How does HEPES contribute to the formation and stability of gold nanostars?

Gold nanostars, there may be many people who don’t know what it is. Gold nanostars refer to gold particles that are shaped into stars. The gold particles can be sent to a tumor, and then manipulated by a laser or magnetic field, and ultimately destroy them by heating the malignant tumor cells. Nano Venus makes the burning hotter. Nano-Venus is a new material for attacking cancer. Now, researchers point out that gold particles can burn even hotter if they are shaped into stars.

Among them, the common method for synthesizing gold nanostars is the non-nuclear and surfactant-free strategy using Good’s buffers HEPES, EPPS and MOPS. These reagents can be used as metal reducing agents, shape directing agents and stabilizers. Nanostars of different sizes and structures can be obtained by adjusting the buffer concentration and the pH of the solution. And what is the connection between HEPES and gold nanostars?

Although HEPES is conducive to the formation and structural stability of gold nanostars, we know very little about the interaction between HEPES and metals. Recently, the remodeling of gold nanostars induced by acidification has been studied, and it was found that its morphology depends on pH and acid composition, and is also affected by the protonation state of HEPES. The zeta potential and DFT method were used to measure the change of the molecular proton state. Surface enhanced Raman (SERS) revealed that the change of pH induces the reversible activation of the amine and sulfonic acid groups of HEPES, and the redistribution of electrons weakens the affinity of HEPES to metals, thereby facilitating adsorption.

Experimental results show that the reconstruction of gold nanostars depends on the protons in the solution, which is consistent with the decomposition behavior of nanospheres with a diameter of about 6 nanometers under acid induction. In addition, the strength and reconstruction rate of gold nanostars have a certain relationship with the affinity of anions and gold. Through research on the related effects of gold nanostars and HEPES, it is found that HEPES is partially substituted by benzene. When benzene adsorption or the chemical enhancement related to the sulfonic acid group of HEPES weakens, HEPES will reorient. The study speculated that the partial desorption of HEPES and the change of electron distribution caused the reorientation.

Hubei New Desheng Materials Co., Ltd. specializes in biochemical raw material manufacturers. It can provide various specifications of biological buffers HEPES, Tris, BICINE, CAPS, TAPS, etc., chemiluminescence reagents, blood collection tube additives, chromogen substrates, enzyme preparations, antigens Antibodies, carbomers, etc., please call for more details!