CN105586041B

CN105586041B - A kind of both sexes quantum dot and its preparation method and application

Info

Publication number: CN105586041B
Application number: CN201511025173.XA
Authority: CN
Inventors: 赖璐; 李中宝; 梅平; 刘义; 颜学敏
Original assignee: Yangtze University
Current assignee: Yangtze University
Priority date: 2015-12-31
Filing date: 2015-12-31
Publication date: 2017-05-31
Anticipated expiration: 2035-12-31
Also published as: CN105586041A

Abstract

The present invention relates to field of nano material preparation, in particular it relates to a kind of both sexes quantum dot, and the both sexes quantum dot preparation method and application.The both sexes quantum dot is with water-soluble quantum dot as matrix, the water-soluble quantum dot surface is at least modified with the alkyl hydrosulfide that carbon number is 8 18, and the alkyl hydrosulfide is combined with quaternary cationic surfactant and anionic type Gemini surface active agent, the water-soluble quantum dot is the water-soluble quantum dot of metallicity, and the particle diameter of the water-soluble quantum dot is 1 15nm.The particle diameter of both sexes quantum dot of the invention can be in the range of 5 15nm, fluorescent emission can be adjustable in the range of 370 800nm, and both sexes quantum dot of the invention all has excellent fluorescence property in the range of pH=1~14, good stability in biofluid, it is uniformly dispersed, and haemocyanin is small in the non-specific adsorption amount of quantum dot surface, all has wide practical use in multiple fields.

Description

A kind of both sexes quantum dot and its preparation method and application

Technical field

The present invention relates to field of nano material preparation, in particular it relates to a kind of both sexes quantum dot, and the both sexes quantum dot Preparation method and application.

Background technology

Quantum dot (QDs), can be described as semiconductor nano again, typically by II-VI, III-V, or group IV-VI element group Into particle diameter is typically in the range of 1~10nm.When the size of semiconductor is less than or is suitable with Exciton Bohr Radius, can produce obvious Quantum confined effect, continuous energy band becomes discrete energy level structure, therefore with special optically and electrically characteristic.With it is traditional Organic fluorescent dye is compared, and quantum dot has that fluorescent emission is adjustable, emission spectrum is narrow and symmetrical, absorption spectrum is wide and light stabilization Property wait unique optical characteristics well.Therefore, quantum dot is applied to the aspects such as biological study and clinical medicine more and more widely, Such as inside and outside imaging, the detection of tumour and treatment, Immunohistochemical detection, medicament transport and treatment, bio-sensing and list Particle spike etc..

The particle diameter of quantum dot is small, with huge surface area.In order to be able to stabilize it presence, or prepared by organic phase Quantum dot goes to water phase, it is necessary to carry out surface modification to quantum dot.At present, the method for modifying of quantum dot surface mainly includes：

First, using combination stronger between the metallic atoms such as the sulphur atom and Cd, Zn in sulfydryl, using small point of sulfydryl Son carries out surface modification, such as mercaptopropionic acid (MPA), N-acetyl-L-cysteine (NAC), glutathione (GSH) and sulfydryl ten One alkanoic acid (MUA) etc.；

2nd, using hydrophobic interaction, surface modification is carried out using amphipathic nature polyalcohol, such as polyethylene glycol, phosphatide, shell gathers Sugar etc.；

3rd, acted on using covalent coupling or non-specific adsorption, surface modification, such as oligomerization core are carried out using large biological molecule Thuja acid, haemocyanin etc..

Above-mentioned preparation method has their own characteristics each, but there is also following deficiency：

First, there is problems with the small numerator modified quantum dot of sulfydryl：PH is too narrow using scope；In biofluid, salt Excessive concentration is easily caused quantum dot and coagulation occurs, so that fluorescent quenching；And haemocyanin quantum dot surface can occur compared with It is serious non-specific adsorption, so as to produce bio-toxicity.

Although the 2, the quantum dot good stability of amphipathic nature polyalcohol surface modification, the hydration particle diameter of quantum dot is excessive.It is small The nano-particle of particle diameter is easier to enter cell, can effectively realize its function.Simultaneously polymer-modified quantum dot surface electric charge Density is excessive, more serious non-specific adsorption can occur with the albumen in biofluid, so as to produce bio-toxicity.

Although the 3, the quantum dot fluorescent stability of large biological molecule modification is good, good biocompatibility.But the hydration of quantum dot Particle diameter is also larger.Quantum dot is also excessively cumbersome with the method for the covalent coupling of albumen, and operation difficulty is big.Additionally, large biological molecule Method of modifying it is relatively costly, be not suitable for being prepared on a large scale.Because the size of large biological molecule is bigger than quantum dot, therefore free life The removal difficulty of thing macromolecular is larger, and the purifying of quantum dot is increasingly complex.

The content of the invention

The purpose of the present invention is that the pH for overcoming prior art to exist uses that scope is too narrow, particle diameter too big and/or fluorescent stabilization A kind of the problems such as property is bad, there is provided both sexes quantum dot, and the both sexes quantum dot preparation method and application.Of the invention two Property quantum dot particle diameter can be in the range of 5-15nm, fluorescent emission can be adjustable in the range of 370-800nm, and this The both sexes quantum dot of invention all has excellent fluorescence property, the stability in biofluid in the range of pH=1~14 Well, it is uniformly dispersed, and haemocyanin is small in the non-specific adsorption amount of quantum dot surface, has in multiple fields and widely should Use prospect.

If it was found by the inventors of the present invention that first by carbon number for the alkyl hydrosulfide modification of 8-18 is smaller in itself in particle diameter Water-soluble quantum dot surface, quaternary cationic surfactant molecule and anion are then caused by hydrophobic effect Type Gemini surface active molecule is combined with the chain alkyl of alkyl hydrosulfide, just can obtain the both sexes with negative ions Quantum dot, this completes the present invention.

The invention provides a kind of both sexes quantum dot, the both sexes quantum dot with water-soluble quantum dot as matrix, the water solubility Quantum dot surface is at least modified with the alkyl hydrosulfide that carbon number is 8-18, and the alkyl hydrosulfide and quaternaries cation surface Activating agent and anionic type Gemini surface active agent are combined, and the water-soluble quantum dot is the water-soluble quantum of metallicity Point, and the particle diameter of the water-soluble quantum dot is 1-15nm.

Present invention also offers a kind of method for preparing both sexes quantum dot, the method is comprised the following steps：

1) will be the water solubility of the metallicity of solution and the mercaptopropionic acid modification of the alkyl hydrosulfide of 8-18 containing carbon number The aqueous solution of quantum dot carries out the first contact, and the particle diameter of the water-soluble quantum dot is 1-15nm；

2) disperse in organic solvent after the product removal solvent after first is contacted；

3) by the water-soluble of the aqueous solution of quaternary cationic surfactant and anionic type Gemini surface active agent A kind of and step 2 in liquid) products therefrom carries out the second contact, then stratification and organic layer is discarded, by gained water phase Carry out dialysis for the first time and obtain the quantum dot aqueous solution；

4) by the water-soluble of the aqueous solution of quaternary cationic surfactant and anionic type Gemini surface active agent Another and step 3 in liquid) products therefrom carries out the 3rd contact, and obtained aqueous solution then is carried out into second dialysis.

Invention further provides the both sexes quantum dot that the method according to the invention is prepared.

Invention additionally provides both sexes quantum dot of the invention in gene transfection, biomarker, bio-separation, immune inspection Application on survey, drug targeting release and target imaging.

Compared with prior art, product of the invention and method advantage at least that：

(1) the hydration particle diameter of gained quantum dot is smaller, can in the range of 5~15nm, and fluorescent emission 370~ 800nm is adjustable；

(2) pH uses wider range, and in the range of pH=1~14, the surface of quantum dot all carries electric charge, surface charge Between repulsive interaction prevent the coagulation of quantum dot, therefore excellent fluorescence property is respectively provided with the range of pH=1~14；

(3) good stability, be uniformly dispersed, salinity higher will not also cause the coagulation of quantum dot；

(4) method is more simple, workable, with low cost.

