CN104062276A

CN104062276A - Method for preparing core-shell raman probe based on DNA (Deoxyribose Nucleic Acid) rapid assembling technique

Info

Publication number: CN104062276A
Application number: CN201410251096.9A
Authority: CN
Inventors: 胡冲娅; 颜娟; 何丹农; 宋世平; 樊春海; 余震
Original assignee: Shanghai National Engineering Research Center for Nanotechnology Co Ltd; Shanghai Jiao Tong University
Current assignee: Shanghai National Engineering Research Center for Nanotechnology Co Ltd; Shanghai Jiao Tong University
Priority date: 2014-06-06
Filing date: 2014-06-06
Publication date: 2014-09-24

Abstract

The invention discloses a method for preparing a core-shell raman probe based on a DNA (Deoxyribose Nucleic Acid) rapid assembling technique. The method comprises the following steps: rapidly assembling a DNA sequence and small molecules on a small-particle-size nanogold surface, and continuing regenerating a gold shell of certain thickness on the surface of the nanogold core surface, thereby obtaining an efficient SERS (Surface Enhanced Raman Scattering) signal because of the specialty of the structure. Compared with other methods, the probe is rapid to assemble, as the raman small molecules are arranged in gaps of fixed sizes between the nanogold core and the nanogold shell, the SERS signals generated in area of each molecule, namely, hot-spot areas, are generally the same and are good in repeatability, and thus the probe can be applied to fields such as biosensors, biomolecule detection and cell imaging.

Description

The preparation method of the nucleocapsid Raman microprobe based on DNA rapid assembly technique

Technical field

The invention belongs to functionalization and the application of nano material, relate to a kind of preparation method of the nucleocapsid Raman microprobe based on DNA rapid assembly technique.

Background technology

Surface enhanced raman spectroscopy (Surface Enhanced Raman Scattering, SERS) effect refers to the phenomenon that the Raman signal of the little molecule that is positioned at roughened metal surface itself is enhanced.This phenomenon is widely used in fields such as Surface Science, analysis science and bio-science, the information that provides level on molecule for structure and the process on the various surfaces of deep sign (interface), as differentiated molecule or ion bonding, configuration and orientation from the teeth outwards and the surface structure of material.Enhancing mechanism about SERS, what comparatively approve at present is Electromagnetic enhancement mechanism, " focus " relating in this mechanism (hot pot) generally refers in the molecular aggregation of some nanoparticles, the region, gap between adjacent nano particle, and the SERS effect in this region is the strongest.But at gold, silver, copper etc., have after strong SERS effect metal needs wants surface roughening to process and just have high SERS activity, this just requires high duplication and the homogeneity of metallic substrates used.

Can there is non-covalent Electrostatic Absorption with amino in nanogold particle, or form strong Au-S covalent bond with sulfydryl, thereby collaurum can be mutually combined with bioactive molecule, and the probe detecting to form living things system, is widely used in the electron microscopic observation research of immuning tissue's dyeing at present.Yet in the application process of colloidal gold solution, also exist nano gold sol stability and be subject to the problem that such environmental effects is serious, in electrolyte solution, easily form irreversible aggrengation, affect its follow-up use.Research shows, the aurosol of DNA modification can stably be present in ion buffer solution, will in the experimental studies such as the nucleic acid molecules sex change existing at salt ion, renaturation, hybridization, have fabulous application prospect.

About the core-shell nano gold bioprobe of DNA modification and the patent of preparation, have been reported, by the retrieval to existing document, find, Chinese invention patent CN103048306A discloses a kind of core-shell nano gold bioprobe and preparation and application with high SERS effect; But in this preparation method, the technology that SH-DNA is assembled into nm of gold surface with reference to Mirkin of Northwestern Univ USA etc., is specially: SH-DNA is added in nano-Au solution, after ambient temperature overnight, successively drip phosphate buffer, and make the final concentration of salt in 0.15M left and right; After end, ambient temperature overnight, realizes SH-DNA in the assembling on nanogold particle surface by the aging step of long salt again; Assembling process comparatively loaded down with trivial details (drip number of times at least 6 times, the time interval is 30min at least) long (need to about 48h) consuming time.

