CN113512431B

CN113512431B - DNA-anionic/cationic surfactant compound vesicle thermotropic liquid crystal and preparation method and application thereof

Info

Publication number: CN113512431B
Application number: CN202110807153.7A
Authority: CN
Inventors: 郝京诚; 陈晓丽; 武文娜; 刘立; 董姝丽
Original assignee: Shandong University
Current assignee: Shandong University
Priority date: 2021-07-16
Filing date: 2021-07-16
Publication date: 2023-10-27
Anticipated expiration: 2041-07-16
Also published as: CN113512431A

Abstract

The invention relates to the technical field of thermotropic liquid crystal preparation, in particular to a DNA-anionic/cationic surfactant compound vesicle thermotropic liquid crystal, a preparation method and application thereof, wherein the thermotropic liquid crystal is prepared by compounding an anionic surfactant and a cationic surfactant to obtain vesicles, and then self-assembling the vesicles with DNA. FDDL-250bp DNA can not form thermotropic liquid crystal, and meanwhile, the DNA thermotropic liquid crystal prepared by vesicle DTAL compounded by cationic surfactant dodecyl trimethyl ammonium bromide with good symmetry degree with sodium laurate has a lower melting point and a wider liquid crystal phase region.

Description

DNA-anionic/cationic surfactant compound vesicle thermotropic liquid crystal and preparation method and application thereof

Technical Field

The present disclosure relates to the technical field of thermotropic liquid crystal preparation, and in particular relates to a DNA-anionic/cationic surfactant compound vesicle thermotropic liquid crystal, a preparation method and an application thereof.

Background

The disclosure of this background section is only intended to increase the understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art already known to those of ordinary skill in the art.

Natural macromolecular DNA has led to extensive research by biologists as a carrier of genetic information. Since the advent of DNA self-assembly nanotechnology, DNA has become a research hotspot as a building element for constructing various nanostructures, and then the development of DNA paper folding technology has further provided options for the design of micro-and nano-scale complex DNA nanostructures.

DNA consists of three parts of four bases, five-carbon sugar and a phosphate skeleton. Firstly, base complementary pairing endows the target molecule with accurate recognition capability, and can realize specific binding and targeting of the target molecule, so that the target molecule has been widely used in the fields of biosensing and bionic material design; in addition, the DNA has structural and functional designability and good biocompatibility, and can be used for constructing bionic catalytic reaction and drug carriers; the negative phosphate skeleton makes DNA as natural polyelectrolyte and may be added to electrolyte to raise conductivity, so that it has wide application in electronic device and other fields. However, most of the DNA is applied in solvent or solid environment, such as aqueous solution, hydrogel, solid gel electrolyte, etc., and the problems of solvent volatilization, difficult storage, high rigidity of solid DNA material, easy breakage, etc. may limit the development of DNA material. In view of the great demands of DNA for intelligent and flexible materials in the current society, research on soft materials such as DNA solvent-free fluid becomes necessary, which will promote development of DNA in the fields of optics, flexible electronic devices, etc.

DNA solvent-free fluid refers to a substance in which DNA exists in a liquid or quasi-liquid state when no solvent is contained. Because of the special structure of DNA molecule, it can not change solid DNA into liquid by conventional heating. In order to solve the problem, liu Kai group found that natural biomacromolecules such as viruses, polypeptides, DNA, RNA and the like can be used for preparing lamellar thermotropic liquid crystals by electrostatic interaction with double-tailed chain surfactants. The DNA thermotropic liquid crystal can maintain the structural integrity of DNA when undergoing solid-liquid crystal-isotropic phase transition, and the melting point, the clearing point and other properties of the DNA thermotropic liquid crystal can be adjusted by changing the selected surfactant. Based on this work, researchers have found that DNA thermotropic liquid crystal responsiveness can be imparted by introducing responsive substances into the building block. Such as the counter ion Br of the surfactant DDAB ^- CeCl with magnetic property ₃ ^- Ferrofluid with magnetic response can be prepared, and directional migration can be realized under the external magnetic field; the introduction of azobenzene in the tail chain of the surfactant ensures that the mechanical strength of the DNA TLC is changed during the switching of visible light/ultraviolet light to realize the phase transition; in addition, the DNA molecule can be constructed by utilizing reversible oxidation-reduction reaction of bases in the DNA moleculeElectrochromic devices based on DNA thermotropic liquid crystals.

