CN102995145A - Integrated microfluidic spinning chip and method for preparing regenerated silk fibroin by using same - Google Patents

Abstract

The invention belongs to the technical field of microfluid spinning, and relates to an integrated microfluid spinning chip and a method for preparing regenerated silk fibroin fibers. The microfluidic chip is a three-layer structure, in which the upper and lower layers of polydimethylsiloxane membranes with grooves are attached to the middle dialysis membrane to form two upper and lower microfluidic channels. The two microfluidic channels are equal in depth and tapered in width. In the preparation method of regenerated silk fibroin fiber of the present invention, the upper channel is injected with spinning solution at room temperature, and the lower channel is injected with a mixed solution of water-absorbing resin and ion regulating solution; the spinning solution is adjusted by ion, sheared, stretched and concentrated , extruded from the outlet and solidified in the air into a silk winding roll. The microfluidic chip of the present invention simulates the complex flow field in the biological spinning process, realizes the shear stretching, component adjustment and concentration of the spinning solution, etc., and is combined with the dry spinning process to obtain performance Excellent regenerated silk fibroin fibers.

Description

An integrated microfluidic spinning chip and method for preparing regenerated silk fibroin fiber

technical field

The invention belongs to the fields of bionics and microfluid spinning, and relates to an integrated microfluid spinning chip and a method for preparing regenerated silk fibroin fibers; in particular, it relates to a method for realizing shearing and pulling of spinning liquid in the same chip. A microfluidic dry spinning method for regenerated silk fibroin fibers integrating multiple functions such as stretching, component adjustment, concentration and spinning.

Background technique

Organisms such as spiders or silkworms can use water as a solvent at normal temperature and pressure to produce protein fibers with excellent mechanical properties. The entire process consumes low energy and does not use organic solvents, which is environmentally friendly. Therefore, the research on biomimetic spinning is of great significance to industrial fiber production.

Although the comprehensive mechanical properties of spider silk are the best, the bionic research of spider silk is greatly restricted due to the variety of spiders and the silk produced by them, which are difficult to obtain in large quantities. Compared with the difficulty of obtaining spider silk, silk has been used by people thousands of years ago, and its mechanical properties and amino acid sequence are similar to those of spider drag silk; and Shao Zhengzhong's research shows that optimizing the spinning process of silk can significantly To improve its mechanical properties, people turn to bionic research on silkworms.

Studies have shown that during the spinning process of organisms, the metal ion content of the spinning solution changes, the pH decreases, and the concentration gradually increases; the tensile shear of the spinning solution when it flows through some special areas of the biological spinner The effect is to change the conformation of animal silk protein from random coil and/or α-helix conformation to water-insoluble β-sheet. Therefore, the spinning process of organisms is a unified and coordinated process that integrates multiple functions such as component adjustment, stretching and shearing, pH reduction, and protein concentration. At present, most of the artificial spinning researches using silk protein as raw materials are wet spinning, dry spinning and electrospinning. Although these spinning methods are mature in technology, due to the simple device and low degree of bionicity, the mechanical properties of the prepared protein fibers are worse than those of natural silk. Due to its special properties, such as laminar flow characteristics of solutions in channels, flexible and controllable channel design, etc., microfluidic technology has attracted widespread attention. The application of microfluidic technology in the field of spinning can achieve conditions that are difficult to achieve in traditional spinning processes. For example, patents WO2007/141131 (A1) and US2010029553 (A1) used the principle of laminar flow diffusion to design a microfluidic chip to realize the adjustment of the pH and metal ion concentration of the regenerated silk fibroin solution. Patent application numbers 201019063008.1 and 201010581835.2 combine microfluidic chips with electrospinning technology to prepare regenerated silk fibroin nanofibers. The patent application number is 201110007230.7. The spinning method combining microfluidic chip with wet spinning, dry spinning and electrospinning is further applied to the regenerated silk fibroin solution system to prepare regenerated animal silk with excellent performance. Patent No. ZL201110007232.6, designed a microfluidic chip with shear stretching function, combined with dry spinning, applied to the regenerated silk fibroin solution system, and realized the shear stretching of the spinning solution, but with Compared with the multiple functions of the biospinning process, the function is single and the degree of biomimesis is low.

Although microfluidic technology has developed to a certain extent in the field of bionic spinning, compared with the biospinning process, the microfluidic spinning chip is still too simple and has a single function, and the cutting of the spinning solution has not been realized in the same chip. Cutting and stretching, component adjustment, concentration and spinning and other functions, there is still a big gap with the real bionic spinning.

Contents of the invention

The invention starts from the biological spinning process of spiders or silkworms, designs complex microfluidic channels, simulates the complex flow field of spinning liquid in living organisms, and adopts multi-layer microfluidic technology and dry spinning process to realize chip The multi-functional integration of multi-function, greatly improved the degree of bionics; 5-50% regenerated silk fibroin aqueous solution is used as the spinning stock solution at room temperature, and the regenerated animal with excellent performance is obtained through the ion regulation, shear stretching and protein concentration of the microfluidic chip. Silk protein fibers.

