Method for preparing nano channel by embedding polyoxyethylene nanofiber

Abstract

The invention relates to the technical field of nano manufacturing, and discloses a method for preparing a nano channel by embedding a polyoxyethylene nanofiber, which comprises the following steps: preparing a PEO solution, electrostatically spinning the PEO nanofiber, preparing a template by using a transparent adhesive tape, selecting and transferring a single PEO nanofiber by using a nano probe, pouring polydimethylsiloxane (PDMS), and dissolving the PEO nanofiber to obtain the nano channel. And bonding with a glass slide to form a nano flow channel. The method can get rid of dependence on expensive equipment in the nanochannel preparation process, does not need a complex technological process, and greatly reduces the nanochannel preparation cost and operation difficulty.

Description

Technical Field

[0001] The invention relates to the technical field of nano manufacturing, and in particular to a method for preparing a nano channel by embedding polyethylene oxide nanofibers. Background Art

[0002] Nanochannels refer to channel structures with nanoscale dimensions, with diameters usually ranging from a few nanometers to several hundred nanometers. Nanochannels have unique physical and chemical properties, such as high specific surface area, high permeability, and surface charge effects, which make them have broad application potential in many fields.

[0003] In the medical field, nanochannels can be used to manufacture artificial organs, such as artificial kidneys and artificial livers. These artificial organs can use the selective permeability of nanochannel membranes to simulate the functions of natural organs and provide patients with alternative treatment options. Nanochannel membranes can also be used for the separation and purification of drugs and cells, improving the purity and safety of drugs, while promoting the development of advanced medical technologies such as cell therapy.

[0004] In the field of biotechnology, nanochannels can be used in processes such as genetic engineering and protein separation. By precisely controlling the pore size and surface properties of nanochannels, efficient separation and purification of target genes or proteins can be achieved. Nanochannels can also be used to construct biosensors, which can monitor and analyze the internal environment of organisms in real time by detecting the transmission characteristics of biomolecules in nanochannels. Especially in the field of single molecule analysis, nanochannels show great application potential. By detecting the changes in current caused by a single molecule passing through a nanochannel, information such as the composition and structure of the molecule can be analyzed. This technology has the advantages of being simple, rapid, and requiring no labeling or amplification, and is widely used in fields such as DNA sequencing and drug screening.

[0005] In the field of environmental protection, nanochannel membranes can effectively separate salt and water in seawater due to their extremely small pore size and channels, achieve seawater desalination, and provide new solutions for areas with water shortages. In wastewater treatment, nanochannels can be used to separate and remove harmful substances in wastewater, such as heavy metal ions, organic matter, etc., to improve the treatment efficiency and purification degree of wastewater. Nanochannel membranes can also be used in the field of air purification to improve air quality by separating and filtering tiny particles and harmful gases in the air. Nanochannels also show great potential in energy storage and conversion. For example, in batteries and supercapacitors, nanochannels can be used to improve the conductivity and ion transfer efficiency of electrode materials, thereby improving the performance of energy storage and conversion.

[0006] There are many methods for preparing nanochannels, including photolithography, electron beam etching, self-assembly, 3D printing, etc. These methods have their own advantages and disadvantages, and the appropriate method can be selected according to the specific application requirements and material properties. For example, photolithography has high precision and can produce complex geometric shapes and patterns, but it is expensive, needs to be carried out in a clean environment, and has certain restrictions on materials. Self-assembly technology is highly flexible and controllable, and is suitable for preparing nanochannels with complex structures, but it is difficult to accurately control the size and shape of the structure, and the repeatability is poor. Nanolithography imprinting technology can produce high-precision nanochannels, but the technical operation is relatively complex and requires a high level of technology and experience.

