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An atmospheric-pressure plasma (APP) treatment was recently reported to render titanium (Ti) surfaces more suitable for osteoblastic cell proliferation and osteogenesis. However, the mechanism of action remains to be clearly demonstrated. In this study, we focused on cell adhesion and examined the effects of the APP treatment on the initial responses of human prenatal-derived osteoblastic cells incubated on chemically polished commercially pure Ti (CP-cpTi) plates. In the medium containing 1% fetal bovine serum, the initial cell adhesion and the actin polymerization were evaluated by scanning electron microscopy and fluorescence microscopy. The expression of cell adhesion-related molecules and osteoblast markers at the messenger RNA level was assessed by real-time quantitative polymerase chain reaction. Although the cells on the APP-treated CP-cpTi surface developed fewer cytoskeletal actin fibers, they attached with higher affinity and consequently proliferated more actively (1.46-fold over control at 72 h). However, most of the cell adhesion molecule genes were significantly downregulated (from 40 to 85% of control) in the cells incubated on the APP-treated CP-cpTi surface at 24 h. Similarly, the osteoblast marker genes were significantly downregulated (from 49 to 63% of control) at 72 h. However, the osteoblast marker genes were drastically upregulated (from 197 to 296% of control) in these cells by dexamethasone and β-glycerophosphate treatment. These findings suggest that the APP treatment improves the ability of the CP-cpTi surface to support osteoblastic proliferation by enhancing the initial cell adhesion and supports osteoblastic differentiation when immature osteoblasts begin the differentiation process.

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Nanoparticle-assembled hydroxyapatite (HA) hollow microspheres have a high surface area and are convenient to handle, owing to their characteristic structure. In this study we characterized the protein adsorption of HA hollow microspheres prepared from CaCl 2 and K 2 HPO 4 by a water-in-oil-in-water (W/O/W) emulsion method assisted by two surfactants: Span 80 and Tween 20. The HA hollow microspheres adsorbed bovine serum albumin, bovine γ-globulin, equine skeletal muscle myoglobin, and chicken egg white lysozyme in 10 mM sodium phosphate buffer (pH 6.8) in a Langmuir-type adsorption and desorbed the proteins in 800 mM sodium phosphate buffer (pH 6.8). The maximum adsorbed amounts of the HA hollow microspheres were 7.5–9.0 times higher than those of the microrods with a similar size range. The composite membranes of the HA microspheres and the poly( l -lactic acid) (PLLA) microporous membranes exhibited a high adsorption capacity for γ-globulin.

Poly(L-lactic acid) (PLLA) membranes prepared via a nonsolvent-induced phase separation method with a nonionic surfactant (Tween 80) have been applied as depth lters in the ltration of bacterial cell suspensions and mammalian cell broths. Finger-like pores captured the cells inside the membrane, avoiding the formation of a dense cell cake on the membrane surface. The ltration rate of lactic acid bacterial cell suspensions increased 4-5 times during depth ltration compared to that observed during screen ltration with a smooth surface. During depth ltration, the connected cellular structure as well as the nger-like pores captured the bacterial cells. The plots of the reciprocal of permeation ux vs. the permeate volume per unit ltration area suggest that capturing the bacterial cells in the pores resulted in reduced blocking constants during depth ltration compared to screen ltration. During the ltration of CHO cell broths, the cells were captured in the nger-like pores of the PLLA depth lter and on the screen lter membranes of cellulose acetate. The permeation ux was sustained at high levels for longer durations during depth ltration compared to screen ltration, although the initial ux was lower than that in screen ltration. The PLLA depth lter will be useful as a pre lter in the ltration of suspensions of compressible bacterial and mammalian cells.