Method for controlling motion behavior of micro-nano motor by adjusting engine distribution asymmetry degree

Abstract

The invention discloses a method for controlling the motion behavior of a micro-nano motor by adjusting the distribution asymmetry degree of an engine, and belongs to the field of intelligent materials and bionic micro-nano device construction. According to the method, on the basis of a liquid-liquid phase separation principle, polyacrylic acid and quaternized glucan are taken as elements, and condensed fluid drops are prepared in a buffer solution to serve as an engine regulator for enriching and protecting a biological enzyme engine; by adjusting the polarity of surface groups of solid-phase carrier microspheres and changing the interfacial tension among a condensate phase, a water phase and a solid phase, the three-phase tentacles among the condensate engine regulator, a solution and a substrate are further adjusted and controlled, so that the distribution asymmetry degree of a micro-nano motor engine is changed, the distribution condition of a biological enzyme engine in an interface area is changed, and the stability of the biological enzyme engine is improved. And regulation and control on the movement speed of the micro-nano motor driven by the biological enzyme are realized. According to the invention, a strategy for realizing micro-nano motor engine distribution asymmetry control by regulating and controlling the three-phase interfacial tension is provided for the first time.

Description

Technical Field

[0001] This invention belongs to the field of smart materials and biomimetic micro / nano device construction and control, specifically relating to a method for controlling the motion behavior of micro / nano motors by adjusting the asymmetry of engine distribution. Background Technology

[0002] Micro / nanomotors, also known as micro / nanorobots, are a new type of intelligent biomimetic material capable of converting different forms of energy (such as chemical energy, light energy, and magnetic energy) into kinetic energy at the micro- and nano-scale to perform specific tasks. With their controllable autonomous movement and active targeting characteristics, micro / nanomotors demonstrate the potential to perform a variety of precision operations in small, complex environments (such as within biological systems and microfluidic chips). For example, in the biomedical field, they can be used to deliver targeted drugs across biological barriers; in environmental remediation, they are suitable for water remediation and the sensing and detection of hazardous substances.

[0003] The driving methods of micro- and nanomotors mainly include catalytic actuation, photodynamic actuation, magnetic actuation, and in vivo actuation. Catalytically driven micro- and nanomotors have the advantage of a wide range of energy sources, can achieve autonomous movement without the need for an external physical field, are not limited by the properties of optical or magnetic media, and can operate in deep tissues or complex environments, making them widely used in the treatment of deep lesions and environmental remediation. Catalytically driven micro- and nanomotors utilize the concentration gradient or bubbles generated by catalytic reactions to provide driving force. The core component responsible for energy conversion is called the "engine," and the asymmetric distribution of the "engine" is the root cause of the directional driving force. Therefore, the asymmetry of the micro- and nanomotor affects the speed of motor movement. Asymmetric micro- and nanomotors are diverse, including those fabricated using sputtering deposition techniques to create "Janus"-like structures (see patent: A method for preparing spherical gallium-magnesium Janus microparticles, CN202210364959.8), flask-shaped or bowl-shaped micro- and nanomotors prepared using directional growth methods (see patent: A method for super-assembly preparation of intelligent temperature-responsive nanomotors, CN202111623694.0), and micro- and nanomotors prepared using a random bonding strategy of bioenzymes on the surface of nanoparticles (see patent: An application of laccase in nanomotor actuation, CN202110413196.7). In these models, the engine is anchored to the asymmetric structure, catalyzing the generation of an asymmetric concentration gradient, inducing self-diffusion or self-electrophoresis to drive the movement of the micro- and nanomotors. However, most reported micro- and nanomotors have fixed asymmetric structures; the engine is permanently fixed to the surface, and its distribution cannot be controlled, making it difficult to achieve speed control by adjusting the asymmetry of the engine distribution. Therefore, there is an urgent need to develop a strategy to achieve fine control of motion behavior by changing the structural characteristics of the motor itself (engine distribution asymmetry). Summary of the Invention

[0004] To address the technical problems of existing catalytically driven micro / nano motors, such as the inability to adjust and modify the asymmetric structure and the difficulty in controlling the movement speed, this invention provides a method for controlling the motion behavior of micro / nano motors by adjusting the asymmetry of the engine distribution. This method constructs an engine regulator based on condensates to effectively regulate the motion behavior of bio-enzyme-driven micro / nano motors. The innovation of this method lies in: utilizing electrostatic interactions to in-situ enrich GOx (or other bio-enzyme engines) within the condensate; and precisely adjusting the interaction forces and interfacial tension between the condensate phase and the solid support interface by controlling the types of surface groups on the solid support (such as silica, titanium dioxide, etc., which can be modified with different surface polarities), thereby changing the three-phase contact angle at the interface. This process directly achieves the adjustment of the asymmetry of the motor engine distribution, controlling the engine distribution on the surface of the micro / nano motor, and ultimately achieving the goal of controlling the motor's motion behavior.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for controlling the motion behavior of micro / nano motors by adjusting the asymmetry of engine distribution, the method being:

[0007] Step 1: Using polyacrylic acid and quaternized dextran as building blocks of condensates, liquid-liquid phase separation occurs in a phosphate buffer solution under certain concentrations and ratios by utilizing the electrostatic interaction of the two polyelectrolytes to prepare a condensate engine regulator, thus establishing a method for constructing a micro / nano motor condensate engine regulator.

