阅读说明：本技术 一种基于生物质的螺旋状mof微米马达的制备方法 (Preparation method of spiral MOF (Metal organic framework) micro motor based on biomass ) 是由 董任峰 郑裕宏 蔡跃鹏 于 2021-09-02 设计创作，主要内容包括：本发明属于微米马达技术领域,具体涉及一种基于生物质的螺旋状MOF微米马达的制备方法,采用本发明方法制备得到的微纳马达同时具备微米马达和MOF材料的双重优势,可以在磁场的驱动下运动并执行任务。本发明方法能够通过原位生长的方式制备出螺旋状的MOF结构,利用生物模板自身的表面基团实现了MOF的原位生长,结合化学镀镍的方法,大幅度降低了马达的制造成本以及门槛,而且可以通过改变滤网孔径的大小实现不同大小的微米结构的制备,从而实现了在更多方面的应用价值。(The invention belongs to the technical field of micro motors, and particularly relates to a preparation method of a spiral MOF (metal organic framework) micro motor based on biomass. The method can prepare the spiral MOF structure in an in-situ growth mode, realizes the in-situ growth of the MOF by utilizing the surface groups of the biological template, greatly reduces the manufacturing cost and the threshold of the motor by combining a chemical nickel plating method, and can realize the preparation of the micrometer structures with different sizes by changing the aperture of the filter screen, thereby realizing the application value in more aspects.)

1. A preparation method of a spiral MOF micro motor based on biomass is characterized by comprising the following steps:

s1, culturing spirulina and collecting 15-70 μm long spirulina;

s2, soaking the spirulina of the step S1 in glutaraldehyde solution for 5-10 hours;

s3, soaking the spirulina of the step S2 in a colloidal palladium solution for activation for 10-12 minutes;

s4 and S3 the activated spirulina is dispersed in NaH₂PO₂·H₂Soaking in water containing O for 1-3 min;

s5, adding the spirulina of the step S4 into the plating solution for nickel plating, and stirring for reaction until the color is unchanged;

s6, dispersing the nickel-plated spirulina of the step S5 into a zinc nitrate methanol solution, dispersing a 2-methylimidazole methanol solution into the zinc nitrate methanol solution containing spirulina, collecting magnetic precipitates by using a magnet after stirring reaction, and finally drying to prepare the spiral MOF micro motor.

2. The method for preparing spiral biomass-based MOF micromotor, according to claim 1, wherein the mass concentration of the glutaraldehyde solution in step S2 is 2.5%.

3. The method for preparing spiral biomass-based MOF micromotor according to claim 1, wherein in step S3, the method for preparing the colloidal palladium solution is as follows:

s31, preparing a solution A: PdCl₂0.01g、SnCl₂·2H₂O 0.0253g、H₂O 2mL、HCl 1mL；

S32, preparing solution B: SnCl₂·2H₂O 0.75g、NaSnO₃·3H₂O 0.07g、HCl 2mL；

S33, stirring and mixing the A, B two solutions at 30 ℃, then preserving the mixture in a water bath at 50-60 ℃ for 3-5 hours, and finally adding ultrapure water to dilute the mixture to 10 mL.

4. A substrate according to claim 1A method for preparing spiral MOF micro motor of biomass, characterized in that in step S4, the NaH₂PO₂·H₂The molar concentration of O was 0.28 moL/L.

5. The method of claim 1, wherein in step S4, the spirulina is mixed with NaH₂PO₂·H₂The feed-liquid ratio of O to water is 3-5g/80 mL.

6. The method of claim 1, wherein the plating solution comprises 35g/L LiSO in step S5₄·6H₂O、20g/LNaH₂PO₂·H₂O、15g/L C₆H₅O₇Na₃·2H₂O、80mL/LNH₃·H₂O。

7. The method for preparing spiral biomass-based MOF micromotor according to claim 1, wherein in step S5, the feed-to-liquid ratio of spirulina to plating solution is 0.1-1g/5-50 mL.

