Poly(ethylene glycol) (PEG) with thiol functionality is routinely used to provide a non-immunogenic, passivating, bio-compatible coating on gold nanoparticles to provide long-term colloidal stability in biological environment. Variability in these coatings/stability can influence biocompatibility and altered biodistribution. Different molecular weights of PEG are used in different products and are often difficult to quantify as unmodified PEG are non-chromophoric, requiring a lot of sample. Accurate quantitation of these coatings with sensitive methods is critical for quality control for medical products. This test method describes a protocol for quantitative assessment of PEG coating on gold nanoparticles or gold nanorods, with commonly available HPLC instrumentation in analytical laboratories with ELSD detection.
Gold nanomaterials are being developed as therapeutic agents for cancer research and for other medical products. Assessing the safety and efficacy of gold nanoparticles requires characterization using standard test methods. This test method is critical to the development of gold nanoparticle-based medical products by industry and the review of such products by regulatory agencies.
The title and scope are in draft form and are under development within this