CN109986073B

CN109986073B - Gold cluster rapid purification method based on ultrafiltration

Info

Publication number: CN109986073B
Application number: CN201910037777.8A
Authority: CN
Inventors: 林振坤; 薛甜甜; 苏宇; 齐金霞; 徐艺; 唐国庭; 刘雨欣
Original assignee: Second Affiliated Hospital and Yuying Childrens Hospital of Wenzhou Medical University
Current assignee: Second Affiliated Hospital and Yuying Childrens Hospital of Wenzhou Medical University
Priority date: 2019-01-15
Filing date: 2019-01-15
Publication date: 2021-06-15
Anticipated expiration: 2039-01-15
Also published as: CN109986073A

Abstract

The invention relates to a gold cluster rapid purification method based on ultrafiltration, which comprises the following steps: 4mL of crude product solution without processing the gold clusters is placed in an inner tube of an ultrafiltration tube (with the specification of 3KDa), then the ultrafiltration tube is placed in a low-speed freezing centrifuge for centrifugation, the rotation speed is 3500 plus 4000 r/min, the centrifugation time is 100 plus 180 min, the temperature is 4 ℃, in the centrifugation process, impurities such as small molecules in the solution are filtered into the outer tube under the centrifugal force, and the purified gold clusters are obtained in the inner tube. The method has the characteristics of convenience in operation, rapidness, high efficiency and environmental friendliness.

Description

Gold cluster rapid purification method based on ultrafiltration

Technical Field

The invention belongs to the field of material purification, and particularly relates to a rapid gold cluster purification method based on ultrafiltration.

Background

Gold clusters generally refer to gold nanomaterials having a size below 2 nm. The gold cluster has a remarkable quantum size effect, so that the gold cluster has a discrete electronic structure at the center of a cluster core, and therefore, the spectrum shows single electron transition similar to a molecule instead of the surface plasmon resonance of common nano materials. The unique geometry and electronic structure of gold clusters give it many interesting properties such as chirality, magnetism, redox properties, photovoltaic properties, etc. (see Santosh Kumar et al, Water-soluble Au₂₅(Capt)₁₈nanoclusters: synthesis, thermal stability, and optical properties, Nanoscale,2012,4, 4222). These characteristics make gold clusters widely used in many fields, and scientists in various fields have conducted efficient research in synthesis characterization and application in recent years.

The most common synthetic methods for gold clusters are two: prepared by carrying out redox reaction on a blocking agent and a reducing agent; and etching the large-size gold nanoparticles under an alkaline condition. The first method, which has achieved significant success and is becoming mature, is currently the most common preparation method used in laboratories. The chemical reduction reaction carried out in the presence of the end-capping reagent and the reducing agent reduces the trivalent gold ions into monovalent and even zero valence state, thereby obtaining the stable gold cluster. (see Su Lei, visual identification of glucose in human serum by ratiometric probe paper, Master academic thesis, university of Chinese science and technology, 2018)

Gold clusters are widely used in the fields of analytical detection, biomedicine and the like. The target substance for analytical detection comprises metal ions (such as Hg)²⁺、Pb²⁺、Cu²⁺) Small organic molecules (such as ascorbic acid, dopamine, glucose, cholesterol and the like), polypeptides, amino acids (such as cysteine, glutathione, ATP), protein molecules, enzymes and the like (refer to xu chao, research on correlation based on gold cluster multi-mode imaging and tumor marker diagnosis, doctor's academic paper of Beijing university of industry, 2017). Applications in the biomedical field include in vitro cell level imaging and in vivo level imaging, drug delivery, enzyme activity regulation, biomarkers and the like (refer to the study of the synthesis of gold nanoparticles and gold nanoclusters and the modification of glucose oxidase, university of Sichuan agriculture, Master academic thesis 2011).

The synthesized gold cluster crude product solution contains a large amount of impurities such as residual reactants, and needs to be purified. The purification methods that have been reported at present include organic solvent precipitation, dialysis, electrophoresis, liquid chromatography, and the like. Polyacrylamide gel electrophoresis is widely applied at present, and the principle is that the size and the charge quantity of gold clusters are different from those of impurities contained in a crude solution, so that the gold clusters have difference in migration speed in an electric field to realize separation, but the method needs to perform subsequent treatment such as sol after purification (refer to Gooddrin and the like, preparation, properties and application of chiral gold clusters, chemical development, 2015). In addition, the dialysis method is also commonly used, and dialysis membranes with different molecular weights are selected according to different gold cluster sizes, and a solution of a gold cluster crude product is generally required to be dialyzed for several days by using the dialysis membranes, and ultrapure water is replaced at regular intervals (see threi Lei, visual identification of glucose in human serum by ratiometric probe test paper, Master academic thesis of Chinese science and technology university, 2018). The methods have the problems of long time consumption, complicated operation, high cost, low yield, dependence on organic reagents (environmental pollution) and the like to different degrees.

Disclosure of Invention

The invention aims to improve the existing gold cluster purification method and provide a new method for rapidly purifying gold clusters based on ultrafiltration. The specific technical scheme is as follows:

placing the crude product solution of the untreated gold clusters (synthesized by a reduction method) in an inner tube (with the specification of 3kDa) of an ultrafiltration tube, then placing the ultrafiltration tube in a low-speed freezing centrifuge for centrifugation at the rotation speed of 3500-.

