Summary of the invention
In view of this, the technical problem that the present invention will solve is to provide a kind of nucleocapsid structure golden nanometer particle and preparation method thereof, and the nucleocapsid structure golden nanometer particle of this method preparation also has good stability and solvability when having temperature-responsive.
The invention provides a kind of nucleocapsid structure golden nanometer particle, be made up of kernel and shell, said kernel is a golden nanometer particle, and shell is for gathering (terepthaloyl moietie-block-N-NSC 11448) multipolymer.
The invention provides a kind of preparation method of nucleocapsid structure golden nanometer particle, may further comprise the steps:
A) gather (terepthaloyl moietie-block-N-NSC 11448) multipolymer with aminolysis reagent carries out aminolysis reaction with what end had two thioester substrates, obtain that single sulfydryl is end capped to gather (terepthaloyl moietie-block-N-isopropyl acrylamide) section multipolymer;
B) with said end capped gathering of single sulfydryl (terepthaloyl moietie-block-N-NSC 11448) multipolymer carry out ligand exchange reaction with the golden nanometer particle that with the Trisodium Citrate is part, obtain the nucleocapsid structure golden nanometer particle.
Preferably, said end (terepthaloyl moietie-block-N-NSC 11448) multipolymer that gathers that has two thioester substrates prepares according to following method:
S1) end capped polyoxyethylene glycol of monomethyl and MALEIC ANHYDRIDE are carried out addition reaction, obtain adduct;
S2) with said adduct and dithiobenzoic acid reaction, obtain macromolecular chain transfer agent based on the end capped polyoxyethylene glycol of monomethyl;
S3) with said macromolecular chain transfer agent based on the end capped polyoxyethylene glycol of monomethyl, Diisopropyl azodicarboxylate and the reaction of N-NSC 11448, what obtain that end has two thioester substrates gathers (terepthaloyl moietie-block-N-NSC 11448) multipolymer.
Preferably, said step S3 temperature of reaction condition is 60~80 ℃.
Preferably, aminolysis reagent is short-chain fat family amido alkane in the said steps A.
Preferably, said short-chain fat family amido alkane is ethamine, propylamine, one or more in Isopropylamine and the TERTIARY BUTYL AMINE.
Preferably, aminolysis reaction is with THF (THF) in the said steps A, and N (DMF) or methylene dichloride are reaction solvent.
Preferably, said aminolysis reaction and ligand exchange reaction carry out under oxygen free condition respectively.
Preferably, the reaction times of said aminolysis reaction is 20~30h.
Preferably, the reaction times of ligand exchange reaction is 60~80h among the said step B.
The present invention provides a kind of nucleocapsid structure golden nanometer particle and preparation method thereof; It is sulfydryl that this method will be gathered the terminal direct aminolysis of two thioesters of (terepthaloyl moietie-block-N-NSC 11448) multipolymer (PEG-b-PNIPAM), obtains that single sulfydryl is end capped to gather (terepthaloyl moietie-block-N-NSC 11448) multipolymer (PEG-b-PNIPAM-SH); Further carry out ligand exchange reaction, segmented copolymer is grafted to the surface of golden nanometer particle, obtain shell for gathering the nucleocapsid structure golden nanometer particle of (terepthaloyl moietie-block-N-NSC 11448) multipolymer with the golden nanometer particle that with the Trisodium Citrate is part.Compare with the golden nanometer particle that the polymkeric substance of homopolymerization in the prior art is protected; Be shell protective money nanoparticle with PEG-b-PNIPAM among the present invention; At first, the solvability of outer block is fine, so the nucleocapsid structure golden nanometer particle of its formation also has good solubility.Secondly, the existence of outer block PEG also provides layer of protecting for the nucleocapsid structure golden nanometer particle, has improved the stability of nucleocapsid structure golden nanometer particle, has suppressed the gathering between the nanoparticle.Once more, thus the solvability of internal layer block PNIPAM changes with the change of temperature gives the nucleocapsid structure golden nanometer particle and has temperature-responsive.
