A rapid and simple approach for the characterization and quantification of gold nanoparticles in cell culture medium by single particle-ICP-MS

Abstract

A rapid and simple methodology based on single particle-ICP-MS (SP-ICP-MS) has been developed for the study of gold nanoparticles (AuNPs) of different sizes in a cell culture medium commonly used in toxicological studies (Dulbecco's Modified Eagle Medium (DMEM) supplemented with 10% fetal bovine serum (FBS) and antibiotics as it is used in cell culture). Key instrumental parameters for the signal acquisition in single particle mode (e.g. dwell time and acquisition time) have been optimized. This new approach accomplishes the characterization and quantification of AuNPs in only one minute of analysis at concentrations in the ng L⁻¹ range with a minimum sample preparation because only dilution was required. Precise determinations of particle size and concentration (%RSD around 1%) were reported with 22.4 nm and 2.1 × 10⁵ particles per L as limit of detection for particle size (LOD_size) and for particle-number concentration (LOD_NP), respectively. AuNPs were incubated with DMEM at 37 °C at different times up to 96 h to study the possible transformations undergone in this medium. The incubation time had an effect on the concentrations (number- and mass-based), even though different trends for AuNP concentrations over time were observed depending on the AuNP size. However, no differences were observed regarding the particle size.