[0007] With the continuous advancement of nanotechnology, the preparation methods of nanochannels will become more diversified and refined. At the same time, the application prospects of nanochannels will become more extensive, involving many fields such as biomedicine, environmental protection, and energy development. Future research will focus on improving the performance of nanochannels, reducing preparation costs, and expanding the scope of application. Summary of the invention

[0008] In view of the shortcomings of the prior art, the present invention provides a method for preparing nanochannels by embedding polyethylene oxide nanofibers, which can get rid of the dependence on expensive equipment in the nanochannel preparation process and does not require complicated process, greatly reducing the cost and operation difficulty of nanochannel preparation.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A method for preparing a nanochannel by embedding PEO nanofibers comprises the following steps:

[0011] (1) adding polyethylene oxide (PEO) powder into deionized water and stirring magnetically until PEO is fully dissolved to obtain a PEO spinning solution with a mass fraction of 3 to 5 wt%;

[0012] (2) injecting the PEO spinning solution of step (1) into a syringe, using an electrospinning process to spin PEO nanofibers under the push of a syringe pump and the action of a high voltage power supply, combining a drum collector and pasting a polydimethylsiloxane (PDMS) membrane on the drum to collect the spun PEO nanofibers;

[0013] (3) Place transparent tape on a glass slide and use a scalpel to carve out two rectangular templates, then remove the excess tape.

[0014] (4) Using a nanoprobe combined with a microscope micromanipulator, select a PEO nanofiber with uniform morphology from the PEO nanofibers collected in step (2) and transfer it to the top of the two rectangular transparent tapes on the glass slide in step (3);

[0015] (5) Place the glass slide in step (4) into a culture dish, pour PDMS, then evacuate to remove bubbles, and heat to dry;

[0016] (6) Cut the PDMS dried in step (5) along the glass slide, place it in the aqueous solution, and heat and magnetically stir until the PEO nanofibers embedded in the PDMS are completely dissolved;

[0017] (7) drilling holes at two rectangular positions in the PDMS in which the PEO nanofibers have been dissolved in step (6), performing plasma hydrophilic treatment, and then bonding to the glass slide again;

[0018] (8) Two glass tubes are bonded to the two through-hole positions of the PDMS bonded in step (7) to form a liquid pool, so that the nanochannel prepared between the two liquid pools becomes the only flow channel.

[0019] Furthermore, in the step (1), the molecular weight (Mw) of PEO is 4,000,000 to 5,000,000. When the molecular weight of PEO is lower than 4,000,000, the spun nanofibers are discontinuous. When the molecular weight is too large, the spun nanofibers have a larger diameter. When the molecular weight is between 4,000,000 and 500,000, the nanofibers have a uniform diameter and a smoother surface. During the dissolution of PEO molecules, the stirring temperature is 60 to 80°C, which can accelerate the dissolution rate of PEO molecules and shorten the stirring time to 3 to 6 hours.

[0020] Furthermore, the process parameters of electrospinning in step (2) are as follows: the spinning voltage is 3-6 kV, the microfluidic pump injection speed is 0.001-0.01 ml / min, the roller receiving distance is 30-50 cm, and a 5-25 cm thick piece of 2When the spinning voltage is lower than 3kV, it is difficult for the PEO droplets to form a Taylor cone. When the spinning voltage is higher than 6kV, the diameter of the spun PEO nanofibers is uneven. When the microfluidic pump injection speed is lower than 0.001ml / mim, the spinning process is discontinuous. When the microfluidic pump injection speed is too fast, the solvent cannot evaporate in time. If the drum receiving distance is too far or too close, it will also affect the flight path of the PEO nanofibers and cause the solvent to evaporate. In the electrospinning process, the molecular weight of the reagent, the solution concentration, the spinning voltage, the microfluidic pump injection speed and the drum receiving distance are mutually restricted. For example, when the molecular weight is low, a higher concentration, a relatively low voltage, a lower injection speed (flow rate) and a shorter receiving distance can be used.

[0021] Furthermore, the transparent tape in step (3) is a smooth surface tape, and the size of the two rectangular templates engraved is 5mm×5mm to 10mm×10mm (it should be noted that the rectangle in the present invention is a broad rectangle, including a square and a narrow rectangle. The square template is preferred.), and the rectangular template should not be too large, which will cause the structure to collapse during the PDMS bonding in step (7). If the rectangular template is too small, it will be difficult to operate the glass tube bonding in step (8). The spacing between the two tape templates is 100μm to 1000μm. It is currently difficult to achieve a spacing of less than 100μm by manual engraving. If the spacing is greater than 1000μm, it will be difficult to completely dissolve the embedded PEO nanofibers, resulting in the PDMS nanochannel being impermeable.

[0022] Furthermore, the PEO nanofibers selected in step (4) have smooth morphology and uniform diameter, ranging from 50 nm to 1000 nm, or even to micrometer scale. If the diameter is less than 50 nm, it is difficult to operate it with a nanoprobe even under a microscope.

