Automatic system for extracting and purifying stem cell exosome

Abstract

The invention relates to the technical field of biology, in particular to an automatic system for extracting and purifying stem cell exosomes. The method comprises the following steps: collecting a stem cell culture supernatant, carrying out pretreatment, and carrying out electrophoretic separation operation on the pretreated stem cell culture supernatant to obtain an exosome enrichment sample; carrying out molecular sieve filtering operation on the exosome enrichment sample, and calculating the impurity residual rate of the exosome sample filtered by the molecular sieve; based on the impurity residual rate, the separation effect is evaluated; and based on the evaluation effect, carrying out iterative optimization on the molecular sieve filtration operation to obtain a purified exosome sample. The problems that a traditional ultracentrifugation method is complex in operation and long in time consumption, the efficiency is low when a large number of samples are treated, and the structure and the function of the exosome are possibly damaged are solved; the precision is limited, and non-target substances are often mixed in an extracted exosome sample; and although part of emerging technologies improve the separation purity, the cost is high, the operation is tedious, and the large-scale popularization is limited.

Description

Technical Field

[0001] The present invention relates to the field of biotechnology, and in particular to an automated system for extracting and purifying stem cell exosomes. Background Art

[0002] With the continuous advancement of exosome research, especially in the field of stem cells, a variety of exosome extraction and purification methods have been developed, and the most commonly used techniques include ultracentrifugation, density gradient centrifugation and column chromatography. The method uses the physical properties of exosomes such as size and density for separation, and can extract exosome samples with relatively high purity. In recent years, with the advancement of nanotechnology and biomaterials, more and more new methods have been introduced for the separation and purification of exosomes, such as ultrafiltration, immunoaffinity capture and microfluidic chip technology. The new method improves the efficiency and purity of exosome separation and promotes the application of exosomes in drug delivery, cell therapy and disease diagnosis.

[0003] However, there are still many problems in the separation and purification of exosomes using the above technologies: first, the traditional ultracentrifugation method is complex and time-consuming, has high equipment requirements, is inefficient when processing large batches of samples, and the large centrifugal force may damage the structure and function of exosomes; second, the accuracy in removing impurities such as proteins and cell debris is limited, and the extracted exosome samples are often mixed with non-target substances, affecting the reliability of the experimental results; in addition, although some emerging technologies such as immunoaffinity capture have improved the separation purity, they still have the problems of high cost and cumbersome operation, which limits the promotion of the above technologies in large-scale applications. The above problems make it difficult for the above technologies to meet the requirements of high efficiency, accuracy and safety of exosome purification. Summary of the invention

[0004] The present invention provides an automated system for extracting and purifying stem cell exosomes to solve the problems of traditional ultracentrifugation, such as complex and time-consuming operation, high equipment requirements, low efficiency when processing large batches of samples, and the possibility of destroying the structure and function of exosomes due to large centrifugal force; limited accuracy in removing impurities such as proteins and cell debris, and non-target substances are often mixed in the extracted exosome samples, affecting the reliability of experimental results; and some emerging technologies such as immunoaffinity capture, although they improve separation purity, are high in cost and cumbersome in operation, limiting their promotion in large-scale applications.

[0005] The present invention provides an automated system for extracting and purifying stem cell exosomes, which specifically includes the following technical solutions:

[0006] An automated method for extracting and purifying stem cell exosomes, comprising the following steps:

[0007] S 1: collecting stem cell culture supernatant and pre-treating it to obtain pre-treated stem cell culture supernatant; combining the nonlinear electric field intensity regulation mechanism, performing electrophoresis separation operation on the pre-treated stem cell culture supernatant to obtain an exosome enriched sample;

[0008] S2: Perform molecular sieve filtration on the exosome enriched sample and calculate the impurity residual rate of the exosome sample after molecular sieve filtration; based on the impurity residual rate, evaluate the separation effect to obtain the evaluation effect; based on the evaluation effect, iteratively optimize the molecular sieve filtration operation to obtain a purified exosome sample.

[0009] Preferably, the S1 specifically includes:

[0010] In the process of implementing the electrophoretic separation operation, a nonlinear electric field strength regulation mechanism is introduced, and the electrophoretic mobility of exosomes is calculated in combination with the electric field strength.

