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Mechanobiology of Disease
Poster Abstracts
86
44-POS
Board 44
Optical Measurements on the Variations of Neuronal Cell Membrane Roughness in
Response to External Treatments
Chia-Wei Lee
1
, Huei-Jyuan Pan
1
, Lan-Ling Jang
1
, Chau-Hwang Lee
1,2,3
.
1
Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan,
2
Institute of
Biophotonics, National Yang-Ming University, Taipei 11221, Taiwan,
3
Department of Physics,
National Taiwan University, Taipei 10617, Taiwan.
Living cells exhibit many topographic features that depend heavily on membrane properties as
well as cytoskeleton configurations. Membrane roughness measured by atomic force microscopy
(AFM) was long proposed as a diagnostic parameter for determining the status of a cell under
external physical or chemical stimulations. However, the imaging speed of AFM is far below the
requirement of high-content screening. In this study, we proposed to use a wide-field optical
profiling technique, non-interferometric wide-field optical profilometry (NIWOP), to quantify
the membrane roughness of mouse neuroblastoma cells (N2a). The NIWOP technique can
acquire membrane roughness of all cells in a field of view within a few seconds. This speed is
much more adequate for obtaining statistical results in a reasonable period.
We treated the N2a cells by 10 uM paclitaxel (Taxol), and found that the membrane roughness
was significantly decreased. A similar trend was observed on fixed cells by using scanning
electron microscopy (SEM). Membrane stiffness increased by Taxol and microtubule
translocation might both take parts in this result. We also found that the membrane roughness
showed transient increase under the hypertonic condition with 75 mM sucrose in the culture
medium. Meanwhile, treatments of oppositely charged gold nanoparticles (AuNPs, 30 nm) were
also executed. Positively charged AuNPs decreased the membrane roughness, while negatively
charged AuNPs showed insignificant effects. We also confirmed that the adsorption efficiency of
positively charged AuNPs on cell membranes was much higher than that of negatively charged
AuNPs by using SEM.
In conclusion, we demonstrated that wide-field optical profilometry could acquire the membrane
roughness of a group of living cells in a few seconds. The membrane roughness reflected the
variations in cytoskeleton configurations, membrane tension, as well as the membrane affinity of
nanoparticles.