Colloidal gold partly modified by polyethylene glycol and preparation method thereof

Abstract

The invention discloses colloidal gold partly modified by polyethylene glycol and a preparation method thereof. The preparation method comprises the following steps of (1) preparing the colloidal gold; (2) fixing nanogold on a glass solid phase carrier; (3) modifying the colloidal gold by using the polyethylene glycol; and (4) preparing a solution of the colloidal gold partly modified by the polyethylene glycol. 80-95% of the surface region of the colloidal gold prepared by the method is covered by the polyethylene glycol, and the other 5-20% of the surface region is still a bare gold surface. The stability of the colloidal gold partly modified by the polyethylene glycol prepared by the preparation method in complex mediums and the selective recognition of the colloidal gold to target proteins are obviously enhanced. Through asymmetrically modifying the colloidal gold, directional adjustment and control of reactions can be realized, and the uncontrollable agglomeration and sedimentation problems caused by isotropic colloidal gold in traditional method are also solved; and the colloidal gold partly modified by the polyethylene glycol is expected to be widely used in nano-assembling and biosensing fields.

Description

technical field [0001] The invention belongs to the field of analytical chemistry, and in particular relates to colloidal gold partially modified with polyethylene glycol and a preparation method thereof. Background technique [0002] Colloidal gold is made from chloroauric acid (HAuCl 4 ) Nano-gold particles polymerized under the action of a reducing agent. These nano-gold particles are dispersed into a stable colloidal state in the solution due to electrostatic interaction, so they are called colloidal gold. Human beings' understanding of colloidal gold can be traced back to 1857. The famous British physicist and chemist Michael Faraday prepared colloidal gold from chloroauric acid aqueous solution by reduction method, and found the colloidal gold solution in electrolyte solution. Discoloration phenomenon. With the development of modern nanotechnology, colloidal gold has been widely used in various fields of physics, chemistry and life sciences, including self-assembly o...

AI Technical Summary

Problems solved by technology

However, the colloidal gold prepared by the sodium citrate reduction method has the following disadvantages in practical application: firstly, the stability of the colloidal gold is greatly affected by the buffer electrolyte

Especially in the case of high salt concentration, due to the partial charge on the surface of gold nanoparticles being neutralized, gold nanoparticles are prone to agglomeration in solution, which may produce false positive or false negative detection results; the second , although the stability of colloidal gold in the electrolyte solution is enhanced after labeling biomacromolecules such as DNA or protein, but in the process of target molecule detection, the combination of colloidal gold and the target will lead to a large amount of colloidal gold agglomeration

As the aggregate increases, the charge on its surface gradually decreases, while the mass continues to increase, so it is difficult to exist in the form of a colloid in an aqueous solution, and it will be precipitated as the reaction time progresses, which is not conducive to Accurate determination of target substances (Small, 2012, DOI: 10.1002 / smll.201201061)

Third, the colloidal gold prepared by the traditional method is not very selective for the target when biomolecular labeling, and is prone to non-specific adsorption, thus affecting the accuracy of the analysis results

However, most of the currently reported methods are isotropically modifying the surface of gold nanoparticles with polyethylene glycol, so they cannot achieve directional reactions to the target, nor can they solve the problem of colloidal gold produced by the agglomeration of a large number of colloidal gold after the target is combined. Settlement problem

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