If they are already stabilized in PBS (phosphate buffered saline) with certain concentration of salts and given pH, then AuNPs have been already protected by a shell (most likely). Otherwise, buffered solution should kill them, if they are not protected.

Phosphine is the group that attached to AuNPs surface, but the charge of AuNPs is determined by functional groups attached to that phosphine.

To determine the charge - DLS + zeta-potential measurements. You will get zeta-potential that describes the potential produced by the molecules and ionic shells on your NPs and, thus, the stability of your colloidal solution.

Could you specify review on which topic (out of 4?!) you want to see?

Thanks you very much ! I had trouble with functionalize oligo thiol onto the PBS buffer gold. I followed normal protocol which specifies using for citrate gold. I am just curious why it does not work for the PBS gold.

I would like to review on: 

+ special properties of gold

+ ligand exchange on gold surface

+ local heating effect due to electromagnetic radiation

Best

Minh

So, because PBS buffered gold NPs are protected already.

Here they mentioned couple of application for hyperthermia treatment with gold: 10.1002/anie.201503384

What does it mean "special properties"? We have two reviews on using gold for electrocatalysis, for instant, 10.1039/C5SC00461F and 10.1021/acs.jpclett.7b00685