Experimental result shows, the average hydrodynamic radius (R of nucleocapsid structure golden nanometer particle of the present invention's preparation
h) reduce R in the time of 25 ℃ to some extent with the increase of temperature
hBe about 26.5nm, R in the time of 50 ℃
hBe about 23nm, have good temperature-responsive.The nucleocapsid structure golden nanometer particle of this method preparation is not all assembled in 15~55 ℃ of TRs simultaneously, has satisfactory stability property.
Embodiment
The invention provides a kind of preparation method of nucleocapsid structure golden nanometer particle; May further comprise the steps: (terepthaloyl moietie-block-N-NSC 11448) multipolymer (PEG-b-PNIPAM) that gathers that A) end is had two thioester substrates carries out aminolysis reaction with aminolysis reagent, obtains that single sulfydryl is end capped to gather (terepthaloyl moietie-block-N-NSC 11448) multipolymer (PEG-b-PNIPAM-SH); B) with said end capped gathering of single sulfydryl (terepthaloyl moietie-block-N-NSC 11448) multipolymer carry out ligand exchange reaction with the golden nanometer particle that with the Trisodium Citrate is part, obtain the nucleocapsid structure golden nanometer particle.
Wherein, said PEG-b-PNIPAM is preferably according to reversible addition-fracture chain transfer (RAFT) method preparation:
S1) end capped polyoxyethylene glycol of monomethyl (mPEG-OH) and exsiccant toluene solution are added in the container, under the nitrogen protection, be heated to mPEG-OH and dissolve fully, add MALEIC ANHYDRIDE (MAh) then, reaction is spent the night.Toluene is removed in decompression, is dissolved in methylene dichloride again, in ether, precipitates, and to remove excessive MAh, vacuum-drying obtains adduct (mPEG-MAh).For mPEG-OH is reacted completely, it is excessive to be preferably MAh, and the mass ratio of mPEG-OH and MAh more preferably 6: 1~10: 1 most preferably is 8: 1.
S2) with reacting 20~24h in 60~70 ℃ after said adduct mPEG-MAh and the dithiobenzoic acid (DTBA) and the airtight degassing of exsiccant tetracol phenixin; After finishing, reaction adds part methylene chloride; And in ether, precipitate; Repeat this process and remove fully to excessive DTBA, 35~45 ℃ of vacuum-dryings obtain the macromolecular chain transfer agent (mPEG-CTA) based on the end capped polyoxyethylene glycol of monomethyl.Temperature of reaction is preferably 65 ℃, and the reaction times is preferably 24h, and the vacuum-drying temperature is preferably 40 ℃.
S3) said mPEG-CTA, Diisopropyl azodicarboxylate, N-NSC 11448 (NIPAM) and exsiccant acetonitrile solution are added in the container; With reaction mixture process freeze-thaw degasification process; Vacuum sealing; Under 55~80 ℃ of conditions, react 20~24h, the product that obtains is used ether sedimentation, 40~55 ℃ of vacuum-drying get terminal have two thioester substrates gather (terepthaloyl moietie-block-N-NSC 11448) multipolymer (PEG-b-PNIPAM).Temperature of reaction is preferably 60~80 ℃, and more preferably 80 ℃, the reaction times is preferably 24h, and the vacuum-drying temperature is preferably 50 ℃.
The present invention is shell protective money nanoparticle with PEG-b-PNIPAM, and at first, the solvability of outer block is fine, so the nucleocapsid structure golden nanometer particle of its formation also has good solubility.Secondly, the existence of outer block PEG also provides layer of protecting for the nucleocapsid structure golden nanometer particle, has improved the stability of nucleocapsid structure golden nanometer particle, has suppressed the gathering between the nanoparticle.Once more, thus the solvability of internal layer block PNIPAM changes with the change of temperature gives the nucleocapsid structure golden nanometer particle and has temperature-responsive.
In order to clearly demonstrate the present invention, below respectively the experimentation of steps A and step B is described in detail.