[0011] Preferably, the S1 specifically includes:

[0012] The electrophoretic mobility of all exosomes was weighted averaged to obtain the mean mobility of exosomes. The time integral term and hyperbolic cosine function were introduced, and the electric field intensity was dynamically regulated in combination with the mean mobility of exosomes.

[0013] Preferably, the S2 specifically includes:

[0014] In the process of implementing the molecular sieve filtration operation, the electric field-regulated molecular sieve filtration mechanism is introduced, and the exosome passing rate is calculated by combining the electric field strength and the diameter of the exosomes, and the exosome sample after molecular sieve filtration is obtained; the specific calculation formula of the exosome passing rate is as follows:

[0015]

[0016] Among them, P(d i , E(t)) is the exosome passing rate, which indicates the probability of the i-th exosome passing through the molecular sieve under the electric field strength E(t) at time t; d i is the diameter of the i-th exosome; d filter is the pore size of the molecular sieve; β is the molecular size adjustment parameter; E(t) is the electric field strength at time t; E0 is the initial electric field strength; γ is the electric field strength adjustment parameter.

[0017] Preferably, the S2 specifically includes:

[0018] Based on the exosome passing rate, the exponential function and logarithmic function were introduced to calculate the impurity residual rate of the exosome sample after molecular sieve filtration, and the updated impurity residual rate was obtained; the impurity residual rate calculation formula is as follows:

[0019]

[0020] in, is the impurity residual rate after update; R is the impurity residual rate before update, and the initial value is the impurity ratio of the exosome enriched sample; α is the residual rate attenuation coefficient; Rδ is the power adjustment term of the impurity residual rate; δ is the residual rate adjustment exponent.

[0021] Preferably, the S2 specifically includes:

[0022] The updated impurity residual rate is compared with the preset target impurity residual rate, the separation effect is evaluated, and an evaluation result is obtained; the evaluation result includes continuing iterative optimization and stopping optimization; when the updated impurity residual rate is greater than the target impurity residual rate, an exponential and logarithmic function is introduced to dynamically optimize the molecular sieve pore size to obtain an updated molecular sieve pore size.

[0023] Preferably, the S2 specifically includes:

[0024] Based on the updated molecular sieve pore size, the separated exosomes and impurities are further subjected to molecular sieve filtration operation, and the impurity residual rate is recalculated after the filtration is completed; when the current impurity residual rate is greater than the target impurity residual rate, the molecular sieve pore size is further adjusted according to the current impurity residual rate, and the next round of iteration is performed until the impurity residual rate is less than or equal to the target impurity residual rate, at which time the iteration is stopped to obtain a purified exosome sample.

[0025] An automated system for extracting and purifying stem cell exosomes, comprising the following parts:

[0026] Sample pretreatment module, dynamic electrophoresis separation module, molecular sieve filtration module, filtration effect evaluation module, purified exosome collection module;

[0027] The sample pretreatment module collects the stem cell culture supernatant and performs pretreatment to obtain the pretreated stem cell culture supernatant; the sample pretreatment module is connected to the dynamic electrophoresis separation module by means of material transmission;

[0028] The dynamic electrophoresis separation module, combined with the nonlinear electric field intensity control mechanism, performs electrophoresis separation on the pretreated stem cell culture supernatant to obtain an exosome-enriched sample; the dynamic electrophoresis separation module is connected to the molecular sieve filtration module by material transmission, and is connected to the filtration effect evaluation module by data transmission;

[0029] The molecular sieve filtration module measures the diameter of exosomes and the impurity residual rate in the exosome enriched sample based on the exosome enriched sample and the molecular sieve pore size; purifies the exosome enriched sample through molecular sieve filtration operation according to the evaluation result of the filtration effect evaluation module, and outputs the purified exosome sample; the molecular sieve filtration module is connected to the filtration effect evaluation module by data transmission, and is connected to the purified exosome collection module by material transmission;

[0030] The filtering effect evaluation module calculates the exosome passing rate based on the diameter of the exosomes, the molecular sieve pore size used by the molecular sieve filtration module and the electric field strength of the dynamic electrophoresis separation module; updates the impurity residual rate based on the exosome passing rate; evaluates the separation effect based on the impurity residual rate to obtain an evaluation result, and updates the molecular sieve pore size according to the evaluation result; the filtering effect evaluation module is connected to the molecular sieve filtration module by data transmission;

[0031] The purified exosome collection module collects purified exosome samples and performs quality detection using nanoparticle tracking analysis.