Summary of the invention

The object of the invention is to overcome the deficiency that above-mentioned prior art exists, a kind of preparation method of the nucleocapsid Raman microprobe based on DNA rapid assembly technique is provided; Except itself thering are all characteristics of nano material, possess outside high SERS effect, can also realize the quick preparation of probe, be applied to the fields such as biomolecule detection and cell imaging.Particularly, in the present invention, regulate the pH of nano-Au solution by acid solution, catalysis equivalent SH-DNA, in the adsorption reaction on nm of gold surface, realizes the assembling of DNA on nm of gold surface and only needs about 30min, and assembling fast, simple to operate; This will improve nucleocapsid Raman microprobe preparation efficiency greatly.

The object of the invention is to be achieved through the following technical solutions:

The invention discloses a kind of preparation method of the nucleocapsid Raman microprobe based on DNA rapid assembly technique, after the rapid-assembling DNA of small particle diameter nm of gold core surface, modify the little molecule of one deck, then continue, at Surface Creation layer of gold shell, to obtain described nucleocapsid Raman microprobe; Between described nucleocapsid, between gap, there is the little molecule with Raman signal.

Preferably, the preparation of described nucleocapsid Raman microprobe comprises the steps:

A, nm of gold core surface-assembled DNA;

B, the reaction of adjusting pH catalytic adsorption;

After C, centrifuge washing, obtain solution I;

D, the little molecule of nm of gold core adsorption;

E, centrifuge washing obtain solution II;

The growth of golden shell is carried out on F, nm of gold core surface;

G, golden shell structure centrifuge washing.

Preferably, described nm of gold core is that particle diameter is the nano Au particle of 5～15nm.Use nm of gold core too small, may cause that the little molecular weight of its surface-assembled Raman is few and to prepare nucleocapsid Raman microprobe size less, thereby affect the SERS efficiency of probe; While using nm of gold core excessive, cause prepared nucleocapsid Raman microprobe excessive, and cause clustering phenomena or affect later stage application (as being applied to biological detection system) etc.

Preferably, described assembled dna is specially: at nm of gold core solution, (solvent is phosphate buffer; The concentration of nm of gold core is 10nM) in add SH-PolyA DNA, to the final concentration of SH-PolyA DNA be 0.1～5 μ M, in mixed solution, the mol ratio of DNA and nm of gold core is about 300:1; Slightly concussion under room temperature.When DNA concentration is too low, be not enough to form the middle gap of nucleocapsid probe, directly affect the SERS efficiency of probe; DNA excessive concentration causes unnecessary waste.

Preferably, step B is specially: concussion limit, limit slowly drips 0.1～2M HCl solution, regulating step A gained pH value of solution to 2～4.More preferably regulate pH to 2.5～4.Applicable pH value promotes the high-level efficiency assembling of DNA, the too low or too high gathering that may cause nm of gold in assembling process.

Preferably, in step C, described centrifuge washing condition is: 4 ℃, 12000～15000rpm/min, 20min, once, cleansing solution is 10mM phosphate buffer (PB) solution of PH7.4, rear 0.1M phosphate buffered saline (PBS) resuspension with pH7.4.The too low loss that causes probe of rotating speed, the too high gathering that may cause probe.

Preferably, step D is specially: in every 5 μ L～5mL solution I, add 1～100 μ L, the little molecular solution of 0.1～1M, absorption ambient temperature overnight; Described little molecule is the little molecule with obvious characteristic peak, be selected from 5,5 '-bis-sulphur two (2-nitrobenzoic acids) (DTNB), phthalazines (PL), 2, one or more in 3-benzodiazine (PHTH), cyanine class A fuel A, bipyridine, fluorescein isothiocyanate (FITC).

Preferably, in step e, described centrifuge washing condition is: 25 ℃, and 12000～15000rpm/min, 20min, three times, the PB solution of the 10mM that cleansing solution is pH7.4, rear 0.1M phosphate buffered saline (PBS) resuspension with pH7.4.

