Caveats to the use of MTT, neutral red, Hoechst and Resazurin to measure silver nanoparticle cytotoxicity.

Journal Article (Journal Article)

The extensive use of silver nanoparticles (AgNPs) in manufactured products will inevitably increase environmental exposure, highlighting the importance of accurate toxicity assessments. A frequent strategy to estimate AgNP cytotoxicity is to use absorbance or fluorescent-based assays. In this study we report that AgNPs - with or without surface functionalizations (polyvinyl pyrrolidone or gum arabic), and of different sizes (2-15 nm) - can interfere with the spectrometric quantification of different dyes commonly used in cytotoxicity assays, such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), neutral red (NR), Hoechst, and Resazurin. Some AgNP types caused more interference than others, which was dependent on the assay. Overall most AgNPs caused the direct reduction of MTT, as well as Hoechst and NR fluorescence quenching, and absorbed light at the same wavelength as NR. None of the AgNPs tested caused the direct reduction of Resazurin; however, depending on AgNP characteristics and concentration, they may still promote fluorescence quenching of this dye. Our results show that AgNPs with different size and coatings can interfere with spectroscopy-based assays to different degrees, suggesting that their cytotoxicity may be underestimated or overestimated. We suggest that when using any spectroscopy-based assay it is essential that each individual nanoparticle formulation be tested first for potential interferences at all intended concentrations.

Full Text

Duke Authors

Cited Authors

  • Mello, DF; Trevisan, R; Rivera, N; Geitner, NK; Di Giulio, RT; Wiesner, MR; Hsu-Kim, H; Meyer, JN

Published Date

  • January 2020

Published In

Volume / Issue

  • 315 /

Start / End Page

  • 108868 -

PubMed ID

  • 31669321

Pubmed Central ID

  • PMC7028487

Electronic International Standard Serial Number (EISSN)

  • 1872-7786

International Standard Serial Number (ISSN)

  • 0009-2797

Digital Object Identifier (DOI)

  • 10.1016/j.cbi.2019.108868


  • eng