CN115382476B - A method for preparing ultra-small particle size polymer nanoparticles - Google Patents

Abstract

The present invention discloses a method for preparing ultra-small particle size polymer nanoparticles, and relates to the field of nanoparticle synthesis using microfluidic chips in flow chemistry. The present invention constructs a complete and simple micro-reaction system based on a multi-channel micro-injection pump and a three-dimensional channel micro-mixing quartz chip finely engraved by femtosecond laser processing technology. By controlling the flow rate at the inlet of the micro-mixing chip, ultra-small particle size (<10 nm) polymer nanoparticles with good repeatability and sustainable mass production can be synthesized. The synthesized polymer nanoparticles can be used as targeted drug delivery carriers, fluorescent probes, etc., and are used in various biomedical fields.

Description

A method for preparing ultra-small particle size polymer nanoparticles

Technical Field

The invention belongs to the field of nanoparticle synthesis using a microfluidic chip in flow chemistry, and specifically relates to a method for synthesizing different types of ultra-small-diameter polymer nanoparticles in a room temperature controllable manner through a microfluidic chip under flow conditions.

Background Art

In recent years, polymeric nanoparticles (PNPs) have attracted great interest due to their small size. The advantages of PNPs as drug carriers include their potential for controlled release, their ability to protect drugs and other bioactive molecules from environmental damage, and their ability to improve their bioavailability and therapeutic index.

In conventional synthesis methods, polymer nanoparticles can be synthesized in a variety of ways, such as nanoprecipitation, solvent evaporation, microemulsion sol-gel, emulsion polymerization, layer-by-layer self-assembly, thin film hydration technology, emulsified solvent evaporation, etc. In PNP synthesis, three steps: nucleation, growth and agglomeration occur simultaneously, and the size distribution of PNPs will change if mixing and separation are not well controlled. In addition, the industrial scale-up of the synthesis batch increases the mixing and mass transfer problems, so the physicochemical properties of PNPs, such as the polydispersity index, cannot be well controlled.

Microfluidic platforms have attracted scientific attention in the synthesis and drug delivery applications of the new generation of PNPs. In particular, the new continuous flow microfluidic system has been widely studied due to its unique characteristics compared with the traditional PNP synthesis method. In the microfluidic system, the nucleation and growth steps of PNP formation can be separated by functions to obtain absolute control over particle size and morphology, thereby increasing the reproducibility of the synthesis batch. And it can greatly reduce the mixing path of solvent and non-solvent to tens of microns, thereby achieving very fast mixing by diffusion within milliseconds or even microseconds. In addition, microfluidic systems usually operate in continuous flow, which can continuously control the quality of products and realize batch production. Therefore, the preparation of polymer nanoparticles with uniform size distribution and excellent performance through microfluidic systems is of great significance for exploring the practical application of this nanomaterial.

Summary of the invention

The purpose of the present invention is to provide a method for synthesizing polymer nanoparticles with ultra-small particle size and good monodispersity.

The specific technical solution for achieving the purpose of the present invention is:

A method for preparing ultra-small particle size polymer nanoparticles, the method comprising the following specific steps:

Step 1: dissolving polymer powder in a good solvent to obtain a polymer good solvent precursor solution A;

Step 2: dilute the precursor solution A in proportion, and add an amphiphilic reagent to functionalize its surface to obtain solution B;

Step 3: Place solution B and its poor solvent C on the syringe pumps respectively, inject the two-phase solution into the three-dimensional microfluidic mixing chip, and then flow the mixed liquid into the flask; finally, remove the good solvent from the colloidal solution in the flask by rotary evaporation, and obtain the ultra-small particle size polymer nanoparticles after drying; wherein:

The good solvent is at least one of tetrahydrofuran, acetone, acetonitrile, N-N-dimethylacetamide, dimethyl sulfoxide (DMSO), and ethanol; the poor solvent is water;

The polymer is a conjugated semiconductor polymer, a polylactic acid-co-glycolic acid polymer or polylactic acid;

The concentration of the good solvent precursor solution A is 1 mg/mL; the concentration of the polymer solution in the solution B is 20-50 ug/mL, wherein the concentration ratio of the polymer solution to the amphiphilic reagent is 5-10:1;

The flow rate ratio of solution B and poor solvent C is 1:1.5-3, the flow rate of solution B is 200-300 uL/min, and the flow rate of poor solvent C is 300-600 uL/min;

The three-dimensional microfluidic hybrid chip is made of quartz glass.