[0032] The beneficial effects of the technical solution of the present invention are:

[0033] 1. The present invention uses dynamic electrophoresis technology, combined with a nonlinear electric field strength regulation mechanism, to utilize the difference in electrophoretic mobility between exosomes and impurity molecules to achieve fine separation of exosomes; regulating the electric field strength can avoid electrophoretic mobility saturation, ensure effective separation of exosomes and impurities, and greatly improve the purity and accuracy of exosome separation.

[0034] 2. The present invention introduces an electric field-regulated molecular sieve filtration mechanism, and optimizes the separation efficiency of the molecular sieve through the dual effects of the electric field strength and the diameter of the exosomes. In the dynamic update process of the molecular sieve pore size, a molecular sieve pore size update formula is introduced. Through the nonlinear relationship between the exosome pass rate and the impurity residual rate, the filtration process can effectively remove impurities and ensure the smooth passage of exosomes, thereby accurately improving the extraction efficiency and purity.

[0035] 3. The present invention dynamically controls the electric field strength and automatically optimizes the molecular sieve pore size, so that the entire exosome extraction process can adapt to different separation conditions in real time, and gradually optimizes each round of separation operation, so that the stem cell exosome extraction and purification system has a high degree of automation, reduces the complexity of manual adjustment, and not only improves the extraction efficiency of exosomes, but also ensures the structural and functional integrity of exosomes. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a structural diagram of an automated system for extracting and purifying stem cell exosomes according to the present invention;

[0037] Figure 2This is a flow chart of an automated method for extracting and purifying stem cell exosomes according to the present invention. DETAILED DESCRIPTION

[0038] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0039] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0040] The specific scheme of an automated system for extracting and purifying stem cell exosomes provided by the present invention is described in detail below with reference to the accompanying drawings.

[0041] See attached Figure 1 , which shows a structural diagram of an automated system for extracting and purifying stem cell exosomes provided by an embodiment of the present invention, the system comprising the following parts:

[0042] Sample pretreatment module, dynamic electrophoresis separation module, molecular sieve filtration module, filtration effect evaluation module, purified exosome collection module;

[0043] The sample pretreatment module collects the stem cell culture supernatant and performs pretreatment, wherein the pretreatment includes removing larger impurities by low-speed centrifugation and adjusting the pH value by using a phosphate buffer to obtain the pretreated stem cell culture supernatant; the sample pretreatment module is connected to the dynamic electrophoresis separation module by means of material transfer;

[0044] The dynamic electrophoresis separation module, combined with the nonlinear electric field strength control mechanism, performs electrophoresis separation on the pretreated stem cell culture supernatant; separates exosomes from impurities by the difference in electrophoretic mobility of different molecules, and enhances the separation effect by adjusting the electric field strength to obtain an exosome-enriched sample; the dynamic electrophoresis separation module is connected to the molecular sieve filtration module by material transmission, and is connected to the filtration effect evaluation module by data transmission;

[0045] The molecular sieve filtration module measures the diameter of exosomes and the impurity residual rate in the exosome enriched sample based on the exosome enriched sample and the molecular sieve pore size; purifies the exosome enriched sample through molecular sieve filtration operation according to the evaluation result of the filtration effect evaluation module, and outputs the purified exosome sample; the molecular sieve filtration module is connected to the filtration effect evaluation module by data transmission, and is connected to the purified exosome collection module by material transmission;

[0046] The filtering effect evaluation module calculates the exosome passing rate based on the diameter of the exosomes, the molecular sieve pore size used by the molecular sieve filtration module and the electric field strength of the dynamic electrophoresis separation module; updates the impurity residual rate based on the exosome passing rate; evaluates the separation effect based on the impurity residual rate to obtain an evaluation result, and updates the molecular sieve pore size according to the evaluation result; the filtering effect evaluation module is connected to the molecular sieve filtration module by data transmission;

[0047] The purified exosome collection module collects purified exosome samples, performs quality inspection through nanoparticle tracking analysis, ensures that the concentration, particle size distribution, morphology and functional integrity of the exosomes meet the requirements, and uses the exosome samples that meet the requirements for subsequent experiments or applications.

