Various techniques are employed to study the uptake of nanoparticles: 1. Fluorescence Microscopy: Uses fluorescently labeled nanoparticles to visualize their distribution within cells. 2. Electron Microscopy: Provides high-resolution images of nanoparticle localization at the cellular and subcellular levels. 3. Flow Cytometry: Measures the uptake of fluorescent nanoparticles by analyzing cell populations. 4. Mass Spectrometry: Quantifies nanoparticles within biological samples by measuring their elemental composition.