[0023] Furthermore, in step (5), the weight ratio of PDMS (main agent: curing agent) is 8:1 to 10:1, and the vacuum time is 30 to 60 minutes after the PDMS is poured. After the bubbles are completely removed, the mixture is heated to 60 to 80°C and maintained for 2 to 4 hours until the PDMS is completely cured. The PDMS ratio should not be too low, as it will cause the PDMS to be soft and lack strength after curing. Vacuuming can effectively remove bubbles in the PDMS. The curing temperature of PDMS is between 60 and 80°C. Too high a temperature will cause pyrolysis and deformation of the PDMS, while too low a temperature will prolong the curing time. Similarly, too short a heating time will result in insufficient curing of the PDMS.

[0024] Furthermore, in step (6), the stirring temperature is 80-100°C and the stirring time is 24 hours or more. The melting point of PEO is 87°C, so the stirring temperature of 80-100°C can accelerate the dissolution rate of PEO nanofibers. The stirring time of more than 24 hours can ensure the full dissolution of PEO nanofibers.

[0025] Furthermore, in step (7), two through holes are punched in the center of two PDMS rectangles using a puncher with an inner diameter of 1 to 2 mm, and then bonded to a glass slide after hydrophilic treatment in an oxygen plasma cleaner for 30 to 60 seconds. Due to the water transport characteristics of PDMS, a puncher with a too small inner diameter can easily make it difficult to inject water into the liquid pool. Hydrophilic treatment in an oxygen plasma cleaner generally only takes a few seconds to tens of seconds. The slightly longer time here is to obtain better hydrophilicity inside the PDMS nanochannel.

[0026] Furthermore, the glass tube used in step (8) has an outer diameter of about 4 to 10 mm, an inner diameter of 2 to 4 mm, and a length of 5 to 10 mm. The specific dimensions of the glass tube are mainly adjusted according to the hole diameter and hole spacing drilled in step (7).

[0027] The preparation method of the present invention is divided into three stages. In the first stage, a cheap water-soluble and biocompatible polyethylene oxide material is first selected to prepare PEO nanofibers using electrostatic spinning technology, and the PEO nanofibers are collected on a PDMS film using a drum collector. Due to the softness of the PDMS film, a single PEO nanofiber can be manipulated above the PDMS film using a nanoprobe. In the second stage, the PEO nanofiber is embedded. Under a microscope and a micro-operation table, a single PEO nanofiber selected is transferred to the top of a transparent tape on a glass slide using a nanoprobe to form a suspended structure, and then the entire slide is placed in a culture dish and cast with PDMS. After the PDMS is fully cured, it is reversed and placed in deionized water to dissolve the PEO nanofibers. The third stage is a drilling and bonding process, in which the PDMS nanochannel is punched and hydrophilic treatment is performed using an oxygen plasma cleaning machine, and finally the PDMS slide is rebonded to form a PDMS nanochannel. During the entire nanochannel preparation process, the process methods and parameters involved, such as PEO concentration, electrospinning process parameters, PDMS drying time and temperature, PEO dissolution time and temperature, punching and bonding methods, etc., need to be determined according to actual conditions.

[0028] Compared with the prior art, the present invention provides a method for preparing nanochannels by embedding polyethylene oxide nanofibers, which has the following beneficial effects:

[0029] (1) The subject material of the present invention has a simple preparation process, and the raw materials are cheap and easily available. The nanochannel preparation process does not require expensive etching equipment and ultra-clean space, nor does it require complicated process, and can achieve low-cost and rapid preparation of single nanochannels and multiple nanochannels.

[0030] (2) The present invention provides a low-cost and simple method for preparing nanochannels. Nanofibers are prepared by using water-soluble polyethylene oxide (PEO) organic molecules. The PEO nanofibers are embedded as sacrificial layers to prepare a single nanochannel. The diameter of the nanochannel can be precisely controlled according to the geometric dimensions of the PEO nanofibers, and channel structures of any size, including microchannels, can be prepared. In addition, the length of the nanochannel is completely determined by the length of the embedded PEO nanofibers, and the length can be prepared to be much longer than the existing nanochannel preparation technology, and can even reach the macroscopic scale.