Although solvent-free DNA thermotropic liquid crystals are primarily explored in the fields of light, electricity, magnetism and the like, the inventor discovers that the type of the surfactant for preparing the DNA thermotropic liquid crystals is single at present, the selection of the surfactant and the preparation of the DNA TLC have no clear structure-activity relationship, and the existing thermotropic liquid crystals have high melting point and narrow liquid crystal phase region. The practical application of the synthesized thermotropic liquid crystal is less explored at present.

Disclosure of Invention

In order to solve the problems in the prior art, the present disclosure provides a DNA-anionic/cationic surfactant compounded vesicle thermotropic liquid crystal, and a preparation method and application thereof, and researches show that FDDL-250bp DNA can not form thermotropic liquid crystal, and meanwhile, the DNA thermotropic liquid crystal prepared by using a cationic surfactant dodecyl trimethyl ammonium bromide compounded vesicle DTAL which has good symmetry with sodium laurate has a lower melting point and a wider liquid crystal phase region. The existence of aromatic structure base and purine in DNA can make the prepared DNA thermotropic liquid crystal emit fluorescence, so that the application of the DNA thermotropic liquid crystal in the optical field can be further promoted. Specifically, the technical scheme of the present disclosure is as follows:

in a first aspect of the disclosure, a DNA-anionic/cationic surfactant complex vesicle thermotropic liquid crystal is prepared by compounding an anionic surfactant and a cationic surfactant to obtain a vesicle, and then self-assembling the vesicle with DNA.

In a second aspect of the present disclosure, a method for preparing a DNA-anionic/cationic surfactant-compounded vesicle thermotropic liquid crystal, comprising: preparing a DNA-anionic/cationic surfactant complex vesicle; and then preparing thermotropic liquid crystal based on the compound vesicle.

In a third aspect of the disclosure, the DNA-anionic/cationic surfactant complex vesicle thermotropic liquid crystals and/or the use of thermotropic liquid crystals prepared by any one of the preparation methods in the field of preparing optical devices.

One or more of the technical schemes in the disclosure have the following beneficial effects:

(1) The natural milt with good low cost and biocompatibility is adopted as a rigid skeleton, the anionic/cationic surfactant compound vesicle is used for providing a flexible chain, the DNA thermotropic liquid crystal synthesis process is simple, the reaction condition is mild, and the complex synthesis means is not involved.

(2) The property of the DNA thermotropic liquid crystal can be regulated by the selected surfactant and DNA, and the compound vesicle DTAL with better symmetry has better thermal reversibility, lower melting point and wider liquid crystal phase region. When the surfactant contains a larger functional group (e.g., ferrocene) near the head group, it is detrimental to the formation of DNA thermotropic liquid crystals. Thermotropic liquid crystals prepared using short-chain DNA have high thermal stability and lower melting and clearing points.

(3) Compared with the synthesized DNA, the synthesized thermotropic liquid crystal by using the natural fish sperm DNA has the advantages of improving the yield of the thermotropic liquid crystal, greatly reducing the cost and being beneficial to further researching the application. Compared with the previously reported work of interaction of DNA and single tailed chain surfactant complex vesicles, only the influence of the chain length of DNA on the aggregation structure in solution is studied, such as forming multilamellar vesicles, super-wall vesicles and the like. The constructed thermotropic liquid crystal lacks in application. In our work, it was found that factors affecting the construction of thermotropic liquid crystals, 50bp DNA, gave thermotropic liquid crystals with higher thermal stability, could facilitate their application in the field of optical devices.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate and explain the exemplary embodiments of the disclosure and together with the description serve to explain the disclosure, and do not constitute an undue limitation on the disclosure.

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

fig. 1 is a graph of example 2 of the present disclosure using c (cationic surfactant): c (anionic surfactant) =55: 45-complex vesicles DTAL (FIGS. 1a,1 d), TTAL (FIGS. 1b,1 e) and CTAL (FIGS. 1c,1 f) with 250bp ssDNA gave polarized light and DSC characterization of the product at isoelectric point. DSC spectra of the three products were compared (FIGS. 1d,1e,1 f).

Fig. 2 is a graph of example 2 of the present disclosure using c (cationic surfactant): c (anionic surfactant) =55: 45-complex vesicles DTAL, TTAL and CTAL and 250bp ssDNA gave a phase diagram of the product at isoelectric point (FIG. 2 a) and thermogravimetric characterization (FIG. 2 b).