The purpose of the present invention is to provide a microfluid spinning chip for simulating biological spinning process and its spinning method for regenerating silk fibroin solution.

An integrated microfluidic spinning chip of the present invention, said integrated microfluidic spinning chip is a three-layer structure, including upper and lower layers of polydimethylsiloxane (PDMS) membranes and an upper 1. The dialysis membrane between the lower two layers of PDMS membranes; the upper and lower layers of PDMS membranes have corresponding grooves, and the grooves of the upper layer of PDMS membranes are attached to one surface of the dialysis membrane to form an upper layer For the microfluidic channel, the groove of the lower PDMS membrane is attached to the other surface of the dialysis membrane to form the lower microfluidic channel; the opening of the groove of the upper PDMS membrane is opposite to the opening of the groove of the lower PDMS membrane.

The upper microfluidic channel is divided into an adjustment section, a stretching section and a shear section according to functions; the width of the upper microfluidic channel changes from the inlet to the outlet, wherein the width of the adjustment section and the shear section are not the same. The width of the stretching section gradually decreases; the horizontal section shape of the adjustment section, the stretching section and the shear section of the lower microfluidic channel is in a mirror image relationship with the horizontal section shape of the upper microfluidic channel; the upper and lower two The depth of the microfluidic channel in the whole layer is equal; when spinning, the solution flows in from the regulating section of the channel, and flows out from the shearing section.

As a preferred technical solution:

An integrated microfluidic spinning chip as described above, the microfluidic channels are arranged longitudinally or horizontally in a serpentine manner on the PDMS membrane; the longitudinal serpentine arrangement refers to the longitudinal and vertical arrangement of the channels Parallel to the short side of the PDMS membrane; the horizontal serpentine arrangement means that the horizontal arrangement of the channels is parallel to the long side of the PDMS membrane;

An integrated microfluidic spinning chip as described above, the channels arranged in a longitudinal serpentine shape have a total of 4 to 6 bends in the adjustment section and the shearing section, and the length of the vertical part of each serpentine channel is 7-14mm, each vertical channel is connected by a semicircle, the diameter of the semicircle is 3-10mm, the outlet of the shear section is located at the center of the short side of the PDMS membrane; the stretch section of the microfluidic channel, The angle between the line of symmetry of the channel and the long side of the PDMS membrane is 20-60°, and the length of the stretching section is 15-30mm; One of exponential, hyperbolic, or straight lines.

An integrated microfluidic spinning chip as described above, the channels arranged in a horizontal serpentine shape have 1 to 3 bends in the adjustment section and the shearing section, and the length of each horizontal part of the serpentine channel is 50 ～80mm, each horizontal channel is connected by a semicircle, the diameter of the semicircle is 4～12mm, the outlet position of the shear section deviates from the center position of the short side of the PDMS membrane by 5～8mm; the stretching of the microfluidic channel section, located in the horizontal part of the channel, parallel to the long side of the PDMS membrane; the length of the stretched section is 15 to 30mm; the traces where the two sides of the stretched section channel intersect the horizontal plane are exponential functions One of a hyperbolic function or a straight line.

In the integrated microfluidic spinning chip as described above, the adjustment section is the widest section of channel, with a width of 1-2.5mm and a length of 60-100mm; the shear section is the narrowest section A channel with a width of 100-500 μm and a length of 20-150 mm.

According to the above-mentioned integrated microfluidic spinning chip, the cross-sectional shape of the groove is rectangular; the regulating section, the stretching section and the shearing section are connected by arcs or directly.

An integrated microfluidic spinning chip as described above, the dialysis membrane is a regenerated cellulose dialysis membrane with a molecular weight cut-off of 5,000 to 30,000 Daltons; the upper and lower layers of the integrated microfluidic spinning chip The PDMS membrane and the dialysis membrane between the upper and lower layers of PDMS membranes are bonded by adhesive packaging; the adhesive is silicone, epoxy resin adhesive or double-sided adhesive one or a combination.

A method for preparing regenerated silk fibroin fibers with an integrated microfluidic spinning chip as described above, using an aqueous regenerated silk fibroin solution with a mass percentage of 5% to 50% as the spinning solution, injecting the upper microfluidic channel into the spinning solution at room temperature For silk liquid, the lower microfluidic channel is injected with a mixture of water-absorbing resin and ion regulating liquid; the spinning liquid passes through the stretching and shearing of the channel with gradually smaller width and the concentration and ion adjustment of the lower channel solution, and is extruded through the outlet. The regenerated silk fibroin fiber is obtained by solidifying into silk in the air and winding on the upper roller. The solution in the lower channel is collected.

A method as described above, wherein the ion regulating solution is an aqueous CaCl ₂ solution; the water-absorbing resin is polyethylene glycol with a molecular weight of 10,000 to 40,000 Daltons, and the concentration of Ca ²⁺ in the mixed solution is 80 ~120g/L, polyethylene glycol concentration is 70~600g/L.

In one method as described above, the air gap between the outlet of the microfluidic channel on the upper layer of the microfluidic chip and the winding roller is 5-30 cm, and the winding speed is 2-10 cm/s.

