Additional file 4: Figure S4. of Rational design of Raman-labeled nanoparticles for a dual-modality, light scattering immunoassay on a polystyrene substrate

SERS probe stability and optical response. The stability of the SERS probes was determined by measuring the optical response of the probes before and after the addition of the SH-PEG. SERS probes fabricated using the synthesis methods described previously were stable for at least 1 month when stored at 4 °C. When SH-PEG was added to the gold nanoparticle solution, it did not significantly displace the Raman reporter. In addition, the aggregation state, optical response, and protein function were not adversely affected by centrifugation. (PDF 163 kb)