Other features and advantages of the present invention will be described in detail in subsequent specific embodiment part.

Brief description of the drawings

Accompanying drawing is, for providing a further understanding of the present invention, and to constitute the part of specification, with following tool Body implementation method is used to explain the present invention together, but is not construed as limiting the invention.In the accompanying drawings：

Fig. 1 is the electromicroscopic photograph of both sexes quantum dot I3 prepared by embodiment 3.

Fig. 2 is both sexes quantum dot I1~I4 fluorescence spectras prepared by embodiment 1-4.

Fig. 3 is CdTe/ZnS quantum dots and embodiment 3 obtained in both sexes quantum of the pH to MPA modifications obtained in preparation example 5 The influence of the fluorescence intensity of point I3.

Fig. 4 is that in cell culture medium, the CdTe/ZnS quantum dots and embodiment 3 of MPA modifications obtained in preparation example 5 are obtained The fluorescence intensity of both sexes quantum dot I3 change with time.

Specific embodiment

Specific embodiment of the invention is described in detail below.It should be appreciated that described herein specific Implementation method is merely to illustrate and explain the present invention, and is not intended to limit the invention.

In the present invention, " alkyl hydrosulfide with quaternary cationic surfactant and anionic type Gemini surface surface Activating agent is combined " refer to：The chain alkyl of alkyl hydrosulfide respectively with the chain alkyl of quaternary cationic surfactant Chain alkyl with anionic type Gemini surface active agent is combined by hydrophobic interaction.

In the present invention, term " particle diameter " refers to being obtained using Malvern Zetasizer Nano nano particle size instrument measurements Average grain diameter.In the present invention, by by quaternary cationic surfactant molecule and anionic type Gemini surface surface Active agent molecule is bonded directly to quantum dot surface, such that it is able to make the size controlling of the both sexes quantum dot of gained 1-15nm's In the range of.

In the present invention, due to the quaternary cationic surfactant and anionic type Gemini surface active agent It is to be combined with the alkyl hydrosulfide of water-soluble quantum dot surface modification with molecular conformation, therefore can't be to gained both sexes quantum dot Particle diameter produce significantly affect, it can be considered that the particle diameter of the both sexes quantum dot be equal to the water-soluble quantum dot grain Footpath.In the art, the particle diameter of the water-soluble quantum dot is commonly nanoscale, the water-soluble quantum dot that the present invention is selected Particle diameter can be 1-15nm, most preferably preferably 1-10nm, more preferably 2-8nm, 2-5nm；Correspondingly, of the invention two Property quantum dot particle diameter can be 1-15nm, preferably 1-10nm, more preferably 2-8nm, most preferably 2-5nm.

In the present invention, the water-soluble quantum dot is the water-soluble quantum dot of metallicity, and its surface modification has carbon atom Number is the alkyl hydrosulfide of 8-18, and the carbon number passes through covalent bond for the alkyl hydrosulfide of 8-18 with the water-soluble quantum dot of metallicity It is combined.Also, the chain alkyl of the alkyl hydrosulfide respectively with the chain alkyl of quaternary cationic surfactant and The chain alkyl of anionic type Gemini surface active agent is combined by hydrophobic interaction.The carbon of the alkyl hydrosulfide is former Subnumber is 8-18, preferably 9-16, more preferably 11-13；Carbochain in the alkyl hydrosulfide can have 0-2 bar side chains, preferably There is no side chain, i.e., the carbochain in described alkyl hydrosulfide is straight chain；The alkyl hydrosulfide has at least one mercapto functional group, preferably With 1-2 mercapto functional group, it is preferable that the mercapto functional group is located at the end of carbochain.The alkyl hydrosulfide for example can be with It is one or more in lauryl mercaptan, n-hexadecyl mercaptan and n-octadecane base mercaptan, most preferably lauryl mercaptan.

In the present invention, there is no particular limitation for the species of the water-soluble quantum dot of the metallicity, for example, can be selected from ZnSe quantum dots, CdTe quantum, CdTe/ZnS quantum dots and Ag₂One or more in S quantum dots.

In the present invention, relative to a water-soluble quantum dot, the carbon number of its surface modification is 8-18 Alkyl hydrosulfide number for can be with 20-60, preferably 40-60.

In the present invention, the surface of the water-soluble quantum dot can also be modified with mercaptopropionic acid, with the water-soluble amount On the basis of the total number of all molecules containing sulfydryl of the surface modification of son point, the content of the mercaptopropionic acid can for 10% with Under, preferably less than 5%, more preferably less than 2%.

In the present invention, the water-soluble quantum dot and the quaternary cationic surfactant and anionic There is no particular limitation for the proportioning of Gemini surface active, such as relative to a water-soluble quantum dot, with the alkane The number that base mercaptan is combined the anionic type Gemini surface active agent can be 5-15, preferably 10-15；With the alkane The number that base mercaptan is combined the quaternary cationic surfactant can meet so that the quaternaries cation Surfactant is 1.01-1.15 with the charge ratio of the anionic type Gemini surface active agent：1, specifically can be according to season The species selection charge ratio of ammonium salt cationoid surfactant.

In the present invention, there is no particular limitation for the quaternary cationic surfactant, is preferably selected from double quaternary ammoniums One or more in salt cationic surfactant and mono-quaternaries cationoid surfactant.Preferably, it is described double Quaternary cationic surfactant has structure shown in formula (1), and the mono-quaternaries cationoid surfactant has Structure shown in formula (2),

In formula (1), m and n is each independently selected from the arbitrary integer in 7-17, and X is halogen；Preferably, m and n are each From the arbitrary integer in 8-15, X is fluorine, chlorine, bromine or iodine element；It is further preferred that m and n are independently of one another Selected from the arbitrary integer in 10-12, X is fluorine, chlorine or bromine element；It is particularly preferred that it is chlorine or bromine element that m and n is 11, X.It is described Bi-quaternary ammonium salt cationoid surfactant can for example be exemplified as N, N '-bis- dodecyl bi-quaternary ammonium salts.

In formula (2), p is selected from the arbitrary integer in 7-17, and X is halogen；Preferably, p is selected from any whole in 8-15 Number, X is fluorine, chlorine, bromine or iodine element；It is further preferred that p is selected from the arbitrary integer in 10-12, X is fluorine, chlorine or bromine element； It is particularly preferred that it is chlorine or bromine element that p is 11, X.The mono-quaternaries cationoid surfactant can for example be exemplified as ten Dialkyl group trimethylammonium bromide (DTAB), DTAC (DTAC) and cetyl trimethylammonium bromide (CTAB)。

In the present invention, the use of the anionic type Gemini surface active agent and quaternary cationic surfactant There is no particular limitation for amount ratio, can be calculated according to charge ratio.For example, when the quaternary cationic surfactant is double During quaternary cationic surfactant, the anionic type Gemini surface active agent is lived with quaternaries cation surface Property agent charge ratio be 1.03-1.08：1, preferably 1.04-1.06：1；When the quaternary cationic surfactant is During mono-quaternaries cationoid surfactant, the anionic type Gemini surface active agent and quaternaries cation surface The charge ratio of activating agent is 1.06-1.15：1, preferably 1.08-1.12：1.

In the present invention, it is preferred to, the anionic type Gemini surface active agent is the sulphur with structure shown in formula (3) Hydrochlorate type Gemini surface active,

Wherein, a and b are each independently selected from the arbitrary integer in 7-17, and Y is alkali metal；Preferably, a and b be each Arbitrary integer in 8-15, Y is lithium, sodium or potassium element；It is further preferred that a and b are each independently selected from Arbitrary integer in 10-12, Y is sodium or potassium element；It is particularly preferred that it is sodium or potassium element that a and b is 11, Y.