8. The method of claim 1, wherein in step S6, the mass concentration of the zinc nitrate methanol solution is 1.5g/37.5mL, the mass concentration of the 2-methylimidazole methanol solution is 1.54g/37.5mL, and the volume ratio of the zinc nitrate methanol solution to the 2-methylimidazole methanol solution is 1: 1.

9. The method of claim 1, wherein in step S6, the ratio of nickel-plated spirulina to zinc nitrate in methanol is 0.2g-0.5g/37.5 mL.

10. The biomass-based spiral MOF micromotor prepared by the preparation method of any one of claims 1 to 9.

Technical Field

The invention belongs to the technical field of micro motors, and particularly relates to a preparation method of a spiral MOF micro motor based on biomass.

Background

Since the first gold-platinum (Au-Pt) bimetallic nanowire appeared in 2004, the artificial micro-nano motor has attracted extensive attention in the field of nanotechnology research. However, due to size limitations, one cannot install conventional engines for micron and nanometer scale structures to provide driving power. With the progress of research, people send that the cash-platinum bimetallic nanowire can realize axial movement in a hydrogen peroxide environment, which shows that the micro-nano motor can realize movement under a microscopic condition by converting chemical energy into mechanical energy, and this means that a highly controllable micro-nano structure is expected to be prepared in a manual synthesis mode, and then various microscopic operations are completed. Then, the research heat tide of the micro-nano motor quickly permeates into a plurality of subjects such as chemistry, biology, physics, medicine and the like, and becomes a hotspot in the current nano science research field. Through the development of more than ten years, the micro-nano motor makes considerable progress in the aspects of motion performance, preparation process and practical application. The micro-nano motor can be divided into a chemical energy driving type generated by chemical reaction and an external physical energy driving type (light energy, sound energy, magnetic energy and electric energy) according to the energy source driven by the motor. The chemical energy driven micro-nano motor is a motor driven by energy generated by chemical reaction, and the physical driving micro-nano motor is a motor providing driving energy by an external physical field. Meanwhile, the form of the micro-nano motor also presents diversified development situations. From simple bimetallic nanowires to the latter shell-like, Janus balls, microtubes and helices, even small fish-like, dart-like motors have emerged. Different types of motors may use different energies to drive themselves. The micro-nano motor is used as a movable micro device, and has better application value in the aspects of drug transportation, cell capture, toxin detection, pollutant degradation, heavy metal adsorption, oil stain treatment and the like. Currently, a micro-nano motor becomes a leading-edge hotspot in the field of nano technology research, and the appearance of the micro-nano motor undoubtedly provides a brand-new idea for solving the practical problems of future micro systems.

However, miniaturization also presents fundamental engineering challenges such as power supply, precision drive, multi-functional integration, and post-injection recovery or biodegradability. To date, several strategies to address actuation and motion control have been reported, including the application of external fields (e.g., magnetic fields, ultrasound, and light), the use of biological motors, the addition of chemical fuels, or combinations of the above, and the like. Among these, magnetic excitation is of particular interest because magnetic fields can continuously transmit power to motor devices in a wireless manner even at relatively high field strengths and have a high penetration capability through the human body, which has been proven by the widespread use of magnetic resonance imaging. In order to achieve micrometer-scale and nanometer-scale magnetic actuation, researchers have developed magnetic motors of various structures, such as rigid-flexible nanowires, microspheres, ellipsoids, helices, and even arbitrary shapes. These magnetic motors with complex geometries, powered by an externally applied magnetic field of a particular form (e.g., gradient, oscillation, rotation, or periodic variation), can be remotely controlled and precisely navigated in an environment filled with biological media (e.g., water, blood, serum, and mucus). Like the helical propulsion of flagellar bacteria (e.g., e.coli), magnetic helical micromotors can use low strength rotating magnetic fields in low reynolds number fluid environments to achieve drive and precise steering. The micro motor has many potential application values in biology and biomedicine, such as targeted drug delivery, accurate cell operation and the like. Currently, in terms of expanding functions (such as traceability, biodegradability and bioactivity) of the micro-nano motor, various engineering strategies can be used to implement the functions, such as surface decoration, chemical component selection, structural design, etc. However, in the preparation process of the existing micro-nano motor, a large amount of prepared samples are needed, the problem of sample shortage is serious, and meanwhile, a large instrument is needed in the preparation process, so that the preparation cost is high, the requirement on operation is also high, and the application of the micro-nano motor is limited to a certain extent.

