CN110900911B

CN110900911B - Die and method for preparing insulating base and application of base in molecular detection

Info

Publication number: CN110900911B
Application number: CN201811088465.1A
Authority: CN
Inventors: 赵新佳; 单欣岩; 陆兴华
Original assignee: Institute of Physics of CAS
Current assignee: Institute of Physics of CAS
Priority date: 2018-09-18
Filing date: 2018-09-18
Publication date: 2020-11-10
Anticipated expiration: 2038-09-18
Also published as: CN110900911A

Abstract

The invention relates to the field of biomolecule detection, in particular to a mold for preparing an insulating base, which comprises the following components: the first die holder is provided with at least one slot, the surface of the first die holder, which is far away from the side of the slot opening of the slot, is provided with at least one groove for containing insulating powder, and the first die holder is also provided with a jack extending from the bottom of the slot to the groove; the tip member is configured to be engageable to the insertion hole and a tip portion of the tip member is insertable into the groove so that the insulating powder contained in the groove can form a concave hole thereon conforming to the tip portion after melt-solidification. The invention also relates to a method for producing an insulating base and to the use of an insulating base for molecular detection. The first die holder and the pointed cone realize the efficient preparation of the insulating base, the die has simple structure and is easy for industrial production so as to reduce the manufacturing cost of the insulating base, and the insulating base produced by the die can be used for preparing the ultrathin solid-state nanopore device efficiently and at low cost.

Description

Die and method for preparing insulating base and application of base in molecular detection

Technical Field

The invention relates to the technical field of biomolecule detection, in particular to a next generation DNA sequencing technology and a molecule detection device based on a solid two-dimensional material.

Background

Nanopores are small-pore devices with diameters of a few nanometers on a two-dimensional thin film. The molecular detection technology based on the nano-pores can realize the detection of single molecules and the analysis of the molecular structure morphology. Nanopore devices are mainly applied to DNA sequencing.

Nanopore devices are mainly classified into two types, biological nanopores and solid-state nanopores. The biological nanopore is composed of native proteins. For example, MspA-based biological nanopores have been available for base sequence determination, but biological nanopores are greatly affected by the environment and have poor stability, and thus inorganic material-based solid-state nanopores are the hot spot of current research. For example, ultra-thin solid state nanopores based on two-dimensional materials have enabled resolution of different bases and reached atomic limits in discrimination of adjacent bases. At present, the biggest challenge of solid-state nanopores is that the motion control of DNA molecules is not ideal, and effective single-base progressive control motion cannot be realized. In addition, the signal noise of the solid-state nanopore is relatively large, which affects the performance of the device. Capacitance is the primary cause of the aforementioned problems with nanopore devices. The solid state nanopores used in the present experiments all use single crystal silicon bases compatible with micromachining processes. Such as silicon dioxide and silicon nitride, are grown on the surface of the Si (110), a suspended film is formed by chemical etching (and transfer), and then nanopores are prepared by ion beams or electron beams. Although the device has a stable structure and is mature in the preparation industry, because the monocrystalline silicon is conductive, the thickness of an insulating layer is only dozens of nanometers to several micrometers, the area of the insulating layer reaches several millimeters square, and the corresponding capacitance is large. The large capacitance has the following negative effects: firstly, the current noise generated by the large capacitor is large; secondly, the large capacitance generates a large charging current during voltage feedback control, which may cause the control circuit to saturate.

Research has shown that the nanopore device prepared by using the insulating material as the base can obviously improve the detection signal-to-noise ratio. For example, the nanopore device prepared on an insulated quartz base can effectively reduce the influence of capacitance, thereby reducing the root mean square noise of the ion current to be below 10 pA. However, the existing manufacturing method for implementing the device needs complex micro-processing equipment and technology, has high cost and is not beneficial to wide application and popularization.

In view of the above, it is desirable to provide an insulating base for fabricating a nanopore device that overcomes the above-mentioned drawbacks, and a method and application for fabricating the insulating base.