In step 1) in, it is described containing carbon number for the solution of the alkyl hydrosulfide of 8-18 is that alkyl hydrosulfide is dissolved in into the Resulting solution in one organic solvent, wherein alkyl hydrosulfide can be 1 with the volume ratio of first organic solvent：600- 1000, preferably 1：800-900.There is no particular limitation for the species of first organic solvent, can be for arbitrarily can be with Alkyl sulfide alcohol and water is miscible and volatile organic solvent, for example, can be selected from the one kind or many in acetone, methyl alcohol and ethanol Plant, preferably acetone.

In step 1) in, the concentration of the water-soluble quantum dot in the aqueous solution of the water-soluble quantum dot is not limited particularly It is fixed, for example can be 50~500 μm of ol/L, preferably 50-250 μm ol/L, more preferably 80-200 μm ol/L.

In step 1) in, the process of first contact includes：Under conditions of stirring, by the water-soluble of water-soluble quantum dot Drop is added in the solution containing alkyl hydrosulfide, and continues stirring.The mode of the dropwise addition has no particular limits, preferably soon Speed is added dropwise, and makes the aqueous solution of the water-soluble quantum dot in 0.5-2.5min (preferably 1-2min) interior completion of dropping.Described The condition of one contact includes：Temperature can be 15-50 DEG C, and preferably 20-30 DEG C, the time can be 20-30h.The stirring is excellent Elect quick stirring as, the speed of stirring is, for example, 200-300r/min.

In step 1) in, the carbon number of the alkyl hydrosulfide is 8-18, more preferably preferably 9-16,11-13；It is described Carbochain in alkyl hydrosulfide can have 0-2 bar side chains, and preferably without side chain, i.e., the carbochain in described alkyl hydrosulfide is straight chain；Institute Alkyl hydrosulfide is stated with least one mercapto functional group, preferably with 1-2 mercapto functional group, it is preferable that the Mercaptofunctional Cumularsharolith is in the end of carbochain.The alkyl hydrosulfide for example can be lauryl mercaptan, n-hexadecyl mercaptan and n-octadecane base sulphur One or more in alcohol, most preferably lauryl mercaptan.

In step 2) in, there is no particular limitation for the method for the product removal solvent by after the first contact, for example may be used With using the method for vacuum distillation.The solvent for being removed refers to above-mentioned first organic solvent (the i.e. solution containing alkyl hydrosulfide In solvent) and water (solvent i.e. in the aqueous solution of water-soluble quantum dot).Recognize when solvent clearance reaches more than 95% For the process for removing solvent can terminate.

In step 2) in, will first contact after product removal solvent after disperse in organic solvent, in order to step 1) Middle first organic solvent for preparing alkyl hydrosulfide solution is mutually distinguished, step 2) used by the organic solvent hereinafter referred to as " Two organic solvents ".There is no particular limitation for the species of second organic solvent, for example, can be the one of arene and chloroform Plant or various, one or more preferably in toluene, benzene and chloroform.

In step 2) in, the volume after the product removal solvent by after the first contact does not have with the volume ratio of organic solvent There is special restriction, for example, can be 1：800-2000, preferably 1：1000-1600.

In step 2) in, there is no particular limitation for the scattered mode, for example, can be ultrasonic disperse.

In step 3) and step 4) in, by quaternary cationic surfactant and anionic type Gemini surface active In obtained quantum dot surface, there is no particular limitation for sequencing, it is preferable that in step 3 for agent substep modification) in from it is cloudy from Subtype Gemini surface active, in step 4) in select quaternary cationic surfactant.

In the present invention, the mol ratio of the water-soluble quantum dot and the anionic type Gemini surface active agent can be with It is 1：1-3, preferably 1：1.7-2.4；The anionic type Gemini surface active agent and quaternaries cation surface active The consumption of agent can determine that such as charge ratio can be 1 according to electric charge：1.01-1.15, specifically can be according to quaternary ammonium salt sun The species selection charge ratio of ionic surface active agent.

In the present invention, the aqueous solution of the quaternary cationic surfactant and the anionic type Gemini surface table There is no particular limitation for the concentration of the aqueous solution of face activating agent, for example, the water of the quaternary cationic surfactant The concentration of solution can be 80-1200 μm of olL^-1, preferably 250-750 μm olL^-1；The anionic type Gemini surface surface The concentration of the aqueous solution of activating agent can be 80-1200 μm of olL^-1, preferably 250-750 μm olL^-1。

In step 3) in, the process of second contact includes：Under conditions of stirring, by step 2) gained dispersion after In the aqueous solution of the aqueous solution and anionic type Gemini surface active agent of product and quaternary cationic surfactant One kind is mixed.The condition of second contact includes：Temperature can be 30-60 DEG C, and preferably 40-50 DEG C, the time can be with It is 20-30h.The stirring is preferably quick stirring, and the speed of stirring is, for example, 200-300r/min.

In step 3) in, there is no particular limitation for the method for the first time dialysis, according to the conventional dialysis in this area Cheng Jinhang.Preferably, the first time dialysis is 0.5 × 10 in concentration^-2~1.5 × 10^-2The phosphate-buffered of mol/L Carried out in solution.It is further preferred that before the first time dialysis is carried out, the product after described second is contacted was carried out Filter, for example, can be filtered with 0.22 μm of filtering head.

In step 4) in, the process of the 3rd contact includes：Under conditions of stirring, by step 3) gained dispersion after In the aqueous solution of the aqueous solution and anionic type Gemini surface active agent of product and quaternary cationic surfactant Another kind is mixed.The condition of the 3rd contact includes：Temperature can be 30-60 DEG C, and preferably 40-50 DEG C, the time can Think 20-30h.The stirring is preferably quick stirring, and the speed of stirring is, for example, 200-300r/min.

In step 4) in, there is no particular limitation for the method for second dialysis, according to the conventional dialysis in this area Cheng Jinhang.Preferably, second dialysis is 0.5 × 10 in concentration^-2~1.5 × 10^-2The phosphate-buffered of mol/L Carried out in solution.It is further preferred that before second dialysis is carried out, the product after described second is contacted was carried out Filter, for example, can be filtered with 0.22 μm of filtering head.

In the present invention, the water-soluble quantum dot is the water-soluble quantum dot of the metallicity of mercaptopropionic acid modification, this hair It is bright by step 1) in the process of the first contact cause most mercaptopropionic acid quilts of the water-soluble quantum dot surface modification Carbon number is the alkyl hydrosulfide substitution (preferably whole mercaptopropionic acids are by carbon number for the alkyl hydrosulfide of 8-18 replaces) of 8-18. There is no particular limitation for the species of water-soluble quantum dot described in the method for the present invention, for example, can be selected from mercaptopropionic acid modification ZnSe quantum dots, the CdTe quantum of mercaptopropionic acid modification, the CdTe/ZnS quantum dots of mercaptopropionic acid modification and mercaptopropionic acid are repaiied The Ag of decorations₂One or more in S quantum dots.In the present invention, the water-soluble quantum dot can be commercially available can also make Standby to obtain, the method for preparation can be the routine operation of this area, for example, obtained by following methods.

1) mercaptopropionic acid (MPA) modification ZnSe quantum dots

The preparation of Zn precursors：Prepare ZnCl₂With the mixed aqueous solution of MPA, wherein ZnCl₂Concentration be 0.008- 0.012mol/L, ZnCl₂It is 1 with the mol ratio of MPA：1.5-2.0.Regulation pH to 11.2-11.7.Then the oxygen in environment is eliminated Gas.

The preparation of NaHSe：Under ice-water bath, by Se powder and NaBH₄Stirred in water to water white transparency, Se powder and NaBH₄'s Weight ratio is 1：1.5-1.65, relative to 1g NaBH₄, the consumption of water is 18-22mL.