[0008] Step 2: Weigh out a certain mass of solid-phase carrier microspheres with negatively charged groups of different polarities (-OH, -COOH, -HSO3), and assemble the condensed engine regulator obtained in Step 1 onto the surface of the solid-phase carrier microspheres with different polar groups using electrostatic interactions to obtain micro / nano motors with different engine distributions; propose the concept of asymmetry in the engine distribution of micro / nano motors by establishing a mathematical model, and analyze and compare the engine distribution in each case; the solid-phase carrier is one or more of silicon dioxide, titanium dioxide, and zinc oxide;

[0009] Step 3: Place one or more micro / nano motors equipped with condensed engine regulators obtained in Step 2 into a glucose oxidase (GOx) solution to enrich GOx in situ, resulting in micro / nano motors with different engine spatial distribution structures. Then, place the motors in a glucose solution and use ImageJ open-source software to track and mark the motor motion process. Calculate the motion performance parameters such as the motion trajectory and speed of different motors in glucose solutions of the same concentration. Analyze the influence of the asymmetry of the engine distribution on the motor motion behavior and establish a method to control the motion behavior of micro / nano motors by adjusting the asymmetry of the engine distribution.

[0010] Further, step one specifically involves: using phosphate buffer solution (PB) as a solvent, preparing PAA (Mw=2~10k) solution and Q-Dex (Mw=10~50k) solution of a certain concentration, and sonicating for 8~10 min until the solid is completely dissolved; placing the two solutions in a volume ratio of 1:1 in a centrifuge tube, and vortexing the two solutions for 3~5 min until the solution becomes a white suspension, centrifuging at high speed for 3~5 min, removing the supernatant and replacing it with an equal volume of PB buffer, and vortexing again for 3~5 min to disperse the agglomerates at the bottom into the solution to form an agglomerate engine regulator suspension, repeating 2~3 times to obtain an agglomerate engine regulator suspension based on PAA and Q-Dex with a certain particle size.

[0011] Furthermore, the PB buffer solution has a pH of 7.4 and a concentration of 50 mM, the PAA solution has a concentration of 0.4~0.6 mg / mL, the Q-Dex solution has a concentration of 4.0~6.0 mg / mL, the vortex mixer has a rotation speed of 2000~3000 rpm, and the centrifugation collection speed is 6000~8000 rpm.

[0012] Furthermore, step two specifically involves:

[0013] (1) Disperse hydroxylated solid-phase carrier microspheres (SMS-OH) in PB buffer solution to obtain SMS-OH suspension. Mix the suspension containing the condensate engine regulator obtained in step one with the SMS-OH suspension at a volume ratio of 1:1. Use a vortex mixer to mix the two solutions in a vortex mixer and let it stand for a period of time to construct a condensate engine regulator with a certain interface contact angle on the surface of SMS-OH. Based on the electrostatic interaction between sodium fluorescein and the condensate engine regulator, add sodium fluorescein to achieve fluorescence localization of the condensate under a laser confocal microscope. Observe and record its contact angle.

[0014] (2) Carboxylated solid-phase carrier microspheres (SMS-COOH) were dispersed in PB buffer solution to obtain SMS-COOH suspension. The suspension containing the condensate engine regulator obtained in step one was mixed with the SMS-COOH suspension at a volume ratio of 1:1. The two solutions were vortexed and mixed using a vortex mixer. After standing for a period of time, a condensate engine regulator with a certain interface contact angle was constructed on the surface of SMS-COOH. Based on the electrostatic interaction between sodium fluorescein and the condensate engine regulator, sodium fluorescein was added to achieve fluorescence localization of the condensate under a laser confocal microscope. The contact angle was observed and recorded.

[0015] (3) Disperse sulfonated solid-phase carrier microspheres (SMS-HSO3) in PB buffer solution to obtain SMS-HSO3 suspension. Mix the suspension containing the condensate engine regulator obtained in step one with the SMS-HSO3 suspension at a volume ratio of 1:1. Use a vortex mixer to mix the two solutions in a vortex mixer and let it stand for a period of time to construct a condensate engine regulator with a certain interface contact angle on the surface of SMS-HSO3. Based on the electrostatic interaction between sodium fluorescein and the condensate engine regulator, add sodium fluorescein to achieve fluorescence localization of the condensate under a laser confocal microscope. Observe and record its contact angle.