In the aspect of mass production of motors, the biological template method is a low-cost, quick and effective method, and is particularly suitable for preparing magnetic spiral micro-motors. The key to the biological template method is to find a suitable biological template. Although there are many templates with spiral microstructures in nature, the templates which are widely available are not many and are not easy to dig. Among them, spirulina is a microorganism with a natural micro-helix structure, and the use of spirulina as a biological template is one of the ideal methods for preparing a magnetic spiral micro motor.

The existing research shows that the MOF has the shapes of regular polyhedron, rod, ellipsoid, fusiform and the like, and the characteristics of the MOF porous material can be utilized to realize the functions of adsorption, medicine carrying and the like. However, no spiral MOF structure micro-nano motor has been reported at present. Meanwhile, the micro-nano motor needs to have more functions, such as traceability, biodegradability and bioactivity, so as to be used as a multipurpose tool for various applications. These can be achieved by various engineering strategies such as surface decoration, chemical composition selection, structural design, or combinations of the above. Due to the excellent properties of the MOF material, the spiral micro-nano motor designed by combining the MOF material can greatly improve the application potential of the motor.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a preparation method of a spiral MOF micro motor based on biomass, the in-situ growth of MOF is realized by utilizing surface groups of a biological template, the manufacturing cost and the threshold of the motor are greatly reduced by combining a chemical nickel plating method, and the prepared motor has the double advantages of the micro motor and MOF materials.

In order to achieve the purpose, the invention adopts the technical scheme that:

a preparation method of a spiral MOF micro motor based on biomass is characterized by comprising the following steps:

s1, culturing spirulina and collecting 15-70 μm long spirulina;

s2, soaking the spirulina of the step S1 in glutaraldehyde solution for 5-10 hours to strengthen the frame strength of the spirulina;

s3, soaking the spirulina of the step S2 in a colloidal palladium solution for activation for 10-12 minutes;

s4 and S3 the activated spirulina is dispersed in NaH₂PO₂·H₂In the water of the oxygen-containing gas,soaking for 1-3min to remove Sn²⁺A protective shell exposing the Pd center;

s5, adding the spirulina of the step S4 into the plating solution for nickel plating, and stirring for reaction until the color is unchanged;

s6, dispersing the nickel-plated spirulina of the step S5 into a zinc nitrate methanol solution, dispersing a 2-methylimidazole methanol solution into the zinc nitrate methanol solution containing spirulina, collecting magnetic precipitates by using a magnet after stirring reaction, and finally drying to prepare the spiral MOF micro motor.

Firstly, a spiral MOF (metal organic framework) micromotor is prepared by a simple method, and the functional group of a biomass template and Zn are utilized⁺The interaction of (a) enables the in situ growth of MOFs on the surface of spirulina. The method of using the biomass template and chemical nickel plating well solves the problem of preparing a large amount of samples in the past. Meanwhile, the biomass template has wide sources and low cost, and a large instrument is not required to be used in the preparation process, so that the manufacturing cost and the threshold of the motor are greatly reduced. The invention combines the motion advantages of the magnetic driving type micro-nano motor and the characteristics of high porosity, multiple active sites and the like of the MOF, improves the adsorption performance of the motor, and increases the selection sites of functional modification.

Preferably, in step S2, the mass concentration of the glutaraldehyde solution is 2.5%.