At room temperature, under strong stirring with to adding above-mentioned NaHSe solution to obtain ZnSe precursor solutions in above-mentioned Zn precursors, Wherein [Zn]:[MPA]:[Se]=1:1.1-1.3:1.3-0.5.By the ZnSe precursor solutions in oil bath 155-165 DEG C it is anti- Answer 10-20 minutes, you can obtain the ZnSe quantum dots of MPA modifications.Washed with isopropanol three times, then dry gained solid.

2) MPA modifications CdTe quantum

The preparation of Cd precursors：Prepare CdCl₂With the mixed aqueous solution of MPA, wherein ZnCl₂Concentration be 0.003- 0.005mol/L, ZnCl₂It is 1 with the mol ratio of MPA：1.5-2.0.Regulation pH to 7.5-8.5.Then the oxygen in environment is eliminated Gas.

The preparation of Te precursors：Under ice-water bath, by Te powder and NaBH₄Stirred in water to water white transparency, Se powder and NaBH₄ Mol ratio be 1：2.2-2.7, relative to 1mmolNaBH₄, the consumption of water is 3.5-4.5mL.

At room temperature, under strong stirring with to adding above-mentioned NaHTe solution to obtain CdTe precursor solutions in above-mentioned Cd precursors, Wherein [Cd]:[MPA]:[Te]=1:1.5-2.0:0.18-0.22.By ZnSe precursor solutions condensing reflux in oil bath 1.5-2.5 hours, you can obtain the CdTe quantum of MPA modifications.

3) MPA modifications CdTe/ZnS quantum dots.

The CdTe quantum of MPA modifications is obtained according to the method described above, by ZnCl₂、Na₂S, MPA and CdTe quantum mix To precursor solution, wherein ZnCl₂、Na₂The mol ratio of the consumption of the CdTe quantum of S, MPA modification is 1：0.18-0.22：4.8- 5.2, relative to 1mmol ZnCl₂, the consumption of water is 35-45mL.Regulation pH value is 10.8-11.2, removes the oxygen in environment, Reactant mixture is reacted the CdTe/ZnS core/shell structure quantum dots for obtaining MPA modifications for 2.5-4 hours at 60-70 DEG C.

4) MPA modifications Ag₂S quantum dots.

In inert gas environment, at a temperature of 105-115 DEG C, to adding AgNO in the ethylene glycol solution of MPA₃, wherein The volume ratio of the consumption of MPA and ethylene glycol is 1：90-110, relative to 100 μ LMPA, AgNO₃Consumption be 0.04- 0.06mmol.145-155 DEG C is warming up to react 12-20 minutes.Centrifugation obtains the Ag of MPA modifications after washing₂S quantum dot solids.

In the present invention, there is no particular limitation for the quantity of the mercaptopropionic acid of the water-soluble quantum dot surface modification, example Such as, relative to a water-soluble quantum dot, the number of the mercaptopropionic acid of surface modification is can be with 20-60, preferably 40- 60, more preferably 50-60.

In the present invention, the particle diameter of the water-soluble quantum dot can be 1-15nm, more preferably preferably 1-10nm, 2- 8nm, most preferably 2-5nm；So as to the particle diameter of, resulting quantum dot of the invention can be 1-15nm, preferably 1-10nm, More preferably 2-8nm, most preferably 2-5nm.

In formula (1), m and n is each independently selected from the arbitrary integer in 7-17, and X is halogen；Preferably, m and n are each From the arbitrary integer in 8-15, X is fluorine, chlorine, bromine or iodine element；It is further preferred that m and n are independently of one another Selected from the arbitrary integer in 10-12, X is fluorine, chlorine or bromine element；It is particularly preferred that it is chlorine or bromine element that m and n is 11, X.It is described Bi-quaternary ammonium salt cationoid surfactant can for example be exemplified as N, the double dodecyl bi-quaternary ammonium salts of N '.

In the present invention, the mono-quaternaries cationoid surfactant can be by being commercially available.Described pair of quaternary ammonium Salt cationic surfactant can be by being commercially available, it is also possible to by preparing, described to prepare bi-quaternary ammonium salt class sun The method of ionic surface active agent may comprise steps of：

Ba) by the alkylamine of structure shown in formula (4) and dihalo- ethane back flow reaction in the 3rd organic solvent, then remove Solvent；

Bb) with the 4th organic solvent to step Ba) products therefrom be recrystallized to give solid powder and then dries；

Wherein e is selected from the arbitrary integer in 7-17, is preferably selected from the arbitrary integer in 8-15, is more preferably selected from appointing in 10-12 Meaning integer, particularly preferably 11.

In step Ba) in, the volume ratio of the alkylamine, dihalo- ethane and the 3rd organic solvent can be 5-9：1：30- 40.The time of the back flow reaction can be 40-60 hours.3rd organic solvent is, for example, isopropanol.The removal is molten The method of agent can be vacuum distillation.

In step Bb) in, the 4th organic solvent is, for example, acetone.The dry temperature can be 30-60 DEG C, institute Stating the dry time can preferably be vacuum dried for 16-30 hours.

In the present invention, the Sulfonic Gemini Surfactants can be by being commercially available, it is also possible to by system Standby to obtain, the method for preparing Sulfonic Gemini Surfactants can be by by N, the double alkylethylene diamines and 1,3- of N- Third sultone is prepared for raw material, the N, and the alkyl being connected with N in the double alkylethylene diamines of N- is the straight chained alkyl of C8-C18, Specific method may comprise steps of：

Sa) sultone of 1,3- third and the double alkylethylene diamines of above-mentioned N, N- are dissolved in the 5th organic solvent, and in indifferent gas It is heated to reflux under the protection of body 20-40 hours, is filtrated to get solid；

Sb) by step Sa) gained solid recrystallized with the organic solvent of mixed solvent the 6th, be then vacuum dried.

In step Sa) in, the double alkylethylene diamines of the N relative to 1g, N-, the consumption of the sultone of 1, the 3- third is 1.5-2.5g, the volume of the 5th organic solvent is 10-20mL.5th organic solvent is, for example, methyl alcohol.The filtering Preferably depressurize suction filtration.

In step Sb) in, the 6th organic solvent is, for example, the mixed solvent of methyl alcohol and chloroform, and its volume ratio can be 1：0.5-2, preferably 1：1-1.5.The dry temperature can be 30-60 DEG C, and the dry time can be small for 16-30 When, preferably it is vacuum dried.

The double alkylethylene diamines of the N, N- can be bought and can also prepare.According to a kind of specific embodiment party of the present invention Formula, the preparation method of the Sulfonic Gemini Surfactants of structure is shown in formula (3)：Ethylenediamine is taken in there-necked flask, Absolute ethyl alcohol is added, brominated alkanes (linear paraffin of the C8-C18 that end points carbon is replaced by bromine), 70-90 DEG C are added dropwise under magnetic agitation Lower back flow reaction 40-60h；Remove solvent under reduced pressure, obtain faint yellow solid powder；Gained solid several times are washed with ether, until being in White；With mixed solvent methanol-chloroform (volume ratio 1：1.8-2.2) gained solid powder is recrystallized 2-3 times, white needles are obtained Solid powder, is vacuum dried 20-40h, and gained white needles powder is N, N '-bis- alkylethylene diamines.Take N, N '-bis- alkyl Ethylenediamine and the sultone of 1,3- third are dissolved in methyl alcohol, and heating reflux reaction 20-30h, the solution of gained is subtracted under nitrogen protection Pressure suction filtration obtains white solid；White solid is recrystallized with methanol-chloroform, obtains white solid powder, be vacuum dried 20- 40h, gained white solid powder is the Sulfonic Gemini Surfactants of structure shown in formula (3).

In the present invention, various organic solvents used are roughly the same in occupation mode, it is desirable in the case of roughly the same, These organic solvents can be with identical, it is also possible to different.