[0031] (3) The nanochannel preparation method proposed in the present invention can be used to prepare not only a single nanochannel but also multiple nanochannels by means of nanoprobe operation.

[0032] (4) The present invention uses PEO materials to prepare nanofibers and PDMS as nanochannel materials, which have good biocompatibility. The nanochannels prepared by the present invention can be used to manufacture nanofluidic chips, which are widely used in the separation, analysis and detection of biological samples and drug delivery research. At the same time, nanochannels are used in nanofluid dynamics research. In the energy field, they can be used to improve the performance of batteries and fuel cells, and have broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of electrospinning and collecting oxidized polyethylene by a roller in Example 1 of the present invention;

[0034] Figure 2 This is a scanning electron microscope photo of a single PEO nanofiber in Example 1 of the present invention;

[0035] Figure 3 Schematic diagram of preparing a single nanochannel by embedding PEO nanofibers in Example 1 of the present invention, wherein Figure 3 a to Figure 3 f is its preparation order;

[0036] Figure 4 This is a photo of the nanoprobe operating table in Example 1 of the present invention, wherein Figure 4 a is a photo of a single PEO nanofiber observed under an optical microscope. Figure 4 b is the morphology photo of the nanoprobe and a single PEO nanofiber under an optical microscope;

[0037] Figure 5 This is a solid photograph of a single nanochannel sample in Example 1 of the present invention;

[0038] Figure 6 This is an optical microscope photograph of a single nanochannel after being filled with fluorescent liquid in Example 1 of the present invention;

[0039] Figure 7 Schematic diagram of measuring nanofluid dynamics of a single nanochannel in Example 1 of the present invention;

[0040] Figure 8 The voltammogram curves of the PDMS single nanochannel in Example 1 of the present invention measured under different salt solutions;

[0041] Fig. 9 This is a signal diagram of a PDMS single nanochannel applied to DNA molecule detection at a bias voltage of 1000mv in Example 1 of the present invention;

[0042] Fig.10 This is an optical microscope photograph of agglomerated molecules spun using a molecular weight of 1,000,000 in the electrospinning process of PEO in Example 2 of the present invention;

[0043] Fig.11 This is a fluorescence microscope photo of the semi-permeable PDMS nanochannel formed due to insufficient dissolution of PEO nanofibers during the preparation process of Example 3 of the present invention;

[0044] Fig.12 This is a comparison chart of the conductivity of PDMS nanochannels formed when PEO nanofibers are fully dissolved and when PEO nanofibers are insufficiently dissolved in the preparation process of Example 3 of the present invention as a function of KCl solution concentration.

[0045] The meanings of the reference numerals in the figures are:

[0046] 1- microfluidic pump; 2- syringe; 3- PEO spinning solution; 4- syringe needle; 5- PEO nanofiber; 6- PDMS film; 7- roller collector; 8- high voltage power supply; 9, 10- transparent tape; 11, 18- glass slide; 12- single PEO nanofiber; 13- nanoprobe; 14- PDMS; 15- PDMS single nanochannel; 16, 17- cylindrical hole; 19, 20, 23, 24- glass liquid pool; 21- micro operation stage; 22- optical microscope; 25, 26- silver / silver chloride electrodes; 27- patch clamp amplifier; 28- computer. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may also include different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0049] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the protection content of the present invention.

[0050] Example 1

[0051] like Figure 1 As shown, the method for preparing nanochannels by embedding polyethylene oxide nanofibers proposed in the present invention comprises the following steps:

[0052] (1) If Figure 1 As shown, Figure 1 The schematic diagram of electrospinning and collecting oxidized polyethylene by roller in the present invention. 5 mg of polyethylene oxide PEO was dissolved in 10 ml of deionized water, and then heated to 60 ° C and magnetically stirred for 1 hour until all PEO molecules were dissolved to obtain PEO spinning solution 3. PEO spinning solution 3 was drawn with a 1 ml syringe 2, syringe 2 was connected to a 25G syringe needle 4, the injection speed of the microfluidic pump 1 was 0.005 ml / min, the rotation speed of the roller collector 7 was 2000 r / min, and a PDMS film 6 with a size of 2 cm × 5 cm was pasted on the center of the roller of the roller collector 7, the distance between the roller and the needle tip was 40 cm, and the electrospinning voltage was 3 to 6 kV (because it is difficult to spin the wire when the voltage is lower than 3 kV, and the morphology of the PEO nanofibers 5 spun by the voltage higher than 6 kV is uneven, and the electrospinning voltage comes from the high voltage power supply 8), and the PEO nanofibers 5 were collected. In order to avoid excessive accumulation of PEO nanofibers 5 collected on the PDMS film 6, the spinning time is as short as possible, about 10 to 30 seconds. Figure 2 Shown is a high-definition scanning electron microscope photograph of a single PEO nanofiber 12, with a diameter of about 265 nm.