Preferably, in step S3, the preparation method of the colloidal palladium solution is:

s31, preparing a solution A: PdCl₂ 0.01g、SnCl₂·2H₂O 0.0253g、H₂O 2mL、HCl 1mL；

S32, preparing solution B: SnCl₂·2H₂O 0.75g、NaSnO₃·3H₂O 0.07g、HCl 2mL；

S33, stirring and mixing the A, B two solutions at 30 ℃, then preserving the mixture in a water bath at 50-60 ℃ for 3-5 hours, and finally adding ultrapure water to dilute the mixture to 10 mL.

Preferably, in step S4, the NaH₂PO₂·H₂The molar concentration of O was 0.28 moL/L.

Preferably, in step S4, the spirulina is mixed with NaH₂PO₂·H₂The feed-liquid ratio of O to water is 3-5g/80 mL.

Preferably, in step S5, the plating solution includes 35g/L NiSO₄·6H₂O、20g/L NaH₂PO₂·H₂O、15g/L C₆H₅O₇Na₃·2H₂O、80mL/L NH₃·H₂O。

Preferably, in step S5, the ratio of spirulina to plating solution is 0.1-1g/5-50 mL.

Preferably, in step S6, the mass concentration of the zinc nitrate methanol solution is 1.5g/37.5mL, the mass concentration of the 2-methylimidazole methanol solution is 1.54g/37.5mL, and the volume ratio of the zinc nitrate methanol solution to the 2-methylimidazole methanol solution is 1: 1.

Preferably, in step S6, the material-to-liquid ratio of the nickel-plated spirulina to the zinc nitrate methanol solution is 0.2g-0.5g/37.5 mL.

Preferably, the stirring reaction in step S6 is a stirring reaction at room temperature for 24-36 hours.

The invention also provides a biomass-based spiral MOF micro motor prepared by the preparation method.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a preparation method of a spiral MOF (metal organic framework) structure motor based on biomass, and the prepared micro-nano motor has the advantages of a micro-motor and MOF materials, and can move and execute tasks under the driving of a magnetic field. The method can prepare the spiral MOF structure in an in-situ growth mode, realizes the in-situ growth of the MOF by utilizing the surface groups of the biological template, greatly reduces the manufacturing cost and the threshold of the motor by combining a chemical nickel plating method, and can realize the preparation of the micrometer structures with different sizes by changing the aperture of the filter screen, thereby realizing the application value in more aspects.

Drawings

FIG. 1 is an SEM image of a spiral MOF micromotor;

FIG. 2 is an XRD pattern of a spiral MOF micromotor;

FIG. 3 is the motion trace of the spiral MOF micromotor under the magnetic field of 3mT and 5 Hz.

Detailed Description

The following further describes the embodiments of the present invention. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The experimental procedures in the following examples were carried out by conventional methods unless otherwise specified, and the test materials used in the following examples were commercially available by conventional methods unless otherwise specified.

Example 1 preparation of spiral MOF-based micromotor

The method comprises the following steps:

(1) culturing Spirulina in Zarrouk culture medium at room temperature in an environment with light but without direct sunlight for 10 days, centrifuging to remove Spirulina from the culture solution, filtering to remove Spirulina of excess length and Spirulina of excess length, and collecting Spirulina of 40-70 μm length.

(2) The filtered spirulina was soaked in 2.5% glutaraldehyde solution for 7.5 hours to strengthen the frame strength of spirulina.

(3) 4g of spirulina was activated by immersing in 80mL of colloidal palladium solution for 11 minutes. The preparation method of the colloidal palladium solution comprises the following steps:

1) preparing a solution A: PdCl₂ 0.01g、SnCl₂·2H₂O 0.0253g、H₂O 2mL、HCl 1mL；

2) Preparing a solution B: SnCl₂·2H₂O 0.75g、NaSnO₃·3H₂O 0.07g、HCl 2mL；

3) A, B the two solutions were mixed with stirring at 30 ℃ and then incubated in a water bath at 55 ℃ for 4 hours, and finally diluted to 10mL with ultrapure water.