According to the present invention, said steps A is specially: PEG-b-PNIPAM is added in the container that reaction solvent is housed, reaction solution is outgased through freeze-thaw remove oxygen wherein; Under nitrogen protection, add aminolysis reagent, behind the vacuum sealing container, react 20~30h under the room temperature; Be preferably 24h; The product that obtains is used ether sedimentation, and the vacuum-drying temperature is 30~50 ℃, is preferably 40 ℃.
Wherein, aminolysis reagent is preferably short-chain fat family amido alkane in the said steps A, ethamine more preferably, and propylamine, one or more in Isopropylamine and the TERTIARY BUTYL AMINE most preferably are propylamine and Isopropylamine.The reaction solvent of said aminolysis reaction is preferably THF, DMF or methylene dichloride, more preferably THF or methylene dichloride.
According to the present invention, said step B is specially: PEG-b-PNIPAM-SH is added in the container that deionized water is housed, the reaction solution freeze-thaw is outgased; Under nitrogen protection and vigorous stirring, adding with the Trisodium Citrate is the golden nanometer particle of part, reacts 60~80h under the room temperature, is preferably 72h; Under coldcondition, be preferably 5 ℃ then, the centrifugal 1~3h of 10000~15000r/min; Its medium speed is preferably 11000r/min, and centrifugation time is preferably 2h, removes supernatant after centrifugal; Repeat this process repeatedly,, be preferably three times until removing unreacted polymkeric substance fully.
Wherein in steps A and step B for preventing that the end that generates from containing the curing reaction between the segmented copolymer generation sulfydryl of sulfydryl, influence ligand exchange reaction, so want in the hierarchy of control definitely anaerobic.
Average hydrodynamic radius (the R of nucleocapsid structure golden nanometer particle of the present invention's preparation
h) reduce R in the time of 25 ℃ to some extent with the increase of temperature
hBe about 26.5nm, R in the time of 50 ℃
hBe about 23nm, have good temperature-responsive.The nucleocapsid structure golden nanometer particle of this method preparation is not all assembled in 15~55 ℃ of TRs simultaneously, has satisfactory stability property.
In order to further specify the present invention, the preparation method of a kind of nucleocapsid structure golden nanometer particle provided by the invention is described in detail below in conjunction with embodiment.
Agents useful for same is commercially available in following examples.
Embodiment 1
1.1 dithiobenzoic acid (DTBA) is synthetic
At one stirrer is housed; The sodium methoxide solution that adds 22.5g 30% in the 250mL three neck round-bottomed flasks of constant pressure funnel and spherical condensation tube; 4g exsiccant sulphur powder; Under room temperature and nitrogen protection, slowly drip the 7.95g benzyl, the back room temperature reaction 30min that finishes is warming up to 70 ℃ of reactions then and spends the night.The ice-water bath cooled and filtered is fallen insolubles, removal of solvent under reduced pressure.Residue is soluble in water again, adds the hcl acidifying of ether and 1.0mol/L, makes it change into DTBA.Sodium hydroxide solution and hydrochloric acid/diethyl ether solution with ice extract three times repeatedly, and the oily liquids that obtains the purified redness of 6.6g at last is DTBA, and productive rate is about 60%.
1.2mPEG-OH addition reaction with MAh
8.0g mPEG-OH and 30mL exsiccant toluene solution are added in the round-bottomed flask of 100mL, under nitrogen protection, be heated to 70 ℃ mPEG-OH is dissolved fully after, add 1.0g MAh rapidly, reaction is spent the night.Toluene is removed in decompression, then reactant is dissolved in methylene dichloride again, in ether, precipitates, and repeats this process three times, and extremely excessive MAh removes fully, and vacuum-drying is two days under 50 ℃ of conditions, obtains the product mPEG-MAh of white.
