were synthesized. The reaction time was 1 min, 3 min, 6 min, 10 min and 30 min, respectively, and the reaction was terminated when the time was up. The transmission electron microscope images of the biomimetic magnetosome nanochains synthesized under different reaction times are shown in Figure 8 .
[0039] As can be seen from Figure 8It can be seen that with the progress of the assembly reaction, the proportion of the bent chain of the biomimetic magnetosome nanochain decreases, the straight chain proportion increases, and after 10 min, there is basically no biomimetic magnetosome nanochain with a particularly large bending degree, proving that the fixation of the magnetic chain shape has been completed at 10 min, and physical operations such as oscillation and centrifugation cannot easily change the morphology of the magnetic rod. And with the extension of the reaction time, the thickness of the silicon shell gradually increases, and the morphology basically does not change after 10 min, only the thickness of the silicon shell can increase. It is proved that the too thin silicon layer cannot form a fixed magnetosome rigid chain, and the thickness of the silicon layer is a key factor for forming the biomimetic magnetosome nanochain.
[0040] Test Example 8 Referring to the synthesis method of Example 1, the concentration of the magnetosome added in the assembly is changed to regulate the length of the biomimetic magnetosome nanochain. The concentration of the magnetosome is 0.0067 mg / mL, 0.013 mg / mL, 0.027 mg / mL, 0.04 mg / mL, 0.053 mg / mL, 0.067 mg / mL and 0.08 mg / mL, respectively. The size table of the biomimetic magnetosome nanochain synthesized by different concentrations of magnetosome is shown in Table 2.
[0041] Table 2 Size table of biomimetic magnetosome nanochain synthesized by different concentrations of magnetosome
[0042] As can be seen from Table 2, the average length of the biomimetic magnetosome nanochain increases with the increase of the concentration of the magnetosome, and the overall trend is increasing. Under the concentration of 0.0067-0.08 mg / mL of the magnetosome, the maximum length of the biomimetic magnetosome nanochain can be realized in the range of 11.93-19.19 μm, and the average length can be regulated in the range of 5.35-9.79 μm. The increase of the concentration of the magnetosome will increase the total number of the magnetosome particles in the assembly solution, and the number of the biomimetic magnetosome nanochain to which the magnetosome is evenly distributed will also increase, eventually increasing the average length of the biomimetic magnetosome nanochain. However, too high concentration will lead to the aggregation of the magnetosome in the assembly, thereby leading to the aggregation of the biomimetic magnetosome nanochain and affecting the dispersibility of the biomimetic magnetic chain.
[0043] Test Example 9 22 nm Fe3O4 magnetic square-shaped nanoparticles are synthesized by a traditional chemical synthesis method (thermal decomposition), the magnetic nanoparticles are mixed with the magnetosome at a ratio of 1:1, the magnetosome is replaced by the above-mentioned 1:1 mixture according to the synthesis method of Example 1, and the magnetic assembly is performed. The transmission electron microscope image of the synthesized biomimetic magnetosome nanochain is shown in Figure 9 .
[0044] From Figure 9It is known that the assembly of mixed particles does not yield a simple hybrid chain. Instead, chemically synthesized magnetic particles tend to align with particles of the same type, and magnetosomes also follow this pattern. This may stem from the differences in magnetic properties and morphology, such as dipole moments, between different types of magnetic particles. This pattern can be used to separate magnetosomes from other magnetic particles.
[0045] Experimental Example 10 Referring to the synthesis method in Example 1, the reagents for assembling the magnetosome chains (isopropanol, water, magnetosomes, ammonia, and tetraethyl orthosilicate) were simultaneously amplified 24-fold and 50-fold, respectively, using 50 mL and 100 mL blue-capped reagent bottles as reaction flasks. Scanning electron microscope images are shown below. Figure 10 As shown, a represents the biomimetic magnetic nanochain obtained after increasing the reagent amount by 24 times, and b represents the biomimetic magnetic nanochain obtained after increasing the reagent amount by 50 times.
[0046] Depend on Figure 10 It can be seen that after the overall amount of assembly reagents is increased by 24 times and 50 times, the biomimetic magnetic nanochains still maintain a straight chain morphology and do not show obvious aggregation. On the contrary, the dispersibility is even better. This makes it possible to further increase the production of biomimetic magnetic nanochains and lays the foundation for mass production.
[0047] Experimental Example 11 Following the synthesis method of Example 1, the concentration of tetraethyl orthosilicate added during assembly was varied to control the thickness of the silicon shell of the biomimetic magnetic nanochains. The tetraethyl orthosilicate concentrations were 0.00265 M, 0.00795 M, 0.01325 M, 0.0265 M, and 0.03975 M, respectively. Transmission electron microscopy images of the biomimetic magnetic nanochains synthesized at different tetraethyl orthosilicate concentrations are shown below. Figure 11 As shown.
[0048] Depend on Figure 11 It can be seen that the average diameter of the biomimetic magnetic nanochains increases with the increase of tetraethyl orthosilicate concentration, with a size range of 95.90-226.50 nm. The maximum and minimum sizes also show an overall increasing trend. When 2.65 mM tetraethyl orthosilicate is added, there are more bent chains. As the amount of tetraethyl orthosilicate added increases, the bent chain structure improves, and local bending occurs, but the overall structure remains straight.