Preferably, step F is specially: in solution II, add successively 0.1～5% polyvinylpyrrolidone aqueous solution (PVP), the oxammonium hydrochloride aqueous solution (NH of 0.1～1M ₂oHHCl), concussion limit in limit adds 0.01～1% aqueous solution of chloraurate (HAuCl ₄), mix concussion 1min; The volume ratio of described solution II, polyvinylpyrrolidone aqueous solution, oxammonium hydrochloride aqueous solution, aqueous solution of chloraurate is 10:5:2:2.

Preferably, in step G, described centrifuge washing condition is: 20 ℃, and 3000～10000rpm/min, 6min, three times, cleansing solution is Milli-Q water (ultrapure water), rear use 10～1000 μ L Milli-Q water resuspensions.

The invention still further relates to the nucleocapsid Raman microprobe with high SERS effect that a kind of aforesaid method prepares, described nucleocapsid Raman microprobe particle diameter is 40～50nm, and concentration is 0.1～1nM.

Compared with prior art, the present invention has following beneficial effect: the present invention passes through at small particle diameter nm of gold surface rapid-assembling section of DNA sequence and the little molecule of Raman, by reducing process at the certain thickness golden shell of golden core Surface Creation, between nucleocapsid, there is the gap of certain size, the little molecule of Raman is just present in this gap, and because the singularity of this structure obtains efficient SERS signal.In addition, the present invention assembles fast, and the little molecule of Raman is present in the gap of fixed measure between nm of gold nucleocapsid (about 1nm), thereby the region at each the molecule place SERS signal that " focus " region produces is basically identical, and has good repeatability.

Accompanying drawing explanation

By reading the detailed description of non-limiting example being done with reference to the following drawings, it is more obvious that other features, objects and advantages of the present invention will become:

Fig. 1 is the TEM picture of nm of gold nucleocapsid probe structure;

Fig. 2 is the efficient SERE effect schematic diagram of the nm of gold nucleocapsid Raman microprobe that makes.

Embodiment

Below in conjunction with specific embodiment, the present invention is described in detail.Following examples will contribute to those skilled in the art further to understand the present invention, but not limit in any form the present invention.It should be pointed out that to those skilled in the art, without departing from the inventive concept of the premise, can also make some distortion and improvement.These all belong to protection scope of the present invention.

embodiment 1

In the nano-Au solution that the particle diameter of 100 μ L, 10nM is 13nm, add 4 μ L, 100 μ M SH-polyA DNA, room temperature is slightly shaken; After add the HCl regulator solution pH of 1M, dropwise concussion limit in limit adds, until pH value of solution is 2.5; 4 ℃, 12000rpm/min, carries out centrifuge washing once under 20min condition, and cleansing solution is PB (10mM, pH7.4), the rear PBS resuspension with 1ml0.1M; The little molecular solution of DTNB of 100 μ L0.1M joins in the above-mentioned solution of 500 μ L, absorption ambient temperature overnight; The solution centrifugal that spends the night washing three times, cleansing solution used is PB (10mM, pH7.4), the rear PBS resuspension with 1ml0.1M; Get the above-mentioned solution of 100 μ L, add the PVP of 50 μ L1%, the NH of 25 μ L10mM ₂oHHCl, concussion limit, limit adds the HAuCl of 20 μ L0.2% ₄, mix after concussion 1min, 20 ℃, 4000rpm/min, centrifuge washing three times, each 6min, cleansing solution used is Milli-Q water, rear use 100 μ L Milli-Q water resuspensions; The golden shell structure particle diameter which prepares is at 40～50nm, and concentration is 1nM, possesses a kind of core-shell nano gold Raman microprobe at the high Enhanced feature of DTNB peak.

Fig. 1 is the TEM picture of the nm of gold nucleocapsid probe structure that makes of the present embodiment, by Fig. 1, is known, by the method, effectively prepared the nucleocapsid structure of nm of gold, and can between nucleocapsid, observe obvious gap structure, this gap size is about 1nm; The little molecule DTNB of Raman, is assembled in the place, gap that nm of gold core surface is positioned at nucleocapsid probe; The position at DTNB place is " focus ", thereby causes efficient SERS effect.