1.3mPEG-CTA synthetic
Add the mPEG-MAh that obtains in the 1.0g step 1.2 at a polymerizing pipe that stirrer is housed, DTBA that makes in the 0.64g step 1.1 and 2mL exsiccant tetracol phenixin react 24h in 65 ℃ after the airtight degassing.After reaction finishes, add part methylene chloride, and in ether, precipitate, this process triplicate, extremely excessive DTBA removes fully.Vacuum-drying gets light red macromolecular chain transfer agent mPEG-CTA two days later under 40 ℃ of conditions.
1.4PEG-b-PNIPAM synthetic
In a polymerizing pipe that stirrer is housed, add the 1.0mg Diisopropyl azodicarboxylate, 0.80g NIPAM, the macromolecular chain transfer agent mPEG-CTA that makes in the 0.20g step 1.3 and 5.5mL exsiccant acetonitrile solution.Through after three freeze-thaw degasification process, tube sealing under the vacuum reacts 24h under 80 ℃ of conditions with reaction mixture.The product that obtains is with ether sedimentation three times, and 50 ℃ of vacuum-dryings obtain PEG-b-PNIPAM two days later, and the monomer whose transformation efficiency is about 50%.
1.5 the aminolysis reaction that segmented copolymer is terminal
The PEG-b-PNIPAM that makes in the 0.20g step 1.4 is joined in the polymerizing pipe that 8.0mL THF solvent is housed, with the reaction solution freeze-thaw degassing three times, under nitrogen protection; After adding the 0.020g propylamine rapidly, solution colour becomes closely colourless rapidly from light red, again with the reaction mixture freeze-thaw degassing three times; Vacuum sealing tube; React 24h under the room temperature, obtain product with ether sedimentation three times, vacuum-drying two days later under 40 ℃ of conditions; Obtain the product P EG-b-PNIPAM-SH behind the aminolysis, productive rate is about 98%.
1.6 with the Trisodium Citrate is the preparation of the golden nanometer particle of part
0.0206g four hydration tetra chlorauric acids and 50mL deionized water are joined 100mL to be equipped with in the round-bottomed flask of stirrer.Vigorous stirring is heated to boiling reflux, adds the sodium citrate aqueous solution of 5mL (33.8mmol/L) rapidly, and solution colour changes the wine redness into by dark yellow; Behind the boiling 10min; Remove heating, continue to stir 15min, obtaining after the cooling with the Trisodium Citrate is the golden nanometer particle of part.Its particle diameter is about 12 ± 1nm.
1.7 the preparation of the nucleocapsid structure golden nanometer particle of temperature-responsive
The PEG-b-PNIPAM-SH that makes in the 0.050g step 1.5 is added in the polymerization bottle that is equipped with in the 20mL deionized water; Then with the reaction solution freeze-thaw degassing three times, under nitrogen protection and vigorous stirring, adding what make in the 0.4mL 1mmol/L step 1.6 rapidly is the solution of gold nanoparticles of part with the Trisodium Citrate; React 72h under the room temperature; Under 5 ℃, centrifugal 2h removes supernatant under the rotating speed of 11000r/min then; Repeat this process three times repeatedly, until removing unreacted polymkeric substance fully.At last, the nucleocapsid structure golden nanometer particle with purifying is dispersed in the deionized water.
Below be each step reaction formula:
A. dithiobenzoic acid (DTBA) is synthetic
The addition reaction of b.mPEG-OH and maleic anhydride (MAh)
C. synthetic (mPEG-CTA) of macromolecular chain transfer agent
D. synthetic (PEG-b-PNIPAM) of segmented copolymer
E. the terminal aminolysis reaction (PEG-b-PNIPAM-SH) of segmented copolymer
F. the preparation of golden nanometer particle (Au NPs)
G. the preparation of the nucleocapsid structure golden nanometer particle of temperature-responsive
The method of utilizing transmission electron microscope is that the nucleocapsid structure golden nanometer particle that obtains in the golden nanometer particle and 1.7 of part is analyzed with the Trisodium Citrate to what obtain in 1.6; Obtain the transmission electron microscope photo of ligand exchange front and back golden nanometer particle, as depicted in figs. 1 and 2 respectively.Through analyzing relatively electromicroscopic photograph, can find out existence owing to nanoparticle polymkeric substance shell, the dispersiveness of golden nanometer particle improves.
