Gradient Polyethylene Surfaces Research Articles

Cellular Behavior of Human Adipose-Derived Stem Cells on Wettable Gradient Polyethylene Surfaces

Appropriate surface wettability and roughness of biomaterials is an important factor in cell attachment and proliferation. In this study, we investigated the correlation between surface wettability and roughness, and biological response in human adipose-derived stem cells (hADSCs). We prepared wettable and rough gradient polyethylene (PE) surfaces by increasing the power of a radio frequency corona discharge apparatus with knife-type electrodes over a moving sample bed. The PE changed gradually from hydrophobic and smooth surfaces to hydrophilic (water contact angle, 90º to ~50º) and rough (80 to ~120 nm) surfaces as the power increased. We found that hADSCs adhered better to highly hydrophilic and rough surfaces and showed broadly stretched morphology compared with that on hydrophobic and smooth surfaces. The proliferation of hADSCs on hydrophilic and rough surfaces was also higher than that on hydrophobic and smooth surfaces. Furthermore, integrin beta 1 gene expression, an indicator of attachment, and heat shock protein 70 gene expression were high on hydrophobic and smooth surfaces. These results indicate that the cellular behavior of hADSCs on gradient surface depends on surface properties, wettability and roughness.

Adhesion comparison of human bone marrow stem cells on a gradient wettable surface prepared by corona treatment

Corona discharge treatment was applied to modify the surface of polyethylene (PE). The wettability of PE surface was gradually increased by power increase of a corona treatment along the PE length, indicating that the hydrophilicity of PE surface increased gradually. The adhesion and proliferation behavior of human bone marrow stem cells (hBMSCs) on the gradient PE surface was evaluated. We found that hBMSCs were adhered to and proliferated on better highly hydrophilic than hydrophobic surfaces. The plot of proliferation rate vs. the water contact angles was parabolic. These results indicate that surface wettability plays an important role in the cell attachment and proliferation.

Preparation of a polymer surface coated with a gradient of quantum dots

In the present study, we generated a polyethylene surface coated with a gradient ofquantum dots for use in imaging experiments. The polyethylene surface was first treatedwith increasing coronal discharge along its length. Next, the surface was reactedwith branched polyethyleneimine followed by biotin to produce a polyethylenesurface with a gradient of biotin. Finally, the biotin-coated surface was reactedwith streptavidin-coated quantum dots. Fluorescent imaging showed that thefluorescence intensity from the quantum dots gradually increased along its length. Suchquantum-dot-modified gradient polyethylene surfaces may be useful in biomedical analyses.

Quantum dots-modified gradient polymer surface

In this work, biotinylated gradient polyethylene (PE) surface was designed to bind a Q-dot streptavidin. Firstly, gradient PE surface was prepared by increasing corona treatment along the PE length. The gradient surface was treated with polyethyleneimine and then biotin. The biotinylated gradient PE surface gave Q-dot-modified gradient PE surface through binding of Q-dot streptavidin with biotinylated gradient PE surface. Q-dot-modified gradient PE surface displayed red fluorescence upon photoirradiation. The red fluorescence that corresponded to a Q-dot streptavidin on the biotinylated gradient PE surface increased gradually on the surface along the PE length. We believed that Q-dot-modified gradient PE surfaces might be applied as a nanotechnology analysis tool in the biomedical application.

Preparation and Characterization of Amine-modified Gradient Polyethylene Surfaces

Abstract A gradient polyethylene (PE) surface was created through corona treatment, in which the corona power increased along the 5-cm length of the PE. The gradient PE surface was treated by amines with varying molecular weights. TOF–SIMS results exhibited the gradient surface images and intensities before and after amine modification on the corona-treated PE surface.

ToF-SIMS imaging of gradient polyethylene and its amine-functionalized surfaces

A ToF-SIMS imaging technique has been used to obtain dye label-free chemical images of gradient polyethylene (PE) and its amine-functionalized surfaces. The gradient PE surface was prepared by a corona treatment with a power increase along the PE length and confirmed by ToF-SIMS. Amine reagents with varying molecular weights (MW 158, 600, 1200, 10,000 and 60,000) were successively reacted with a gradient PE surface and examined using ToF-SIMS. Our work found that the lower the molecular weight of amine reagent, the more gradient surface of amine surface density was generated. The amine-functionalized gradient surface can be used as a template surface for evaluating bioactive molecules on the gradient surface in just one experiment.

First Preparation of Biotinylated Gradient Polyethylene Surface to Bind Photoactive Caged Streptavidin

A gradient polyethylene (PE) surface was created through corona treatment, in which the corona power increased along the 5 cm length of the PE. The gradient surface was treated with polyethyleneimine and then biotin. Fluorescein-conjugated streptavidin (SAV) caged within 5-carboxymethoxy-2-nitrobenzyl (CMNB) adsorbed onto the biotinylated gradient PE surface following molecular recognition principles. Photoirradiation decomposed the CMNB cage and allowed the fluorescein-conjugated SAV to fluoresce, the intensity of which increased gradually along the PE surface.

