Nanoparticles have been under increasing investigation in many different fields (medicine, food industry, environmental science, etc) due to their potential in a variety of applications. These applications range from determining nanomedicine effectiveness, engineered nanomaterial safety assurance to quantifying nanoparticle uptake by cells.
Given the substance specific dependence of cellular uptake on size, shape, surface charge, temperature and media properties (presence of serum proteins, etc), determining the optimal conditions for the uptake of specific nanoparticles is of critical importance for pharmaceutical purposes.
This is especially important in the delivery of nanomedicine, where reduction of non-specific uptake via precise surface modification of the desired particles and the environment in which the uptake occurs is a key goal of researchers.
Various analytical techniques have been employed to assess nanoparticle uptake including transmission electron microscopy, inductively coupled plasma mass spectrometry, ICP-atomic emission spectrometry, confocal microscopy, transmission X-ray microscopy, whole cell tomography and so forth.
The advantages flow cytometry offers in comparision to the above methods are obvious – high throughouput, statistical power, measurement of individual cells rather than averaged signals, ease of sorting cells depending on uptake and other parameters, and non-destruction of the measured cells. Indeed, cells can be sorted via FACS and preserved for further analysis and experimentation.
Flow cytometer analysis is based on the measurement of light scattering (or fluorescence) if single particles (such as cells) in the flow stream. Since forward and side scattering vary depending on the size and complexity (respectively) of the cells, this can be used to differentiate, and sort different subpopulations. When nanoparticles are uptaken by cells their side scatter increases, enabling side scattering to be used to quantify nanoparticle uptake, both in mammalian cells and bacteria.
However, not all nanoparticles have an optimized light scattering response to the standard 488 nm excitation laser used in FACS (SSC channel). If you wish to apply all the myriad benefits of FACS to your own nanoparticle uptake research we at Merkel stand ready to recommend the devices and experimental parameters best suited to optimize your results and save you valuable research time.