FAQs – Webinar on Gold nanoparticles

Our webinar  on gold nanoparticles focused on the optimization of conjugates and the importance of size, shape and surface properties in different applications. Thank you to everyone who attended, if you missed the webinar you can now watch it on demand.

There were many interesting questions posted in the Q&A session, here is a snapshot of some of the questions and answers:

1. Can you coat any gold particle?

A: There are many particles that we have not tested, but we have coated 40nm nanoparticles from all of the well-known suppliers. We have also used the coat with particles from 10nm to 80nm size.

2. Why use gold to make the nanoparticles? Can other metal be used to make nanoparticles?

A: Nanoparticles have been made from many different materials. Our webinar just focused on the properties and applications of gold nanoparticles, but the nanoparticle field is far broader.

3. What is the best Raman dye?

A: We have not done a huge amount of work on Raman, so I am probably not the best person to answer this question. However, Rhodamine 6G seems to be quite popular.

4. Is a disulphide as good as a di-thiol for the self-assembly approach?

A: Generally speaking, thiols give tighter binding than disulphides. So if you want a stable attachment probably the dithiol is better.

5. Is it possible to coat gold nanoparticle with fluorescent markers?

A: This is difficult to answer without knowing the specific materials in mind. If the fluorescent markers have thiol groups then there is a high probability that you could attach them to gold. Generally it is harder to attach small molecules that lack thiols, unless you use a pre-coated gold (e.g. InnovaCoat GOLD) which can have a range of functional groups. For example, a carboxylated molecule could be covalently attached to gold with an aminated surface.

6. Can I attach oligos to InnovaCoat GOLD?

A:Yes, the easiest option is to use the maleimide-gold derivative. You need a thiol on the oligo, but this can be added during synthesis.

7. Can the one-step conjugate kit be used with proteins, not antibodies?

A: We’ve optimised the kit for antibodies, but as long as your protein has lysines then in principle yes it can be used. You may need to try different amounts of protein to optimise the system.

8. Do you have to do covalent conjugation at different pH values?

A: No, it seems to be very different from the passive method. All reactions are done using the same conditions, the only variable is how much antibody you add, but we provide advice with the kit. It’s fairly predictable, generally you try just three amounts.

9. Can you provide bulk quantities of coated gold or do you just have a kit?

A: Yes, we coat 50,000 OD of gold at a time. We can freeze dry vials at any scale so the kit gets bigger bit the process stays the same. You just add the antibody to the freeze dried mixture.

10. At low and high pH value can gold particle disperse? Why?

A: If the particles all have the same charge you may see a repulsive effect. For example at high pH the surface may be negatively charged (similar to the situation with citrate ions). At low pH a net positive charge may be present, again resulting in repulsion of particles. I am not sure this is the explanation in your case, if you can send further details of your experiment we can perhaps comment further.


We are regularly developing new webinars on a variety of scientific topics that we believe will be interesting to our listeners. If you would like us to let you know about our upcoming webinars then please get in touch.

We would also love to hear from you if you have an area of interest that we haven’t yet covered, we will do our best to accommodate requests.

Find our list of webinars available to watch on demand here.