Disclosure of Invention

It is therefore an object of the present invention to provide a nanopore base, whereby the above-mentioned disadvantages of the prior art are overcome.

In order to accomplish the above task, according to one aspect of the present invention, there is provided a mold for preparing an insulating base, comprising: the die comprises a first die holder and a second die holder, wherein the first die holder is provided with at least one slot, the surface of the first die holder, which is far away from the slot opening side of the slot, is provided with at least one groove for containing insulating powder, and the first die holder is also provided with a jack which extends from the slot bottom of the slot to the groove; a tip member configured to be engageable to the insertion hole and a tip end portion of the tip member being insertable into the groove so that the insulating powder contained in the groove can form a concave hole thereon conforming to the tip end portion after melt-solidification; a support having a flat surface and configured for uniformly spreading the above-mentioned insulating powder, the groove of the first die holder and the support together defining a solidified shape of the melted insulating powder.

In one embodiment, the mold further comprises: the second die holder is provided with insert blocks, the insert blocks are configured to be inserted into the joint parts arranged on two sides of the insertion grooves so as to realize the joint of the first die holder and the second die holder, and inserting and combining holes are formed between the adjacent insert blocks; a spacer configured to be inserted into the assembled first and second die holders through the insertion hole and the engagement portion and to conform to an outer wall of the insertion groove to define a solidified shape of the melted insulating powder.

Preferably, a plurality of the grooves are configured to be arranged at intervals along a length direction of the insertion groove.

Preferably, the first die holder and the pointed cone are made of materials with the same or similar thermal expansion coefficients.

Alternatively or additionally, the spike is secured to the socket by a heat cured elastomeric membrane.

Preferably, the insulating powder is a powder of polymethyl methacrylate.

According to another aspect of the present invention, there is provided a method of preparing an insulating base, the method comprising the steps of: providing a first shoe of a mold as described above; providing a pointed cone of a mold as described above; freely inserting the pointed cone into the receptacle of the first die holder; and filling insulating powder in the groove of the first die holder, heating and melting the insulating powder, and forming the insulating base after the melted insulating powder is solidified and molded.

Additionally, the method further comprises the steps of: providing a support with a flat surface; spraying a release agent on the bottom of the first die holder and the surface of the support; and uniformly spreading insulating powder on the support, and placing the first die holder on the support.

In a further embodiment, the method further comprises the steps of: providing a second die holder arranged with an insert block configured to be insertable into an engagement portion arranged on both sides of the insertion slot to effect engagement of the first and second die holders; assembling the first die holder with the pointed cone piece and the second die holder; heating the insulating powder until a molten state is reached; inserting a spacer in the assembled first and second die beds and conforming the spacer to an outer wall of the insertion slot to define a solidified shape of the melted insulating powder.

Preferably, a surface of the first die holder on a side away from the slot opening of the insert slot is polished.

Optionally, a viscous fluid that cures upon heating to form an elastic membrane is applied adjacent the receptacle to secure the pointed member relative to the receptacle.

According to a further aspect of the present invention there is provided the use of an insulating base made by the above method in the detection of biomolecules.

Preferably, the insulating base is configured for two-dimensional material transfer thereon and for preparing ultra-thin solid state nanopores for DNA sequence detection.

Additional features and advantages of the invention will be set forth in part in the description which follows, and in part will be apparent to those having ordinary skill in the art upon examination of the following, or may be learned from the practice of the invention.

Drawings

Embodiments of the invention are described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 is a perspective view of a first die holder of the die of the present invention;

FIG. 2 is a bottom view of the first die holder of the die of the present invention;

FIG. 3 is a top view of the first die holder of the die of the present invention;

FIG. 4 is a perspective view of a first die holder of the die of the present invention;

FIG. 5 is a perspective cross-sectional view of a first die holder of the die of the present invention;

FIG. 6 is a partial cross-sectional view of a first die holder of the die of the present invention;

FIG. 7 is a perspective view of the spike of the present invention;

FIG. 8 is a perspective view of a second die holder of the present invention;

FIG. 9 is an assembly view of the mold of the present invention;

FIG. 10 is an assembled perspective view of the inventive die;

FIG. 11 is an exploded view of the inventive die;

fig. 12 is another assembly view of the inventive die.