Fig. 3 is example 3c (cationic surfactant) of the present disclosure: c (anionic surfactant) =5: 2. cryo-TEM pictures of the complex vesicles FDDL (FIG. 3 a) and FTML (FIG. 3 b), and polarization characterization of the product (FIG. 3c FDDL-250bp DNA, FIG. 3d FTML-250bp DNA) was obtained at isoelectric point of both vesicles and 250bp ssDNA.

FIG. 4 is a thermogravimetric comparison of FDDL-250bp DNA, FTML-250bp DNA at isoelectric point (FIG. 4 a), a round two-color characterization of supernatant after centrifugation of FDDL and FTML vesicles with 250bp DNA (FIG. 4 b), an infrared spectrum of FDDL-250bp DNA complex at different DNA concentrations (FIG. 4 c) according to example 3 of the present disclosure.

FIG. 5 is a nuclear magnetic resonance spectrum comparison of ferrocene surfactant FDDA, 250bp DNA, FDDL-250bp DNA of example 3 of the present disclosure at DNA concentration of 0.9mM and 1.4mM, with deuterated chloroform as solvent.

FIG. 6 is a phase diagram (FIG. 6 a) and thermogravimetric (FIG. 6 b) comparison of thermotropic liquid crystals prepared using 50bp and 250bp DNA selected in example 4 of the present disclosure with DTAL and FTML vesicles.

FIG. 7 is a light blue fluorescence image (FIG. 7 a) of 250bp DNA under 365nm UV light, a fluorescence image (FIG. 7 b) of 250bp DNA-DTAL thermotropic liquid crystal under 365nm UV light, a fluorescence image (FIG. 7 c) of 250bp DNA-DTAL thermotropic liquid crystal under 420nm excitation at-80℃and a fluorescence image (FIG. 7 d) of 30℃under 250bp DNA-DTAL thermotropic liquid crystal under 420nm excitation in example 4 of the present disclosure.

Detailed Description

The disclosure is further illustrated below in conjunction with specific embodiments. It should be understood that these examples are merely illustrative of the present disclosure and are not intended to limit the scope of the present disclosure. The experimental procedures, which do not address the specific conditions in the examples below, are generally carried out under conventional conditions or under conditions recommended by the manufacturer.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The reagents or materials used in the present invention may be purchased in conventional manners, and unless otherwise indicated, they may be used in conventional manners in the art or according to the product specifications. In addition, any methods and materials similar or equivalent to those described herein can be used in the methods of the present invention. The preferred methods and materials described herein are presented for illustrative purposes only.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments in accordance with the present disclosure. As used herein, the singular forms also are intended to include the plural forms unless the context clearly indicates otherwise, and furthermore, it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, and/or combinations thereof.

In one embodiment of the present disclosure, a DNA-anionic/cationic surfactant complex vesicle thermotropic liquid crystal is formulated from an anionic surfactant and a cationic surfactant to obtain a vesicle, and then the vesicle is self-assembled with DNA.

The natural fishery waste, namely, the DNA of the fish sperm and the complex vesicle of the anionic/cationic surfactant are taken as construction elements, and are subjected to self-assembly through electrostatic interaction, so that the solvent-free DNA-complex vesicle thermotropic liquid crystal is finally prepared. Further deepens understanding of DNA Thermotropic Liquid Crystal (TLC), clearly influences factors forming the DNA TLC and factors regulating the property of the DNA TLC, thereby designing the DNA TLC according to actual requirements and further promoting the application development of the DNA TLC.

In one embodiment of the present disclosure, the anionic surfactant is sodium laurate (NaL).

In one embodiment of the present disclosure, the cationic surfactant is one of DTAB (dodecyltrimethylammonium bromide), TTAB (tetradecyltrimethylammonium bromide), CTAB (hexadecyltrimethylammonium bromide), FDDA (ferrocenylmethyldodecyldimethylammonium bromide) and FTMA (11-ferrocenylundecyltrimethylammonium bromide), preferably DTAB (dodecyltrimethylammonium bromide).

The anion/cation surfactant compound vesicle provides a flexible chain, the DNA thermotropic liquid crystal synthesis process is simple, the reaction condition is mild, and the complex synthesis means is not involved.

In one embodiment of the disclosure, the DNA is a short-chain 50bp DNA or a long-chain 250bp DNA; preferably, it is a short-chain 50bp DNA.