(4) Filtering with 800 mesh filter screen to collect activated Spirulina.

(5) Dispersing 4g of collected Spirulina in 80mL of water bath at 30 deg.C containing 0.28moL/L NaH₂PO₂·H₂Soaking in O water for 1min to remove Sn²⁺A protective shell exposing the Pd center.

(6) Adding 0.5g of soaked spirulina into 30mL of plating solution, stirring and plating nickel in a water bath at 55 ℃, and gradually lightening the color of the plating solution from dark blue along with the reaction until the color is unchanged.

The plating solution comprises the following components: 35g/L NiSO₄·6H₂O、20g/L NaH₂PO₂·H₂O、15g/L C₆H₅O₇Na₃·2H₂O、80mL/L NH₃·H₂O。

(7) 1.5g of zinc nitrate hexahydrate and 1.54g of 2-methylimidazole were dispersed in 37.5mL of methanol to form two clear solutions, and 0.35g of nickel-plated spirulina was added to the methanol solution of zinc nitrate and uniformly dispersed. Then the methanol solution of 2-methylimidazole is poured into the methanol solution of zinc nitrate dispersed with spirulina, then the mixed solution is stirred for 24 hours at room temperature, finally, the magnetic precipitate is collected by a magnet and dried at 60 ℃, and the spiral MOF micromotor (also called spiral ZIF-8) is prepared.

The morphology of the spiral MOF micromotor was observed by scanning electron microscopy on the prepared spiral MOF micromotor model MAIA3 from TESCAN corporation (SEM picture of fig. 1).

The in situ growth of ZIF-8 (generated from zinc nitrate hexahydrate and 2-methylimidazole) on spirulina was successfully achieved by testing the prepared spiral MOF micromotor by Bruker's X-ray diffractometer model D8 ADVANCE and comparing with standard XRD data simulated for metal organic framework material ZIF-8 (XRD pattern of fig. 2).

Dispersing a 2mg micrometer motor sample in a 1.5mL centrifuge tube filled with ultrapure water, placing 1.0-2.5 microliter of the dispersed solution in a three-axis Helmholtz rotating magnetic field coil, adjusting the parameters of the magnetic field to be 3mT and 5Hz respectively, observing the motion condition of the motor through a Nikon TI-S inverted fluorescence microscope, and tracking the motion track of the motor by NIS-Elements AR software. Fig. 3 shows the motion trajectory of the motor in the magnetic field for two times of switching the motion direction, and illustrates that the spiral MOF micro motor can precisely control the direction in the magnetic field.

Example 2 preparation of spiral MOF-based micromotors

The method comprises the following steps:

(1) culturing Spirulina in Zarrouk culture medium at room temperature in an environment with light but without direct sunlight for 10 days, centrifuging to remove Spirulina from the culture solution, filtering to remove Spirulina of excessive length and short length, and collecting Spirulina of 15-40 μm length.

(2) The filtered spirulina was soaked in 2.5% glutaraldehyde solution for 5 hours to strengthen the frame strength of the spirulina.

(3) 4g of spirulina was activated by immersing in 80mL of colloidal palladium solution for 10 minutes. The preparation method of the colloidal palladium solution comprises the following steps:

1) preparing a solution A: PdCl₂ 0.01g、SnCl₂·2H₂O 0.0253g、H₂O 2mL、HCl 1mL；

2) Preparing a solution B: SnCl₂·2H₂O 0.75g、NaSnO₃·3H₂O 0.07g、HCl 2mL；

3) A, B the two solutions were mixed with stirring at 30 ℃ and then incubated in a water bath at 50 ℃ for 5 hours, and finally diluted to 10mL with ultrapure water.

(4) Filtering with 800 mesh filter screen to collect activated Spirulina.

(5) Dispersing 3g of collected Spirulina in 80mL of water bath at 30 deg.C containing 0.28moL/L NaH₂PO₂·H₂Soaking in O water for 2min to remove Sn²⁺A protective shell exposing the Pd center.