Detailed Description

An exemplary scheme of a nanopore base according to the present invention will now be described in detail with reference to the accompanying drawings. The drawings are provided to present embodiments of the invention, but the drawings are not necessarily to scale of the particular embodiments, and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present disclosure. The position of some components in the drawings can be adjusted according to actual requirements on the premise of not influencing the technical effect. The appearances of the phrase "in the drawings" or similar language in the specification are not necessarily referring to all of the drawings or the examples.

Certain directional terms used hereinafter to describe the drawings, such as "inner", "outer", "upper", "lower", and other directional terms, will be understood to have their normal meaning and refer to those directions as they relate to when the drawings are normally viewed. Unless otherwise indicated, the directional terms described herein are generally in accordance with conventional directions as understood by those skilled in the art.

The terms "first," "second," and the like, as used herein, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another.

The present invention provides a mold 1 for preparing an insulating base, as shown in FIGS. 1 to 12, the moldThe die 1 comprises a first die shoe 10, a pointed cone 12 and a support 14. Wherein, referring in particular to fig. 1 to 6, the first die holder 10 is arranged with at least one slot 100, and at least one groove 102 is provided on a surface of the first die holder 10 on a side away from the slot 100 (i.e. a bottom surface of the first die holder 10), the groove 102 being open in a width direction of the slot 100, the groove 102 being used to fill or contain an insulating powder 2, which may be a powder of polymethyl methacrylate (PMMA) which has good insulation and is low in cost and easy to process. As shown in fig. 4-6, the first mold base 10 is further provided with a receptacle 104, and the receptacle 104 extends from the bottom of the slot 100 to the recess 102 and communicates with the recess 102. Preferably, the receptacle 104 is arranged vertically with respect to the socket 100 and the recess 102. The above-described spike 12 is configured to engage into the socket 104, wherein the tip 120 is insertable into the recess 102 to form a notch 108 (shown in FIG. 10) where the recess 102 and the socket 104 communicate. As shown in fig. 7, the pointed cone 12 includes a tip 120 and a shaft 122, the shaft 122 can guide the movement of the pointed cone 12 in the slot 100, the tip 120 can contact the insulating powder 2 in the groove 102 through the notch 108, after the insulating powder melted by heating is solidified, the tip 120 can form a concave hole matching the shape of the solidified part (the product formed by solidifying the insulating powder), and the insulating base with the concave hole can be manufactured into an ultra-thin solid nano hole in the subsequent processing. The size of the insulating base prepared by the method can be selected to be 3 x 0.5mm³The diameter of the concave hole formed on the substrate can reach 10 μm approximately. The shaft portion 122 of the tapered member 12 may be configured in a cylindrical structure, such as a cylinder, a prism, etc., wherein the prism-shaped shaft portion 122 is preferably a regular prism. Preferably, tip portion 120 may be configured to have an opening angle of 90 °, although it is contemplated by those skilled in the art that the opening angle of tip portion 120 may be determined according to the size of the desired recess, and that the tip angle of tip portion 120 may be adapted according to actual needs, which obviously falls within the protection scope of the present invention. The support 14 has a flat surface and may be, for example, a silicon wafer having a superior flatness. The superior flatness of the silicon wafer can be expressed by TIR < 3 μm. Of course, other materials having smoothness satisfying the above flatness may be usedThe structure of the surface is beneficial to the insulating base to form a corresponding flat surface for transferring two-dimensional materials. The insulating powder 2 may be uniformly spread on the support 14, the first die holder 10 is placed on the support 14, and the insulating powder 2 may fill the groove 102, so that the flat surface of the support 14 and the groove 102 of the first die holder 10 may define a solidified shape of the melted insulating powder 2. When only the first mold shoe 10 is used, the first mold shoe 10 is substantially in the form of a regular quadrilateral, with the outermost recesses 102 being closed at their outwardly facing edges (not shown). The invention realizes the high-efficiency preparation of the insulating base by adopting the first die holder 10 and the pointed cone 12 which are designed, and the die 1 can be industrially produced due to the simple structure and no need of adopting micro-processing equipment and technology with complicated operation, thereby reducing the manufacturing cost of the insulating base and further realizing the high-efficiency and cost-saving preparation of the ultrathin solid-state nanopore device by utilizing the insulating base produced by the die 1. In addition, compared with the traditional silicon-based semiconductor, the insulating base manufactured by the die 1 has good insulating property, and can effectively reduce the noise influence caused by parasitic capacitance, thereby improving the signal-to-noise ratio and the molecular motion control performance.