In one embodiment of the present disclosure, a method for preparing a DNA-anionic/cationic surfactant-compounded vesicle thermotropic liquid crystal, comprising: preparing a DNA-anionic/cationic surfactant complex vesicle; and then preparing thermotropic liquid crystal based on the compound vesicle.

The property of the DNA thermotropic liquid crystal can be regulated by the selected surfactant and DNA, and the compound vesicle DTAL with better symmetry has better thermal reversibility, lower melting point and wider liquid crystal phase region. The presence of a surfactant with a larger functional group (e.g., ferrocene) near the head group may be detrimental to the formation of DNA thermotropic liquid crystals. Thermotropic liquid crystals prepared using short-chain DNA have high thermal stability and lower melting and clearing points.

In one embodiment of the present disclosure, preparing a DNA-anionic/cationic surfactant complex vesicle comprises: the cationic surfactant and the anionic surfactant are mixed in equal volumes and stored in a constant temperature incubator at 25 ℃ for 2-4 weeks.

In one embodiment of the present disclosure, the concentration ratio of cationic surfactant to anionic surfactant is 5:2 or 55:45.

In one embodiment of the present disclosure, single-stranded DNA is prepared by a pyrolysis method, and a complex vesicle is mixed with a single-stranded DNA solution to obtain a mixture; standing the mixture, centrifuging to remove supernatant; freeze drying the precipitate.

In one embodiment of the present disclosure, the concentration of the single stranded DNA is 10-30mM.

In one embodiment of the present disclosure, the DNA-anionic/cationic surfactant complex vesicle thermotropic liquid crystals and/or the thermotropic liquid crystals prepared by any one of the preparation methods are used in the field of preparing optical devices.

In order to enable those skilled in the art to more clearly understand the technical solutions of the present disclosure, the technical solutions of the present disclosure will be described in detail below with reference to specific embodiments.

Example 1: preparing 250bp single-stranded DNA and 50bp single-stranded DNA and anion/cation surfactant compound vesicles.

Pyrolyzing the double-stranded DNA solution at 95 ℃ for 45min, and then rapidly entering an ice-water bath for 2h to prevent renaturation, thus obtaining 250bp and 50bp single-stranded DNA;

the fixed anionic surfactant is sodium laurate (NaL), the five cationic surfactants are respectively DTAB (dodecyl trimethyl ammonium bromide), TTAB (tetradecyl trimethyl ammonium bromide), CTAB (hexadecyl trimethyl ammonium bromide), FDDA (ferrocenyl methyl dodecyl dimethyl ammonium bromide) and FTMA (11-ferrocenyl undecyl trimethyl ammonium bromide), and the five complex vesicles are respectively named DTAL, TTAL, CTAL, FDDL and FTML.

c (cationic surfactant): c (anionic surfactant) =55: the preparation method of 45 complex vesicles DTAL, TTAL and CTAL comprises the following steps: 110mM DTAB (TTAB, CTAB) was mixed with 90mM NaL stock solution in equal volumes and stored in a constant temperature incubator at 25℃for 3 weeks for use.

c (cationic surfactant): c (anionic surfactant) =5: 2, preparing the complex vesicle DTAL, FDDL and FTML: 10mM DTAB (FDDL, FTML) was mixed with equal volumes of 4mM NaL stock solution and stored in a constant temperature incubator at 25℃for 3 weeks for use.

Example 2: preparation of DNA anionic/cationic surfactant complex vesicle thermotropic liquid crystals-cationic surfactants of different alkyl chain lengths were used.

First, 20mM of 250bp ssDNA was prepared by pyrolysis, 4mL of positively charged complex vesicles (c (cationic surfactant): c (anionic surfactant) =55:45, DTAL, TTAL, CTAL) were added dropwise to different volumes of single-stranded DNA solution (20 mM), ultrapure water was added to a total volume of 8mL, and the DNA concentration in the resulting mixture was 0-10mM. After standing for a few minutes, white insoluble substances are separated out, centrifuging for 30 minutes at 12000rpm, removing supernatant (preserving supernatant to determine isoelectric points of DNA combined with positive vesicles by measuring zeta potential, and isoelectric points of DTAL, TTAL, CTAL vesicle solution combined with 250bp with concentration ratio of 55:45 being 6.8mM, 6.7 mM and 8mM respectively), and placing the precipitate part in a freeze dryer for freeze drying for 12 hours to obtain the white solvent-free DNA-anionic surfactant complex vesicle.