Fig. 2 is the efficient SERS result of the nm of gold nucleocapsid Raman microprobe that makes of the present embodiment, and the peak position occurring in figure and the characteristic peak of DTNB match.

embodiment 2

In the nano-Au solution that the particle diameter of 100 μ L, 10nM is 13nm, add 4 μ L, 100 μ M SH-polyA DNA, room temperature is slightly shaken; After add the HCl regulator solution pH of 1M, dropwise concussion limit in limit adds, until pH value of solution is 3; 4 ℃, 12000rpm/min, carries out centrifuge washing once under 20min condition, and cleansing solution is PB (10mM, pH7.4), the rear PBS resuspension with 1ml0.1M; The little molecular solution of DTNB of 100 μ L0.1M joins in the above-mentioned solution of 500 μ L, absorption ambient temperature overnight; The solution centrifugal that spends the night washing three times, cleansing solution used is PB (10mM, pH7.4), the rear PBS resuspension with 1ml0.1M; Get the above-mentioned solution of 100 μ L, add the PVP of 50 μ L1%, the NH of 25 μ L10mM ₂oHHCl, concussion limit, limit adds the HAuCl of 20 μ L0.2% ₄, mix after concussion 1min, 20 ℃, 4000rpm/min, centrifuge washing three times, each 6min, cleansing solution used is Milli-Q water, rear use 100 μ L Milli-Q water resuspensions; The golden shell structure particle diameter which prepares is at 40～50nm, and concentration is 1nM, possesses a kind of core-shell nano gold Raman microprobe at the high Enhanced feature of DTNB peak.

embodiment 3

In the nano-Au solution that the particle diameter of 100 μ L, 10nM is 13nm, add 4 μ L, 100 μ M SH-polyA DNA, room temperature is slightly shaken; After add the HCl regulator solution pH of 1M, dropwise concussion limit in limit adds, until pH value of solution is 3.5; 4 ℃, 12000rpm/min, carries out centrifuge washing once under 20min condition, and cleansing solution is PB (10mM, pH7.4), the rear PBS resuspension with 1ml0.1M; The little molecular solution of DTNB of 100 μ L0.1M joins in the above-mentioned solution of 500 μ L, absorption ambient temperature overnight; The solution centrifugal that spends the night washing three times, cleansing solution used is PB (10mM, pH7.4), the rear PBS resuspension with 1ml0.1M; Get the above-mentioned solution of 100 μ L, add the PVP of 50 μ L1%, the NH of 25 μ L10mM ₂oHHCl, concussion limit, limit adds the HAuCl of 20 μ L0.2% ₄, mix after concussion 1min, 20 ℃, 4000rpm/min, centrifuge washing three times, each 6min, cleansing solution used is Milli-Q water, rear use 100 μ L Milli-Q water resuspensions; The golden shell structure particle diameter which prepares is at 40～50nm, and concentration is 1nM, possesses a kind of core-shell nano gold Raman microprobe at the high Enhanced feature of DTNB peak.

embodiment 4

In the nano-Au solution that the particle diameter of 100 μ L, 10nM is 13nm, add 4 μ L, 100 μ M SH-polyA DNA, room temperature is slightly shaken; After add the HCl regulator solution pH of 1M, dropwise concussion limit in limit adds, until pH value of solution is 4; 4 ℃, 12000rpm/min, carries out centrifuge washing once under 20min condition, and cleansing solution is PB (10mM, pH7.4), the rear PBS resuspension with 1ml0.1M; The little molecular solution of DTNB of 100 μ L0.1M joins in the above-mentioned solution of 500 μ L, absorption ambient temperature overnight; The solution centrifugal that spends the night washing three times, cleansing solution used is PB (10mM, pH7.4), the rear PBS resuspension with 1ml0.1M; Get the above-mentioned solution of 100 μ L, add the PVP of 50 μ L1%, the NH of 25 μ L10mM ₂oHHCl, concussion limit, limit adds the HAuCl of 20 μ L0.2% ₄, mix after concussion 1min, 20 ℃, 4000rpm/min, centrifuge washing three times, each 6min, cleansing solution used is Milli-Q water, rear use 100 μ L Milli-Q water resuspensions; The golden shell structure particle diameter which prepares is at 40～50nm, and concentration is 1nM, possesses a kind of core-shell nano gold Raman microprobe at the high Enhanced feature of DTNB peak.