In a preferred embodiment, in order to facilitate demoulding and to improve the efficiency of manufacturing the insulating base, the mould 1 further comprises a second die shoe 16 and a partition 18, as shown in figures 8 to 9. Wherein the second die holder 16 is provided with an insert 160, and correspondingly, the two sides of the slot 100 of the first die holder 10 are provided with the engaging portion 106, and the insert 160 is configured to be inserted into the engaging portion 106, so as to combine the first die holder 10 and the second die holder 16. An insertion hole 162 is provided between the adjacent insertion blocks 160, after the second die holder 16 and the first die holder 10 are assembled, the insertion hole 162 of the second die holder 16 corresponds to the slot 100 of the first die holder 10, and the width of the insertion hole 162 (the width is taken from the distance in the direction perpendicular to the insertion block 160 from the insertion hole 162) is greater than the width of the slot 100 (the width is taken in the same direction as the insertion hole 162), the partition 18 is configured to be inserted into the first die holder 10 and the second die holder 16 sequentially through the insertion hole 162 and the engaging portion 106, and the partition 18 is fitted to the outer wall of the slot 100 of the first die holder 10 to define the boundary of the solidified shape of the molten insulating powder in the width direction. The space defined by the insertion hole 162 and the engaging portion 106 for accommodating the partitioning member 18 is defined to the extent that the partitioning member 18 is allowed to be freely inserted and withdrawn therein. Additional fastening connections can also be made between the first die holder 10 and the second die holder 16 by means of connections 164, such as bolts, as shown in fig. 12, which are correspondingly and uniformly arranged on the first die holder 10 and the second die holder 16. A glass sheet may be used as the separator 18 to spatially divide the insulating base to be formed.

