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Quantitative analysis of PEG-functionalized colloidal gold nanoparticles using charged aerosol detection.
Mackensie C Smith1, Rachael M Crist, Jeffrey D Clogston
1Nanotechnology Characterization Laboratory, Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA.
Analytical and Bioanalytical Chemistry
|March 10, 2015
Summary
Quantitative methods accurately measure polyethylene glycol (PEG) on gold nanoparticles, crucial for biocompatibility. New displacement and dissolution techniques precisely determine PEG quantity and presentation, surpassing qualitative assessments.
Area of Science:
- Nanotechnology
- Materials Science
- Biochemistry
Background:
- Surface characteristics of nanoparticles, like polyethylene glycol (PEG) functionalization, are vital for biocompatibility.
- Conventional methods (UV-vis, DLS, zeta potential) offer only qualitative assessment of PEG on gold nanoparticles.
- Existing techniques lack sensitivity to differentiate PEG quantity, density, or presentation, hindering precise biocompatibility evaluation.
Purpose of the Study:
- To develop and validate quantitative methods for measuring PEG on PEGylated gold nanoparticles.
- To provide sensitive techniques capable of distinguishing differences in PEG quantity, density, and presentation.
- To enable accurate assessment of both total and fractionated (bound vs. unbound) PEG for improved biocompatibility predictions.
Main Methods:
- A displacement method using dithiothreitol to detach PEG from gold surfaces, followed by RP-HPLC separation and charged aerosol detection.
- A dissolution method using potassium cyanide to dissolve gold nanoparticles, liberating PEG for RP-HPLC separation and charged aerosol detection.
- Validation using 2-, 5-, 10-, and 20-kDa PEGylated 30-nm colloidal gold nanoparticles.
Main Results:
- Developed two quantitative methods (displacement and dissolution) for PEG measurement on gold nanoparticles.
- Successfully quantified PEG using charged aerosol detection against a standard curve.
- Demonstrated the ability to differentiate and quantify both total PEG and distinct bound/unbound PEG fractions.
Conclusions:
- The displacement and dissolution methods provide accurate, quantitative measurements of PEG on gold nanoparticles.
- These techniques offer superior sensitivity compared to conventional methods for assessing PEGylation.
- Quantifying bound and unbound PEG fractions is critical for understanding and predicting nanoparticle biocompatibility.
