Flow Cytometry-Based Quantification of Cellular Au Nanoparticles.

There has been a great deal of research regarding the cellular association of nanoparticles (NPs), although there are only a few methods available yet for the quantitative measurements of cellular NPs. In this study, we propose a simple and quantitative method to estimate the cellular uptake of Au NPs into cervical cancer cells (HeLa) based on their side scattering (SSC) intensities measured by flow cytometry (FCM). We have compared SSC intensities of HeLa cells exposed to eight different types of Au NPs (40-100 nm size, with positive or negative surface charge) with the amount of cellular Au NPs measured by inductively coupled plasma mass spectrometry (ICPMS). On the basis of these comparisons, we have found linear correlations between the cellular Au NPs and the SSC intensities and used them to estimate the amount of Au NPs associated with HeLa cells. Once the correlations were found for specific cell lines and types of nanoparticles, this approach is useful for simple and quantitative estimation of the cellular Au NPs, without performing labor-intensive and complicated sample preparation procedures required for the ICPMS approach.