According to the above-mentioned method, the spinning solution, the ion regulating solution and the water-absorbing resin are all injected by a micro-syringe pump.

According to a method as described above, the diameter of the regenerated silk fibroin fibers is 7-30 μm; the regenerated silk fibroin fibers are long filaments or short fibers.

The operation steps of the above method are as follows:

(1) The preparation method of the microfluidic chip proposed by the present invention uses a glass slide (75×25mm) as the substrate, and exposes the SU-8 photoresist coating to ultraviolet exposure under a mask printed with microchannel patterns. After development, a positive mold with a microchannel pattern can be obtained, and then the PDMS prepolymer and its curing agent are cast on the mold, and after curing, a PDMS membrane with a microchannel pattern can be obtained. Finally, the upper and lower layers of the PDMS membrane and the dialysis membrane are packaged and bonded with an adhesive after plasma treatment.

(2) Degumming silkworm cocoons with 0.5% (mass volume ratio) Na ₂ CO ₃ , dissolving them in 9.0 mol/L BrLi solution, then centrifugal dialysis, and performing preliminary concentration to obtain the final spinning solution;

(3) Dissolve polyethylene glycol and CaCl ₂ ·2H ₂ O in a certain amount of deionized water according to the required ratio to obtain a mixture of a concentrated solution and an ion-adjusting solution with a specific concentration;

(4) Use a low-concentration regenerated silk fibroin aqueous solution as the spinning solution, inject the spinning solution into the upper channel of the microfluidic chip at room temperature, and inject the mixed solution of water-absorbing resin and ion regulating solution into the lower channel, and the spinning solution After flowing through the channel of the upper chip, it is extruded through the outlet, solidified into filaments in the air and wound on the upper roll.

Beneficial effect

(1) The prepared microfluidic chip simulates the complex flow field of the spinning solution in the organism according to the shape characteristics of the spider or silkworm gland, and realizes the adjustment of the components of the spinning solution, shear stretching and concentration, It realizes multifunctional integration and is a three-dimensional multifunctional integrated microfluidic chip;

(2) The low-concentration regenerated silk fibroin aqueous solution can be directly used as the spinning stock solution, without the need for further concentration, adjustment of pH and metal ions in the early stage, and the use of organic solvents is avoided, which effectively simplifies the operation steps and reduces production cost;

(3) Combining the microfluidic technology with the dry spinning process, the spinning process is improved, the spinning effect is improved, and the degree of bionic spinning is further improved.

Description of drawings

Figure 1 is a microfluidic chip spinning process diagram

Figure 2 is a schematic cross-sectional view of a microfluidic chip

Figure 3 is a schematic diagram of the channel structure of the upper microfluidic chip arranged in a horizontal serpentine shape

Figure 4 is a schematic diagram of the channel structure of the lower microfluidic chip arranged in a horizontal serpentine shape

Figure 5 is a schematic diagram of the channel structure of the upper microfluidic chip arranged in a longitudinal serpentine shape

Figure 6 is a schematic diagram of the channel structure of the lower microfluidic chip arranged in a longitudinal serpentine shape

1. The adjustment section of the channel

2. Stretch section of channel

3. Cutting section of the channel

4. Upper PDMS membrane

5. Dialysis membrane

6. Lower PDMS membrane

7. Mixed solution of PEG aqueous solution and ion regulator solution

8. Regenerated silk fibroin solution

9. Micro injection pump

10. Roller

11. Solution collection device

12. Upper layer microfluidic channel

13. Lower layer microfluidic channel

Detailed ways

The present invention will be further described below in combination with specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

An integrated microfluidic spinning chip of the present invention, said integrated microfluidic spinning chip is a three-layer structure, comprising two layers of PDMS diaphragms 4, 6 on the upper and lower layers and two layers of PDMS membranes between the upper and lower layers The dialysis membrane 5 between the sheets 4 and 6; the upper and lower PDMS membranes have corresponding grooves; the grooves of the upper PDMS membrane 4 are attached to the dialysis membrane 5 to form an upper microfluidic channel 12. The groove of the lower PDMS membrane 6 is attached to the dialysis membrane 5 to form the lower microfluidic channel 13; the groove opening of the upper PDMS membrane 4 is opposite to the groove opening of the lower PDMS membrane 6.

The upper microfluidic channel 12 is sequentially divided into an adjustment section 1 , a stretching section 2 and a shearing section 3 according to functions. The width of the upper layer microfluidic channel 12 changes from the inlet to the outlet, wherein the width of the adjustment segment 1 and the shear segment 3 is constant, and the width of the stretching segment 2 gradually becomes smaller; the width of the lower layer microfluidic channel 13 The horizontal cross-sectional shape of the adjustment section 1, the stretching section 2 and the shearing section 3 is in a mirror image relationship with the horizontal cross-sectional shape of the upper microfluidic channel 12; the depths of the upper and lower two-layer microfluidic channels 12, 13 are equal; The solutions 7 and 8 both flow in from the regulating section 1 of the channel by the micro-injection pump 9 and flow out from the shearing section 3 .