The amphiphilic agent is any one of polystyrene maleic anhydride (PSMA), polystyrene (PS) and styrene-polyethylene glycol-carboxyl (PS-PEG-COOH).

The three-dimensional microfluidic hybrid chip is made of quartz glass and is prepared by using ultrafast laser-assisted chemical etching of quartz glass.

The conjugated semiconductor polymers are poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazole-4,8-diyl)] (F8BT), poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO) and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylethynyl] (MEH-PPV).

The present invention successfully prepares polymer nanoparticles using a three-dimensional microfluidic chip. Compared with the traditional method of synthesizing polymer nanoparticles using nanoprecipitation in bulk solution, the microfluidic method used in the present invention has the following advantages:

1) The synthesized polymer nanoparticles have uniform particle size and good monodispersity, and most of the materials have a particle size less than 10nm after synthesis, which is much smaller than the particle size of nanoparticles synthesized from bulk solution.

2) No ultrasonic energy consumption process is required and the operation is simple.

3) The three-dimensional channels of the microchip are finely engraved using femtosecond laser processing technology. The specific three-dimensional mixing method makes it have ultra-high mixing efficiency. The eight mixing units in the microfluidic chip can accelerate the mixing degree between the good solvent and the poor solvent. The mixing is completed before the nanoparticles aggregate, thus forming ultra-small particle size polymer nanoparticles.

4) Compared with the traditional microfluidic chip made of PDMS, the microfluidic chip in the present invention is made of glass, and when the organic solvent is introduced, the chip will not swell. Therefore, continuous flow reaction can be carried out in the channel to mass produce polymer nanoparticles.

5) The synthesized polymer nanoparticles can also be surface functionalized for later applications such as biofunctionalization.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a diagram of an apparatus used in the present invention;

FIG2 is a schematic diagram of the structure of a three-dimensional microfluidic hybrid chip according to the present invention;

FIG3 is an absorption spectrum of polymer nanoparticles obtained in Example 1;

FIG4 is a fluorescence emission spectrum of the polymer quantum dot fluorescent probe obtained in Example 1;

FIG5 is a transmission electron microscope (TEM) photograph of the polymer quantum dot PFO fluorescent probe obtained in Example 1;

FIG6 is a transmission electron microscope (TEM) photograph of the polymer quantum dot F8BT fluorescent probe obtained in Example 2;

FIG7 is a transmission electron microscope (TEM) photograph of the polymer quantum dot MEH-PPV fluorescent probe obtained in Example 3;

FIG8 is a transmission electron microscope (TEM) photograph of the polymer quantum dot PFO fluorescent probe obtained in Comparative Example 1;

FIG. 9 is a transmission electron microscope (TEM) photograph of the polymer quantum dot F8BT fluorescent probe obtained in Comparative Example 2.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

The endpoints and any values of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, the endpoint values of each range and the individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

Unless otherwise defined, technical or scientific terms used in the present disclosure shall have the common meanings understood by one of ordinary skill in the art to which the present invention belongs.

The present invention provides a method for preparing ultra-small particle size polymer nanoparticles, which specifically comprises:

1) Dissolve the polymer powder in a good solvent to obtain a polymer good solvent precursor solution A.

2) Solution A is diluted at a fixed ratio, and a certain proportion of amphiphilic reagent is added to functionalize its surface to obtain solution B.