As can be seen from fig. 1a, 1b and 1c, when three compounds are subjected to polarization observation at 60 ℃, focal conic texture can be observed, and the scattering peak ratio of 1:2 in the SAXS spectrum further indicates that the three compounds can form lamellar thermotropic liquid crystals. As can be seen from DSC spectra comparison of the three products (figures 1d,1e and 1 f), the DTAL-250bp DNA thermotropic liquid crystal has good thermal reversibility, and the peak position is not changed obviously in the cyclic heating and cooling scanning processes of the thermotropic liquid crystal. As can be seen from the comparison of thermogravimetry (FIG. 2 b), all three composites had better thermal stability at 180 ℃. From the comparison of the phase diagrams (figure 2 a), it can be found that the DNA thermotropic liquid crystal prepared by vesicle DTAL compounded by the cationic surfactant dodecyl trimethyl ammonium bromide, which has better symmetry degree with sodium laurate, has lower melting point and wider liquid crystal phase area.

Example 3: preparation of DNA anionic/cationic surfactant complex vesicle thermotropic liquid crystal-different ferrocene cationic surfactants are used.

First, 10mM of 250bp ssDNA was prepared by pyrolysis, 4mL of positively charged complex vesicles (c (cationic surfactant): c (anionic surfactant) =5:2, FDDL, FTML) were added dropwise to different volumes of single-stranded DNA solution (10 mM), ultrapure water was added to a total volume of 8mL, and the DNA concentration in the resulting mixture was 0-5mM. After standing for a few minutes, yellow insoluble substances are separated out, centrifuging for 30 minutes at 12000rpm, removing supernatant (the isoelectric points of FDDL and FTML vesicle solution combined with 250bp are respectively 1.4mM and 1.8mM with the concentration ratio of 5:2), and freeze-drying the precipitate for 12 hours to obtain the yellow solvent-free DNA-anionic-cationic surfactant compound vesicle compound.

c (cationic surfactant): c (anionic surfactant) =5: 2 complex vesicles FDDL (FIG. 3 a) and FTML (FIG. 3 b) cryo-TEM pictures, and polarized characterization of the product (FIG. 3c FDDL-250bp DNA, FIG. 3d FTML-250bp DNA) was obtained at isoelectric point of both vesicles and 250bp ssDNA. The cryo-TEM proves that FDDL and FTML can be successfully prepared, the FTML-250bp DNA in polarization characterization can observe oil texture, the scattering peak ratio in SAXS is 1:2, so that the FTML-250bp DNA can form lamellar thermotropic liquid crystal, and the FDDL-250bp DNA has no polarization texture and can not form thermotropic liquid crystal.

Thermogravimetric comparison of FDDL-250bp DNA, FTML-250bp DNA at isoelectric point (FIG. 4 a), round dichroism characterization of supernatant after centrifugation of FDDL and FTML vesicles with 250bp DNA (FIG. 4 b), infrared spectra of FDDL-250bp DNA complex at different DNA concentrations (FIG. 4 c). As shown in thermogravimetric comparison, rapid weightlessness starts to occur when the FDDL-250bp DNA complex is higher than 140 ℃, and the thermal stability is poor. The circular dichroism spectrum comparison shows that the positive peak and the negative peak of the characteristics of the DNA are not obviously changed after the FDDL and the FTML vesicles are mixed with 250bp DNA, which indicates that the secondary structure of the DNA is not the reason for the poor stability of the FDDL-250bp DNA complex. As can be seen from the infrared spectrum, 1237cm was observed with increasing DNA concentration ^-1 PO at ^2- Asymmetric telescopic vibration moves to 1240cm ^-1 ，1105cm ^-1 The peak intensity of the stretching vibration at ferrocenyl c=c decreases, and the bending vibration characteristic absorption peak of ferrocenyl H-C at 807cm-1 shifts to 817cm ^-1 Where it is located. This suggests that the strong interaction between the DNA and ferrocene moiety may result in the failure of FDDL-250bp DNA to form thermotropic liquid crystals.

The ferrocene surfactant FDDA, 250bp DNA and FDDL-250bp DNA are compared with nuclear magnetic hydrogen spectrum at the concentration of 0.9mM and 1.4mM of DNA, and the solvent is deuterated chloroform. Chemical shift 4.39ppm was attributed to 9 hydrogens on ferrocenyl, and this peak shifted to the low field in the FDDL-250bp DNA complex. It is speculated that the interaction of ferrocenyl with the DNA base alters the density of electron clouds around ferrocenyl, thereby affecting chemical shift.

