Hi, I'm planning on adapting the methodology from this paper (http://www.nature.com/nprot/journal/v3/n2/full/nprot.2008.1.html) in order to produce a visual color change for the addition of an antigen to a solution of the conjugate (AuNP+Antibody).

I was wondering if

1. i could use a NH2-PEG-SH linker

2. whether the color change would be visible at those concentrations

3. if there is anyone who has any other advice or improvements

Thanks