A method for the production of polymer nanoparticles in microchannels

Abstract

This invention provides a method for preparing polymer nanoparticles using microchannels, a method that allows for precise control of polymer nanoparticle size. The method involves introducing a polymer solution, an antisolvent, and a gas through three inlets of a cross-shaped microchannel, respectively. The gas enhances the mass transfer process during nanoprecipitation, enabling continuous preparation of polymer nanoparticles via nanoprecipitation. Compared to traditional nanoprecipitation methods, this invention allows for precise control of polymer nanoparticle size and can produce nanoparticles with diameters below 20 nm. This reduces steric hindrance caused by large nanoparticles, improves nanoparticle transport capacity, enhances targeting specificity and binding affinity, and significantly promotes the application of polymer nanoparticles in biomedicine and other fields.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterials technology, specifically relating to a method for preparing polymer nanoparticles, and more particularly to a method for preparing polymer nanoparticles using microchannels. Background Technology

[0002] In recent years, the emerging nanotechnology has become a highly effective tool for life science research. Nanoparticles (NPs), which possess unique properties through size modification, can be applied in fields such as biology, medicine, and pharmaceuticals. When used for disease diagnosis and treatment, nanoparticles have demonstrated higher efficiency as drug delivery carriers compared to micron-sized particles that can be rapidly eliminated by the immune system.

[0003] Polymer nanoparticles (PNPs) have shown great potential as drug delivery carriers. The nanoscale size of PNPs gives them unique properties, allowing them to penetrate blood vessels, infiltrate tissues, and enter target cells. Furthermore, surface-modified PNPs can be specifically targeted to lesion sites, making targeted drug release highly effective for many diseases, such as cancer. Nanotechnology utilizes specifically expressed receptor responses to visualize and identify cancer cells. Subsequently, various surface-modified PNPs encapsulate medical drugs; their small size facilitates targeted drug delivery to specific sites, achieving high drug concentrations and bioactivity only at specific sites or organs. This enables targeted detection and treatment, overcoming the adverse side effects and toxicity of existing treatments.

[0004] However, the transport of PNPs from blood to tissues and into pathological cells is strongly dependent on size. Changing the size of PNPs can significantly alter their controllable transport in vivo by affecting circulation time and the rate of interception by the immune system. Generally, larger PNPs are easily cleared by organs such as the liver and spleen, while PNPs prepared using traditional nanoprecipitation methods typically have particle sizes larger than 20 nm. Therefore, there is an urgent need to develop a method for the controllable preparation of smaller PNPs.

[0005] This invention employs a continuous and controllable microfluidic nanoprecipitation method. Gas is introduced into a cross-shaped inlet microchannel to enhance the nanoprecipitation process of polymer solution and antisolvent, successfully preparing polymer nanoparticles. The size of the polymer nanoparticles can be precisely controlled, achieving the preparation of nanoparticles below 20 nm. Summary of the Invention

[0006] The purpose of this invention is to prepare nanoparticles with small particle size and good monodispersity in a highly controllable manner, and to solve the problems caused by large-sized nanoparticles, such as steric hindrance and interference with the targeting specificity and binding affinity of grafted biomolecules. A process method for preparing polymer nanoparticles using microfluidic nanoprecipitation is proposed.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing polymer nanoparticles in a microchannel involves introducing a polymer solution, an antisolvent, and a gas into three inlets of a cross-shaped inlet microchannel, respectively. The gas enhances the mass transfer process during nanoprecipitation, allowing for the continuous preparation of nanoparticles of the desired particle size via nanoprecipitation. The fourth inlet of the cross-shaped inlet microchannel is connected to a receiving tube for collecting the nanoparticles. The method includes the following steps:

[0009] Step 1: At room temperature, dissolve the polymer in an organic solvent and dilute it to obtain a polymer solution of a specific concentration.

[0010] The polymers mentioned include polylactic acid-glycolic acid copolymer (PLGA), poly(9,9-dioctylfluorene-co-benzothiadiazole) (PFBT), polyethylene glycol (PEG), gelatin, chitosan, etc.

[0011] The organic solvents mentioned include tetrahydrofuran (THF), acetonitrile (ACN), acetone (AC), dioxane (EEW), etc.

[0012] The concentration of the polymer solution obtained by diluting with an organic solvent is 1–1000 μg / mL, preferably 10–200 μg / mL.

[0013] Step 2: Construct a cross-shaped inlet microchannel, including three inlets and one outlet, where the section from the cross intersection to the outlet is the microchannel nanoprecipitation mass transfer section.

[0014] The cross-shaped inlet microchannel consists of two intersecting and interconnected tubular structures made of materials including glass, metal, and rubber. The diameter of the tubular structures ranges from 1 to 1000 μm.