[0016] (4) A Cartesian coordinate system is established with the centroid of the solid carrier microsphere as the origin. Based on the size of the solid carrier microsphere and the condensate droplet and the three-phase contact angle, a two-phase flow wetting wall model is established in the finite element simulation software. The software is used to simulate the process of the condensate engine regulator gradually wetting the solid carrier microsphere from top to bottom. The centroid ordinate of the condensate engine regulator under different three-phase contact angles is calculated. A mathematical model is established to define the asymmetry of the micro-nano motor engine distribution. The mathematical relationship between the centroid ordinate of the engine regulator and the asymmetry is constructed. The engine distribution asymmetry of the micro-nano motor under different conditions is calculated.

[0017] Further, in step (1), the diameter of the SMS-OH is 0.5~3 μm, the concentration of the suspension of the condensate engine regulator is 1~2 mg / mL, the concentration of the SMS-OH suspension is 1~2 mg / mL, the pH of the PB buffer solution is 7.4, the concentration is 50 mM, the rotation speed of the vortex mixer is 1000~2000 rpm, the mixing time is 3~5 min, the settling time is 3~5 min, and the concentration of the sodium fluorescein is 1~2 μg / mL.

[0018] Further, in step (2), the diameter of the SMS-COOH is 0.5~3 μm, the concentration of the suspension of the condensate engine regulator is 1~2 mg / mL, the concentration of the SMS-COOH suspension is 1~2 mg / mL, the pH of the PB buffer solution is 7.4, the concentration is 50 mM, the rotation speed of the vortex mixer is 1000~2000 rpm, the mixing time is 3~5 min, the settling time is 3~5 min, and the concentration of the sodium fluorescein is 1~2 μg / mL.

[0019] Further, in step (3), the diameter of the SMS-HSO3 is 0.5~3 μm, the concentration of the suspension of the condensate engine regulator is 1~2 mg / mL, the concentration of the SMS-HSO3 suspension is 1~2 mg / mL, the pH of the PB buffer solution is 7.4, the concentration is 50 mM, the rotation speed of the vortex mixer is 1000~2000 rpm, the mixing time is 3~5 min, the settling time is 3~5 min, and the concentration of the sodium fluorescein is 1~2 μg / mL.

[0020] Furthermore, in step (4), during the finite element simulation calculation of the centroid's ordinate, the domain probe tool is used to define the integral phase field variable in the computational domain. (Condensate phase) =1, surrounding environment =0) to calculate the centroid, the specific calculation formula is defined as ;in Here, y is the centroid ordinate, y is the longitudinal coordinate of each spatial point in the computational domain, and dA is the area element. Based on this formula, the system calculates and tracks the centroid ordinate of the condensate engine regulator in real time; the mathematical formula is as follows: Where DA is the degree of asymmetry, m1 is the mass of the condensate engine regulator, and m2 is the mass of the solid-phase carrier microspheres.

[0021] Furthermore, step three specifically includes:

[0022] (1) Add one or more micro-nano motor suspensions equipped with condensate engine regulators obtained in step two to GOx solution and let stand for 3-5 min. GOx is enriched in situ into condensate engine regulators.

[0023] (2) Take the three micro-nano motor suspensions from step (1) and add them to a glucose PB (pH=7.4, 50 mM) solution. Use a fluorescence inverted microscope to photograph the motion trajectory of the micro-nano motors. Use the TrackMate function of the ImageJ open source software to perform motion tracking and path analysis. Finally, obtain the motion trajectory and motion speed of the micro-nano motors and obtain the relationship between motion speed and the asymmetry of the micro-nano motors.

[0024] Further, in step (1), the concentration of the solid-phase carrier micro-nano motor suspension equipped with the condensate engine regulator is 1~2 mg / mL, the concentration of the GOx solution is 4~6 mg / mL, and the volume ratio is 1:1; in step (2), the concentration of the glucose PB solution is 100~200 mM, the volume ratio of the micro-nano motor suspension to the glucose PB solution is 10~20 μL: 0.5~1 mL, the shooting frame rate of the fluorescence inverted microscope is 25 frames / s, and the shooting time is 20 s.

[0025] The advantages of this invention over the prior art are as follows:

[0026] 1. Compared with traditional micro / nano motor substrate material construction methods and bio-enzyme immobilization strategies, this invention constructs a condensed engine regulator to address the problem of uncontrollable engine distribution asymmetry. It achieves in-situ enrichment of bio-enzyme engines through a gentle, non-bonded method. By adjusting the functional group type on the surface of the solid-phase carrier microspheres, the three-phase contact angle of the condensed phase-solid phase-liquid phase is controlled, thereby realizing the dynamic adjustment of the micro / nano motor engine distribution asymmetry.

