In order to quantify the effect of the substrata surface topography on cellular behaviour, planar and micro-textured silicon substrata were produced and made suitable for cell culture by radio frequency glow discharge treatment. These substrata possessed parallel surface grooves with a groove and ridge width of 2.0 (SÍID02), 5.0 (SÍID05) and 10/¿m (SÍID10). Groove depth was approximately 0 .5 /m Rat dermal fibroblasts (RDFs) were cultured on these substrata and a tissue culture polystyrene control surface for 1, 2, 3, 5 and 7 days. After incubation the cell proliferation was quantified with a Coulter Counter, and RDF size, shape and orientation with digital image analysis. Cell counts proved that neither the presence of the surface grooves nor the dimension of these grooves had an effect on the cell proliferation. However, RDFs on SIID02, and to a lesser extent on SÜD05 substrata, were elongated and aligned parallel to the surface grooves. Orientation of the RDFs on SÍID10 substrata proved to be almost comparable to the SIID00 substrata. Finally, it was observed that the cells on the micro-textured substrata were capable of spanning the surface grooves. © 1996 Elsevier Science Limited Correspondence to E.T. den Braber.Most of the studies are focussed on the role of contact guidance in fundamental organogenesis phenomena like surface implanted biomaterials has only been recognized for last few years. Brunette et a l"'l0, for example, the micro-e implant surfaces to prevent epithelial downgrowth around skin-penetrating devices. Campbell and von Rocum11 described the use of surface micro-patterns as a tool to implantreduce the inflammatory response at tissue interface. Although these studies have provided important information, the fundamental mechanism of, and optimal parameters for, cell control by guidance are still unknown. In addition, the reported results are often based on subjective, qualitative observations. To surpass this lack of knowledge it is evident that a systematic study of the influence of surface topography on the cellular behaviour is required. Therefore, the objective of our studies is to approach this guidance principle in a more orderly way.In our first study12 we reported on the surface treatment on the wettability of surfaces and on 1093

To evaluate the effect of surface treatment and surface mi crotexture on cellular behavior, sm ooth and microtextured silicone substrata were produced. The microtextured sub strata possessed parallel surface grooves w ith a width and spacing of 2.0 (SilD02), 5.0 (SilDOS), and 10 [xm (SilDIO), The groove depth w as approxim ately 0.5 [xm. Subse quently, these substrata were either left untreated (NT) or treated by ultraviolet irradiation (UV), radiofrequency glow discharge treatment (RFGD), or both (UVRFGD). After characterization of the substrata, rat dermal fibroblasts (RDF) were cultured on the UV, RFGD, and UVRFGD treated surfaces for 1, 3, 5, and 7 days. Comparison be tween the NT and UV substrata revealed that UV treatment did not influence the contact angles and surface energies of surfaces with a similar surface topography. H owever, the contact angles of the RFGD and UVRFGD substrata were significantly smaller than those of the UV and NT sub strata. The dim ension of the surface microevents did not influence the wettability characteristics. Cell culture exper iments revealed that RDF cell growth on UV-treated sur faces w as lower than on the RFGD and UVRFGD substrata. SEM examination demonstrated that the parallel surface grooves on the SilD02 and SilDOS substrata were able to induce stronger cell orientation and alignm ent than the events on SilDIO surfaces. By combining all of our find ings, the most important conclusion was that p h ysico chemical parameters such as wettability and surface free energy influence cell growth but play no measurable role in the shape and orientation of cells on microtextured sur faces.

No abstract

No abstract

K E Y w 0 RD s. Transmission electron microscopy, X-ray microanalysis, energy dispersive, low X-ray background, extraneous X-rays, carbon-polymer, support grids, low-Z materials, low-cost production. S U M M A R YA simple and rapid procedure for the production of low-cost carbon-polymer support grids is described. These grids are particularly useful for X-ray microanalysis of thin specimens because of their low X-ray background properties. The grids can be prepared for immediate use, which guarantees constant quality.In electron probe X-ray microanalysis it is important to reduce the generation and detection of X-rays from outside the specimen area under study ('extraneous X-rays') (Panessa, 1979; Smits et al., 1979; Nicholson et al., 1982). To this end, materials of low atomic number, such as beryllium (Z=4), carbon (Z=6) or aluminium (Z=13), are often used for the construction and/or the covering of the specimen environment (Smits et al., 1979; Nicholson et al., 1982).Since the specimen support is the part the closest to the specimen, considerable effort should be made to ensure that the support contributes as little as possible to the detected X-ray intensity. For the X-ray microanalysis of thin specimens in T E M or STEM, film-coated grids are normally used for specimen support. Therefore, the support grids are also made preferably of low Z materials.Commercially available low Z grids are made of beryllium, of nylon, of aluminium or of carbon-polymer mixture. Beryllium grids are expensive and cleaning for re-utilization may be hazardous (Panessa, 1979). Nylon grids may suffer from poor film or specimen adhesion due to their woven texture and material properties. Moreover, thesc grids are not electrically conductive. Aluminium grids have a relatively high atomic number and produce, as a consequence, more X-rays when irradiated then the aforementioned grids. Carbon-polymer grids are conductive and do not impose toxicological problems, but the grids commercially available are expensive. Moreover, re-utilization is not practicable, since the grids become brittle with ageing. Here we describe a simple procedure we use for the production of low cost single-and multi-hole carbon-polymer support grids. The production of thc grids is rapid, making it simple to maintain a fresh stock.A mixture is made of spectroscopically pure carbon powder (quality RW-A; RingsdorffWerke, Bonn, F.R.G.) and a 2.5",, (wiw) solution of parlodion (grade A purified; Mallinckrodt, St Louis, U.S.A.) in amyl acetate (grade: Rein; Merck, Darmstadt, F.R.G.). We found that a carbon to parlodion ratio of 4 to 1 by weight gives the best results with respect to electrical conductivity and handling properties of the grids. When 1 ml of the mixture is spread out evenly j Y 1983 The Royal Microscopical Society 129