[0015] Step 3: The two ends of the cross-shaped inlet microchannel are connected to the syringe containing the antisolvent and polymer solution respectively through PTFE tubes. The syringe is connected to the injection pump. The two ends of the other tube are connected to the gas flow meter and the receiving tube respectively. The end connected to the receiving tube is the outlet of the cross-shaped inlet microchannel. The outlet of the receiving tube is placed in the sample bottle to collect the sample.

[0016] The syringe mentioned is a glass syringe, an organic plastic syringe, etc.

[0017] Step 4: First, gas is introduced into the entire cross-shaped inlet microchannel. The gas flow rate is controlled by a gas flow meter. When the entire microchannel is in a stable state, the injection pump is turned on, and the reaction begins. While the gas continues to be introduced, the polymer solution and antisolvent are introduced into the other two inlets. The three substances converge and mix at the cross intersection and flow towards the outlet. The reaction occurs at room temperature in this section. The gas is used to enhance the mass transfer process of nanoprecipitation. The product is collected at the outlet and then post-processed to remove the organic solvent.

[0018] During the reaction, the gas flow rate is adjusted by a gas flow meter, and the fluid flow rates of the polymer solution and antisolvent are controlled by a flow pump. This allows for the adjustment of different flow patterns (Taylor flow, stirred flow, annular flow, etc.) to enhance the nanoprecipitation mass transfer process and prepare nanoparticles. The particle size and distribution of the nanoparticles are detected by dynamic light scattering (DLS) and transmission electron microscopy (TEM), achieving a particle size below 20 nm.

[0019] The gas flow rate is 1–80 mL / min; the polymer solution flow rate is 0.005–0.32 mL / min; and the antisolvent flow rate is 0.5–8 mL / min. The antisolvent includes water, methanol (MeOH), and ethanol (EtOH), preferably water.

[0020] This invention introduces gas into microchannels to enhance the mass transfer process of nanoprecipitation under different flow patterns (Taylor flow, stirred flow, annular flow, etc.), enabling the continuous and controllable preparation of nanoparticles with the desired particle size. The introduction of gas provides greater flexibility for nanoparticle size control.

[0021] At the end of the reaction, the collected sample is purged with nitrogen to remove the organic solvent.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention provides a microfluidic nanoprecipitation method for preparing polymer nanoparticles. By utilizing the enhanced mass transfer effect of gas under different flow patterns (Taylor flow, stirred flow, annular flow, etc.), small-sized nanoparticles can be prepared without reducing the concentration of polymer solution, thereby increasing the mass concentration of nanoparticles in aqueous solution.

[0024] (2) The present invention provides a microfluidic nanoprecipitation method for preparing polymer nanoparticles. This method overcomes the experimental error caused by manual injection in the traditional nanoprecipitation method, realizes precise control of the particle size of polymer nanoparticles, and improves the repeatability of the results.

[0025] (3) The present invention provides a microfluidic nanoprecipitation method for preparing polymer nanoparticles. Under the same preparation conditions, the polymer nanoparticles prepared by this method have smaller particle sizes, reaching below 20 nm, and better controllability.

[0026] (4) The present invention provides a microfluidic nanoprecipitation method for preparing polymer nanoparticles. This method is simple to operate and has a certain degree of universality. It can be used for the preparation of other types of polymer nanoparticles.

[0027] In summary, the technical solution of this invention can solve the problems of large particle size and poor controllability in the preparation of nanoparticles by traditional methods, and makes a certain contribution to promoting the application of polymer nanoparticles in the biomedical field.

[0028] Based on the above reasons, the present invention can precisely control the size of polymer nanoparticles, improve the repeatability of experimental results, and realize the preparation of polymer nanoparticles below 20 nm. At the same time, the present invention can also be applied to the preparation of other polymer nanoparticles. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of a system for precisely controlling the size of polymer nanoparticles to achieve the preparation of nanoparticles below 20 nm, as described in this invention.

[0030] Figure 2 The flow pattern within the microchannel during the preparation of nanoparticles using the above method in Example 1 is Taylor flow.

[0031] Figure 3 The image shows the TEM results of the nanoparticles prepared using the above method in Example 1. Detailed Implementation

[0032] The present invention will be further described below with reference to specific embodiments.

[0033] Example 1

[0034] The preparation method of polymer nanoparticles in this embodiment includes the following steps:

[0035] 1. Solution preparation: Dissolve 1 mg of polylactic acid-glycolic acid copolymer (PLGA) in 1 mL of tetrahydrofuran (THF) and dilute to obtain a polymer solution of PLGA at 100 μg / mL for experimental use.