Referring to fig. 10 to 12, the recess 102 in the first die holder 10 may be designed in plural, and the plural recesses 102 are preferably arranged at intervals along the length direction (perpendicular to the width direction) of the insert groove 100. The grooves 102 are configured to be recessed from the bottom surface of the first die holder 10 toward the groove bottom of the insert groove 100, and the transition portions between the adjacent grooves 102 are flush with the bottom surface of the first die holder 10. The design of the plurality of grooves 102 can manufacture the required insulation bases in the first die holder 10 in batches at one time, thereby improving the preparation efficiency of the insulation bases. Specifically, as shown in the drawing, 5 insertion grooves 100 are provided in the first die holder 10, the insertion grooves 100 are separated by the joint 106, the joint 106 located on the outermost side is not closed (provided only when the fitting spacer 18 and the second die holder 16 are present), and the joint 106 located between the insertion grooves 100 is closed around the circumference thereof to form a substantially rectangular region and penetrates the first die holder 10 in the depth direction of the insertion grooves 100. Those skilled in the art can adapt the shape, arrangement and depth of the engaging portion 106 according to actual needs without departing from the scope of the present invention. In the case of preparing the insulating base only by using the first die holder 10 without using the separating element 18, the insulating powder 2 in the grooves 102 of the first die holder 10 can flow in the width direction of the slots 100 in a molten state, so that the insulating base solidified and formed in the row of grooves 102 corresponding to each slot 100 (for example, 5 grooves 102 are provided along the slots 100) and the insulating base solidified and formed in the row of grooves 102 corresponding to the adjacent slots 100 are connected to each other, which has a certain difficulty for demolding and needs to be cut and formed according to a required size in subsequent operations, thereby increasing the manufacturing steps of the insulating base, while the problem is well solved by adding the separating element 18 in the die 1, wherein the insulating base to be prepared and formed is in a hexahedral structure, three surfaces of which are in contact with the surfaces of the grooves 102 of the first die holder 10, and one surface of which is in contact with the supporting element 14 (i.e. a silicon wafer), the remaining two faces can then come into contact with the partition 18, which reduces the contact area of the insulating base to be prepared with the first die holder 10, making the finished insulating base easier to demould, and since the partition 18 blocks the continuity of the flow of the insulating powder in the molten state, the insulating powder 2 is shaped only in a defined space, thus eliminating the subsequent cutting step. The amount of insulating powder added is determined according to the actual requirements, and in this particular embodiment, in the case of 25 recesses 102, the amount of insulating powder applied is between about 1-2 g.

Furthermore, the first die holder 10 and the pointed cone 12 can be made of materials having the same or similar coefficients of thermal expansion. Preferably, the second die holder 16 is also made of such a material. The use of materials having the same or similar coefficients of thermal expansion can prevent the first mold base 10 and/or the second mold base 16 from being damaged or failing to produce an insulating base having a cavity due to mismatched degrees of thermal expansion.

The above-described pointed conical elements 12 may also be secured to each other relative to the receptacle 104 by applying a heat curable viscous fluid adjacent the receptacle 104 to form an elastomeric membrane after insertion into the receptacle 104. The elastic membrane may be formed of a PDMS (polydimethylsiloxane) material, but is not limited thereto. As known to those skilled in the art, the PDMS elastic membrane is prepared by mixing a main agent (liquid PDMS) and a curing agent, which are usually dow corning 184, usually in a weight ratio of 10:1 to form a viscous liquid, and then heating and curing the viscous liquid. Wherein the consistency of the viscous liquid is approximately similar to that of SAE40 engine oil. The viscous liquid can be cured at a temperature in the range of 25-150 c without exotherm and without secondary curing to form a tough, transparent elastomer, resulting in an elastomeric membrane that positions the tip 12 in the receptacle 104 of the first die holder 10 in the above-described embodiment.

Other materials for forming the elastic membrane are also contemplated, such as materials that satisfy the following conditions: (1) curing; (2) before curing, has a suitable viscosity that is suitable for being at the edge of the receptacle 104 without flowing into it; (3) with suitable elasticity that avoids smooth fluctuation of the silicon wafer surface and damage to the tip portion 120 of the pointed cone 12 in the event of non-uniform thermal expansion.

The present invention also provides a method of preparing an insulating base, the method comprising the steps of: providing a first die holder 10 of a die as described above (e.g., manufactured using a machining process, such as milling, drilling, etc.); providing a pointed cone 12 of a mold as described above (e.g., fabricated using a machining process or an electrochemical etching process); inserting the machined pointed cone 12 into the insertion hole 104 of the first die holder 10; the grooves 102 of the first mold base 10 are filled with the insulating powder 2, and the insulating powder is heated (generally at a temperature of 180-270 ℃, in a vacuum drying oven, for about 0.5-1 hour) until the melted insulating powder is solidified and molded, so as to form the desired insulating base. The material of the above-mentioned pointed cone 12 may be tungsten or steel, for example, the pointed cone 12 is prepared by electrochemically etching a high purity tungsten wire or by mechanically grinding a steel needle, and the diameter of the rod portion 122 of the pointed cone 12 is slightly smaller than the insertion hole 104 of the first die holder 10, so that the pointed cone 12 can be freely inserted into the insertion hole 104 without friction. When inserting the tip 12 into the receptacle 104 of the first die holder 10, care must be taken not to apply any external force to force the tip 12 into the receptacle 104 in order to deform and passivate the tip 120 of the tip 12 and affect the quality of the recess of the resulting insulating base.