Preparation of a Gradient Biotinylated Polyethylene Surface To Bind Streptavidin−FITC

A novel biotinylated gradient surface was designed to bind a streptavidin-FITC. The gradient polyethylene (PE) surface was prepared by a corona treatment with a power increase along the PE length, and successively, biotinylated gradient PE surface was prepared by the reaction of polyethylenimine (PEI) and biotin. Surface properties of the gradient PE surface changed according to PE length and chemical modification. The biotinylated gradient PE surface provided a continuous gradient of streptavidin-FITC through binding of avidin-biotin. The luminosity of fluorescence that corresponds to a streptavidin-bound FITC on the biotinylated gradient PE surface increased gradually on the surface along the PE length.

Proliferation rate of fibroblast cells on polyethylene surfaces with wettability gradient

AbstractSurface wettability on anchorage‐dependent cells has an important role in cell growth rate. In our previous studies, we prepared a wettability gradient on polyethylene (PE) surfaces using corona discharge treatment from a knife‐type electrode whose power increased gradually along the sample length. The PE surfaces were oxidized gradually with increasing power and characterized by Fourier transform infrared spectroscopy, contact angle goniometry, and electron spectroscopy for chemical analysis. The purpose of this study is to determine the rate of proliferation on polymer surfaces with different wettability. The behavior of cell growth for NIH/3T3 fibroblast cells attached on the polymer surfaces with different hydrophilicity was investigated using wettability gradient PE surfaces prepared by corona discharge treatment. They were investigated for the number of grown cells from 24 to 60 h in terms of surface wettability. From the slope of cell number on PE gradient surface versus culture time, the proliferation rates (number of cell/cm2 · h) were calculated. It was observed that the proliferation rate was increased more on positions with moderate hydrophilicity of the wettability gradient surface than on the more hydrophobic or hydrophilic positions, i.e., 1111 (number of cell/cm2 · h) of 57° of water contact angle at the 2.5‐cm position (P < 0.05). This result seems closely related to the serum protein adsorption on the surface: the serum proteins were also adsorbed more on the moderately hydrophilic surface. In conclusion, surface wettability plays an important role in cell adhesion, spreading, and proliferation on the polymer surfaces. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 599–606, 2004

The effect of surface wettability on induction and growth of neurites from the PC-12 cell on a polymer surface

Surface properties of polymeric devices that are used to regenerate nervous damage are a point to be considered for axon regeneration in nerve system. In our previous studies, we prepared a wettability gradient on polyethylene (PE) surfaces using a corona discharge treatment from a knife-type electrode whose power increases gradually along the sample length. The PE surfaces were oxidized gradually with increasing power. The effect of surface wettability on the different types of cells has an important role for cell adhesion and proliferation. The purpose of this study is to investigate neurite formation on polymer surfaces with different wettability. Induction and growth of neurites from the rat pheochromocytoma (PC-12) cells attached on the polymer surfaces with different hydrophilicity were investigated using the wettability gradient PE surfaces prepared by a corona discharge treatment. Neurites were investigated for number and length of neurites in terms of surface wettability. It was observed that neurite formation of PC-12 cells was increased more onto the positions with moderate hydrophilicity of the wettability gradient surface than onto the more hydrophobic or hydrophilic positions. From those results, it could be assumed that initial adhesion of PC-12 cells was caused by more calf serum (CS) protein than nerve growth factor (NGF), whereas the neurite formation of PC-12 cells was caused by more NGF than CS protein. It follows from what has been said thus far that PC-12 cells are a differentiated neuronal phenotype with a long neurite at around the position 2.5 cm (water contact angle of about 55 deg). In conclusion, surface wettability plays an important role for neurite formation on the polymer surfaces for axon regeneration.

Adhesion of blood platelets under flow to wettability gradient polyethylene surfaces made in a shielded gas plasma

Adhesion and activation of platelets are important steps in the thrombosis of blood after contact with a biomaterial surface and are governed, in part, by the wettability of the surface. Since most implanted devices are in contact with blood under flow conditions, it is important to study the effect of wettability of device surfaces on the behavior of platelets also under flow. To this end, wettability gradient polyethylene surfaces were prepared through glow discharge with partial shielding over a length of 5 cm, with advancing water contact angles varying from 95 to 45 degrees and a contact angle hysteresis of 30 degrees. The role of blood flow on the adhesion of platelets was examined by incubating these gradient surfaces in anticoagulated, whole human blood under static conditions or in blood under a flow of 10 or 40 ml/min through a 3 mm diameter circuit or for 5 or 15 min with either the hydrophobic or hydrophilic end upstream. Generally, more platelets adhered on the hydrophilic end of the wettability gradient than on the hydrophobic end, although the increment along the wettability gradient was dependent on both the flow conditions and direction. More platelets adhered under a flow of 10 ml/min than under static conditions, due to higher mass transport. Especially when the hydrophilic end was upstream, there was a more pronounced adhesion. This can be explained in terms of immediate platelet activation by shear stress imposed at the upstream end. During flow of 40 ml/min, platelet adhesion on an upstream hydrophilic end was less than on a downstream hydrophilic end. We conclude that platelets detach from the hydrophilic end at high shear stress due to the spherical form of adhered platelets. Platelets on the hydrophobic end could withstand detachment by strong, flat shaped platelet-material contact.