embodiment 5

In the nano-Au solution that the particle diameter of 100 μ L, 10nM is 13nm, add 4 μ L, 100 μ M SH-polyA DNA, room temperature is slightly shaken; After add the HCl regulator solution pH of 1M, dropwise concussion limit in limit adds, until pH value of solution is 4; 4 ℃, 12000rpm/min, carries out centrifuge washing once under 20min condition, and cleansing solution is PB (10mM, pH7.4), the rear PBS resuspension with 1ml0.1M; The little molecular solution of DTNB of 100 μ L0.1M joins in the above-mentioned solution of 500 μ L, absorption ambient temperature overnight; The solution centrifugal that spends the night washing three times, cleansing solution used is PB (10mM, pH7.4), the rear PBS resuspension with 1ml0.1M; Get the above-mentioned solution of 100 μ L, add the PVP of 100 μ L1%, the NH of 25 μ L10mM ₂oHHCl, concussion limit, limit adds the HAuCl of 20 μ L0.2% ₄, mix after concussion 1min, 20 ℃, 4000rpm/min, centrifuge washing three times, each 6min, cleansing solution used is Milli-Q water, rear use 100 μ L Milli-Q water resuspensions; The golden shell structure particle diameter which prepares is at 40～50nm, and concentration is 1nM, possesses a kind of core-shell nano gold Raman microprobe at the high Enhanced feature of DTNB peak.

embodiment 6

In the nano-Au solution that the particle diameter of 100 μ L, 10nM is 13nm, add 4 μ L, 100 μ M SH-polyA DNA, room temperature is slightly shaken; After add the HCl regulator solution pH of 1M, dropwise concussion limit in limit adds, until pH value of solution is 4; 4 ℃, 12000rpm/min, carries out centrifuge washing once under 20min condition, and cleansing solution is PB (10mM, pH7.4), the rear PBS resuspension with 1ml0.1M; The little molecular solution of pyridine of 100 μ L0.1M joins in the above-mentioned solution of 500 μ L, absorption ambient temperature overnight; The solution centrifugal that spends the night washing three times, cleansing solution used is PB (10mM, pH7.4), the rear PBS resuspension with 1ml0.1M; Get the above-mentioned solution of 100 μ L, add the PVP of 100 μ L1%, the NH of 25 μ L10mM ₂oHHCl, concussion limit, limit adds the HAuCl of 20 μ L0.2% ₄, mix after concussion 1min, 20 ℃, 4000rpm/min, centrifuge washing three times, each 6min, cleansing solution used is Milli-Q water, rear use 100 μ L Milli-Q water resuspensions; The golden shell structure particle diameter which prepares is at 40～50nm, and concentration is 1nM, possesses a kind of core-shell nano gold Raman microprobe at the high Enhanced feature of pyridine peak.

embodiment 7

In the nano-Au solution that the particle diameter of 100 μ L, 10nM is 13nm, add 4 μ L, 100 μ M SH-polyA DNA, room temperature is slightly shaken; After add the HCl regulator solution pH of 1M, dropwise concussion limit in limit adds, until pH value of solution is 4; 4 ℃, 12000rpm/min, carries out centrifuge washing once under 20min condition, and cleansing solution is PB (10mM, pH7.4), the rear PBS resuspension with 1ml0.1M; The little molecular solution of PHTH of 100 μ L0.1M joins in the above-mentioned solution of 500 μ L, absorption ambient temperature overnight; The solution centrifugal that spends the night washing three times, cleansing solution used is PB (10mM, pH7.4), the rear PBS resuspension with 1ml0.1M; Get the above-mentioned solution of 100 μ L, add the PVP of 100 μ L1%, the NH of 25 μ L10mM ₂oHHCl, concussion limit, limit adds the HAuCl of 20 μ L0.2% ₄, mix after concussion 1min, 20 ℃, 4000rpm/min, centrifuge washing three times, each 6min, cleansing solution used is Milli-Q water, rear use 100 μ L Milli-Q water resuspensions; The golden shell structure particle diameter which prepares is at 40～50nm, and concentration is 1nM, possesses a kind of core-shell nano gold Raman microprobe at the high Enhanced feature of PHTH peak.

