Tris can be used for green synthesis of gold nanoparticles
Among the many metal nanomaterials, gold nanoparticles have good biocompatibility and molecular recognition functions, and have been regarded as the best carrier for the targeted transport of biomacromolecules, nucleic acid molecules or drug molecules in cells. Because there are some defects in the synthesis in many preparation methods, the researchers used tris (Tris) as a reducing agent for the first time to reduce the chloroauric acid solution under alkaline conditions, by adjusting the ratio of Tris and NaOH, and the reaction time And adding stabilizers to control the synthesis of stable gold nanoparticles, the particle size is between 15-47nm.
The influence of TRIS and NaOH on the synthesis of gold nanoparticles
Experiments have found that Tris can show its reducibility only under strong alkali conditions, and a small amount of NaOH cannot promote the reaction. A sufficient amount of NaOH solution must be added as a cofactor during the reaction, and the order of addition of NaOH will also have a great impact on the experimental results. NaOH can only be added to the chloroauric acid solution when it is mixed with Tris or after Tris. To complete the experiment. If NaOH is added to the chloroauric acid solution first, the reaction cannot proceed.
TRIS can be used as a stabilizer to synthesize gold nanoparticles
Experiments have found that the Tris-NaOH mixture reduces chloroauric acid, and a stable gold nanoparticle solution can be obtained regardless of the presence of stabilizers. It shows that Tris itself can also be used as a stabilizer in the reaction process, so the presence or absence of other stabilizers has little effect on the size of the gold nanoparticles. The difference is that after adding a small amount of sodium citrate, citrate is coated on the surface of the gold particles to make it The particle size becomes slightly larger, so the effect of sodium citrate in the reaction can be ignored.
Advantages of TRIS synthesis of gold nano-ions
The Tris ultrasonic method reduces chloroauric acid. The experimental operation is safe and simple, and the reaction conditions are mild. It will not cause pollution and damage to the environment. It is a "green" reduction method. Using Tris as the reducing agent, reducing the chloroauric acid solution under alkaline conditions, by adjusting the ratio of Tris and NaOH, the reaction time and adding stabilizers, stable gold nanoparticles can be synthesized.
Precautions for TRIS synthesis of gold nano-ions
(1) Tris can carry out the reduction reaction only under the promotion of NaOH, and it has a lot to do with the order of NaoH addition. The experiment can only be completed when it is mixed with Tris or added to the reaction solution after Tris. (2) Tris itself can As a stabilizer, there is no need to add other stabilizers.
(3) The reaction time will have a certain influence on the size of the gold nanoparticles. The longer the reaction time, the larger the particles formed. Temperature is the key factor for the success of the experiment. Tris cannot spontaneously reduce chloroauric acid to form Au at room temperature.
(4) During the reaction, 2ml Tris+2mlNaOH mixture can be reduced to produce relatively stable and dispersed gold nanoparticles. By adjusting the experimental conditions, it is possible to control the synthesis of monodisperse spherical gold nanoparticles of various sizes.
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