[0027] 2. Compared with traditional asymmetric micro-nano motors, which cannot measure the asymmetry of engine distribution and whose relationship with motion behavior is unclear, this invention establishes a mathematical model to measure the asymmetry of engine distribution in micro-nano motors, reveals the relationship between engine distribution asymmetry and the motion speed of micro-nano motors, and realizes the regulation of the motion behavior of micro-nano motors. Attached Figure Description

[0028] Figure 1 Laser confocal microscopy image of the PAA / Q-Dex condensate engine regulator;

[0029] Figure 2 A schematic diagram of a method for constructing a micro / nano motor with a condensed engine regulator;

[0030] Figure 3 Laser confocal microscopy image of a micromotor based on a SiO2-COOH substrate;

[0031] Figure 4A scanning electron microscope image of a micromotor based on a SiO2-COOH substrate;

[0032] Figure 5 A schematic diagram of the mathematical model for calculating the asymmetry of micro / nano motors;

[0033] Figure 6 The physical model diagram for the finite element simulation of the wetting process of SiO2-COOH surface condensates;

[0034] Figure 7 This is a laser confocal microscope image of a micromotor based on a SiO2-OH substrate;

[0035] Figure 8 Laser confocal microscopy image of a micromotor based on a SiO2-HSO3 substrate;

[0036] Figure 9 Statistical histograms of the three-phase contact angles on the surfaces of three types of SiO2 microspheres;

[0037] Figure 10 The image shows the motion trajectory of a SiO2 micromotor in a 100 mM glucose solution.

[0038] Figure 11 A statistical histogram of the motion velocity of a SiO2 micromotor in a 100 mM glucose solution;

[0039] Figure 12 Statistical histograms of the three-phase contact angles on the surfaces of three types of TiO2 microspheres;

[0040] Figure 13 The image shows the motion trajectory of a TiO2 micromotor in a 100 mM glucose solution.

[0041] Figure 14 The histogram shows the motion velocity of the TiO2 micromotor in a 100 mM glucose solution. Detailed Implementation

[0042] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0043] This invention utilizes the electrostatic interaction between PAA and Q-Dex to construct LLPS condensate droplets as engine regulators for micro / nano motors. This regulator can gently enrich bioenzymes (such as GOx) in situ within the condensate through electrostatic interactions. Simultaneously, by controlling the polarity of the surface functional groups of the solid-phase support microspheres (such as silica, titanium dioxide, or other solid-phase supports with different surface polarity modifications), the interfacial tension between the condensate phase, aqueous phase, and solid phase can be altered. This, in turn, controls the three-phase contact angle between the condensate engine regulator and the substrate surface and solution, ultimately achieving the regulation of the asymmetry in the distribution of the micro / nano motor engine, thereby controlling the speed of the micro / nano motor. Based on the dynamic regulation advantages achieved by the above technical solution, this invention establishes a micro / nano motor motion control strategy based on the regulation of engine distribution asymmetry, which is the core innovation of this invention.

[0044] This invention aims to address the challenges faced by existing bio-enzyme-driven micro / nanomotors: the asymmetry of the distribution of bio-enzyme engines in micro / nanomotors is difficult to dynamically control, hindering speed regulation. To address this, this invention constructs a condensate dynamic engine regulator, revealing the correlation mechanism between the asymmetry of micro / nanomotor asymmetry and its motion behavior, thereby enhancing the motion control capability of enzyme-driven micro / nanomotors. Specifically, using silica microspheres or titanium dioxide microspheres as the substrate material, PAA and Q-Dex as the condensate regulator building blocks, and GOx as the driving engine, an enzyme-driven micro / nanomotor system with a condensate engine regulator is constructed. By adjusting the polarity of the functional groups on the surface of silica or titanium dioxide, changing the interfacial tension of the three phases, and controlling the three-phase contact angle, the speed regulation effect of the motor based on adjusting the asymmetry of the micro / nanomotor engine distribution is achieved. This system is simple to construct, the immobilization and regulation conditions of the bio-enzyme are mild, and the dynamic condensate engine regulator effectively regulates the asymmetry of the motor engine distribution, thus providing a new method for regulating the speed of bio-enzyme-driven micro / nanomotors. This invention can be applied to the fabrication of intelligent biomimetic micro / nano actuators (such as micro / nano motors) and the precise control of their motion behavior.