An integrated microfluidic spinning chip as described above, the microfluidic channels are arranged in a longitudinal or horizontal serpentine shape on the PDMS membrane; the horizontal serpentine arrangement described in Figure 3 and Figure 4 refers to the channel's The horizontally arranged part is parallel to the long side of the PDMS membrane; the longitudinal serpentine arrangement described in Figure 5 and Figure 6 means that the longitudinal and vertically arranged part of the channel is parallel to the short side of the PDMS membrane.

An integrated microfluidic spinning chip as described above, the horizontal serpentine-shaped channels described in Fig. The length of the horizontal part of the channel is 50-80 mm, and each horizontal channel is connected by a semicircle with a diameter of 4-12 mm. The outlet position of the shear section 3 is 5-8 mm away from the center of the short side of the PDMS diaphragm; The stretching section 2 of the microfluidic channel is located in the horizontal part of the channel and is parallel to the long side of the PDMS membrane; the length of the stretching section 2 is 15-30 mm; the two sides of the stretching section 2 channel The trace where the side surface intersects the horizontal plane is one of exponential function, hyperbolic function or straight line.

An integrated microfluidic spinning chip as described above, the channel arranged in a longitudinal serpentine shape as shown in Fig. 5 and Fig. 6 has a total of 4 to 6 bends in the regulating section 1 and the shearing section 3, and each serpentine The length of the vertical part of the channel is 7-14mm, each vertical channel is connected by a semicircle, the diameter of the semicircle is 3-10mm, and the outlet of the shear section 3 is located at the center of the short side of the PDMS diaphragm; The stretching section 2 of the microfluidic channel, the angle between the symmetry line of the channel and the long side of the PDMS membrane is 20-60°, the length of the stretching section 2 is 15-30mm; the stretching section 2 The intersection of the two sides of the channel with the horizontal plane is one of exponential function, hyperbolic function or straight line.

According to the above-mentioned integrated microfluidic spinning chip, the adjustment section 1 is the widest section of channel, with a width of 1-2.5 mm and a length of 60-100 mm.

In the integrated microfluidic spinning chip described above, the shearing section 3 is the narrowest section of channel, with a width of 100-500 μm and a length of 20-150 mm.

A kind of integrated microfluidic spinning chip as mentioned above, the cross-sectional shape of the groove of described upper layer PDMS diaphragm 4 and lower layer PDMS diaphragm 6 is rectangular; The cut sections 3 are connected through circular arcs or directly.

In the integrated microfluidic spinning chip described above, the dialysis membrane 5 is a regenerated cellulose dialysis membrane with a molecular weight cut-off of 5000-30000 Daltons.

An integrated microfluidic spinning chip as described above, the upper PDMS membrane 4, the lower PDMS membrane 6 and the upper and lower PDMS membranes 4, 6 of the integrated microfluidic spinning chip The dialysis membrane 5 is packaged and bonded by an adhesive; the adhesive is one or a combination of silica gel, epoxy resin adhesive or double-sided tape.

A method for preparing regenerated silk fibroin fibers with an integrated microfluidic spinning chip as described above, using an aqueous regenerated silk fibroin solution with a mass percentage of 5% to 50% as the spinning solution 8, and at room temperature, the upper layer of the microfluidic channel 12 The spinning solution 8 is injected, and the lower microfluidic channel 13 is injected with the mixed solution 7 of the water-absorbing resin aqueous solution and the ion regulating solution; Ion adjustment effect, after being extruded at the outlet, it is solidified into silk in the air and wound on the upper roller 11 to obtain regenerated silk fibroin fibers. The rate is 1-10%; at the same time, the solution 7 flowing out of the lower channel 13 is collected by the collecting device 11 at the outlet.

In the above-mentioned method, the ion regulating liquid of the lower channel 13 and the ion regulating liquid of the water-absorbing resin mixed aqueous solution 7 are CaCl ₂ , and the water-absorbing resin is polyethylene glycol with a molecular weight of 10,000-40,000 Daltons, wherein the mixed The concentration of Ca ²⁺ in the liquid is 80-120g/L, and the concentration of polyethylene glycol is 70-600g/L.

In one method described above, the air gap between the outlet of the microfluidic channel 12 on the upper layer of the microfluidic chip and the roller 10 is 5-30 cm, and the winding speed of the roller 10 is 2-10 cm/s.

In one method as described above, the mixed solution 7 of the spinning solution 8 , the ion regulating solution and the water-absorbing resin is all injected by a micro-injection pump 9 .

According to a method as described above, the diameter of the regenerated silk fibroin fibers is 7-30 μm; the regenerated silk fibroin fibers are long filaments or short fibers.