[0053] (2) If Figure 3 As shown in a, a transparent tape is pasted on the top of the glass slide 11, and a scalpel is used to carve two rectangles with a size of 0.5 cm × 1 cm on the adhered transparent tape. The distance between the two rectangles is 100 μm to 1000 μm. This distance directly determines the length of the prepared PDMS single nanochannel 15 and can be adjusted according to the device requirements.

[0054] (3) If Figure 3 As shown in FIG. 2 , the PEO nanofibers 5 collected on the PDMS film 6 in step (1) are placed under an optical microscope 22 for observation, and a single PEO nanofiber 12 with uniform diameter and smooth morphology is selected from the PEO nanofibers 5. With the assistance of the micro-operation platform 21, the selected single PEO nanofiber 12 is picked up by a nanoprobe 13 and placed on top of the two rectangular transparent tapes 9, 10 on the glass slide 11 prepared in step (2). The micro-operation platform 21 is as shown in FIG. Figure 4 As shown in a, the morphology of the nanoprobe 13 and the single PEO nanofiber 12 under an optical microscope 22 is as follows: Figure 4 As shown in b.

[0055] (4) If Figure 3 As shown in Figure c, the sample prepared in step (3) is placed in a culture dish, PDMS14 is poured in the culture dish, and the PDMS14 and curing agent are installed in a ratio of 8:1 (weight ratio). The entire culture dish is placed in a vacuum oven, and vacuum is first drawn and maintained for 30 minutes to remove all bubbles in the PDMS14. After the bubbles are removed, the vacuum valve is opened and the PDMS14 is dried at 80°C for 2 hours until the PDMS14 is completely cured.

[0056] (5) If Figure 3 As shown in FIG. d, the PDMS 14 cured in step (4) is cut and peeled off from the substrate of the glass slide 11. The cut PDMS 14 is subjected to hydrophilic treatment and then placed in deionized water to dissolve the single PEO nanofiber 12 embedded in the PDMS 14. In order to fully dissolve the embedded single PEO nanofiber 12, it is stirred with a magnetic stirrer and heated to 90° C. for 24 hours. After the single PEO nanofiber 12 is completely dissolved, the PDMS single nanochannel 15 can be obtained.

[0057] (6) Figure 3As shown in Figure e, the PDMS single nanochannel 15 prepared in step (5) is punched. When punching, a puncher with a suitable aperture can be selected according to the needs, and a hole is punched in the center of each of the two rectangles of PDMS 14. After the cylindrical holes 16 and 17 are punched, the surface of PDMS 14 is hydrophilized using an oxygen plasma cleaner, and finally the treated PDMS 14 is bonded to the glass slide 18.

[0058] (7) Figure 3 As shown in f, two glass liquid pools 19 and 20 are respectively bonded on the two holes of the PDMS 14 bonded in step (6), and the adhesive is PDMS. After the adhesive is dried, the sample entity is as shown in Figure 5 shown.

[0059] In order to verify that the single PEO nanofiber 12 embedded in the PDMS single nanochannel 15 prepared in Example 1 is fully dissolved, Figure 5 Fluorescent solution was injected into the two glass liquid pools of the sample shown in the figure. Figure 5 The sample shown is subjected to hydrophilic treatment by oxygen plasma cleaning machine for 30 seconds, and then a fluorescent solution is injected, using Rhodamine 123 ethanol solution, and the solution is allowed to stand for 1 hour. After the fluorescent solution completely fills the PDMS single nanochannel 15, an optical microscope 22 is used to observe under dark field, and it can be seen that the fluorescent solution completely fills the PDMS single nanochannel 15, as shown in FIG. Figure 6 As shown, it is fully verified that the embedded single PEO nanofiber 12 has been completely dissolved to form a PDMS single nanochannel 15.