Invention further provides the both sexes quantum dot that the method according to the invention is prepared.Both sexes quantum dot of the invention Particle diameter in the range of 5-15nm, and particle diameter by quantum point or different quantum dots can be chosen, can be with Make fluorescence emission wavelengths adjustable in 370-800nm, specifically, when quantum point grain diameter increases, the ripple of fluorescent emission can be made Length is higher, when particle diameter is reduced, the wavelength of fluorescent emission can be made relatively low.And the pH of both sexes quantum dot of the invention uses model Enclose wider, in the range of pH=1~14, the surface of quantum dot all carries electric charge, and the repulsive interaction between surface charge is prevented The coagulation of quantum dot, therefore it is respectively provided with excellent fluorescence property in the range of pH=1~14；And both sexes amount of the invention Son is put good stability, is uniformly dispersed, and salinity higher will not also cause the coagulation of quantum dot.

In addition, the invention provides both sexes quantum dot of the invention in gene transfection, biomarker, bio-separation, immune Application on detection, drug targeting release and target imaging.Both sexes quantum dot of the invention is due to above-mentioned superiority Can, it is therefore particularly suitable for gene transfection, biomarker, bio-separation, immune detection, drug targeting release and target imaging Deng field.

Preparation example 1

The preparation example is used for Sulfonic Gemini Surfactants of the invention.

5.4g ethylenediamines are taken in there-necked flask, 100mL absolute ethyl alcohols are added, stirring is lower to be added dropwise 16.4g bromododecanes Hydrocarbon, back flow reaction 48h at 80 DEG C；Reaction process is detected with thin-layer chromatography TLC, question response removes anhydrous second under reduced pressure after carrying out completely Alcohol, obtains faint yellow solid powder；Gained solid several times are washed with ether, until faint yellow solid powder becomes white；With mixing Solvent methanol-chloroform (1:2) gained white solid powder is recrystallized 3 times, obtains white needles powder, be vacuum dried 24h, Gained white needles powder is N, N '-bis- alkylethylene diamines.Take 3.2g N, N '-bis- alkylethylene diamines and 5.75g1,3- third Sultone is dissolved in 50mL methyl alcohol, under nitrogen protection heating reflux reaction 24h, and the solution decompression suction filtration of gained is obtained into white solid Body；White solid is recrystallized with methanol-chloroform, obtains white solid powder, be vacuum dried 24h, gained white solid powder End is Sulfonic Gemini Surfactants SGS, by the analysis of infrared spectrum and nucleus magnetic hydrogen spectrum, its structure such as formula (5) shown in,

Preparation example 2

The preparation example is used for double quaternary ammonium salt type surfactant of the invention.

30.29mL N, N- dimethyl dodecyl base tertiary amines and 4.31mL Bromofumes are taken, 150mL isopropanols, 85 DEG C is dissolved in Back flow reaction 48h, removes solvent isopropanol under reduced pressure.Product is recrystallized with 150mL acetone, obtains white solid powder, 40 DEG C vacuum drying 24h.Products therefrom is bi-quaternary ammonium salt, is designated as BAS, by the analysis of infrared spectrum and nucleus magnetic hydrogen spectrum, Shown in its structural formula such as formula (6).

Preparation example 3-6 is used to prepare water-soluble quantum dot of the invention.

Preparation example 3

The preparation example is used to prepare mercaptopropionic acid (MPA) modification ZnSe quantum dots.

The preparation of Zn precursors：Weigh 0.9mmol ZnCl₂With 1.53mmol MPA, it is dissolved in 90mL ultra-pure waters.Stir on side While being added dropwise over 1molL^–1NaOH solution (ultra-pure water preparation) adjusts pH to 11.5.Solution is transferred in there-necked flask, is adopted Schlenk technologies are used, pumping inflation (high-purity Ar) six times repeatedly eliminates the oxygen in solution.

The preparation of NaHSe：Weigh 0.0632g Se powder and 0.1g NaBH₄, it is placed in the centrifuge tube of 10mL, add 2mL to surpass Pure water, stirring reaction is to colourless transparent solution under ice-water bath.

At room temperature, under strong stirring with syringe to adding freshly prepd NaHSe solution, [Zn] in Zn precursors: [MPA]:[Se]=1:1.2:0.4.During ZnSe precursor solutions are added into digester, then digester is placed in oil bath, 160 DEG C anti- Answer 15 minutes, you can obtain the ZnSe quantum dots of MPA modifications.A certain amount of isopropanol to solution turned cloudy is added, centrifugation is abandoned Clearly, in triplicate.The precipitation that will be collected by centrifugation is placed in vacuum drying chamber, and 35 DEG C dry 48h.

By the analysis of infrared spectrum and fluorescence spectrum, (namely MPA molecules are logical to obtain MPA modifications ZnSe quantum dots Cross the sulfydryl of its own to be combined with metal ZnSe quantum dot surfaces).By icp mses and elementary analysis Detection understands, relative to a water-soluble quantum dot, the number of the mercaptopropionic acid of surface modification averagely about 40.Separately Outward, detected through Malvern Zetasizer Nano nano particle sizes instrument, the particle diameter of the ZnSe quantum dots that obtained MPA is modified is about 5nm。

Preparation example 4

The preparation example is used to prepare MPA modification CdTe quantums.

The preparation of Cd precursors：Weigh 0.2mmol CdCl₂With 0.34mmol MPA, 50mL ultra-pure waters are dissolved in.While stirring It is added dropwise over 1molL^–1NaOH solution (ultra-pure water preparation) adjusts pH to 8.0.Solution is transferred in there-necked flask, is used Schlenk technologies pumping inflation (high-purity Ar) six times repeatedly, eliminate the oxygen in solution.

The preparation of Te precursors：Weigh 0.2mmol Te powder and 0.5mmol NaBH₄, it is placed in the centrifuge tube of 10mL, add 2mL ultra-pure waters, stirring reaction under ice-water bath is until into colourless transparent solution.

At room temperature, syringe is used under strong stirring to the addition freshly prepd NaHTe solution of 0.4mL in Cd precursors (0.04mmol), [Cd]:[MPA]:[Te]=1:1.7:0.2.There-necked flask is placed in oil bath, condensing reflux is obtained for 2 hours The CdTe quantum of MPA modifications.

By the analysis of infrared spectrum and fluorescence spectrum, (namely MPA molecules are logical to obtain MPA modifications CdTe quantum Cross the sulfydryl of its own to be combined with metal CdTe quantum surface).By icp mses and elementary analysis Detection understands, relative to a water-soluble quantum dot, the number of the mercaptopropionic acid of surface modification averagely about 52.Separately Outward, detected through Malvern Zetasizer Nano nano particle sizes instrument, the particle diameter of the CdTe quantum that obtained MPA is modified is about 5nm。

Preparation example 5

The preparation example is used to prepare MPA modification CdTe/ZnS quantum dots.

By 1mmol ZnCl₂、0.2mmol Na₂S and 5mmol MPA solution and back gained CdTe quantum are mixed into 40mL precursor solutions, 1mol L are added dropwise in stirring^–1NaOH solution, adjusts pH11.0, controls [Zn]:[MPA]:[S]= 1:5:0.2, lead to nitrogen 30 minutes to eliminate the oxygen in solution as far as possible.Reactant mixture is heated into 65 DEG C to react 3 hours Obtain the CdTe/ZnS core/shell structure quantum dots of MPA modifications.

By the analysis of infrared spectrum and fluorescence spectrum, (namely MPA points of MPA modifications CdTe/ZnS quantum dots are obtained Son is combined by the sulfydryl of its own with metal CdTe/ZnS quantum dot surfaces).By icp mses and Elementary analysis detection understands that, relative to a water-soluble quantum dot, the number of the mercaptopropionic acid of surface modification is averagely about 54.In addition, being detected through Malvern Zetasizer Nano nano particle sizes instrument, the CdTe/ZnS quantum that obtained MPA is modified The particle diameter of point is about 8nm.