[0048] See attached Figure 2 , which shows a flow chart of an automated method for extracting and purifying stem cell exosomes provided by an embodiment of the present invention, the method comprising the following steps:

[0049] S 1: collecting stem cell culture supernatant and pre-treating it to obtain pre-treated stem cell culture supernatant; combining the nonlinear electric field intensity regulation mechanism, performing electrophoresis separation operation on the pre-treated stem cell culture supernatant to obtain an exosome enriched sample;

[0050] First, the stem cell culture supernatant is collected and pretreated to obtain the pretreated stem cell culture supernatant; the pretreatment includes using low-speed centrifugation to remove larger impurities and using phosphate buffer to adjust the pH value. Specifically, large cell fragments and macromolecular impurities in the stem cell culture supernatant are removed by low-speed centrifugation to obtain centrifuged stem cell culture supernatant, so as to improve the separation accuracy of exosomes and reduce larger particles that may interfere with the extraction of exosomes in subsequent operations, laying the foundation for subsequent extraction and purification operations; the centrifuged stem cell culture supernatant is added to phosphate buffer, and the pH value is adjusted to 7.4 to ensure that the pretreated stem cell culture supernatant can maintain stable charge and migration behavior during electrophoretic separation;

[0051] Then, the pretreated stem cell culture supernatant is subjected to electrophoretic separation, and the separation of exosomes and impurities is achieved through the difference in electrophoretic mobility of different molecules. The migration of the molecules is regulated by the electric field strength. The greater the electric field strength, the faster the migration speed of the charged molecules. Specifically, the dynamic electrophoresis technique is used to introduce the pretreated stem cell culture supernatant into the electrophoresis system, and the migration behavior of the exosomes and impurities in the electric field is controlled by adjusting the electric field strength. A larger electric field strength can make the exosomes with a large charge migrate faster, thereby effectively separating the exosomes and impurities according to the difference in electrophoretic mobility;

[0052] The electrophoretic mobility formula is as follows:

[0053]

[0054] Wherein, μi(t) is the electrophoretic mobility of exosomes, which represents the electrophoretic mobility of the i-th exosome at time t; t represents time; q i is the net charge of the ith exosome, which is measured by the existing electrophoretic light scattering method; E(t) is the electric field strength at time t, which is provided by the voltage control system in the electrophoresis device; ηη is the dynamic viscosity of the electrophoresis medium, which is set according to the physical properties of the buffer solution and the specific implementation scenario; r i is the radius of the ith exosome, which is measured by nanoparticle tracking analysis. The nanoparticle tracking analysis is a prior art and will not be described in detail here; E max It is the maximum electric field strength of the electrophoresis system, which is determined by the design limit of the electrophoresis equipment and is a physical parameter of the electrophoresis equipment;

[0055] The electrophoretic mobility formula introduces a nonlinear electric field strength regulation mechanism, which controls the electrophoretic mobility of exosomes by adjusting the electric field strength to achieve fine separation. Compared with traditional electrophoresis methods, regulation by electric field strength can prevent electrophoretic mobility saturation and improve the separation of exosomes from other molecules, that is, exosomes from impurities;

[0056] The electric field strength is dynamically regulated by the electric field strength optimization formula, which is as follows:

[0057]

[0058] Wherein, E(t) is the electric field strength at time t; E0 is the initial electric field strength, which is the electric field strength set on the electrophoresis device at the beginning of the experiment according to the specific implementation scenario; λ is the attenuation coefficient of the electric field strength, obtained by experimental fitting; exp is an exponential function, which represents the attenuation behavior of the electric field strength and reflects the nonlinear change of the electric field strength during the electrophoretic separation process; t′ is the integral variable; is the mean mobility of exosomes, which is calculated by taking the weighted average of the electrophoretic mobility of all exosomes; is the mean mobility of exosomes The time integral term of is used to reflect the cumulative migration effect of exosomes within time t; cosh is the hyperbolic cosine function, which is used to describe the periodic fluctuation of the electric field intensity; ω is the angular frequency of the electric field modulation, which is obtained by experimental tuning;

[0059] The electric field strength optimization formula introduces the time integral term and the hyperbolic cosine function, and dynamically regulates the electric field strength according to the mean mobility of exosomes, so that the electric field strength can change dynamically during the electrophoresis separation process to improve the extraction efficiency of exosomes and ensure the balance of the electric field strength during the separation process, while maximizing the exosome separation efficiency and avoiding damage to exosomes caused by excessive electric fields;

[0060] After electrophoresis separation, an exosome-enriched sample is obtained; the exosome-enriched sample contains a relatively high concentration of exosomes, but is still mixed with some impurities and needs to be further purified.