Above specific embodiments of the invention are described.It will be appreciated that, the present invention is not limited to above-mentioned specific implementations, and those skilled in the art can make various distortion or modification within the scope of the claims, and this does not affect flesh and blood of the present invention.

Claims

1. A method for preparing a core-shell Raman probe based on DNA rapid assembly technology, characterized in that, after the DNA is rapidly assembled on the surface of a small particle size nano-gold core, a layer of small molecules is modified, and then a layer of small molecules is continuously generated on the surface A gold shell, that is, the core-shell Raman probe; small molecules with Raman signals exist in the gap between the core-shell.

2. the preparation method of the core-shell Raman probe based on DNA rapid assembly technology as claimed in claim 1, is characterized in that, the preparation of described core-shell Raman probe comprises the steps:

A. Nano gold core surface assembly DNA;

B. Adjust the pH to catalyze the adsorption reaction;

C, obtain solution I after centrifugal washing;

D. Adsorption of small molecules on the surface of nano gold cores;

E, centrifugal washing obtains solution II;

F, the growth of the gold shell on the surface of the nano-gold core;

G. Centrifugal washing of the gold shell structure.

3 . The method for preparing a core-shell Raman probe based on DNA rapid assembly technology according to claim 1 , wherein the nano-gold core is a nano-gold particle with a particle diameter of 5-15 nm. 4 .

4. The preparation method of the core-shell Raman probe based on DNA rapid assembly technology as claimed in claim 1, is characterized in that, described assembling DNA is specifically: add SH-PolyA DNA in nano-gold nucleus solution, to SH - The final concentration of PolyA DNA is 0.1-5 μM, and the molar ratio of DNA to nano-gold core in the mixed solution is about 300:1; shake slightly at room temperature.

5. The preparation method of the core-shell Raman probe based on DNA rapid assembly technology as claimed in claim 1, characterized in that, step B is specifically: slowly add 0.1 ~ 2M HCl solution dropwise while shaking, and adjust the solution obtained in step A pH to 2-4.

6. The preparation method of the core-shell Raman probe based on DNA rapid assembly technology as claimed in claim 1, characterized in that, in step C, the centrifugal washing condition is: 4°C, 12000～15000rpm/min, 20min , once, the washing solution was 10 mM PB solution with pH 7.4, and then resuspended with 0.1 M phosphate-buffered saline with pH 7.4.

7. The preparation method of the core-shell Raman probe based on DNA rapid assembly technology as claimed in claim 1, characterized in that, step D is specifically: adding 1-100 μL, 0.1-1M small Molecular solution, adsorb overnight at room temperature; the small molecule is a small molecule with obvious characteristic peaks, selected from 5,5'-dithiobis(2-nitrobenzoic acid), phthalazine, 2,3-naphthyridine , cyanine fuel, bipyridine, fluorescein isothiocyanate or one or more.

8. The preparation method of the core-shell Raman probe based on DNA rapid assembly technology as claimed in claim 1, characterized in that, in step E, the centrifugal washing condition is: 25°C, 12000～15000rpm/min, 20min , three times, the washing solution was 10 mM PB solution with pH 7.4, and then resuspended with 0.1 M phosphate-buffered saline with pH 7.4.

9. The preparation method of the core-shell Raman probe based on DNA rapid assembly technology as claimed in claim 1, characterized in that, step F is specifically: adding 0.1 to 5% polyvinylpyrrolidone aqueous solution successively in solution II, 0.1 ～1M hydroxylamine hydrochloride aqueous solution, add 0.01～1% chloroauric acid aqueous solution while shaking, mix and shake for 1min; the volume ratio of described solution II, polyvinylpyrrolidone aqueous solution, hydroxylamine hydrochloride aqueous solution, chloroauric acid aqueous solution is 10: 5:2:2.

10. The preparation method of the core-shell Raman probe based on DNA rapid assembly technology as claimed in claim 1, characterized in that, in step G, the centrifugal washing condition is: 20°C, 3000～10000rpm/min, 6min , three times, the washing solution was Milli-Q water, and then resuspended with 10-1000 μL Milli-Q water.

11. A core-shell Raman probe with high SERS effect prepared by the method according to any one of claims 1 to 10, the particle diameter of the core-shell Raman probe is 40 to 50 nm, and the concentration is 0.1～1nM.