Preparation example 6

The preparation example is used to prepare MPA modifications Ag₂S quantum dots, are designated as AS.

10mL ethylene glycol is placed in there-necked flask, after being passed through Ar air flow exhausts 30min, 110 DEG C is warming up to, while stirring 100 μ L MPA are added, then by 0.05mmol AgNO₃It is added in reaction solution.It is warming up to 150 DEG C.When reaction 15 minutes Afterwards, stop stirring and heat, reaction solution is cooled to room temperature, add ultra-pure water, be centrifuged after after solution muddiness, MPA modifications Ag₂S quantum dots.

By the analysis of infrared spectrum and fluorescence spectrum, MPA modifications Ag is obtained₂S quantum dots (namely MPA molecules are logical Cross the sulfydryl of its own and metal Ag₂S quantum dot surfaces combination).By icp mses and elementary analysis Detection understands, relative to a water-soluble quantum dot, the number of the mercaptopropionic acid of surface modification averagely about 24.Separately Outward, detected through Malvern Zetasizer Nano nano particle sizes instrument, the Ag that obtained MPA is modified₂The particle diameter of S quantum dots is about 2nm。

Following examples are used to illustrate the present invention by quaternary cationic surfactant and anionic type Gemini surface table Face activating agent modifies the method on water-soluble quantum dot surface, and the both sexes quantum dot for preparing.

Embodiment 1

1) the ZnSe quantum dots for taking the MPA modifications of the preparation of preparation example 3 are dissolved in ultra-pure water, and the concentration of the quantum dot aqueous solution is 100μmol·L^-1.Take in addition during 6 μ L lauryl mercaptans are dissolved in 5mL acetone and lauryl mercaptan solution is obtained.To gained lauryl mercaptan solution The middle above-mentioned quantum dot aqueous solution 5mL of fast drop (1min completion of dropping), then strong stirring 24h (mixing speeds at 25 DEG C About 250r/min).

2) by step 1) gained mixture removes solvent to 5 μ L under reduced pressure, is subsequently adding 5mL toluene and ultrasonic disperse.

3) to step 2) gained mixture in add 5mL preparation example 1 obtained by SGS the aqueous solution (concentration be 240 μ mol·L^-1) so that SGS is 2.4 with the mol ratio of quantum dot：1, then by gained mixture at about 45 DEG C DEG C strong stirring 24h (mixing speed is about 250r/min).Stand after being layered, discard toluene layer.By above-mentioned solution with 0.22 μm of filtering head mistake After filter, with 1 × 10^-2mol·L^-1PBS (pH=7.4) is dialysed.

4) in the quantum dot aqueous solution (5mL) after dialysis, add bi-quaternary ammonium salt surface obtained in 5mL preparation examples 2 and live Property agent BAS (concentration is 252 μm of olL^-1) so that the charge ratio of SGS and BAS is about 1.05：1, then gained mixture is existed DEG C strong stirring 24h at about 45 DEG C (mixing speed is about 250r/min).After above-mentioned solution is filtered with 0.22 μm of filtering head, use 1×10^-2mol·L^-1PBS (pH=7.4) is dialysed, and obtains both sexes quantum dot, is designated as I1.

By the analysis of infrared spectrum, lauryl mercaptan is connected to metal ZnSe quantum dots by the sulfydryl of its own Surface, and lauryl mercaptan chain alkyl respectively with the chain alkyl of SGS and the chain alkyl of BAS by hydrophobic interaction It is combined.

Embodiment 2

1) CdTe quantum for taking the MPA modifications of the preparation of preparation example 4 is dissolved in ultra-pure water, and the concentration of the quantum dot aqueous solution is 80μmol·L^-1.Take in addition during 8 μ L lauryl mercaptans are dissolved in 7mL acetone and lauryl mercaptan solution is obtained.To gained lauryl mercaptan solution The middle above-mentioned quantum dot aqueous solution 7mL of fast drop (1.5min completion of dropping), then strong stirring 24h (stirs speed at 25 DEG C Degree is about 250r/min).

2) by step 1) gained mixture removes solvent to 5 μ L under reduced pressure, is subsequently adding 7mL toluene and ultrasonic disperse.

3) to step 2) gained mixture in add 7mL preparation example 1 obtained by SGS the aqueous solution (concentration be 160 μ mol·L^-1) so that SGS is 2.0 with the mol ratio of quantum dot：1, then by gained mixture at about 45 DEG C DEG C strong stirring 24h (mixing speed is about 250r/min).Stand after being layered, discard toluene layer.By above-mentioned solution with 0.22 μm of filtering head mistake After filter, with 1 × 10^-2mol·L^-1PBS (pH=7.4) is dialysed.

4) in the quantum dot aqueous solution (7mL) after dialysis, 7mL DTABs (DTAB) are added (concentration is 176 μm of olL^-1) so that the charge ratio of SGS and DTAB is about 1.1：1, then by gained mixture at about 45 DEG C DEG C strong stirring 24h (mixing speed is about 250r/min).After above-mentioned solution is filtered with 0.22 μm of filtering head, with 1 × 10^- ²mol·L^-1PBS (pH=7.4) is dialysed, and obtains both sexes quantum dot, is designated as I2.

By the analysis of infrared spectrum, lauryl mercaptan is connected to metal CdTe quantum by the sulfydryl of its own Surface, and the chain alkyl of lauryl mercaptan passes through hydrophobic interaction with the chain alkyl of SGS and the chain alkyl of DTAB respectively And be combined.

Embodiment 3

1) take preparation example 5 preparation MPA modification CdTe/ZnS quantum dots be dissolved in ultra-pure water, the quantum dot aqueous solution it is dense It is 120 μm of olL to spend^-1.Take in addition during 10 μ L lauryl mercaptans are dissolved in 8mL acetone and lauryl mercaptan solution is obtained.To the sulphur of gained 12 The above-mentioned quantum dot aqueous solution 8mL of fast drop (2min completion of dropping) in alcoholic solution, then strong stirring 24h (is stirred at 25 DEG C Mix speed about 250r/min).

2) by step 1) gained mixture remove solvent to 5 μ L under reduced pressure, be subsequently adding 8mL benzo ultrasonic disperses.

3) to step 2) gained mixture in add 8mL preparation example 1 obtained by SGS the aqueous solution (concentration be 204 μ mol·L^-1) so that SGS is 1.7 with the mol ratio of quantum dot：1, then by gained mixture at about 45 DEG C DEG C strong stirring 24h (mixing speed is about 250r/min).Stand after being layered, discard toluene layer.By above-mentioned solution with 0.22 μm of filtering head mistake After filter, with 1 × 10^-2mol·L^-1PBS (pH=7.4) is dialysed.

4) in the quantum dot aqueous solution (8mL) after dialysis, 8mL DTACs (DTAC) are added (concentration is 220 μm of olL^-1) so that the charge ratio of SGS and DTAC is about 1.08：1, then by gained mixture at about 45 DEG C Lower DEG C of strong stirring 24h (mixing speed is about 250r/min).After above-mentioned solution is filtered with 0.22 μm of filtering head, with 1 × 10^- ²mol·L^-1PBS (pH=7.4) is dialysed, and obtains both sexes quantum dot, is designated as I3.

By the analysis of infrared spectrum, lauryl mercaptan is connected to metal CdTe/ZnS quantum by the sulfydryl of its own The surface of point, and the chain alkyl of lauryl mercaptan passes through hydrophobic mutual with the chain alkyl of SGS and the chain alkyl of DTAC respectively Act on and be combined.

