Introduction: Cellular nanomechanics has been proved to play important roles in regulating cell behaviors and showing great potential for cancer diagnosis and therapy[1]. However, conventional measurement of cell nanomechanics that is processed on non-patterned surface lacks control of cell morphology that significantly influence cellular nanomechanical properties. In this study, we prepared micropatterned surfaces by photolithography to provide controllable and reproducible cell morphology. Using the micropatterned plates, we compared the nanomechanics of mesenchymal stem cells (MSCs), osteoblasts (NHOst) andosteosarcoma (MG-63) on the same surface.
Materials and Methods: Photo-reactive PVA micropatterned TCP surfaces were prepared as previously described[2]. MSCs, NHOst and MG-63 cells were then seeded onto the micropatterns and cultured for 1 d before AFM test. Elasticity and non-specific adhesion force were calculated from the force curves. F-actin was stained to show the cytoskeleton of the micropatterned cells. Ezrin staining and surface scanning were performed to characterized cell membrane properties. Cell migration was test based on a newly developed ‘contact transfer assay’.
Results and Discussion: Elastic modulus of MSCs and osteoblasts increased with increase of spreading area due to the ordering of cytoskeleton. Disrupting F-actin assembly by cytochalasin D treatment reduced cell elasticity. Meanwhile, cell spreading area influenced the expression of phosphoezrin that affects cell surface roughness. Rough cell membrane was accompanied with high non-specific adhesion force and migration rate. However, MG-63 cells behaved less dependently on their microenvironment as their cytoskeleton did not change much by manipulating spreading area (Figure 1).
Conclusion: In this study, the micropatterns were prepared and used for comparasion of nanomechanics of normal and cancer cells. Our findings suggest that the nanomechanical differences between normal and cancer cells can be used as a biomarker to assist diagnosis of cancer. The use of micropatterns should be very useful to compare the nanomechanics of cells on the same surface.
This work was supported by the World Premier International Research Center Initiative on Materials Nanoarchitectonics and JSPS KAKENHI Grant Number 24300177 and 15J01781 (Grant-in-Aid for Scientific Research (B)).
References:
[1] QS. Li, GYH. Lee, CN. Ong, CT. Lim. Biochem. Biophys. Res. Commun.2008, 374, 609.
[2] X. Wang, W. Song, N. Kawazoe, G. Chen, Soft Matter2012, 9, 4160.