(334z) Magnetic Characterization and Quantification of Magnetic Nanoparticle Endocytosis Mechanisms By Particle Tracking Velocimetry

Magnetic characterization is of much importance in the fields of cell labeling, cell purification, cell physiology, endocytosis, biochemical micro assays, endosome research, cell separation, drug targeting, and in vivo diagnostics. The Hyperflux^TM velocimeter is utilized to measure magnetophoretic mobility, size and other morphological parameters of magnetic particles and labeled cells by particle tracking velocimetry. Magnetic cytometry by velocimetry records the motion of labeled cells in an isodynamic magnetic field thereby estimating the key parameter, magnetophoretic mobility of labeled cells. The calibration capability of the instrument has been extended in order to estimate the actual particle size and thereby estimating the intrinsic magnetic properties of several commercial beads. The optical density method and chain velocity method has been explored to estimate the magnetophoretic mobility of a single bead of nanoparticle chains. The rapid estimation of magnetophoretic mobility by the instrument and collection of multiple thousand data points facilitates cellular uptake quantification and kinetic studies in less time than any other existing technique. The receptor-independent uptake by cultured CHO (Chinese Hamster Ovary) cells of 100 nm iron oxide nanoparticles with different surface coatings, namely starch, amino groups, and polyethylene glycol (PEG 2K Daltons), was studied to reveal the role of nanoparticle endocytosis mechanisms. Caveolae-mediated and clathrin-coated endocytosis are revealed by using specific mechanism-based inhibitors. The cellular survival rate, toxicity, and uptake of nanoparticles during endocytosis by different mechanisms with the different surface coatings have been investigated. This research facilitates the rapid estimation of intrinsic magnetic properties, the optimization of MNP coatings, a better understanding of cell labeling, and different cellular endocytosis mechanisms.

Research Interests: magnetic cytometry, biomedical research, cell biology, semiconductor development, process intensification