[0045] This invention aims to address a key problem in the field of enzyme-driven micro / nanomotors: the difficulty in dynamically controlling the asymmetry of the distribution of enzyme engines on the surface of micro / nanomotors, leading to the inability to regulate motion behavior. The core of this invention lies in: based on the principle of liquid-liquid phase separation (LLPS), using polyacrylic acid (PAA) and quaternized dextran (Q-Dex) as building blocks, condensed droplets are prepared in a buffer solution as engine regulators to enrich and protect the enzyme engines; by adjusting the polarity of the surface groups of solid microspheres (SMS), the interfacial tension between the condensed phase, aqueous phase, and solid phase is changed, thereby controlling the three-phase contact angle between the condensed engine regulator and the solution and substrate, resulting in a change in the asymmetry of the micro / nanomotor engine distribution, thus achieving the regulation of the motion speed of the enzyme-driven micro / nanomotor. This invention is the first to propose a strategy for controlling the asymmetry of the micro / nanomotor engine distribution by regulating the three-phase interfacial tension, providing a novel method for regulating the motion speed of micro / nanomotors by adjusting the asymmetry of engine distribution.

[0046] Example 1:

[0047] The analysis of the motion behavior of engine regulators and micromotors constructed on SiO2-OH, SiO2-COOH, and SiO2-HSO3 surfaces was carried out according to the following steps:

[0048] 1. Prepare PAA solution (0.5 mg / mL) and Q-Dex solution (6.0 mg / mL) in 50 mM PB buffer solution at pH 7.4, and sonicate for 10 min until the solid is completely dissolved. Take 1 mL of each solution and place them in a centrifuge tube and mix them. Use a vortex mixer to mix the two solutions for 3 min, centrifuge (6000 rpm, 3 min) to remove the supernatant and replace it with an equal volume of PB buffer solution. Use a vortex mixer to disperse the aggregates at the bottom for 3 min. Repeat 2-3 times to obtain a PAA and Q-Dex-based aggregate engine regulator suspension.

[0049] 2. A certain mass of SiO2-OH, SiO2-COOH and SiO2-HSO3 with a particle size of 3 μm were dispersed in PB buffer solution to obtain three SiO2 suspensions with different surface polarities (1 mg / mL). The suspension containing the condensate engine regulator obtained in step 1 was mixed with the three SiO2 suspensions in a 1:1 ratio. The two solutions were mixed using a vortex mixer (2000 rpm, 3 min) and allowed to stand for 5 min to obtain three micron motors with condensate engine regulators with different interfacial contact angles. Sodium fluorescein (1 μg / mL) was added to fluoresce the condensates and observed under a laser confocal microscope. The contact angles were recorded and the average values ​​were calculated.

[0050] III. Establish a Cartesian coordinate system with the centroid of the SiO2 microspheres as the origin. Based on the dimensions of the SiO2 microspheres and the condensate engine regulator, establish a two-phase flow wetting wall model. Use finite element simulation software to simulate the centroid ordinate of the condensate engine regulator under the three conditions in step two. Then, use the formula... Calculate the asymmetry and use the density formula to calculate the mass of the condensate engine regulator: m1 = 0.795 × 10⁻⁶. -5 The mass of ng and SiO2 is m2 = 3.235 × 10⁻⁶. -5 Finally, the asymmetry of SiO2-OH was found to be DA=0.10, the asymmetry of SiO2-COOH was DA=0.33, and the asymmetry of SiO2-HSO3 was DA=0.39.

[0051] IV. Three types of SiO2 micromotors equipped with condensed engine regulators were placed in 200 μL of GOx solution (6 mg / mL) and allowed to stand for 3 min. GOx was enriched in situ into the condensed engine regulator, resulting in three micromotor suspensions with different asymmetries. 10 μL of each of the three micromotor suspensions was added to 0.5 mL of 100 mM glucose in PB (pH=7.4 50 mM) solution. The motion trajectory of the motors was captured using a fluorescence inverted microscope (25 frames / s, 20 s). The Track Mate function of the ImageJ open-source software was used for motion tracking and path analysis to obtain the motion trajectory and speed of the three motors.

