The International Organization for Standardization (ISO) recently published two standards for nanomaterials. ISO/TS 21633:2021, “Label-free impedance technology to assess the toxicity of nanomaterials in vitro,” describes a methodology of a label-free and real-time detection for non-invasive monitoring of cell-based assays to assess toxicity of nanomaterials to eukaryotic and prokaryotic cells. ISO/TS 23034:2021, “Nanotechnologies — Method to estimate cellular uptake of carbon nanomaterials using optical absorption,” describes a near-infrared optical absorption method to estimate the in vitro cellular uptake of carbon nanomaterials, including both internalized and/or tightly adhered to the cell membrane from liquid dispersions. ISO states that “[t]his is a simple method to screen carbon nanomaterials uptake; additional analysis using a different technique can be required if quantification is desired.”