[0036] 2. Pre-experimental preparation: Using a 1 mL glass syringe, draw 0.5 mL of a 100 μg / mL polymer solution. Attach the syringe to the syringe pump and connect it to the cross-shaped inlet microchannel device via a 0.5 mm inner diameter PTFE tube. Using a 50 mL glass syringe, draw 40 mL of deionized water. Attach the syringe to the syringe pump and connect it to the cross-shaped inlet microchannel device via a 0.5 mm inner diameter PTFE tube. Connect the last inlet of the cross-shaped inlet microchannel to a gas flow meter via a 0.5 mm inner diameter PTFE tube. Connect the outlet of the cross-shaped inlet microchannel to a 5 cm long, 0.8 mm inner diameter PTFE tube receiving tube to collect the sample into a sample vial. Prepare to observe and record the flow pattern at 1 cm of the nanoprecipitation mass transfer section of the microchannel using an OLYMPUS microscope.

[0037] 3. Start the experiment: First, adjust the gas flow rate of the gas flow meter to 8 mL / min and stabilize for 3 min. Then, set the flow rate of the polymer solution syringe pump to 0.08 mL / min and the flow rate of the deionized water syringe pump to 8 mL / min, stabilize for 3 min, and then start collecting samples. Set the volume of polymer solution added to 0.1 mL, and simultaneously observe and record the flow pattern in the microchannel using an OLYMPUS microscope. Finally, turn off the syringe pump and the gas flow meter in sequence.

[0038] 4. Sample preparation: After the reaction, the collected sample was purged with nitrogen at 50°C until THF was removed. Finally, polymer nanoparticles were obtained suspended in deionized water.

[0039] 5. Sample characterization: The nanoparticles obtained after THF removal were detected by dynamic light scattering (DLS) and transmission electron microscopy (TEM) and were found to be 5 nm in size, which are spherical nanoparticles with uniform sphericity.

[0040] Example 2

[0041] The preparation method of polymer nanoparticles in this embodiment includes the following steps:

[0042] 1. Solution preparation: Dissolve 1 mg of polylactic acid-glycolic acid copolymer (PLGA) in 1 mL of tetrahydrofuran (THF) and dilute to obtain a polymer solution of PLGA at 100 μg / mL for experimental use.

[0043] 2. Pre-experimental preparation: Using a 1 mL glass syringe, draw 0.7 mL of a 100 μg / mL polymer solution. Attach the syringe to the syringe pump and connect it to the cross-shaped inlet microchannel device via a 0.5 mm inner diameter PTFE tube. Using a 50 mL glass syringe, draw 40 mL of deionized water. Attach the syringe to the syringe pump and connect it to the cross-shaped inlet microchannel device via a 0.5 mm inner diameter PTFE tube. Connect the last inlet of the cross-shaped inlet microchannel to a gas flow meter via a 0.5 mm inner diameter PTFE tube. Connect the outlet of the cross-shaped inlet microchannel to a 5 cm long, 0.8 mm inner diameter PTFE tube receiving tube to collect the sample into a sample vial. Prepare to observe and record the flow pattern at 1 cm of the nanoprecipitation mass transfer section of the microchannel using an OLYMPUS microscope.

[0044] 3. Start the experiment: First, adjust the gas flow rate of the gas flow meter to 18 mL / min and stabilize for 3 minutes. Then, set the flow rate of the polymer solution syringe pump to 0.12 mL / min and the flow rate of the deionized water syringe pump to 6 mL / min, stabilize for 3 minutes, and then start collecting samples. Set the volume of polymer solution added to 0.2 mL, and simultaneously observe and record the flow pattern in the microchannel using an OLYMPUS microscope. Finally, turn off the syringe pump and the gas flow meter in sequence.

[0045] 4. Sample preparation: After the reaction, the collected sample was purged with nitrogen at 50°C until THF was removed. Finally, polymer nanoparticles were obtained suspended in deionized water.

[0046] 5. Sample characterization: The nanoparticles obtained after THF removal were detected by dynamic light scattering (DLS) and transmission electron microscopy (TEM) and were found to be 15 nm in size, which are spherical nanoparticles with uniform sphericity.

[0047] Example 3

[0048] The preparation method of polymer nanoparticles in this embodiment includes the following steps:

[0049] 1. Solution preparation: Dissolve 1 mg of poly(9,9-dioctylfluorene-co-benzothiadiazole) (PFBT) in 1 mL of tetrahydrofuran (THF) and dilute to obtain a polymer solution with PFBT concentration of 100 μg / mL for experimental use.