[0061] S2: Perform molecular sieve filtration on the exosome enriched sample and calculate the impurity residual rate of the exosome sample after molecular sieve filtration; based on the impurity residual rate, evaluate the separation effect to obtain the evaluation effect; based on the evaluation effect, iteratively optimize the molecular sieve filtration operation to obtain a purified exosome sample.

[0062] The exosome-enriched sample is further purified by molecular sieve filtration, which filters exosomes smaller than a specific pore size and intercepts larger impurities to improve the purity of the exosomes. The molecular sieve is a filter material with uniform pore size, which is used to selectively separate substances according to molecular size and can filter and purify nanoparticles such as exosomes. Molecular sieve filtration selects a suitable pore size to allow exosomes smaller than the pore size to pass through the sieve, while intercepting larger impurities to improve separation purity.

[0063] The molecular sieve filtration operation introduces an electric field-regulated molecular sieve filtration mechanism. During the molecular sieve filtration process, the electric field strength and the diameter of the exosomes are combined to optimize the separation efficiency, enhance the filtration effect of the molecular sieve, and improve the separation purity of exosomes and impurities.

[0064] The following probability formula is used to calculate the probability of exosomes passing through the molecular sieve, i.e., the exosome passing rate, which is used to evaluate the passing rate of exosomes during the molecular sieve filtration process to determine the separation effect of exosomes and impurities;

[0065] The probability formula is as follows:

[0066]

[0067] Among them, P(d i, E(t)) is the exosome passing rate, which indicates the probability of the i-th exosome passing through the molecular sieve under the electric field strength E(t) at time t; d i is the diameter of the i-th exosome, which is measured by selecting equipment according to the specific implementation scenario; d filter is the pore size of the molecular sieve, and the initial value of the pore size of the molecular sieve is set according to the specific implementation scenario using the expert experience method; β is the molecular size adjustment parameter, which is used to reflect the influence of the diameter of the exosomes on the passage through the molecular sieve, and is obtained through experimental fitting; E(t) is the electric field strength at time t; E0 is the initial electric field strength; γ is the electric field strength adjustment parameter, which is used to reflect the influence of the electric field strength on the probability of exosomes passing through the molecular sieve, and is obtained through experimental fitting;

[0068] The probability formula introduces the electric field strength and the diameter of the exosomes, reflecting the nonlinear effects of the electric field strength and the exosome diameter on the exosome passing rate, and accurately controls the probability of the exosomes passing through the molecular sieve through power adjustment, making the effects of the exosome diameter and the electric field strength on the separation process more flexible;

[0069] Then, the impurity residual rate of the exosome sample after molecular sieve filtration was calculated to evaluate the effect of impurity separation;

[0070] The calculation formula of impurity residual rate is as follows:

[0071]

[0072] in, is the impurity residual rate after update; R is the impurity residual rate before update, and the initial value is the proportion of impurities remaining in the exosome-enriched sample, which is measured by nanoparticle tracking analysis; α is the residual rate attenuation coefficient, which is used to control the rate of exponential decay and determines the reduction rate of impurity residues, and is obtained by experimental fitting; R δ is the power adjustment term of the impurity residual rate; δ is the residual rate adjustment index, which is used to control the nonlinear change of the impurity residual rate during the optimization process. It is obtained through experimental fitting. The larger the value of the residual rate adjustment index, the more drastic the reduction of the impurity residual rate during the iteration process.

[0073] The impurity residual rate calculation formula introduces exponential function and logarithmic function, so that the impurity residual rate shows nonlinear attenuation, so as to accurately control the reduction rate of impurity residual. The power adjustment term of the impurity residual rate is used to enhance the flexibility of different separation conditions, so that the impurity residual rate calculation formula can adapt to complex experimental environments, ensuring a smoother and more efficient separation process.