[0052] Figure 1 The image shows a laser confocal microscope image of the PAA / Q-Dex condensate engine regulator in step one. It can be seen that the condensate droplets formed by liquid-liquid phase separation are spherical with a particle size of about 2.3 μm. Figure 2 This is a schematic diagram of the construction method of the micron motor with the condensed engine regulator in step two. Figure 3This is a laser confocal microscope image of the SiO2-COOH micromotor with a condensed matter engine regulator from step two. Figure 4 The image shows a scanning electron microscope image of the SiO2-COOH micromotor with a condensate engine regulator in step two, which shows that the condensate was assembled onto the SiO2-COOH surface. Figure 5 The diagram below shows the mathematical model of asymmetry in step three. The asymmetry of the motor can be obtained using parameters such as the centroid coordinates and mass of the condensate and silica. Figure 6 The diagram shows the physical model of the finite element simulation of the wetting process of SiO2-COOH surface condensates. The centroid coordinates of the condensate engine regulator can be obtained from the numerical simulation. Figure 7 Laser confocal microscopy images of the condensate engine regulator constructed on the SiO2-OH surface show that the condensate was assembled onto the SiO2-OH surface. Figure 8 Laser confocal microscopy images of the condensate engine regulator constructed on the SiO2-HSO3 surface show that the condensate was assembled onto the SiO2-HSO3 surface. Figure 9 The bar chart is a statistical histogram of the contact angles of the SiO2-OH, SiO2-COOH, and SiO2-HSO3 surface condensate engine regulators in step two. It can be seen that the three-phase contact angle of the SiO2-OH surface condensate engine regulator is approximately 17.00°, and the simulated and calculated asymmetry DA = 0.10; the three-phase contact angle of the SiO2-COOH surface condensate engine regulator is approximately 43.31°, and the simulated and calculated asymmetry DA = 0.33; the three-phase contact angle of the SiO2-HSO3 surface condensate engine regulator is approximately 59.72°, and the simulated and calculated asymmetry DA = 0.39. Figure 10 This is a tracking image of the micromotor's motion trajectory in a 100 mM glucose solution during step four. Figure 11 The histogram of the velocity of the micromotors in step four in a 100 mM glucose solution shows that the three types of micromotors exhibited significant movement in the glucose solution. The velocity of the SiO2-OH micromotor was approximately 2.01 μm / s, the velocity of the SiO2-COOH micromotor was approximately 2.51 μm / s, and the velocity of the SiO2-HSO3 micromotor was approximately 3.14 μm / s.

[0053] Example 2:

[0054] The analysis of the motion behavior of engine regulators and micromotors constructed on TiO2-OH, TiO2-COOH, and TiO2-HSO3 surfaces was carried out according to the following steps:

[0055] The difference between this embodiment and embodiment 1 is that in step two, a certain mass of TiO2-OH, TiO2-COOH and TiO2-HSO3 with a particle size of 3 μm are dispersed in PB buffer solution to obtain three TiO2 suspensions, which are then assembled with the condensate engine regulator and subsequently tested.

[0056] Figure 12 The statistical histograms of the contact angles of the surface condensate engine regulators for TiO2-OH, TiO2-COOH, and TiO2-HSO3 show that the three-phase contact angle of the TiO2-OH surface condensate engine regulator is approximately 14.49°, with a simulated and calculated asymmetry DA = 0.08; the three-phase contact angle of the TiO2-COOH surface condensate engine regulator is approximately 38.64°, with a simulated and calculated asymmetry DA = 0.31; and the three-phase contact angle of the TiO2-HSO3 surface condensate engine regulator is approximately 51.50°, with a simulated and calculated asymmetry DA = 0.37. Figure 13 The image shows the motion trajectory tracking of three TiO2-based micromotors in a 100 mM glucose solution. Figure 14 The histograms of the motion velocities of three TiO2-based micromotors in 100 mM glucose solution show that the three micromotors exhibited significant motion in the glucose solution. The motion velocity of the TiO2-OH micromotor was approximately 1.97 μm / s, that of the TiO2-COOH micromotor was approximately 2.42 μm / s, and that of the TiO2-HSO3 micromotor was approximately 2.95 μm / s.

[0057] Data analysis from the above embodiments shows that both PAA / Q-Dex condensate engine regulators can be assembled onto the surface of solid-phase carrier microspheres to in-situ enrich GOx and construct micro-motors. In both sets of embodiments, the SMS-HSO3 solid-phase surface exhibits the largest contact angle and asymmetry with the condensate, resulting in the most concentrated engine distribution. This leads to a larger local concentration gradient in the catalytic substrate decomposition, exhibiting the strongest asymmetric driving force and the highest movement speed. The SMS-COOH solid-phase surface has the second largest contact angle with the condensate, a relatively large asymmetry, and a relatively concentrated engine distribution, also exhibiting strong asymmetric driving force and a high movement speed. The SMS-OH solid-phase surface has the smallest contact angle with the condensate, the smallest asymmetry, and the most dispersed engine distribution, exhibiting the weakest asymmetric driving force and the lowest movement speed. Therefore, the asymmetry and movement speed of the motor can be controlled by adjusting the surface polarity of the solid-phase substrate: by adjusting the type and proportion of polar groups, the polarity of the solid-phase substrate surface is controlled, thereby adjusting the wetting condition (three-phase contact angle) of the condensate engine regulator, which in turn affects the asymmetry of the engine distribution and controls the movement speed of the motor. Within a certain range, the greater the asymmetry, the larger the local concentration gradient and the faster the movement speed; the smaller the asymmetry, the smaller the local concentration gradient and the slower the movement speed.