According to the processing method, the insulating powder is processed in a powder hot-press molding mode, only a heating instrument is needed in the preparation process, the processing cost of the insulating base is reduced, the whole preparation process is simple and easy to operate, batch production of the insulating base is realized through a mold with a simple structure, and the production efficiency of the insulating base is improved.

In the above steps, after the pointed cone 12 is inserted into the insertion hole 104 of the first mold base 10, the aforementioned viscous liquid (for example, PDMS viscous liquid) may be further applied to the edge of the insertion hole 104, and the viscous liquid may be cured by heating to form an elastic film, and the elastic film may fix the pointed cone 12 relative to the insertion hole 104, so as to avoid the possible position movement of the pointed cone 12 in the insertion hole 104, and thus ensure the product yield of the formed insulating base.

In addition, the method for preparing the insulating base further comprises the following steps: providing a flat-surfaced support 14, the support 14 being intended to support the first die holder 10, the bottom surface of the first die holder 10 contacting a surface of the support 14, the recess 102 of the first die holder 10 and the surface of the support 14 together forming a shape that circumscribes the pre-formed insulating base; a release agent is sprayed on the bottom of the first die holder 10 and the surface of the support member 14, so that the formed insulating base can be rapidly and completely released, and the release efficiency and the yield are improved; the insulating powder 2 is evenly spread on the surface of the support 14, then the first die holder 10 is placed on the support 14, the insulating powder 2 is heated and melted, and the insulating powder is naturally cooled until the melted insulating powder is solidified and molded, so that the insulating base can be formed.

Preferably, the method of preparing an insulating base further comprises the steps of: providing the second die holder 16 (e.g., manufactured by a machining process) with the insert block 160 on the second die holder 16, the insert block 160 having a structure that it can be inserted into the engaging portions 106 arranged on both sides of the slot 100 of the first die holder 10 to enable the second die holder 16 to be engaged to the first die holder 10; assembling the first die holder 10 and the second die holder 16 with the pointed cone 12 inserted; filling the insulating powder 2 in the groove 102 of the first die holder 10, and melting the insulating powder 2 by heating; a divider 18 is inserted in the assembled first die holder 10 and second die holder 16, the divider 18 abutting against the outer wall of the insert slot 100, and preferably being closed at both opposite open sides of the recess 102 by the divider 18, the divider 18 cooperating with the support 14 to form a closed molding space with the recess 102 for the molten insulating powder to be solidified and molded therein into a final shape.

In order to make the first die holder 10 and the support 14 closely fit, a bottom surface of the first die holder 10 (i.e., a surface of the first die holder 10 on a side away from the notch of the socket 100) is polished by a polishing technique to obtain a smooth surface, so as to avoid leakage of the molten insulating powder due to a fit gap between the first die holder 10 and the support 14.

The invention also provides application of the insulating base prepared by the method in biomolecule detection. The insulating base prepared by the method can be used for transferring a two-dimensional material on the insulating base to prepare the ultrathin solid nanopore, so that the DNA sequence can be detected.