Example 4: preparation of DNA anionic/cationic surfactant complex vesicle thermotropic liquid crystals-50 bp ssDNA was used.

First, 20mM of 50bp ssDNA was prepared by pyrolysis, 4mL of positively charged complex vesicles (c (cationic surfactant): c (anionic surfactant) =5:2, DTAL, FTML) were added dropwise to different volumes of single-stranded DNA solution (20 mM), ultrapure water was added to a total volume of 8mL, and the DNA concentration in the resulting mixture was 0-10mM. After standing for a few minutes, white insoluble substances are separated out, centrifuging for 30 minutes at 12000rpm, removing supernatant (isoelectric points of the DTAL and FTML vesicle solutions with the concentration ratio of 5:2 and 50bp are respectively 4mM and 6mM, isoelectric points of the DTAL vesicle solutions with the concentration ratio of 5:2 and 250bp are respectively 2 mM), and freeze-drying the precipitate for 12 hours to obtain the white solvent-free DNA-anionic surfactant complex vesicle.

Phase diagrams and thermogravimetric contrast diagrams of thermotropic liquid crystals prepared by using 50bp and 250bp DNA and DTAL and FTML vesicles are selected. By polarizing and SAXS characterization, we demonstrate that all four complexes can form lamellar thermotropic liquid crystals, and from phase diagrams and thermogravimetric comparison, it can be seen that thermotropic liquid crystals prepared by using short-chain 50bp DNA have lower melting point and clearing point, and are thermally stable up to 220 ℃, which is very beneficial for future device design.

The fluorescence characterization is carried out on 250bp DNA-DTAL thermotropic liquid crystal, the thermotropic liquid crystal has excitation-dependent fluorescence color conversion, light blue fluorescence is emitted under 365nm ultraviolet irradiation, and a 420nm light source is used as excitation light, so that yellow fluorescence can be emitted. As can be seen from the temperature-changing fluorescence spectrum, the change of the thermotropic liquid crystal is not obvious in the temperature range of 0-100 ℃, the prepared DNA thermotropic liquid crystal can be used as fluorescent powder to cover a substrate by virtue of the temperature dependence of the DNA thermotropic liquid crystal, the DNA thermotropic liquid crystal is attached to the device substrate by heating to an isotropic phase, and then the fluorescent DNA thermotropic liquid crystal is fixed by slow cooling, so that a fluorescent device is constructed.

The foregoing description is only a preferred embodiment of the present invention, and the present invention is not limited thereto, but it is to be understood that modifications and equivalents of some of the technical features described in the foregoing embodiments may be made by those skilled in the art, although the present invention has been described in detail with reference to the foregoing embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The application of the DNA-anionic/cationic surfactant compounded vesicle thermotropic liquid crystal in the field of preparing fluorescent devices is characterized in that the thermotropic liquid crystal is prepared by compounding an anionic surfactant and a cationic surfactant to obtain vesicles, and then self-assembling the vesicles with DNA;

the anionic surfactant is sodium laurate, and the cationic surfactant is dodecyl trimethyl ammonium bromide; the DNA is short-chain 50bp single-chain DNA or long-chain 250bp single-chain DNA obtained by pyrolyzing the fish sperm DNA.

2. The use according to claim 1, wherein the preparation method of the DNA-anionic/cationic surfactant complex vesicle thermotropic liquid crystal comprises the following steps: preparing a DNA-anionic/cationic surfactant complex vesicle; and then preparing thermotropic liquid crystal based on the compound vesicle.

3. The use of claim 2, wherein preparing the DNA-anionic/cationic surfactant complex vesicles comprises: the cationic surfactant and the anionic surfactant are mixed in equal volumes and stored in a constant temperature incubator at 25 ℃ for 2-4 weeks.

4. Use according to claim 3, wherein the concentration ratio of cationic surfactant to anionic surfactant is 5:2 or 55:45.

5. The use according to claim 2, wherein the single-stranded DNA is prepared by a pyrolysis method, and the complex vesicle is mixed with the single-stranded DNA solution to obtain a mixture; standing the mixture, centrifuging to remove supernatant; freeze drying the precipitate.

6. The use according to claim 5, wherein the concentration of single stranded DNA is 10-30mM.