[0074] Next, a target impurity residual rate is set according to a specific implementation scenario, and the updated impurity residual rate is compared with a preset target impurity residual rate, and the separation effect is evaluated to obtain an evaluation result; the evaluation result includes continuing iterative optimization and stopping optimization; if the updated impurity residual rate is less than or equal to the target impurity residual rate, it is considered that the separated exosomes have reached the expected purity, and the optimization is stopped; otherwise, the molecular sieve pore size is updated, and based on the updated molecular sieve pore size, the molecular sieve filtration operation continues to be iteratively optimized;

[0075] The molecular sieve pore size update formula is as follows:

[0076]

[0077] in, is the updated molecular sieve pore size; d filter is the pore size of the molecular sieve before updating; ζ is the filtration adjustment coefficient, which is used to control the rate of molecular sieve pore size contraction to adjust the intensity of molecular sieve pore size adjustment; is the comprehensive exosome passage probability, which is expressed by the exosome passage rate P(d i , E(t)) is obtained by weighted average; τ is the residual rate adjustment index, which is used to control the influence of the impurity residual rate on the change of the molecular sieve pore size; θ is the pass rate adjustment index, which is used to control the influence of the exosome pass rate on the molecular sieve pore size update; the filtration adjustment coefficient, residual rate adjustment index, and pass rate adjustment index are all obtained through experimental fitting;

[0078] The molecular sieve pore size update formula introduces a combination of exponential and logarithmic functions to dynamically optimize the molecular sieve pore size. By comprehensively considering the nonlinear relationship between the exosome passing rate and the impurity residual rate, the filtration process can effectively remove impurities while ensuring the smooth passage of exosomes, accurately improving the extraction efficiency and purity.

[0079] After the molecular sieve pore size is updated, the molecular sieve filtration operation is optimized for the next round of iteration. Specifically, the updated molecular sieve pore size is used to further purify the separated exosomes and impurities, further screen out larger impurities, and allow the exosomes to pass through. After the separation is completed, the impurity residual rate is recalculated. If the current impurity residual rate is greater than the target impurity residual rate, the molecular sieve pore size is adjusted according to the current impurity residual rate, and the next round of iteration is performed until the impurity residual rate is less than or equal to the target impurity residual rate, and the iteration is stopped to obtain a purified exosome sample.

[0080] Finally, the purified exosome samples are collected and quality tested by nanoparticle tracking analysis to ensure that the concentration, particle size distribution, morphology and functional integrity of the exosomes meet the requirements. The exosome samples that meet the requirements can be used for subsequent experiments or applications, such as drug delivery, cell therapy or diagnostic research.

[0081] In summary, an automated system for extraction and purification of stem cell exosomes was completed.

[0082] The order of the embodiments of the invention is for description only and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0083] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0084] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. An automated method for extracting and purifying stem cell exosomes, characterized in that: The following steps are involved: S1: collecting stem cell culture supernatant and pre-treating it to obtain pre-treated stem cell culture supernatant; combining the nonlinear electric field intensity regulation mechanism, performing electrophoresis separation operation on the pre-treated stem cell culture supernatant to obtain an exosome enriched sample; S2: Perform molecular sieve filtration on the exosome enriched sample and calculate the impurity residual rate of the exosome sample after molecular sieve filtration; Based on the impurity residual rate, the separation effect is evaluated to obtain the evaluation effect; based on the evaluation effect, the molecular sieve filtration operation is iteratively optimized to obtain a purified exosome sample.

2. The automated method for extracting and purifying stem cell exosomes according to claim 1, characterized in that: The S1 specifically includes: In the process of implementing the electrophoretic separation operation, a nonlinear electric field strength regulation mechanism is introduced, and the electrophoretic mobility of exosomes is calculated in combination with the electric field strength.

3. The automated method for extracting and purifying stem cell exosomes according to claim 2, characterized in that: The S1 specifically includes: The electrophoretic mobility of all exosomes was weighted averaged to obtain the mean mobility of exosomes. The time integral term and hyperbolic cosine function were introduced, and the electric field intensity was dynamically regulated in combination with the mean mobility of exosomes.