While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified by incorporating any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

List of reference numerals

1 mold 122 shank

10 first die holder 14 support

100 slot 16 second die holder

102 groove 160 insert

104 jack 162 insertion hole

106 joint 164 connection

108 notch 18 divider

12-point cone 2 insulating powder

120 tip part

Claims

1. Mould (1) for the preparation of insulating bases, characterized in that it comprises:

the die holder comprises a first die holder (10), wherein at least one slot (100) is arranged in the first die holder (10), at least one groove (102) used for containing insulating powder (2) is formed in the surface of the side, away from the opening of the slot (100), of the first die holder (10), and a jack (104) extending from the bottom of the slot (100) to the groove (102) is further formed in the first die holder (10);

a spike (12), the spike (12) being configured to be engageable to the receptacle (104) and a tip portion (120) of the spike (12) being insertable into the recess (102) to enable an insulating powder (2) contained in the recess (102) to form a recessed hole thereon conforming to the tip portion (120) after melt solidification;

a support (14), said support (14) having a flat surface and being configured for uniformly laying the above insulating powder (2), said recess (102) of said first die holder (10) defining, together with said support (14), a solidified shape of the melted insulating powder (2).

2. The mold (1) according to claim 1, characterized in that said mold (1) further comprises:

a second die holder (16), wherein the second die holder (16) is provided with insert blocks (160), the insert blocks (160) are configured to be inserted into the engagement parts (106) arranged at two sides of the slot (100) to realize the engagement of the first die holder (10) and the second die holder (16), and insert holes (162) are arranged between the adjacent insert blocks (160);

a partition (18), the partition (18) being configured to be inserted in the assembled first die holder (10) and second die holder (16) through the insertion hole (162) and the engagement portion (106) and to conform to the outer wall of the insertion groove (100) and to define, together with the groove (102), a solidified shape of the melted insulating powder (2).

3. The mold (1) according to claim 2, wherein a plurality of the grooves (102) are configured to be arranged at intervals along a length direction of the socket (100).

4. Mould (1) according to claim 1, characterized in that said first die shoe (10) and said pointed element (12) are made of materials having the same or similar thermal expansion coefficient.

5. Mould (1) according to claim 1, characterized in that said conical members (12) are fixed to each other with respect to said receptacles (104) by means of an elastic membrane formed by heat curing.

6. Mould (1) according to claim 1, characterized in that said insulating powder (2) is a powder of polymethyl methacrylate.

7. A method of making an insulating base comprising the steps of:

providing a first shoe (10) of a mould according to claim 1;

providing a tip (12) of the mold of claim 1;

-inserting the pointed element (12) freely in the receptacle (104) of the first die holder (10);

and filling insulating powder (2) in the groove (102) of the first die holder (10), heating and melting the insulating powder (2), and forming the insulating base after the melted insulating powder (2) is solidified and molded.

8. The method of claim 7, further comprising the steps of:

providing a support (14) with a flat surface;

spraying a release agent on the bottom of the first die holder (10) and the surface of the support (14);

uniformly spreading an insulating powder (2) on the support (14), and placing the first die holder (10) on the support (14).

9. The method of claim 7, further comprising the steps of:

providing a second die shoe (16), the second die shoe (16) being arranged with an insert block (160), the insert block (160) being configured to be insertable into an engagement portion (106) arranged on both sides of the insert slot (100) to effect engagement of the first die shoe (10) and the second die shoe (16);

assembling the first die holder (10) with the pointed cone (12) with the second die holder (16);

heating the insulating powder (2) until a molten state is reached;

-inserting a spacer (18) in the assembled first (10) and second (16) die holders and bringing the spacer (18) into abutment with the outer wall of the insert slot (100) and defining, together with the groove (102), a solidified shape of the molten insulating powder (2).

10. The method according to claim 7, characterized in that the surface of the first die shoe (10) on the side remote from the slot of the insert groove (100) is polished.

11. A method according to claim 7, characterized by applying a heat-cured elastic film-forming viscous liquid in the vicinity of the receptacle (104) to fix the pointed conical element (12) relative to the receptacle (104).

12. Use of an insulating base for biomolecule detection, characterized in that the insulating base is made by the method of any of claims 7 to 11.

13. The use of claim 12, wherein the insulating base is configured for two-dimensional material transfer thereon and for preparing ultra-thin solid state nanopores for DNA sequence detection.