Example 1

The microfluidic chip of the present invention is a three-layer structure, including the upper and lower PDMS membranes and the middle dialysis membrane layer. There are grooves on the PDMS membrane, and the grooved surfaces of the upper and lower membranes are bonded to the dialysis membrane to form an upper and lower membrane. Two microfluidic channels; the channels have an equal depth of 50 μm throughout. The horizontal cross-sectional shape of the microfluidic channel in the lower layer is in a mirror image relationship with the horizontal cross-sectional shape of the upper layer channel. The channels are arranged in a longitudinal serpentine shape on the diaphragm: the serpentine channel in the adjustment section has 3 bends, the width is 2mm, the vertical part of the channel is 7mm long, and the diameter of the semicircle of the curved part is 4mm; the shearing section has 3 Each bend has a width of 150 μm, the length of the vertical part of the serpentine channel is 14 mm, and the diameter of the semicircle of the curved part is 3 mm. The length of the tensile section of the microfluidic channel is 15mm, and the angle between the long side of the PDMS membrane of the chip is 20°, and the traces where the two sides of the channel intersect the horizontal plane are first-order exponential function curves, and the formula of the exponential function is: R(x )=e ^a*ln(x) . The arc radians connecting each section of passage is 6. The outlet position of the lower channel is 8mm away from the midpoint of the short side of the PDMS membrane. The upper and lower layers of PDMS membranes of the chip and the dialysis membrane between the upper and lower layers of PDMS membranes are packaged and bonded by epoxy resin and silicone adhesive.

A kind of preparation method of regenerated silk fibroin fiber of the present invention, at room temperature, with 5% regenerated silk fibroin aqueous solution as spinning liquid, ^the Ca concentration in ion regulating liquid and water-absorbent resin mixed liquid is 80g/L, The concentration of water-absorbent resin is 600g/L, and the molecular weight is 10000 polyethylene glycol (PEG-10000) aqueous solution; the molecular weight cut-off of the dialysis membrane is 5000, and the spinning solution is injected into the upper channel at a flow rate of 5 μL/min, PEG-10000 aqueous solution and ions The mixed solution of conditioning solution was injected into the lower channel at a speed of 10 μL/min; the spinning solution was extruded from the outlet of the microchannel and solidified into filaments in the air and wound up on the upper roller; the air gap from the outlet to the winding roller was 5 cm, and the winding The speed is 2cm/s.

The diameter of the regenerated silk fibroin fiber prepared by the present invention is 7 μm, the strength of the regenerated silk fibroin fiber is 20 MPa, and the elongation at break is 7%. The regenerated silk fibroin fibers are short fibers.

Example 2

The microfluidic chip of the present invention is a three-layer structure, including the upper and lower PDMS membranes and the middle dialysis membrane layer. There are grooves on the PDMS membrane, and the grooved surfaces of the upper and lower membranes are bonded to the dialysis membrane to form an upper and lower membrane. Two microfluidic channels; the horizontal cross-sectional shape of the lower microfluidic channel is in a mirror image relationship with the horizontal cross-sectional shape of the upper channel. The depth of the entire microfluidic channel is equal to 100 μm. The microfluidic channels are longitudinally arranged in a serpentine shape on the diaphragm: the serpentine channel in the adjustment section has 2 bends, the width is equal to 2.5 mm, the vertical part of the channel is 8 mm long, and the diameter of the semicircle of the curved part is 10 mm; The cut section has 2 bends, the width is 200 μm, the vertical part of the serpentine channel is 10 mm long, and the diameter of the semicircle of the curved part is 4 mm. The length of the stretching section is 30mm, and the angle between it and the long side of the chip is 60°. The intersection of the two sides and the horizontal plane is a second-order exponential function curve, and the formula of the exponential function is R(x)=ae ^bx +ce ^dx . The arc radians connecting each section of passage is 6. The outlet position of the lower channel is 8mm away from the midpoint of the short side of the PDMS membrane. The upper and lower layers of PDMS membranes of the chip and the dialysis membrane between the upper and lower layers of PDMS membranes are packaged and bonded by double-sided adhesive.

A kind of preparation method of regenerated silk fibroin fiber of the present invention, at room temperature, with 40% regenerated silk fibroin aqueous solution as spinning solution, ^the Ca concentration in ion regulating solution and water-absorbing resin mixed solution is 95g/L, The concentration of water-absorbent resin is 70g/L, and the molecular weight is 20000 polyethylene glycol (PEG-20000) aqueous solution; the molecular weight cut-off of the dialysis membrane is 14000, and the spinning solution is injected into the upper channel at a flow rate of 3 μL/min, PEG-20000 aqueous solution and ions The conditioning solution mixture was injected into the lower channel at a speed of 7 μL/min; the spinning solution was extruded from the outlet of the microchannel, solidified into filaments in the air and wound up on the upper roller; the air gap from the outlet to the winding roller was 12 cm, and the winding The speed is 6cm/s.

The diameter of the regenerated silk fibroin fiber prepared by the present invention is 20 μm, the strength of the regenerated silk fibroin fiber is 50 MPa, and the elongation at break is 8%. The regenerated silk fibroin fibers are filaments.