Embodiment 4

1) Ag of the MPA modifications of the preparation of preparation example 6 is taken₂S quantum dots are dissolved in ultra-pure water, and the concentration of the quantum dot aqueous solution is 100μmol·L^-1.Take in addition during 6 μ L n-hexadecyl mercaptan are dissolved in 5mL acetone and lauryl mercaptan solution is obtained.To the sulphur of gained 12 The above-mentioned quantum dot aqueous solution 5mL of fast drop (1min completion of dropping) in alcoholic solution, then strong stirring 24h (is stirred at 25 DEG C Mix speed about 250r/min).

2) by step 1) gained mixture removes solvent to 5 μ L under reduced pressure, is subsequently adding 5mL chloroforms and ultrasonic disperse.

3) to step 2) gained mixture in add 5mL preparation example 1 obtained by SGS the aqueous solution (concentration be 220 μ mol·L^-1) so that SGS is 2.2 with the mol ratio of quantum dot：1, then by gained mixture at about 45 DEG C DEG C strong stirring 24h (mixing speed is about 250r/min).Stand after being layered, discard toluene layer.By above-mentioned solution with 0.22 μm of filtering head mistake After filter, with 1 × 10^-2mol·L^-1PBS (pH=7.4) is dialysed.

4) in the quantum dot aqueous solution (5mL) after dialysis, 5mL cetyl trimethylammonium bromides (CTAB) are added (concentration is 246 μm of olL^-1) so that the charge ratio of SGS and CTAB is about 1.12：1, then by gained mixture at about 45 DEG C Lower DEG C of strong stirring 24h (mixing speed is about 250r/min).After above-mentioned solution is filtered with 0.22 μm of filtering head, with 1 × 10^- ²mol·L^-1PBS (pH=7.4) is dialysed, and obtains both sexes quantum dot, is designated as I4.

By the analysis of infrared spectrum, n-hexadecyl mercaptan is connected to metal Ag by the sulfydryl of its own₂S is measured The surface of son point, and the chain alkyl of n-hexadecyl mercaptan passes through with the chain alkyl of SGS and the chain alkyl of CTAB respectively Hydrophobic interaction and be combined.

Embodiment 5

Method according to embodiment 1 is carried out, except that, the addition sequence of SGS and BAS is exchanged, i.e., in step 3) Middle addition BAS, in step 4) middle addition SGS.Both sexes quantum dot is finally given, I5 is designated as.

By the analysis of infrared spectrum, n-hexadecyl mercaptan is connected to metal ZnSe and measures by the sulfydryl of its own The surface of son point, and the chain alkyl of lauryl mercaptan passes through hydrophobic mutual with the chain alkyl of SGS and the chain alkyl of BAS respectively Act on and be combined.

Comparative example 1

Method according to embodiment 1 is carried out, except that, the ZnSe quantum of the MPA modifications for directly preparing preparation example 3 Point solid add 5mL toluene in and ultrasonic disperse.Result finds that the water-soluble quantum dot cannot be dispersed in toluene, obtains not To the organic solution of water-soluble quantum dot, therefore cannot continue the step of below, so as to both sexes quantum dot cannot be obtained.

Test case

Both sexes quantum dot I1~I5 that embodiment 1-5 is prepared is tested, and result is remembered in accordance with the following methods In table 1.

(1) electron microscope photo scanning：The both sexes quantum dot I3 that embodiment 3 is prepared carries out electron-microscope scanning, acquired results See Fig. 1, from figure 1 it appears that quantum dot is approximately spherical in shape, Size Distribution is relatively concentrated, favorable dispersibility, lattice bar Line is clear.

(2) particle diameter：Detected using Malvern Zetasizer Nano nano particle sizes instrument, acquired results are shown in Table 1.

(3) fluorescence emission wavelengths：Detected using LS-55 XRFs (U.S., PE companies), acquired results are shown in Table 1；Separately Outward, it is that be plotted in their fluorescence spectra in Fig. 2 by representative by I1~I4 obtained in embodiment 1-4, prepares as can be seen from Figure 2 The quantum dot fluorescence emission peak for obtaining is symmetrical, and the fluorescence emission wavelengths of different quantum dots can cover the scope of 370-800nm, Therefore by selecting different quantum dots, fluorescent emission can be realized adjustable in 370-800nm the present invention.

(4) influences of the pH to fluorescence intensity：By to adding 1molL in quantum dot solution^-1HCl or NaOH is adjusted PH, with the fluorescence intensity of LS-55 XRFs instrument (U.S., PE companies) determination sample.Repaiied with MPA obtained in preparation example 5 As a example by the CdTe/ZnS quantum dots of decorations and both sexes quantum dot I3 obtained in embodiment 3, the result that will be measured is plotted in Fig. 3.From Fig. 3 As can be seen that anion and cationic surfactant modification to be arrived the table of water-soluble quantum dot by using the method for the present invention Face, the both sexes quantum dot obtained by can making more is stablized, and excellent fluorescence property is respectively provided with the range of pH=1~14； And the water-soluble quantum dot before being modified is more unstable, fluorescent quenching is there occurs when pH is relatively low, pH uses narrow range.

(5) influence of the cell culture medium to fluorescence intensity：A certain amount of quantum dot solution is taken, DMEM cell culture mediums are added In, different time is placed, respectively with the fluorescence intensity of LS-55 XRFs instrument (U.S., PE companies) determination sample.To make As a example by the CdTe/ZnS quantum dots and both sexes quantum dot I3 obtained in embodiment 3 of MPA modifications obtained in standby example 5, the knot that will be measured Fruit is plotted in Fig. 4.From fig. 4, it can be seen that anion and cationic surfactant are modified by using the method for the present invention To the surface of water-soluble quantum dot, the both sexes quantum dot obtained by can making more is stablized in cell culture medium, with more Excellent performance.

(6) quantum yield (%)：TU-1900 ultraviolet-visible spectrophotometers and LS-55 XRFs are used respectively, are surveyed Determine the uv-visible absorption spectra and fluorescence emission spectrum of quantum dot solution.With rhodamine 6G as reference (except that ZnSe is measured Son point is with quinoline sulfate (0.1molL^-1H₂SO₄Solution) be reference), the quantum yield of measurement synthesis gained quantum dot solution. Assay method is as follows：The quantum dot solution and rhodamine 6G solution of a series of various concentrations are prepared, above-mentioned solution is determined and is being excited Absorbance (absorbance is no more than 0.1) and fluorescence emission spectrum at wavelength.By the fluorescence peak peak area in fluorescence emission spectrum Absorbance is mapped, slope can be obtained after linear fit.According to formula (7), quantum yield can be tried to achieve by slope：

In formula：Φ_XAnd Φ_STIt is respectively the quantum yield of testing sample (quantum dot) and reference (rhodamine 6G)；Grad_XWith Grad_STIt is respectively the slope of the fluorescence peak area to absorbance of testing sample (quantum dot) and reference (rhodamine 6G)；η is solvent Refractive index.

(7) effect is combined：Can be obtained by the detection of icp mses and elementary analysis, relative to One water-soluble quantum dot, with the quaternaries cation table that the alkyl hydrosulfide of water-soluble quantum dot surface modification is combined Repair on the mean number of face activating agent, the mean number of anionic type Gemini surface active agent, and water-soluble quantum dot surface The mean number of the alkyl hydrosulfide of decorations, as shown in table 1.

Table 1

Can be seen that the method according to the invention from the result of test can be by quaternary cationic surfactant point Son and anionic type Gemini surface active agent molecule are directly 8-18's with the carbon number of water-soluble quantum dot surface modification Alkyl hydrosulfide is combined, and the method process is simple, easily operation and with low cost, and gained quantum yield in the art It is of a relatively high.Also, the particle diameter of both sexes quantum dot of the invention can be controlled in the range of 1-15nm, and fluorescent emission is in 370- Adjustable in the range of 800nm, good stability is uniformly dispersed, and excellent fluorescence property is respectively provided with the range of pH=1~14.