[0050] 2. Pre-experimental preparation: Using a 1 mL glass syringe, draw 0.5 mL of a 100 μg / mL polymer solution. Attach the syringe to the syringe pump and connect it to the cross-shaped inlet microchannel device via a 0.5 mm inner diameter PTFE tube. Using a 50 mL glass syringe, draw 30 mL of deionized water. Attach the syringe to the syringe pump and connect it to the cross-shaped inlet microchannel device via a 0.5 mm inner diameter PTFE tube. Connect the last inlet of the cross-shaped inlet microchannel to a gas flow meter via a 0.5 mm inner diameter PTFE tube. Connect the outlet of the cross-shaped inlet microchannel to a 5 cm long, 0.8 mm inner diameter PTFE tube receiving tube to collect the sample into a sample vial. Prepare to observe and record the flow pattern at 1 cm of the nanoprecipitation mass transfer section of the microchannel using an OLYMPUS microscope.

[0051] 3. Start the experiment: First, adjust the gas flow rate of the gas flow meter to 9 mL / min and stabilize for 3 min. Then, set the flow rate of the polymer solution syringe pump to 0.06 mL / min and the flow rate of the deionized water syringe pump to 3 mL / min, stabilize for 3 min, and then start collecting samples. Set the volume of polymer solution added to 0.2 mL, and simultaneously observe and record the flow pattern in the microchannel using an OLYMPUS microscope. Finally, turn off the syringe pump and the gas flow meter in sequence.

[0052] 4. Sample preparation: After the reaction, the collected sample was purged with nitrogen at 50°C until THF was removed. Finally, polymer nanoparticles were obtained suspended in deionized water.

[0053] 5. Sample characterization: The nanoparticles obtained after THF removal were detected by dynamic light scattering (DLS) and transmission electron microscopy (TEM) and were found to be 20 nm in size, which are spherical nanoparticles with uniform sphericity.

[0054] The embodiments described above are merely illustrative of the implementation methods of the present invention, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A method for preparing polymer nanoparticles using microchannels, characterized in that, The method involves introducing a polymer solution, an antisolvent, and a gas into three inlets of a cross-shaped microchannel, respectively, to enhance the mass transfer process of nanoprecipitation and continuously prepare nanoparticles of the desired particle size. The method includes the following steps: Step 1: At room temperature, the polymer is dissolved in an organic solvent and diluted to obtain a polymer solution with a concentration of 1~1000 µg / mL; the polymer is selected from polylactic acid-glycolic acid copolymer, poly(9,9-dioctylfluorene-co-benzothiadiazole), polyethylene glycol, gelatin or chitosan; Step 2: Construct a cross-shaped inlet microchannel, including three inlets and one outlet, wherein the section from the intersection of the cross to the outlet is the microchannel nanoprecipitation mass transfer section; the diameter of the cross-shaped inlet microchannel is 1 ~ 1000 µm; Step 3: The two ends of the cross-shaped inlet microchannel are connected to the syringe containing the antisolvent and polymer solution respectively through PTFE tubes. The syringe is connected to the injection pump. The two ends of the other tube are connected to the gas flow meter and the receiving tube respectively. The end connected to the receiving tube is the outlet of the cross-shaped inlet microchannel. The outlet of the receiving tube is placed in the sample bottle to collect the sample. Step 4: First, gas is introduced into the entire cross-shaped inlet microchannel. When the entire microchannel is in a stable state, gas is continued to be introduced while the injection pump is turned on, that is, polymer solution and antisolvent are introduced into the other two inlets. During the reaction, the gas flow rate is adjusted by the gas flow meter, and the fluid flow rates of polymer solution and antisolvent are controlled by the flow pump, thereby adjusting different flow patterns. Gas is used to enhance the nanoprecipitation mass transfer process to prepare nanoparticles with a particle size of less than 20 nm. The antisolvent is selected from water, methanol or ethanol.

2. The method for preparing polymer nanoparticles using microchannels according to claim 1, characterized in that, The organic solvent mentioned in step 1 is selected from tetrahydrofuran, acetonitrile, acetone or dioxane.

3. The method for preparing polymer nanoparticles via microchannels according to claim 1, characterized in that, The cross-shaped inlet microchannel described in step 2 consists of two cross-shaped intersecting and interconnected tubular structures, made of glass, metal or rubber.

4. The method for preparing polymer nanoparticles using microchannels according to claim 1, characterized in that, The gas flow rate in step 4 is 1 ~ 80 mL / min; the polymer solution flow rate is 0.005 ~ 0.32 mL / min; and the antisolvent flow rate is 0.5 ~ 8 mL / min.

5. The method for preparing polymer nanoparticles via microchannels according to claim 4, characterized in that, The antisolvent mentioned in step 4 is water.

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