Example 3

The microfluidic chip of the present invention is a three-layer structure, including the upper and lower PDMS membranes and the middle dialysis membrane layer. There are grooves on the PDMS membrane, and the grooved surfaces of the upper and lower membranes are bonded to the dialysis membrane to form an upper and lower membrane. Two microfluidic channels; the horizontal cross-sectional shape of the lower microfluidic channel is in a mirror image relationship with the horizontal cross-sectional shape of the upper channel. The depth of the whole microfluidic channel is equal to 85 μm. The microfluidic channels are arranged in a longitudinal serpentine shape on the membrane: the serpentine channel in the adjustment section has 3 bends, the width is equal to 2.5 mm, the vertical part of the channel is 7 mm long, and the diameter of the semicircle of the curved part is 9 mm; The section has a bend with a width of 300 μm, the vertical part of the serpentine channel is 10 mm long, and the diameter of the semicircle of the curved part is 4 mm. The length of the stretching section is 25mm, and the angle between it and the long side of the chip is 45°. The intersection of the two sides and the horizontal plane is a straight line, and the function formula of the straight line is R(x)=ax+b. The arc radians connecting the passages of each section is 5. The outlet position of the lower channel is 6mm away from the midpoint of the short side of the PDMS membrane. The upper and lower layers of PDMS membranes of the chip and the dialysis membrane between the upper and lower layers of PDMS membranes are packaged and bonded by silicone adhesive.

A kind of preparation method of regenerated silk fibroin fiber of the present invention, at room temperature, with 35% regenerated silk fibroin aqueous solution as spinning liquid, ^the Ca concentration in ion regulating liquid and water-absorbing resin mixed liquid is 90g/L, The concentration of water-absorbing resin is 200g/L, and the component is polyethylene glycol (PEG-20000) aqueous solution of 20000; The conditioner mixture was injected into the lower channel at a speed of 5 μL/min; the spinning solution was extruded from the outlet of the microchannel and solidified into filaments in the air and wound up on the upper roller; the air gap from the outlet to the roller was 10 cm, and the winding The speed is 5cm/s.

The diameter of the regenerated silk fibroin fiber prepared by the present invention is 18 μm, the strength of the regenerated silk fibroin fiber is 42 MPa, and the elongation at break is 10%. The regenerated silk fibroin fibers are short fibers.

Example 4

The microfluidic chip of the present invention is a three-layer structure, including the upper and lower PDMS membranes and the middle dialysis membrane layer. There are grooves on the PDMS membrane, and the grooved surfaces of the upper and lower membranes are bonded to the dialysis membrane to form an upper and lower membrane. Two microfluidic channels; the horizontal cross-sectional shape of the lower microfluidic channel is in a mirror image relationship with the horizontal cross-sectional shape of the upper channel. The depth of the entire microfluidic channel is equal to 80 μm. The microfluidic channel is arranged in a horizontal serpentine shape on the membrane: the entire serpentine channel has only one bend, the width of the adjustment section is equal to 2.0 mm, the horizontal part of the channel is 80 mm long, and the diameter of the semicircle of the curved part is 5 mm; The section width was 100 μm, the length was 20 mm, and the diameter of the semicircle of the bent portion was 12 mm. The stretched sections of the microfluidic channel are arranged horizontally, and the traces where the two sides intersect the horizontal plane are second-order exponential function curves and are symmetrical about the central axis of the channel. The exponential function formula is: R(x)=ae ^bx +ce ^dx ; The length of the extension is 20mm, and the outlet position of the lower channel is 5mm away from the midpoint of the short side of the PDMS membrane. The upper and lower layers of PDMS membranes of the chip and the dialysis membrane between the upper and lower layers of PDMS membranes are packaged and bonded by silicone adhesive.

A kind of preparation method of regenerated silk fibroin fiber of the present invention, at room temperature, with 35% regenerated silk fibroin aqueous solution as spinning liquid, ^the Ca concentration in ion regulating liquid and water-absorbing resin mixed liquid is 108g/L, The concentration of water-absorbent resin is 300g/L, and the molecular weight is 30000 polyethylene glycol (PEG-30000) aqueous solution; the molecular weight cut-off of the dialysis membrane is 14000, and the spinning solution is injected into the upper channel at a flow rate of 15μL/min, PEG-30000 aqueous solution and ions The conditioning liquid mixture was injected into the lower channel at a speed of 15 μL/min; the spinning solution was extruded from the outlet of the microchannel, solidified into filaments in the air and wound up on the upper roller; the air gap from the outlet to the winding roller was 16 cm, and the winding The speed is 10cm/s.

The diameter of the regenerated silk fibroin fiber prepared by the present invention is 20 μm, the strength of the regenerated silk fibroin fiber is 100 MPa, and the elongation at break is 1%. The regenerated silk fibroin fibers are filaments.