[0060] like Figure 7 , which is a schematic diagram of studying the nano-ionic current characteristics of the PDMS single nanochannel 15 of the present invention and applying it to biomolecule detection.

[0061] In the measurement of the nano-ionic current voltammetric curve (IV) of the PDMS single nanochannel 15, deionized water and potassium chloride salt solutions (KCl) of different concentrations are injected into the glass liquid pools 23 and 24 in sequence, and silver / silver chloride electrodes 25 and 26 are inserted into the glass liquid pools 23 and 24. The ionic current signal is collected by a patch clamp amplifier 27, and the collected data is transmitted to a computer 28. When measuring the IV curves of KCl solutions of different concentrations, the time voltage is -500mV to 500mV, and the voltage increases by 100mV. The IV curves of different KCl solutions measured are as follows: Figure 8As shown. According to the IV curve, it can be observed that as the KCl concentration increases, the conductivity of the PDMS single nanochannel 15 also increases, which once again proves that the PDMS single nanochannel 15 is completely permeable. At the same time, it can be seen from the IV curve that the conductivity of the PDMS single nanochannel 15 in 1M KCl solution is only higher than that in 0.5M KCl solution, and the mobility of 1M KCl ions in the PDMS single nanochannel 15 is much smaller than the bulk value.

[0062] In the application of measuring 48kb λ-DNA, the diameter of the PDMS single nanochannel 15 is 100nm-200nm, the length is 1μm-2μm, and a 0.5M KCl solution is used as a buffer. The 48kb λ-DNA molecule is injected into the glass liquid pool 23 on the negative electrode side. Since the DNA molecule is negatively charged in the KCl solution, under the bias voltage of 1000mV, the λ-DNA flows through the PDMS single nanochannel 15 to the positive electrode glass liquid pool 24 driven by the electrophoretic force. In the process of the λ-DNA molecule flowing through the PDMS single nanochannel 15, due to the space occupancy effect, the reference ion current in the PDMS single nanochannel 15 decreases. Fig. 9 As shown, the baseline ion current is stable at 5.1 nA, and the average current drop caused by the λ-DNA molecule occupying the PDMS single nanochannel 15 is △I=0.22 nA. The current drop amplitude is relatively small, which is mainly due to the large diameter of the PDMS single nanochannel 15. If the geometric dimensions of the PDMS nanochannel 15 are further optimized, a detection signal with a better signal-to-noise ratio will be obtained.

[0063] Example 2

[0064] In the process of electrospinning PEO nanofibers, PEO uses a molecular weight of Mw = 1000000. Similarly, 5 mg of polyethylene oxide PEO is dissolved in 10 ml of deionized water, and then heated to 60 ° C and magnetically stirred for 1 hour until all PEO molecules are completely dissolved to obtain a PEO spinning solution 3. The PEO spinning solution 3 is sucked by a 1 ml syringe 2, and the syringe 2 is connected to a 25G syringe needle 4. The injection speed of the microfluidic pump 1 is 0.01-0.001 ml / min, and the rotation speed of the roller collector 7 is 2000 r / min. A PDMS film 6 with a size of 2 cm × 5 cm is pasted in the center of the roller of the roller collector 7. The distance between the roller and the needle tip is 30-50 cm. The electrospinning voltage is 3kV-8kV to spin PEO nanofibers, such as Fig.10As shown, the particles ejected under the high voltage electric field are all in the form of floccules, and PEO nanofibers cannot be prepared. It can be found from Example 2 that if a solution is prepared using a lower molecular weight PEO powder, no matter how the voltage, the injection speed of the microfluidic pump 1 and the receiving distance of the roller are adjusted during the electrospinning process, PEO nanofibers cannot be spun.

[0065] Example 3

[0066] Based on Example 1, if the dissolution time is insufficient in the step of dissolving the PEO nanofibers, the PEO nanofibers are not fully dissolved, which will directly lead to the PDMS single nanochannel 15 being impermeable. In the process of verifying with fluorescent liquid, it will be found that the PEO nanofibers are partially dissolved, such as Fig.11 Similarly, insufficient dissolution of PEO nanofibers will result in the conductivity of the PDMS single nanochannel 15 remaining unchanged as the concentration of KCl solution changes when the IV curve is measured later, as shown in Fig.12 As shown in Example 1, if the PEO nanofibers are fully dissolved, the PDMS single nanochannel 15 will be permeable, and its conductivity will increase with the increasing concentration of the KCl solution. Therefore, the full dissolution of the PEO nanofibers is a key step of the present invention, and the full dissolution of the PEO nanofibers can ensure the success of the subsequent device preparation.

