The effects of organo-clays on cell morphology

Anna Gromadzka, Stony Brook University Courteney Cannon Lenny Slutsky Lourdes Collazo Tatsiana Mironava Miriam Rafailovich

Abstract In the past ten years different nanotechnologies had made a significant impact in improving consumer products, electronics, biomedical devices and even personal care products. Recently, concerns have begun to surface as to their safety when in direct contact with biological tissue. Since the particle dimensions are much smaller than those of living cells, the concerns are centered on the ability of the particles to penetrate the cells and affect their functions. Clays are layered compounds that can be exfoliated into particles of nanoscale dimensions. They are used extensively in producing many consumer materials ranging from car parts to beauty supplies. Despite their wide use, very little is known regarding their interactions with cells. Therefore, in this experiment we focused on the cytotoxicity of nanoclays to osteoblast-like cells (MC-3T3-E1). Polydimethylsiloxane (PDMS) was utilized as a scaffold due to its wide range of medical applications and the results were compared with those of cells cultured on glass cover slips. The PDMS substrate was cross-linked in a ratio of 10:1. Additional samples were prepared where we added 0.5, 1.0, and 2.0 percent of Na clay. Cross-linked spherical plug molds were then made of each sample and placed in 24-well plates. Cell counts were obtained after 24 hours and four days. The cells were also stained and imaged under a confocal microscope (Leica-SP). We found that clay nanoparticles enhance cell growth rather than interfere with it on PDMS surfaces. The results will be discussed in terms of the clay concentration and culture time.

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