Example 5

The microfluidic chip of the present invention is a three-layer structure, including the upper and lower PDMS membranes and the middle dialysis membrane layer. There are grooves on the PDMS membrane, and the grooved surfaces of the upper and lower membranes are bonded to the dialysis membrane to form an upper and lower membrane. Two microfluidic channels; the horizontal cross-sectional shape of the lower microfluidic channel is in a mirror image relationship with the horizontal cross-sectional shape of the upper channel. The overall depth of the microfluidic channel is 80 μm, and the microfluidic channel is arranged in a horizontal serpentine shape on the membrane: the serpentine channel in the adjustment section has a bend, the width is equal to 1.0 mm, and the horizontal part of the channel is long 60mm, the diameter of the semicircle of the curved part is 6mm; the shear section has 2 bends, the width is 500μm, the horizontal part of the serpentine channel is 55mm long, and the diameter of the semicircle of the curved part is 4mm. The stretched sections of the microfluidic channel are arranged horizontally, and the traces where the two sides intersect the horizontal plane are hyperbolic function curves. The formula of the hyperbolic function is: R(x)=1/2(e ^x -e ^-x ), stretching The length of the segment is 15 mm; the outlet position of the lower channel is 8 mm away from the midpoint of the short side of the PDMS membrane. The upper and lower layers of PDMS membranes of the chip and the dialysis membrane between the upper and lower layers of PDMS membranes are packaged and bonded by epoxy resin adhesive.

A kind of preparation method of regenerated silk fibroin fiber of the present invention, at room temperature, with 50% regenerated silk fibroin aqueous solution as spinning solution, ^the Ca concentration in ion regulating solution and water-absorbing resin mixed solution is 120g/L, The concentration of polyethylene glycol (PEG-40000) water-absorbing resin with a molecular weight of 40,000 is 100g/L; the molecular weight cut-off of the dialysis membrane is 30,000, and the spinning solution is injected into the upper channel at a flow rate of 5 μL/min. The aqueous solution of PEG-40000 and ions The conditioner mixture is injected into the lower channel at a speed of 10 μL/min; the spinning solution is extruded from the outlet of the microchannel, solidified into filaments in the air and wound up on the upper roller; the air gap from the outlet to the winding roller is 30 cm, and the winding The speed is 6cm/s.

The diameter of the regenerated silk fibroin fiber prepared by the present invention is 30 μm, the strength of the regenerated silk fibroin fiber is 60 MPa, and the elongation at break is 8%. The regenerated silk fibroin fibers are filaments.

Example 6

The microfluidic chip of the present invention is a three-layer structure, including the upper and lower PDMS membranes and the middle dialysis membrane layer. There are grooves on the PDMS membrane, and the grooved surfaces of the upper and lower membranes are bonded to the dialysis membrane to form an upper and lower membrane. Two microfluidic channels; the horizontal cross-sectional shape of the lower microfluidic channel is in a mirror image relationship with the horizontal cross-sectional shape of the upper channel. The entire depth of the microfluidic channel is equal to 100 μm, and the microfluidic channel is arranged in a horizontal serpentine shape on the diaphragm: the serpentine channel in the adjustment section has a bend, the width is equal to 1.5mm, and the horizontal part of the channel is long 50mm, the diameter of the semicircle of the curved part is 6mm; the shear section has 2 bends, the width is 350μm, the horizontal part of the serpentine channel is 66mm long, and the diameter of the semicircle of the curved part is 4mm. The stretched sections of the microfluidic channel are arranged horizontally, and the traces where the two sides of the channel intersect the horizontal plane are straight lines. The formula of the straight line is: R(x)=ax+b, and the length of the stretched section is 30mm; the outlet position of the lower channel deviates from The midpoint of the short side of the PDMS membrane is 6mm. The upper and lower layers of PDMS membranes of the chip and the dialysis membrane between the upper and lower layers of PDMS membranes are packaged and bonded by epoxy resin and double-sided adhesive tape.

A kind of preparation method of regenerated silk fibroin fiber of the present invention, at room temperature, with 40% regenerated silk fibroin aqueous solution as spinning solution, ^the Ca concentration in ion regulating solution and water-absorbing resin mixed solution is 105g/L, The concentration of polyethylene glycol (PEG-30000) water-absorbent resin with a molecular weight of 30,000 is 200g/L; the molecular weight cut-off of the dialysis membrane is 20,000, and the spinning solution is injected into the upper channel at a flow rate of 6 μL/min. The aqueous solution of PEG-30000 and ions The mixed solution of the conditioning liquid is injected into the lower channel at a speed of 10 μL/min; the spinning solution is extruded from the outlet of the microchannel, solidified into filaments in the air and wound up on the upper roller; the air gap from the outlet to the winding roller is 20 cm, and the winding The speed is 6cm/s.

The diameter of the regenerated silk fibroin fiber prepared by the present invention is 28 μm, the strength of the regenerated silk fibroin fiber is 70 MPa, and the elongation at break is 5%. The regenerated silk fibroin fibers are short fibers.

