Polystyrene latex nanoparticles (100 nm particle diameter for all surface chemistries) with different surface chemistries (unmodified, amine-modified, and carboxylatemodified) stock were prepared to maintain the same particle concentration (corresponding to a constant surface area of polystyrene nanoparticle) across all samples studied. Supplier provided equations were used to determine total nanoparticle concentration for consistent normalization of sample concentration across all three sample chemistries studied.