Apolipoprotein E (ApoE) particles are responsible for packing and transporting lipids throughout aqueous environments. We detail steps to assess in vitro particles forming from artificial membranes using right-angle light scattering and to measure their size using dynamic light scattering. We further describe how to generate in cellulo ApoE particles containing triacylglycerol under fatty-acid-induced stress. We also detail steps to isolate them from cell secretome by immunoprecipitation and analyze their lipid cargo by thin-layer chromatography. For complete details on the use and execution of this protocol, please refer to Lindner et al. (2022) : https://archive-ouverte.unige.ch/unige:160627