Characterization of binding and uptake of biomimetic nanoparticles by flow cytometry

To establish a method for characterization of the nanoparticle-cell interaction without labeling, the changes in granularity of Caco-2 cells due to association of biomimetic nanoparticles, consisting of PLGA and wheat germ agglutinin (WGA), were monitored by side scattering using flow cytometry. The reliability was confirmed by a temperature-dependent linear correlation between side scatter data and cell-associated fluorescence intensities of cells loaded with fluorescent biomimetic nanoparticles. Moreover, not only the binding to but also the uptake of the nanoparticles into the cells was detected. Whereas the cell-binding of nanoparticles with lowest WGA-densities was controlled by temperature-dependent diffusional processes, the cytoinvasive properties of the WGA-corona prevailed at higher lectin densities. Due to the multiparametric character of the flow cytometric analysis useful additional information on the viability and agglomeration of cells is provided at the same time.