Utilize X ray energy dispersion spectrum; Nucleocapsid structure golden nanometer particle to obtaining in 1.7 carries out ultimate analysis; There are Au, C, N, O and S element in the proof products therefrom; Because the polymkeric substance shell is that the sulfydryl grafting through end is surperficial with golden nanometer particle, and C, N, O, S are the component of segmented copolymer PEG-b-PNIPAM, have confirmed the existence of polymkeric substance shell.
Detect through temperature-responsive, the result shows nucleocapsid structure golden nanometer particle average flow mechanics radius R
hReduce R in the time of 25 ℃ to some extent with the increase of temperature
hBe about 26.5nm, R in the time of 50 ℃
hBe about 23nm.Mainly be because the deliquescent change with temperature of the block PNIPAM of internal layer causes: along with the rising of temperature; The solubleness of PNIPAM in water descends; Anhydrating turns into taking place, and the polymkeric substance of internal layer begins gradually to collapse and caused the R of whole nucleocapsid structure golden nanometer particle simultaneously
hReduce.
Through to Detection of Stability, the result shows in 15~55 ℃ of scopes and does not assemble.This mainly is because the existence of outer block PEG has suppressed the gathering between the nanoparticle.
Can know that by above experimental result the present invention is incorporated into the segmented copolymer of environmental influence property in the golden nanometer particle system,, also give the golden nanometer particle temperature-responsive increasing nanoparticle stability and deliquescent while.
Embodiment 2
Prepare each middle and final product with embodiment 1 same mode, have only segmented copolymer PEG-b-PNIPAM synthetic as follows:
In a polymerizing pipe that stirrer is housed, add the 1.0mg Diisopropyl azodicarboxylate; 0.80g NIPAM, mPEG-CAT that obtains among the 0.20g 1.4 and 5.5mL exsiccant acetonitrile solution, with reaction mixture through three freeze-thaw degasification process; Tube sealing under the vacuum is in 60 ℃ of reaction 24h.The product that obtains with ether sedimentation three times after, vacuum-drying is two days under 50 ℃ of conditions, obtains segmented copolymer PEG-b-PNIPAM, monomer conversion is about 30%.
Embodiment 3
Prepare each middle and final product with embodiment 1 same mode, have only the terminal aminolysis reaction of segmented copolymer following:
The PEG-b-PNIPAM that obtains among the 1.0g 1.5 is joined in the polymerizing pipe that the 10mL dichloromethane solvent is housed; With the reaction solution freeze-thaw degassing three times, under nitrogen protection, add the 0.11g propylamine rapidly; Solution colour becomes closely colourless rapidly from light red; Again with the reaction mixture freeze-thaw degassing three times, vacuum sealing tube, room temperature reaction 24h.The product that obtains is with ether sedimentation three times, and 40 ℃ of vacuum-drying two days obtains the product P EG-b-PNIPAM-SH behind the aminolysis, and productive rate is about 98%.
Embodiment 4
Prepare each middle and final product with embodiment 1 same mode, have only the terminal aminolysis reaction of segmented copolymer following:
1.0g PEG-b-PNIPAM is joined in the polymerizing pipe that the 10mL dichloromethane solvent is housed; With the reaction solution freeze-thaw degassing three times, under nitrogen protection, add the 0.12g isopropylamine rapidly; Solution colour becomes closely colourless rapidly from light red; Again with the reaction mixture freeze-thaw degassing three times, vacuum sealing tube, room temperature reaction 24h.Obtain product with ether sedimentation three times, 40 ℃ of vacuum-drying two days obtains the product P EG-b-PNIPAM-SH behind the aminolysis, and productive rate is about 98%.
The above only is a preferred implementation of the present invention; Should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; Can also make some improvement and retouching, these improvement and retouching also should be regarded as protection scope of the present invention.