4. The automated method for extracting and purifying stem cell exosomes according to claim 3, characterized in that: The S2 specifically includes: In the process of implementing the molecular sieve filtration operation, the electric field-regulated molecular sieve filtration mechanism is introduced, and the exosome passing rate is calculated by combining the electric field strength and the diameter of the exosomes, and the exosome sample after molecular sieve filtration is obtained; the specific calculation formula of the exosome passing rate is as follows: Among them, P(d i , E(t)) is the exosome passing rate, which indicates the probability of the i-th exosome passing through the molecular sieve under the electric field strength E(t) at time t; d i is the diameter of the i-th exosome; d filter is the pore size of the molecular sieve; β is the molecular size adjustment parameter; E(t) is the electric field strength at time t; E0 is the initial electric field strength; γ is the electric field strength adjustment parameter.

5. The automated method for extracting and purifying stem cell exosomes according to claim 4, characterized in that: The S2 specifically includes: Based on the exosome passing rate, the exponential function and logarithmic function were introduced to calculate the impurity residual rate of the exosome sample after molecular sieve filtration, and the updated impurity residual rate was obtained; the impurity residual rate calculation formula is as follows: in, is the impurity residual rate after update; R is the impurity residual rate before update, and the initial value is the impurity ratio of the exosome enriched sample; α is the residual rate attenuation coefficient; R δ is the power adjustment term of the impurity residual rate; δ is the residual rate adjustment exponent.

6. The automated method for extracting and purifying stem cell exosomes according to claim 5, characterized in that: The S2 specifically includes: The updated impurity residual rate is compared with the preset target impurity residual rate, the separation effect is evaluated, and an evaluation result is obtained; the evaluation result includes continuing iterative optimization and stopping optimization; when the updated impurity residual rate is greater than the target impurity residual rate, an exponential and logarithmic function is introduced to dynamically optimize the molecular sieve pore size to obtain an updated molecular sieve pore size.

7. The automated method for extracting and purifying stem cell exosomes according to claim 6, characterized in that: The S2 specifically includes: Based on the updated molecular sieve pore size, the separated exosomes and impurities are further subjected to molecular sieve filtration operation, and the impurity residual rate is recalculated after the filtration is completed; when the current impurity residual rate is greater than the target impurity residual rate, the molecular sieve pore size is further adjusted according to the current impurity residual rate, and the next round of iteration is performed until the impurity residual rate is less than or equal to the target impurity residual rate, at which time the iteration is stopped to obtain a purified exosome sample.

8. An automated system for extracting and purifying stem cell exosomes, applied to the automated method for extracting and purifying stem cell exosomes as claimed in claim 1, characterized in that: Includes the following parts: Sample pretreatment module, dynamic electrophoresis separation module, molecular sieve filtration module, filtration effect evaluation module, purified exosome collection module; The sample pretreatment module collects stem cell culture supernatant and performs pretreatment to obtain pretreated stem cell culture supernatant; The sample pretreatment module is connected to the dynamic electrophoresis separation module by means of material transmission; The dynamic electrophoresis separation module, combined with the nonlinear electric field intensity control mechanism, performs electrophoresis separation on the pretreated stem cell culture supernatant to obtain an exosome-enriched sample; The dynamic electrophoresis separation module is connected to the molecular sieve filtration module by means of material transmission, and is connected to the filtration effect evaluation module by means of data transmission; The molecular sieve filtration module measures the diameter of exosomes and the residual rate of impurities in the exosome-enriched sample based on the exosome-enriched sample and the molecular sieve pore size; purifies the exosome-enriched sample through molecular sieve filtration operation according to the evaluation result of the filtration effect evaluation module, and outputs the purified exosome sample; The molecular sieve filtration module is connected to the filtration effect evaluation module by means of data transmission, and is connected to the purified exosome collection module by means of material transmission; The filtration effect evaluation module calculates the exosome passage rate based on the diameter of the exosomes, the pore size of the molecular sieve used in the molecular sieve filtration module, and the electric field strength of the dynamic electrophoresis separation module; Update the impurity residual rate based on the exosome passage rate; Based on the impurity residual rate, the separation effect is evaluated to obtain the evaluation result, and the molecular sieve pore size is updated according to the evaluation result; the filtration effect evaluation module is connected to the molecular sieve filtration module by data transmission; The purified exosome collection module collects purified exosome samples and performs quality detection using nanoparticle tracking analysis.

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