3) Place solution B and its poor solvent C on the syringe pumps respectively, inject the two-phase solution into the three-dimensional micro-mixing chip at a certain flow rate, and then flow the mixed liquid into the flask. Finally, the colloidal solution in the flask is evaporated to remove the good solvent to obtain a polymer nanoparticle solution.

The present invention will be further described below by way of examples.

The following embodiments are all completed using the device shown in Figure 1. In the figure, two injection pumps 1 are respectively connected to two sample inlets 4 of a three-dimensional microfluidic mixing chip 3 through pipelines 2; the sample outlet 5 of the three-dimensional microfluidic mixing chip 3 is connected to a storage bottle 6 through pipelines 2.

Figure 2 is a schematic diagram of the structure of a three-dimensional microfluidic mixing chip 3, in which Figure a is an appearance diagram of the three-dimensional microfluidic mixing chip; Figure b is a local structural diagram of the mixing unit in the microfluidic mixing chip, Figure c is an actual mixing diagram, and Figure d is a local top view of the chip.

Example 1

Weigh 5 mg of PFO and dissolve it in 5 mL of tetrahydrofuran to make a 1 mg/mL solution, then dilute it with tetrahydrofuran to 50 ug/mL, take 1 mL of the solution with a syringe and place it on a syringe pump. Place 2 mL of ultrapure water on another syringe pump. The flow rates of the two syringe pumps are 200 uL/min and 400 uL/min respectively. The two syringe pumps are connected to the inlet of the three-dimensional microfluidic mixing chip, start the reaction, and take out the product at the outlet.

The product was then subjected to rotary evaporation to evaporate the tetrahydrofuran solvent to obtain PFO semiconductor polymer quantum dots. The absorbance of the obtained nanoparticle solution is shown in FIG3 , the fluorescence emission graph is shown in FIG4 , and the transmission electron micrograph is shown in FIG5 , FIG5 (a) TEM image of PFO nanoparticles in this embodiment; (b) PFO nanoparticle size distribution diagram; the average particle size is 1.96 nm.

Example 2

Weigh 5 mg of F8BT and dissolve it in 5 mL of tetrahydrofuran to make a 1 mg/mL solution, then dilute it with tetrahydrofuran to 50 ug/mL, take 1 mL of the solution with a syringe and place it on a syringe pump. Place 2 mL of ultrapure water on another syringe pump. The flow rates of the two syringe pumps are: 210 uL/min and 450 uL/min respectively. Connect the two syringe pumps to the chip inlet, start the reaction, and take out the product at the outlet.

The product was then subjected to rotary evaporation to evaporate the tetrahydrofuran solvent to obtain F8BT semiconductor polymer quantum dots. The transmission electron microscopy is shown in Figure 6, where (a) is a TEM image of F8BT nanoparticles in this embodiment; (b) is a particle size distribution diagram of F8BT nanoparticles; the average particle size is 1.74 nm.

Example 3

Weigh 5 mg of MEH-PPV and dissolve it in 5 mL of tetrahydrofuran to make a 1 mg/mL solution, then dilute it with tetrahydrofuran to 30 ug/mL, and add the amphiphilic polymer PSMA with a final concentration of 10 ug/mL. Take 1 mL of the solution with a syringe and place it on a syringe pump. Place 2 mL of ultrapure water on another syringe pump. The flow rates of the syringe pumps are: 263uL/min and 500uL/min. The two syringe pumps are connected to the chip inlet, start the reaction, and take out the product at the outlet.

The product was then subjected to rotary evaporation to evaporate the ethanol solvent to obtain MEH-PPV semiconductor polymer quantum dots. Transmission electron microscopy is shown in Figure 7, where (a) is a TEM image of MEH-PPV nanoparticles in this embodiment; (b) is a particle size distribution diagram of MEH-PPV nanoparticles; the average particle size is 2.06 nm.

Comparative Example 1

Weigh 5 mg of PFO and dissolve it in 5 mL of tetrahydrofuran to make a 1 mg/mL solution, then dilute it with tetrahydrofuran to 50 ug/mL, take 1 mL of the solution with a syringe and place it in a glass bottle. Take 2 mL of ultrapure water in another syringe. Pour the ultrapure water into the glass bottle containing the polymer solution and ultrasonicate for 1 minute to obtain the product.