Claims (10)

1. An integrated microfluidic spinning chip, characterized in that: the integrated microfluidic spinning chip is a three-layer structure, comprising an upper and a lower two-layer PDMS diaphragm and an upper and lower two-layer PDMS membrane The dialysis membrane between the sheets; the upper and lower PDMS membranes have corresponding grooves; the groove of the upper PDMS membrane is attached to one surface of the dialysis membrane to form an upper microfluidic channel, and the lower PDMS The groove of the membrane is attached to the other side of the dialysis membrane to form a lower microfluidic channel; the groove opening of the upper PDMS membrane is opposite to the groove opening of the lower PDMS membrane; The upper microfluidic channel is divided into an adjustment section, a stretching section and a shear section according to functions; the width of the upper microfluidic channel changes from the inlet to the outlet, wherein the width of the adjustment section and the shear section are not the same. , the width of the stretched section gradually decreases; The horizontal cross-sectional shape of the regulating section, the stretching section and the shearing section of the lower microfluidic channel is in a mirror image relationship with the horizontal cross-sectional shape of the upper microfluidic channel; The depths of the upper and lower layers of the microfluidic channel are equal throughout; during spinning, the solution flows in from the regulating section of the channel, and flows out from the shearing section. 2. A kind of integrated microfluidic spinning chip according to claim 1, is characterized in that, described microfluidic channel is vertically or transverse serpentine arrangement on PDMS diaphragm; Described longitudinal serpentine arrangement It means that the longitudinal vertical arrangement of the channel is parallel to the short side of the PDMS membrane; the horizontal serpentine arrangement means that the horizontal arrangement of the channel is parallel to the long side of the PDMS membrane; The channels arranged in the longitudinal serpentine shape have a total of 4 to 6 bends in the adjusting section and the shearing section, and the length of the vertical part of each serpentine channel is 7 to 14 mm, and each vertical channel passes through a semicircle The arc is connected, the diameter of the semicircle is 3-10mm, and the outlet of the shearing section is located at the center of the short side of the PDMS membrane; the stretching section of the microfluidic channel is clamped between the symmetry line of the channel and the long side of the PDMS membrane. The angle is 20-60°, and the length of the stretching section is 15-30 mm; the intersection trace between the two sides of the stretching section channel and the horizontal plane is one of exponential function, hyperbolic function or straight line. The channel arranged in a horizontal serpentine shape has 1 to 3 bends in the adjusting section and the shearing section, and the length of the horizontal part of each serpentine channel is 50 to 80 mm, and each horizontal channel is connected by a semicircular arc , the diameter of the semicircle is 4-12mm, and the outlet position of the shear section deviates from the center position of the short side of the PDMS membrane by 5-8mm; the stretching section of the microfluidic channel is located in the horizontal part of the channel, and the The long sides are parallel; the length of the stretching section is 15-30 mm; The intersection of the two side surfaces of the channel of the stretching section and the horizontal plane is one of exponential function, hyperbolic function or straight line. 3. A kind of integrated microfluid spinning chip according to claim 1, characterized in that, the adjustment section is a channel with the widest width, with a width of 1-2.5 mm and a length of 60-100 mm; The shear section is the narrowest section of channel, with a width of 100-500 μm and a length of 20-150 mm. the 4. A kind of integrated microfluid spinning chip according to claim 1, is characterized in that, the cross-sectional shape of described groove is rectangle, and the depth of groove is 50～100 μ m; The extension segment and the shear segment are connected by an arc or directly. 5. The integrated microfluidic spinning chip according to claim 1, wherein the dialysis membrane is a regenerated cellulose dialysis membrane with a molecular weight cut-off of 5000 to 30000 Daltons; the integrated microfluidic The upper and lower layers of PDMS membranes of the spinning chip and the dialysis membrane between the upper and lower layers of PDMS membranes are bonded by adhesive packaging; the adhesive is silica gel, epoxy resin One or a combination of adhesive or double-sided tape. 6. The method for preparing regenerated silk fibroin fibers according to any one of the integrated microfluidic spinning chips described in claims 1 to 5, characterized in that: the regenerated silk fibroin aqueous solution with a mass percentage of 5% to 50% is used as the spinning Silk liquid, at room temperature, the upper microfluidic channel is injected with spinning solution, and the lower microfluidic channel is injected with a mixture of water-absorbent resin aqueous solution and ion regulating solution; Concentration and ion adjustment effect, after being extruded at the outlet, it is solidified into silk in the air and wound on the upper roll to obtain regenerated silk fibroin fiber. The fracture strength of the obtained regenerated silk fibroin fiber is 20-100MPa, The elongation rate is 1-10%; at the same time, the solution in the lower channel is collected at the outlet. 7. The method according to claim 6, wherein the ion regulating liquid is CaCl2 aqueous solution; the water-absorbing resin is polyethylene glycol with a molecular weight of 10,000 to 40,000 Daltons, wherein Ca in the mixed liquid The concentration of ²⁺ is 80-120g/L, and the concentration of polyethylene glycol is 70-600g/L. 8 . The method according to claim 6 , wherein the air gap between the outlet of the microfluidic channel on the upper layer of the microfluidic chip and the winding roller is 5-30 cm, and the winding speed is 2-10 cm/s. 9. The method according to claim 6, characterized in that, the spinning liquid, the ion regulating liquid and the water-absorbing resin are all injected by a micro-injection pump. 10. The method according to claim 12, characterized in that, the diameter of the regenerated silk fibroin fibers is 7-30 μm; The regenerated silk fibroin fibers are long filaments or short fibers. the

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