With extensive development of nanotechnology in last few years, scientists have discovered that nanoparticles (NPs) can be used as an efficient Drug Delivery System (DOS). In order to develop better NPs based drug delivery tool, it is imperative to understand the interaction between the NPs and the cell membrane. In our earlier studies, cerium oxide nanoparticles (CNPs) have been reported to have therapeutic properties, specifically against abnormalities associated with oxidative stress. Therefore, CNPs with different sizes and morphology were selected to understand the interaction with cell. We analyzed the mechanical property of human nasal septum tumor cells membranes using Atomic Force Microscopy (AFM) with and without CNPs. In particular, Force-Distance spectroscopy mode was used to estimate the elasticity of cells membrane. Different concentrations (0, 50, 125 and 250 µM) of CNPs were added to the cells (squamous cells; CCL30) and incubated for different time periods (0, 15, 30 and 60 minutes). Cell membrane elasticity/Young's modulus was calculated using a modified Hertz model. Changes in the cell elasticity were observed in high concentration of CNPs when treated with one hour. Significant changes in cell elasticity were observed at high concentration of CNPs for one hour of incubation. No significant change in cell elasticity was observed over one hour time period for 50 µM of CNPs. Moreover, by using selected inhibitors to block different cell mediated internalization pathways, we also investigated the correlation between the cellular uptake and the tracking of NPs with their size. Specifically, similar change in cell elasticity was observed after blocking the cell energy production for CNPs with smaller diameter (3-5 nm). On the other hand, bigger size NPs (20-30 nm) showed no change in cell elasticity after blocking the cell energy production. These results indicate that 3-5 nm particles internalize cell by non-energy dependent pathway i.e. passive diffusion whereas 20-30 nm particles entered in cell by energy dependent pathways i.e. endocytosis of particles. Further, we have also identified the cellular uptake of 20-30 nm particles is by enclosing those CNPs in membrane vesicles in caveolae-mediated endocytosis mechanism. In summary, these results indicate that the nanoparticles-cell interaction has pronounced influence on the shape and size of the nanoparticles. These interactions can be further monitored by real time mechanical property measurement of cell membrane.


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Graduation Date





Seal, Sudipta


Master of Science in Materials Science and Engineering (M.S.M.S.E.)


College of Engineering and Computer Science


Materials Science Engineering

Degree Program

Materials Science and Engineering








Release Date

May 2015

Length of Campus-only Access


Access Status

Masters Thesis (Open Access)


Dissertations, Academic -- Engineering and Computer Science; Engineering and Computer Science -- Dissertations, Academic