Claims

1. A method for controlling the motion behavior of micro / nano motors by adjusting the asymmetry of engine distribution, characterized in that: The method is as follows: Step 1: Using polyacrylic acid (PAA) and quaternized dextran (Q-Dex) as building blocks of the aggregate, an aggregate engine regulator was prepared in a phosphate buffer solution; Step 2: Assemble the condensed engine regulators obtained in Step 1 onto the surface of solid-phase carrier microspheres with different polar groups to obtain micro-nano motors with different engine distributions. The concept of asymmetry in the distribution of micro / nano motors is proposed by establishing a mathematical model, and the motor distribution in each case is analyzed and compared; the solid support is one or more of silicon dioxide, titanium dioxide, and zinc oxide; Step 3: Place one or more micro / nano motors equipped with condensed engine regulators obtained in Step 2 into a glucose oxidase (GOx) solution to enrich GOx in situ, resulting in micro / nano motors with different engine spatial distribution structures. Then, place the motors in a glucose solution and use ImageJ open-source software to track and mark the motor motion process. Calculate the motion performance parameters such as the motion trajectory and speed of different motors in glucose solutions of the same concentration. Analyze the influence of the asymmetry of the engine distribution on the motor motion behavior and establish a method to control the motion behavior of micro / nano motors by adjusting the asymmetry of the engine distribution.

2. The method for controlling the motion behavior of micro / nano motors by adjusting the asymmetry of engine distribution according to claim 1, characterized in that: Step one specifically involves: using phosphate buffer (PB) as a solvent, preparing PAA (Mw=2~10k) solution and Q-Dex (Mw=10~50k) solution of a certain concentration, and sonicating for 8~10 min until the solid is completely dissolved; placing the two solutions in a volume ratio of 1:1 in a centrifuge tube, and vortexing the two solutions for 3~5 min until the solution becomes a white suspension, centrifuging at high speed for 3~5 min, removing the supernatant and replacing it with an equal volume of PB buffer, and vortexing again for 3~5 min to disperse the agglomerates at the bottom into the solution to form an agglomerate engine regulator suspension, repeating 2~3 times to obtain an agglomerate engine regulator suspension based on PAA and Q-Dex with a certain particle size.

3. The method for controlling the motion behavior of micro / nano motors by adjusting the asymmetry of engine distribution according to claim 2, characterized in that: The PB buffer solution has a pH of 7.4 and a concentration of 50 mM, the PAA solution has a concentration of 0.4~0.6 mg / mL, the Q-Dex solution has a concentration of 4.0~6.0 mg / mL, the vortex mixer has a rotation speed of 2000~3000 rpm, and the centrifugation collection speed is 6000~8000 rpm.

4. The method for controlling the motion behavior of micro / nano motors by adjusting the asymmetry of engine distribution according to claim 1, characterized in that: Step two specifically involves: (1) Disperse hydroxylated solid-phase carrier microspheres (SMS-OH) in PB buffer solution to obtain SMS-OH suspension. Mix the suspension containing the condensate engine regulator obtained in step one with the SMS-OH suspension at a volume ratio of 1:

1. Use a vortex mixer to vortex mix the two solutions and let them stand for a period of time to construct a condensate engine regulator with a certain interface contact angle on the surface of SMS-OH. Based on the electrostatic interaction between sodium fluorescein and the condensate engine regulator, add sodium fluorescein to achieve fluorescence localization of the condensate under a laser confocal microscope. Observe and record its contact angle. (2) Carboxylated solid-phase carrier microspheres (SMS-COOH) were dispersed in PB buffer solution to obtain SMS-COOH suspension. The suspension containing the condensate engine regulator obtained in step one was mixed with the SMS-COOH suspension at a volume ratio of 1:

1. The two solutions were vortexed and mixed using a vortex mixer. After standing for a period of time, a condensate engine regulator with a certain interface contact angle was constructed on the surface of SMS-COOH. Based on the electrostatic interaction between sodium fluorescein and the condensate engine regulator, sodium fluorescein was added to achieve fluorescence localization of the condensate under a laser confocal microscope. The contact angle was observed and recorded. (3) Disperse sulfonated solid-phase carrier microspheres (SMS-HSO3) in PB buffer solution to obtain SMS-HSO3 suspension. Mix the suspension containing the condensate engine regulator obtained in step one with the SMS-HSO3 suspension at a volume ratio of 1:

1. Use a vortex mixer to mix the two solutions in a vortex mixer and let it stand for a period of time to construct a condensate engine regulator with a certain interface contact angle on the surface of SMS-HSO3. Based on the electrostatic interaction between sodium fluorescein and the condensate engine regulator, add sodium fluorescein to achieve fluorescence localization of the condensate under a laser confocal microscope. Observe and record its contact angle. (4) A Cartesian coordinate system is established with the centroid of the solid carrier microsphere as the origin. Based on the size of the solid carrier microsphere and the condensate droplet and the three-phase contact angle, a two-phase flow wetting wall model is established in the finite element simulation software. The software is used to simulate the process of the condensate engine regulator gradually wetting the solid carrier microsphere from top to bottom. The centroid ordinate of the condensate engine regulator under different three-phase contact angles is calculated. A mathematical model is established to define the asymmetry of the micro-nano motor engine distribution. The mathematical relationship between the centroid ordinate of the engine regulator and the asymmetry is constructed. The engine distribution asymmetry of the micro-nano motor under different conditions is calculated.

