Gold nanoparticles ions release?

[Prof.Nikolai]

Several authors in various papers attribute the toxic effects of nanomaterials to the release of ions from the main nanostructure (nanoparticles, nanorods, etc.). This is easy to perceive in the case of metal oxides and in the case of metals such as silver (1st Ionization energy of silver: 731.0 kJ·mol⁻¹). About gold? Why gold nanoparticles induces toxic effects in living cells? It is possible that gold ions are released by gold nanoparticles (1st Ionization energy of gold: 890.1 kJ·mol⁻¹)?

[chilled_fluorine]

Several authors in various papers attribute the toxic effects of nanomaterials to the release of ions from the main nanostructure (nanoparticles, nanorods, etc.). This is easy to perceive in the case of metal oxides and in the case of metals such as silver (1st Ionization energy of silver: 731.0 kJ·mol⁻¹). About gold? Why gold nanoparticles induces toxic effects in living cells? It is possible that gold ions are released by gold nanoparticles (1st Ionization energy of gold: 890.1 kJ·mol⁻¹)?

 

Gold ions? I dunno... Doesn't sound to likely. You'd need something pretty reactive to go about getting gold ions...

[Enthalpy]

Same process as asbestos?

[Prof.Nikolai]

I also believe that the gold nanoparticles can not release ions. But the question is that I can not explain to myself the toxic effects. Some authors have demonstrated that the toxicity of the gold nanoparticles is due to their interaction with the proteins of lysosomes. So cell death is given by the blockade of vesicular trafficking (Quantitative Evaluation of Cellular Uptake and Trafficking of Plain and Polyethylene Glycol-Coated Gold Nanoparticles, Small 2010)

The lysosome has an internal pH of 4.0-4.5, can allow the ionization of gold?

Yet another question concerns the output of gold ions from the lysosome. The biological membrane is permeable to gold ions?

Thank you all for your help.

[chilled_fluorine]

I also believe that the gold nanoparticles can not release ions. But the question is that I can not explain to myself the toxic effects. Some authors have demonstrated that the toxicity of the gold nanoparticles is due to their interaction with the proteins of lysosomes. So cell death is given by the blockade of vesicular trafficking (Quantitative Evaluation of Cellular Uptake and Trafficking of Plain and Polyethylene Glycol-Coated Gold Nanoparticles, Small 2010)

The lysosome has an internal pH of 4.0-4.5, can allow the ionization of gold?

Yet another question concerns the output of gold ions from the lysosome. The biological membrane is permeable to gold ions?

Thank you all for your help.

 

Ph isn't always what makes something corrosive. But corrosive things often have an extreme ph. Why does aqua regia, but not perchloric acid dissolve gold? Perchloric is the stronger acid. I find it difficult to believe something organic with a ph of 4 could ionize gold. But I would like to be proven wrong. The toxicity is pretty much a mystery to me. If you knew what the other component of the ionic substance was, it would make this a much easier problem to solve. Unless you think you have pure gold ions. lol

[mississippichem]

Just a guess but Au(I) ions have a pretty strong affinity for sulphide ligands. Perhaps there could be some binding with protein cystine or methionine residues which would of course wreak havoc on said protein's tertiary or secondary structure, possibly altering or destroying the proteins intended functionality.

 

Again just a guess but at least there is some logical grounding to my speculation.

 

I have a feeling that to investigate the effects of the whole nanoparticle we will need to consider some quite complicated zeta potential effects and macromolecular crowding as the trends of interest are probably not quite as simple as the comparison of ionization energies.

[Prof.Nikolai]

I repeated the experiments to study the ionization of gold nanoparticles. The presence of gold ions in the solution of nanoparticles is due to the presence of metal gold. I have experimentally confirmed by TEM analysis that the gold nanoparticles do not ionize in lysosomes. The toxicity of this nanomaterial is very complex and it is due to multiple factors. Only in the case of metal oxides the ionization of nanomaterials explains the cause of their toxicity as demonstrated by Zhang, H. in their recent work "Use of metal oxide nanoparticle band gap to develop a predictive paradigm for oxidative stress and acute pulmonary inflammation" ACS Nano, 2012 May 22;6(5):4349-68