Both sexes quantum point grain diameter of the invention is smaller, and quantum yield is high, can in cell culture fluid stable existence, can be with Used in the range of broader pH.Therefore, quantum dot of the invention is used as Gene transfer vector, biomarker probe, immune inspection Probing pin, drug targeting release vehicle and cell imaging probe are used, and have the performance of more excellent stabilization.

The preferred embodiment of the present invention described in detail above, but, the present invention is not limited in above-mentioned implementation method Detail, in range of the technology design of the invention, various simple variants can be carried out to technical scheme, this A little simple variants belong to protection scope of the present invention.It is further to note that described in above-mentioned specific embodiment Each particular technique feature, in the case of reconcilable, can be combined by any suitable means, in order to avoid not Necessary repetition, the present invention is no longer separately illustrated to various possible combinations.Additionally, a variety of implementations of the invention Can also be combined between mode, as long as it is without prejudice to thought of the invention, it is public that it should equally be considered as institute of the invention The content opened.

Claims

1. a kind of both sexes quantum dot, it is characterised in that the both sexes quantum dot with water-soluble quantum dot as matrix, the water-soluble quantum Point surface is at least modified with the alkyl hydrosulfide that carbon number is 8-18, and the alkyl hydrosulfide and quaternaries cation surface active Agent and anionic type Gemini surface active agent are combined, and the water-soluble quantum dot is the water-soluble quantum dot of metallicity, and The particle diameter of the water-soluble quantum dot is 1-15nm；

The water-soluble quantum dot is ZnSe quantum dots, CdTe quantum, CdTe/ZnS quantum dots and Ag₂In S quantum dots one Kind；

The quaternary cationic surfactant is selected from bi-quaternary ammonium salt cationoid surfactant and mono-quaternaries class sun One or more in ionic surface active agent, the bi-quaternary ammonium salt cationoid surfactant has structure shown in formula (1), The mono-quaternaries cationoid surfactant has structure shown in formula (2),

In formula (1), m and n is each independently selected from the arbitrary integer in 7-17, and X is halogen, and in formula (2), p is selected from 7-17 In arbitrary integer, X is halogen；

The anionic type Gemini surface active agent is the sulfonate type Gemini surface-actives with structure shown in formula (3) Agent,

Wherein, a and b are each independently selected from the arbitrary integer in 7-17, and Y is alkali metal.

2. both sexes quantum dot according to claim 1, wherein, relative to a water-soluble quantum dot, surface modification The carbon number for 8-18 alkyl hydrosulfide number be 20-60.

3. both sexes quantum dot according to claim 1, wherein, the surface of the water-soluble quantum dot is also modified with sulfydryl third Acid, on the basis of the total number of all molecules containing sulfydryl of the surface modification of the water-soluble quantum dot, the mercaptopropionic acid Content be less than 10%.

4. both sexes quantum dot according to claim 1, wherein, relative to a water-soluble quantum dot, with the alkane The number that base mercaptan is combined the anionic type Gemini surface active agent is 5-15, with the institute that the alkyl hydrosulfide is combined It is 1.01-1.15 that quaternary cationic surfactant is stated with the charge ratio of the anionic type Gemini surface active agent： 1。

5. both sexes quantum dot according to claim 4, wherein, relative to a water-soluble quantum dot, with the alkane The number that base mercaptan is combined the anionic type Gemini surface active agent is 10-15.

6. both sexes quantum dot according to claim 1, wherein, when the quaternary cationic surfactant is double seasons During ammonium salt cationoid surfactant, the anionic type Gemini surface active agent and quaternaries cation surface active The charge ratio of agent is 1.03-1.08：1, when the quaternary cationic surfactant is mono-quaternaries cationoid surface During activating agent, the anionic type Gemini surface active agent is with the charge ratio of quaternary cationic surfactant 1.06-1.15：1.

7. a kind of method for preparing both sexes quantum dot, it is characterised in that the method is comprised the following steps：

1) will be the water-soluble quantum of the metallicity of solution and the mercaptopropionic acid modification of the alkyl hydrosulfide of 8-18 containing carbon number The aqueous solution of point carries out the first contact, and the particle diameter of the water-soluble quantum dot is 1-15nm；

3) by the aqueous solution of the aqueous solution of quaternary cationic surfactant and anionic type Gemini surface active agent It is a kind of with step 2) products therefrom carries out the second contact, then stratification and discards organic layer, gained water is mutually carried out Dialysis for the first time obtains the quantum dot aqueous solution；

4) by the aqueous solution of the aqueous solution of quaternary cationic surfactant and anionic type Gemini surface active agent It is another with step 3) products therefrom carries out the 3rd contact, and obtained aqueous solution then is carried out into second dialysis；

The water-soluble quantum dot is the ZnSe quantum dots of mercaptopropionic acid modification, CdTe quantum, the sulfydryl of mercaptopropionic acid modification The CdTe/ZnS quantum dots of propionic acid modification and the Ag of mercaptopropionic acid modification₂One kind in S quantum dots；

8. method according to claim 7, wherein, in step 1) in, first contact is included water-soluble quantum dot The aqueous solution be added drop-wise to containing carbon number for 8-18 alkyl hydrosulfide solution in.

9. method according to claim 7, wherein, the condition of first contact includes：Temperature is 15-50 DEG C, time It is 20-30h.

10. method according to claim 7, wherein, water-soluble quantum dot in the aqueous solution of water-soluble quantum dot it is dense It is 50~500 μm of ol/L to spend.

11. methods according to claim 7, wherein, alkyl hydrosulfide and solvent in the solution containing alkyl hydrosulfide Volume ratio be 1：600-1000.

12. methods according to claim 7, wherein, the solvent in the solution containing alkyl hydrosulfide is acetone.

13. methods according to claim 7, wherein, the solution containing alkyl hydrosulfide and the water-soluble quantum dot The aqueous solution volume ratio be 1：0.5-2.

14. methods according to claim 7, wherein, in step 2) in, the organic solvent is in toluene, benzene and chloroform One or more.

15. methods according to claim 7, wherein, it is described by first contact after product removal solvent after volume with The volume ratio of organic solvent is 1：800-2000.

16. methods according to claim 7, wherein, it is described to be separated into ultrasonic disperse.

17. methods according to claim 7, wherein, the water-soluble quantum dot and the anionic type Gemini surface surface The mol ratio of activating agent is 1：1-3.

18. methods according to claim 17, wherein, the water-soluble quantum dot and the anionic type Gemini surface surface The mol ratio of activating agent is 1：1.7-2.4.

19. methods according to claim 7, wherein, in step 3) in, the condition of second contact includes：Temperature is 30-60 DEG C, the time is 20-30h.

20. methods according to claim 7, wherein, in step 4) in, the condition of the 3rd contact includes：Temperature is 30-60 DEG C, the time is 20-30h.

21. methods according to claim 7, wherein, the aqueous solution of the quaternary cationic surfactant it is dense It is 80-1200 μm of olL to spend^-1, the concentration of the aqueous solution of the anionic type Gemini surface active agent is 80-1200 μm of ol L^-1。

22. method according to any one in claim 7-21, wherein, the particle diameter of the water-soluble quantum dot is 2- 10nm。

23. methods according to claim 7, wherein, relative to a water-soluble quantum dot, the sulfydryl of surface modification The number of propionic acid is 20-60.

24. method according to any one in claim 7-21, wherein, when the quaternaries cation surface active When agent is bi-quaternary ammonium salt cationoid surfactant, the anionic type Gemini surface active agent and quaternaries cation The charge ratio of surfactant is 1.03-1.08：1, when the quaternary cationic surfactant is mono-quaternaries class sun During ionic surface active agent, the electric charge of the anionic type Gemini surface active agent and quaternary cationic surfactant Than being 1.06-1.15：1.

The both sexes quantum dot that method in 25. claim 7-24 described in any one is prepared.

Both sexes quantum dot in 26. claim 1-6 and 25 described in any one gene transfection, biomarker, bio-separation, Application on immune detection, drug targeting release and target imaging.