The product is then subjected to rotary evaporation to evaporate the tetrahydrofuran solvent to obtain PFO semiconductor polymer quantum dots. Transmission electron microscopy is shown in Figure 8. It can be clearly found that the particle size of the nanoparticles synthesized using the microfluidic device of the present invention is much smaller than the particle size of the semiconductor polymer nanoparticles synthesized by the conventional method, and the monodispersity is better.

Comparative Example 2

Weigh 5 mg of F8BT and dissolve it in 5 mL of tetrahydrofuran to make a 1 mg/mL solution, then dilute it with tetrahydrofuran to 50 ug/mL, take 1 mL of the solution with a syringe and place it on a syringe pump. Place 2 mL of ultrapure water on another syringe pump. The flow rates of the two syringe pumps are 50 uL/min and 250 uL/min respectively. Connect the two syringe pumps to the chip inlet, start the reaction, and take out the product at the outlet.

The product was then subjected to rotary evaporation to evaporate the tetrahydrofuran solvent to obtain F8BT semiconductor polymer quantum dots. The transmission electron microscope is shown in Figure 9. It can be clearly found that the particle size of the nanoparticles synthesized using the flow rate range of the present invention is much smaller than the particle size of the semiconductor polymer nanoparticles synthesized at other flow rates, and the monodispersity is better.

The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims (3)

1. A method for preparing ultra-small particle size polymer nanoparticles, characterized in that the method comprises the following specific steps: Step 1: dissolving polymer powder in a good solvent to obtain a polymer good solvent precursor solution A; Step 2: dilute the precursor solution A in proportion, and add an amphiphilic reagent to functionalize its surface to obtain solution B; Step 3: Place solution B and its poor solvent C on the syringe pumps respectively, inject the two-phase solution into the three-dimensional microfluidic mixing chip, and then flow the mixed liquid into the flask; finally, remove the good solvent from the colloidal solution in the flask by rotary evaporation, and obtain the ultra-small particle size polymer nanoparticles after drying; wherein: The good solvent is at least one of tetrahydrofuran, acetone, acetonitrile, N-N-dimethylacetamide, dimethyl sulfoxide and ethanol; the poor solvent is water; The polymer is a conjugated semiconductor polymer; The concentration of the good solvent precursor solution A is 1 mg/mL; the concentration of the polymer solution in the solution B is 20-50 ug/mL, wherein the concentration ratio of the polymer solution to the amphiphilic reagent is 5-10:1; The flow rate ratio of solution B and poor solvent C is 1:1.5-3, the flow rate of solution B is 200-300 uL/min, and the flow rate of poor solvent C is 300-600 uL/min; The three-dimensional microfluidic hybrid chip is made of quartz glass; The three-dimensional microfluidic mixing chip is a three-dimensional channel with a total of 8 mixing units. The structure of each mixing unit is: a confluent inlet is connected to two N-type channels symmetrically arranged up and down, and the two N-type channels are respectively connected to an L-type channel and merge into an outlet, and the outlet is connected to the next confluent inlet; the good solvent and the poor solvent enter the mixing unit through the confluent channel, and each time passing through a unit, the liquids in the two channels are divided into two tributaries. As the fluid moves, the good solvent and the poor solvent move up and down alternately, showing exponential growth. The three-dimensional mixing method makes it have ultra-high mixing efficiency, and the mixing is completed before the nanoparticles aggregate to form ultra-small particle size polymer nanoparticles. 2. The preparation method according to claim 1, characterized in that the amphiphilic reagent is any one of polystyrene maleic anhydride and styrene-polyethylene glycol-carboxyl. 3. The preparation method according to claim 1 is characterized in that the conjugated semiconductor polymer is poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazole-4,8-diyl)], poly(9,9-di-n-octylfluorenyl-2,7-diyl) and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylethynyl].