Orthogonal Analysis of Functional Gold Nanoparticles for Biomedical Applications

Published

September 11, 2015

Author(s)

De-Hao D. Tsai, Yi-Fu Lu, Frank W. DelRio, Tae Joon Cho, Suvajyoti S. Guha, Michael R. Zachariah, Fan Zhang, Andrew J. Allen, Vincent A. Hackley

Abstract

We report a comprehensive strategy based on implementation of orthogonal measurement techniques to provide critical and verifiable material characteristics for functionalized gold nanoparticles (AuNPs) used in biomedical applications. Thiolated polyethylene glycol (SH-PEG)-conjugated AuNPs with different terminal groups (methyl-, carboxylic-, and amine-) were chosen as a model system due to their high relevancy in nanomedicine. Electrospray-differential mobility analysis, asymmetric-flow field flow fractionation, transmission electron microscopy, scanning electron microscopy, atomic force microscopy, inductively coupled plasma mass spectrometry, and small-angle X-ray scattering were employed to provide both complementary and orthogonal information on (1) particle size and size distribution, (2) particle concentration, (3) molecular conjugation properties (i.e., conformation and surface packing density), and (4) colloidal stability. Samples were analyzed before and after ≈ 50 months of cold storage. Results show that SH-PEGs are stably conjugated on the surface of AuNPs to form a brush-like polymer corona. The surface packing density of SH-PEG is ≈ 0.42 nm-2 for the methyl-SH-PEG AuNPs, ≈ 0.26 nm-2 for the amine-SH-PEG AuNPs, and ≈ 0.18 nm-2 for the carboxylic-SH-PEG AuNPs prior to cold storage. By analyzing the change in particle size distribution and number concentration in solution following cold storage, the long term colloidal stability is shown to be substantially improved via functionalization with methyl-SH-PEG and carboxylic-SH-PEG. The work described here provides a generic strategy to track and analyze the material properties of functional AuNPs intended for biomedical applications, and highlights the importance of a multi-technique analysis. The effects of long term storage on the physical state of the particles, and on the stability of the ligand-AuNP conjugates, are employed to demonstrate the capacity of this approach to address critical issues.

Citation

Analytical and Bioanalytical Chemistry

Volume

407

Issue

28

Pub Type

Journals

Download Paper

https://doi.org/10.1007/s00216-015-9011-9

Local Download

Keywords

gold nanoparticle, polyethylene glycol, functionalization, stability, biomedical, nanomedicine, cold storage, particle size, conjugation

Citation

Tsai, D. , Lu, Y. , DelRio, F. , Cho, T. , Guha, S. , Zachariah, M. , Zhang, F. , Allen, A. and Hackley, V. (2015), Orthogonal Analysis of Functional Gold Nanoparticles for Biomedical Applications, Analytical and Bioanalytical Chemistry, [online], https://doi.org/10.1007/s00216-015-9011-9, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=918793 (Accessed February 11, 2025)