5. The method for controlling the motion behavior of micro / nano motors by adjusting the asymmetry of engine distribution according to claim 4, characterized in that: In step (1), the diameter of the SMS-OH is 0.5~3 μm, the concentration of the suspension of the condensate engine regulator is 1~2 mg / mL, the concentration of the SMS-OH suspension is 1~2 mg / mL, the pH of the PB buffer solution is 7.4, the concentration is 50 mM, the rotation speed of the vortex mixer is 1000~2000 rpm, the mixing time is 3~5 min, the settling time is 3~5 min, and the concentration of the sodium fluorescein is 1~2 μg / mL.

6. The method for controlling the motion behavior of micro / nano motors by adjusting the asymmetry of engine distribution according to claim 4, characterized in that: In step (2), the diameter of the SMS-COOH is 0.5~3 μm, the concentration of the suspension of the condensate engine regulator is 1~2 mg / mL, the concentration of the SMS-COOH suspension is 1~2 mg / mL, the pH of the PB buffer solution is 7.4, the concentration is 50 mM, the rotation speed of the vortex mixer is 1000~2000 rpm, the mixing time is 3~5 min, the settling time is 3~5 min, and the concentration of the sodium fluorescein is 1~2 μg / mL.

7. The method for controlling the motion behavior of micro / nano motors by adjusting the asymmetry of engine distribution according to claim 4, characterized in that: In step (3), the diameter of the SMS-HSO3 is 0.5~3 μm, the concentration of the suspension of the condensate engine regulator is 1~2 mg / mL, the concentration of the SMS-HSO3 suspension is 1~2 mg / mL, the pH of the PB buffer solution is 7.4, the concentration is 50 mM, the rotation speed of the vortex mixer is 1000~2000 rpm, the mixing time is 3~5 min, the settling time is 3~5 min, and the concentration of the sodium fluorescein is 1~2 μg / mL.

8. The method for controlling the motion behavior of micro / nano motors by adjusting the asymmetry of engine distribution according to claim 4, characterized in that: In step (4), during the finite element simulation calculation of the centroid's ordinate, the domain probe tool is used to define the integral phase field variable in the computational domain. (Condensate phase) =1, surrounding environment =0) to calculate the centroid, the specific calculation formula is defined as ;in, Here, y is the centroid ordinate, y is the longitudinal coordinate of each spatial point in the computational domain, and dA is the area element. Based on this formula, the system calculates and tracks the centroid ordinate of the condensate engine regulator in real time; the mathematical formula is as follows: Where DA is the degree of asymmetry, m1 is the mass of the condensate engine regulator, and m2 is the mass of the solid-phase carrier microspheres.

9. The method for controlling the motion behavior of micro / nano motors by adjusting the asymmetry of engine distribution according to claim 1, characterized in that: Step three specifically involves: (1) Add one or more micro-nano motor suspensions equipped with condensate engine regulators obtained in step two to GOx solution and let stand for 3-5 min. GOx is enriched in situ into condensate engine regulators. (2) Take the three micro-nano motor suspensions from step (1) and add them to a glucose PB (pH=7.4, 50 mM) solution. Use a fluorescence inverted microscope to photograph the motion trajectory of the micro-nano motors. Use the Track Mate function of the ImageJ open-source software to perform motion tracking and path analysis. Finally, obtain the motion trajectory and motion speed of the micro-nano motors and obtain the relationship between motion speed and the asymmetry of the micro-motor.

10. A method for controlling the motion behavior of micro / nano motors by adjusting the asymmetry of engine distribution according to claim 9, characterized in that: In step (1), the concentration of the solid-phase carrier micro-nano motor suspension equipped with the condensate engine regulator is 1~2 mg / mL, the concentration of the GOx solution is 4~6 mg / mL, and the volume ratio is 1:1; in step (2), the concentration of the glucose PB solution is 100~200 mM, the volume ratio of the micro-nano motor suspension to the glucose PB solution is 10~20 μL: 0.5~1 mL, the shooting frame rate of the fluorescence inverted microscope is 25 frames / s, and the shooting time is 20 s.

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