Ultra-Stable Plasmonic Colloidal Aggregates for Accurate and Reproducible Quantitative SE(R)RS in Protein-Rich Biomedia

Ziwei Ye, Chunchun Li, Qinglu Chen, Yikai Xu*, Steven Bell*

*Corresponding author for this work

Research output: Contribution to journalArticle


Au/Ag colloids aggregated with simple salts are amongst the most commonly used substrates in surface-enhanced (resonance) Raman spectroscopy (SE(R)RS). However, salt-induced aggregation is a dynamic process, which means that SE(R)RS enhancements vary with time and that measurements therefore need to be taken at a fixed time point, normally within a short time-window of a few minutes. Here, we present an emulsion templated method which allows formation of densely-packed quasi-spherical Au/Ag colloidal aggregates. Since the particles in the product aggregates retain their weakly adsorbed charged ligands and the ionic strength remains low these charged aggregates resist further aggregation while still providing intense SE(R)RS enhancement which remains stable for days. This eliminates a major source of irreproducibility in conventional colloidal SE(R)RS measurements and paves the way for SE(R)RS analysis in complex systems, such as protein-rich bio-solutions where conventional aggregated colloids fail.
Original languageEnglish
Number of pages6
JournalAngewandte Chemie (International ed. in English)
Issue number2-8
Early online date25 Oct 2019
Publication statusEarly online date - 25 Oct 2019


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