[0049] Experimental Example 12 Fe3O4 magnetic nanoparticles (MNP22 and MNP59) of 22 nm and 59 nm were synthesized using a traditional chemical synthesis method (thermal decomposition) and assembled into magnetic rods (C-MNC22 and C-MNC59). Naked magnetosomes were extracted from the magnetotactic bacterium MSR-1 and simultaneously synthesized with magnetosome chains from natural magnetotactic bacteria (MSR-1) and the biomimetic magnetosome nanochains (B-MNC) from Example 1 at a frequency of 144.10 kHz and a magnetic field strength of 34.7 kA∙m. -1 Under the conditions, the magnetocaloric properties were evaluated and compared. The morphology of each material as shown in the transmission electron microscope is shown below. Figure 12 The evaluation and comparison results are as follows Figure 13 As shown.
[0050] Depend on Figure 13 It can be seen that the temperature change of conventionally chemically synthesized Fe3O4 magnetic nanoparticles (MNP22 and MNP59) is lower than that of bare magnetosomes, indicating that their magnetocaloric properties are relatively poor. In contrast, the temperature change of the in vitro assembled magnetosome nanochains (B-MNC) in Example 1 is significantly higher than that of the magnetosome chains (MSR-1) in natural magnetotactic bacteria and the chemically synthesized magnetic rods (C-MNC22 and C-MNC59). The coercivity of the biomimetic magnetosome nanochain of Example 1 was measured to be 33.55 mT, which is about 5 times that of the bare magnetosome, 1.4 times that of magnetotactic bacteria, and 2.2 times that of the chemically synthesized magnetic nanochain (C-MNC22). Furthermore, it exhibits near-ideal single-domain magnetic behavior with a Mrs / Ms ratio of 0.5, which is superior to that of the magnetosome (0.35), magnetotactic bacteria (0.46), and C-MNC22 (0.27). Under an alternating magnetic field, its specific absorption rate (SAR) reaches 903.19 W / g, which is 2.3 times that of the bare magnetosome.
[0051] Experimental Example 13 Using MB49 bladder cancer cells as experimental material, the magnetothermal therapeutic efficacy of the biomimetic magnetic nanochains described in Example 3 was verified through cell experiments under an alternating magnetic field with a frequency of 339.85 Hz. The results are as follows: Figure 14 As shown, a is the PBS control group, b is bare magnetic polyp + no magnetic field, c is biomimetic magnetic polyp nanochain + no magnetic field, and d is bare magnetic polyp + low alternating magnetic field (50 kA m). -1 e represents a biomimetic magnetic nanochain + a low alternating magnetic field (50 kA m). -1 f is a bare magnetic body + a high alternating magnetic field (60 kA m). -1 g is a biomimetic magnetic nanochain + a high alternating magnetic field (60 kA m). -1 ), h is a schematic diagram of the experiment.
[0052] Depend on Figure 14It can be seen that the in-vitro experiment proves that the biocompatibility and treatment effect of the biomimetic magnetosome nanochain of Example 1 are significantly improved: after 20 minutes of hyperthermia at 42 DEG C, the killing efficiency on MB49 bladder cancer cells reaches 71.4%, while the naked magnetosome is only 12.4%. The biomimetic method significantly improves the magnetothermal therapy performance of the magnetosome, and provides a promising platform for clinical cancer treatment.
[0053] The above merely describes preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement or improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A method for synthesizing biomimetic magnetic nanochains in vitro, characterized in that, The steps are as follows: (1) Culturing magnetotactic bacteria and isolating magnetosomes, then ultrasonically dispersing them into single or short-chain magnetosomes in PBS solution; (2) Wash the magnetosomes with deionized water or PBS solution, and then disperse the magnetosomes in the solvent; (3) The magnetic particles are linearly arranged under the action of an external magnetic field, and then tetraethyl orthosilicate and ammonia are added to react and form silica coating to obtain biomimetic magnetic particle nanochains.
2. The method for synthesizing biomimetic magnetosome nanochains in vitro as described in claim 1, characterized in that, In step (1), the magnetotactic bacteria is the MSR-1 strain.
3. The method for synthesizing biomimetic magnetic nanochains in vitro as described in claim 1, characterized in that, In step (1), ultrasound is performed at 20 kHz for 0.5-1.5 h.
4. The method for synthesizing biomimetic magnetic nanochains in vitro as described in claim 1, characterized in that, In step (2), the solvent is a 50-80 vt% isopropanol aqueous solution.
5. The method for synthesizing biomimetic magnetic nanochains in vitro as described in claim 1, characterized in that, In step (3), the magnetic field strength of the external magnetic field is 20-400 mT and the application time is 10-60 min.
6. The method for synthesizing biomimetic magnetosome nanochains in vitro as described in claim 1, characterized in that, In step (3), the concentration ratio of the magnetic microparticle, tetraethyl orthosilicate and ammonia is 0.0067-0.08 mg / mL: 0.03-0.04 M: 0.1-0.5 M; the reaction time is 0.5-12 h.
7. The method for synthesizing biomimetic magnetic nanochains in vitro as described in claim 1, characterized in that, In step (3), the biomimetic magnetic nanochains are further modified with polyethylene glycol carboxylic acid to improve biocompatibility.
8. The biomimetic magnetic nanochains prepared by the method for in vitro synthesis of biomimetic magnetic nanochains according to any one of claims 1-7.
9. The biomimetic magnetic nanochain as described in claim 8, characterized in that, It has a length of 10.70±4.47 μm and a width of 160 nm.
10. The application of the biomimetic magnetic nanochains of claim 8 in the preparation of products for magnetothermal therapy.