(6) Adding 0.1g of soaked spirulina into 5mL of plating solution, stirring and plating nickel in a water bath at 50 ℃, and gradually lightening the color of the plating solution from dark blue along with the reaction until the color is unchanged.

The plating solution comprises the following components: 35g/L NiSO₄·6H₂O、20g/L NaH₂PO₂·H₂O、15g/L C₆H₅O₇Na₃·2H₂O、80mL/L NH₃·H₂O。

(7) 1.5g of zinc nitrate hexahydrate and 1.54g of 2-methylimidazole were dispersed in 37.5mL of methanol to form two clear solutions, and 0.2g of nickel-plated spirulina was added to the methanol solution of zinc nitrate and uniformly dispersed. Then the methanol solution of 2-methylimidazole is poured into the methanol solution of zinc nitrate dispersed with spirulina, then the mixed solution is stirred for 30 hours at room temperature, finally, the magnetic precipitate is collected by a magnet and dried at 60 ℃, and the spiral MOF micromotor (also called spiral ZIF-8) is prepared.

The SEM test results, XRD test results, and the motion trajectory under magnetic field were the same as or similar to those of example 1.

Example 3 preparation of spiral MOF-based micromotor

The method comprises the following steps:

(1) culturing Spirulina in Zarrouk culture medium at room temperature in an environment with light but without direct sunlight for 10 days, centrifuging to remove Spirulina from the culture solution, filtering to remove Spirulina of excess length and Spirulina of excess length, and collecting Spirulina of 40-70 μm length.

(2) The filtered spirulina was soaked in 2.5% glutaraldehyde solution for 10 hours to strengthen the frame strength of the spirulina.

(3) 4g of spirulina was activated by immersing in 80mL of colloidal palladium solution for 12 minutes. The preparation method of the colloidal palladium solution comprises the following steps:

1) preparing a solution A: PdCl₂ 0.01g、SnCl₂·2H₂O 0.0253g、H₂O 2mL、HCl 1mL；

2) Preparing a solution B: SnCl₂·2H₂O 0.75g、NaSnO₃·3H₂O 0.07g、HCl 2mL；

3) A, B the two solutions were mixed with stirring at 30 ℃ and then incubated in a water bath at 60 ℃ for 3 hours, and finally diluted to 10mL with ultrapure water.

(4) Filtering with 800 mesh filter screen to collect activated Spirulina.

(5) Dispersing 5g of collected Spirulina in 80mL of water bath at 30 deg.C containing 0.28moL/L NaH₂PO₂·H₂Soaking in O water for 3min to remove Sn²⁺A protective shell exposing the Pd center.

(6) Adding 1g of soaked spirulina into 50mL of plating solution, stirring and plating nickel in a water bath at 60 ℃, and gradually changing the color of the plating solution from dark blue to light along with the reaction until the color is unchanged.

The plating solution comprises the following components: 35g/L NiSO₄·6H₂O、20g/L NaH₂PO₂·H₂O、15g/L C₆H₅O₇Na₃·2H₂O、80mL/L NH₃·H₂O。

(7) 1.5g of zinc nitrate hexahydrate and 1.54g of 2-methylimidazole were dispersed in 37.5mL of methanol to form two clear solutions, and 0.5g of nickel-plated spirulina was added to the methanol solution of zinc nitrate and uniformly dispersed. Then the methanol solution of 2-methylimidazole is poured into the methanol solution of zinc nitrate dispersed with spirulina, then the mixed solution is stirred for 36 hours at room temperature, finally, the magnetic precipitate is collected by a magnet and dried at 60 ℃, and the spiral MOF micromotor (also called spiral ZIF-8) is prepared.

The SEM test results, XRD test results, and the motion trajectory under magnetic field were the same as or similar to those of example 1.

The embodiments of the present invention have been described in detail, but the present invention is not limited to the described embodiments. It will be apparent to those skilled in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, and the scope of protection is still within the scope of the invention.