[0067] It should be noted that, in this application, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements.

[0068] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing nanochannels by embedding polyethylene oxide nanofibers, characterized in that: The following steps are involved: Adding polyethylene oxide (PEO) powder into deionized water and stirring magnetically until PEO is fully dissolved to obtain a PEO spinning solution; The obtained PEO spinning solution is injected into a syringe, and the PEO nanofibers are spun by an electrospinning process; A polydimethylsiloxane (PDMS) membrane is pasted on the drum of a drum collector to collect the spun PEO nanofibers; Put transparent tape on the glass slide, carve out two rectangular templates on the transparent tape, and then remove the excess tape; A PEO nanofiber with uniform morphology was selected from the collected PEO nanofibers and placed on top of two rectangular transparent tapes, and then placed in a culture dish together with a glass slide, PDMS was poured, and then vacuum was applied to remove bubbles, and then heated and dried; The dried PDMS was cut along the glass slide and placed in the aqueous solution, and heated and magnetically stirred until the PEO nanofibers embedded in the PDMS were completely dissolved; The PDMS of the dissolved PEO nanofibers was respectively perforated at two rectangular positions, and subjected to plasma hydrophilic treatment, and then bonded to the glass slide again; Two glass tubes are bonded at the two through-hole positions of the bonded PDMS to form a liquid pool, so that the nanochannel prepared between the two liquid pools becomes the only flow channel.

2. The method for preparing nanochannels by embedding polyethylene oxide nanofibers according to claim 1, characterized in that: The magnetic stirring is carried out until PEO is fully dissolved, and the stirring temperature is 60-80° C. and the stirring time is 3-6 hours.

3. The method for preparing nanochannels by embedding polyethylene oxide nanofibers according to claim 1, characterized in that: The process parameters of the electrospinning are as follows: the spinning voltage is 3-6 kV, the microfluidic pump injection speed is 0.001-0.01 ml / min; the roller receiving distance is 30-50 cm, and a 5-25 cm thick piece of 2 Size of PDMS membrane.

4. The method for preparing nanochannels by embedding polyethylene oxide nanofibers according to claim 1, characterized in that: The transparent tape is a smooth surface tape, and the two rectangular templates engraved are 25mm in size. 2 ~100mm 2 , the distance between the two transparent tapes is 100μm to 1000μm.

5. The method for preparing nanochannels by embedding polyethylene oxide nanofibers according to claim 1, characterized in that: The selecting a PEO nanofiber with uniform morphology means that the selected PEO nanofiber has a smooth morphology and uniform diameter, and the diameter is not less than 50 nm.

6. The method for preparing nanochannels by embedding polyethylene oxide nanofibers according to claim 1, characterized in that: The specific method of pouring PDMS, vacuuming to remove bubbles, and heating and drying is as follows: the PDMS weight ratio is 8:1-10:1, the vacuuming time is 30-60 minutes after pouring PDMS, and after the bubbles are completely removed, the temperature is heated to 60-80° C. and maintained for 2-4 hours, waiting for the PDMS to be completely cured.

7. The method for preparing nanochannels by embedding polyethylene oxide nanofibers according to claim 1, characterized in that: The heating magnetic stirring is performed until the PEO nanofibers embedded in the PDMS are completely dissolved, and the stirring temperature is 80-100° C., and the stirring time is at least 24 hours.

8. The method for preparing nanochannels by embedding polyethylene oxide nanofibers according to claim 1, characterized in that: Two through holes were punched in the center of two rectangles of PDMS using a puncher with a diameter of 1 to 2 mm, and then bonded to a glass slide after hydrophilic treatment in an oxygen plasma cleaner for 30 to 60 seconds.

9. The method for preparing nanochannels by embedding polyethylene oxide nanofibers according to claim 1, characterized in that: The glass tube has an outer diameter of 4 to 10 mm, an inner diameter of 2 to 4 mm, and a length of 5 to 10 mm.

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