The technical scheme has the characteristics of convenience in operation, rapidness, high efficiency and environmental friendliness. Meanwhile, most of the solvent and impurities are filtered to the outer tube, so that the gold clusters in the inner tube are greatly concentrated. Therefore, the gold lump purification method provided by the invention has a concentration effect at the same time.

Drawings

FIG. 1 is a photograph of a comparison of the prior embodiment gold clusters before and after purification in an ultrafiltration tube (before ultrafiltration on the left and after ultrafiltration on the right);

FIG. 2 is a graph of the UV spectrum before and after purification of a gold cluster according to the preferred embodiment (red is before purification and black is after purification);

FIG. 3 is a TEM image of a purified gold cluster according to the preferred embodiment;

FIG. 4 comparative photographs of gold clusters before and after purification in an ultrafiltration tube of example 1 (before ultrafiltration on the left and after ultrafiltration on the right);

FIG. 5 is a UV spectrum before and after purification of the gold clusters of example 1 (red is before purification, and black is after purification);

FIG. 6 comparison photographs of gold clusters before and after purification in an ultrafiltration tube of example 2 (before ultrafiltration on the left, after ultrafiltration on the right);

FIG. 7 is a UV spectrum before and after purification of the gold clusters of example 2 (red is before purification, and black is after purification);

FIG. 8 is a technical roadmap of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.

Description of the preferred embodiments

The technical scheme of the embodiment is as follows: adding 4mL of the crude product solution of the untreated gold clusters into an inner tube (the specification is 3kDa) of an ultrafiltration tube, placing the ultrafiltration tube in a low-speed freezing centrifuge for centrifugation, wherein the rotation speed is 4000 revolutions per minute, the centrifugation time is 100min, and the temperature is 4 ℃. FIG. 1 shows that after centrifugation, the volume of the solution containing purified and concentrated gold clusters in the inner tube is about 150uL, and most of the solvent and small molecular impurities in the original solvent are centrifuged into the outer tube. FIG. 2 shows that a large number of impurity peaks exist in the wavelength range of 200-300 nm in the ultraviolet spectrum before purification, which shows that various impurities exist in the gold cluster crude product solution, and the characteristic peak (near 650 nm) of the gold cluster is weak; the impurity peaks disappear after purification, and meanwhile, the characteristic peaks of the gold clusters are obviously enhanced, so that the impurities are filtered, and the method has a good purification effect. FIG. 3 shows a Transmission Electron Microscope (TEM) image of the gold cluster after purification according to the preferred embodiment, which shows that the gold cluster has a particle size distribution of about 2nm, is uniformly dispersed, and no other impurities are observed.

Example 1

The technical scheme of the embodiment is as follows: adding 4mL of the crude product solution of the untreated gold clusters into an inner tube (with the specification of 3kDa) of an ultrafiltration tube, placing the ultrafiltration tube in a low-speed freezing centrifuge for centrifugation at 3800 rpm for 160min at 4 ℃. FIG. 4 shows that after centrifugation, the volume of the solution containing purified and concentrated gold clusters in the inner tube is about 150uL, and most of the solvent and small molecular impurities in the original solvent are centrifuged into the outer tube. FIG. 5 shows that a large number of impurity peaks exist in the wavelength range of 200-300 nm in the ultraviolet spectrum before purification, which shows that various impurities exist in the gold cluster crude product solution, and the characteristic peak (near 650 nm) of the gold cluster is weak; the impurity peaks disappear after purification, and meanwhile, the characteristic peaks of the gold clusters are obviously enhanced, so that the impurities are filtered, and the method has a good purification effect.

Example 2

The technical scheme of the embodiment is as follows: adding 4mL of the crude product solution of the untreated gold clusters into an inner tube (with the specification of 3kDa) of an ultrafiltration tube, placing the ultrafiltration tube in a low-speed freezing centrifuge for centrifugation at the rotation speed of 3500 rpm for 100min at the temperature of 4 ℃. FIG. 4 shows that after centrifugation, the volume of the solution containing purified and concentrated gold clusters in the inner tube is about 150uL, and most of the solvent and small molecular impurities in the original solvent are centrifuged into the outer tube. FIG. 5 shows that a large number of impurity peaks exist in the wavelength range of 200-300 nm in the ultraviolet spectrum before purification, which shows that various impurities exist in the gold cluster crude product solution, and the characteristic peak (near 650 nm) of the gold cluster is weak; the impurity peaks disappear after purification, and meanwhile, the characteristic peaks of the gold clusters are obviously enhanced, so that the impurities are filtered, and the method has a good purification effect.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention, and it is therefore to be understood that the invention is not limited by the scope of the appended claims.

Claims

1. A gold cluster rapid purification method based on ultrafiltration is characterized by comprising the following steps: placing the crude product solution of the gold cluster which is synthesized by the reduction method and is not processed into an inner tube of an ultrafiltration tube, then placing the ultrafiltration tube into a centrifuge for centrifugation, wherein the rotation speed is 3500-4000 r/min, the centrifugation time is 100-180 min, and in the centrifugation process, small molecules in the solution are filtered into an outer tube under the action of centrifugal force, and the purified gold cluster is obtained in the inner tube;

4mL of the crude product solution, wherein the temperature during centrifugation is 4 ℃;

the specification of the ultrafiltration tube is 3KDa;

the centrifugation adopts a low-speed freezing centrifuge.