Surface Nanoroughness Research Articles

Self-assembly of nanostructures towards transparent, superhydrophobic surfaces

High transparency is important to the performance of optical equipment and devices, such as windows, lenses, solar panels, and safety goggles. As many of them are constantly exposed to various environmental conditions, it is highly desirable to develop a self-cleaning coating that can prevent microbial growth, fouling, corrosion and icing. One of these technologies is superhydrophobic coating. In this review, we discuss recent progress in design, synthesis and fabrication of transparent, superhydrophobic surfaces. First, we revisit different models of superhydrophobicity and present the potential challenges in the nanofabrication of transparent superhydrophobic surfaces. We then discuss the general fabrication methods, including the top-down fabrication methods and self-assembly approaches, to create roughness with a size in the sub-visible wavelength with or without post-hydrophobilization steps. While top-down fabrication offers well-defined size and shape of surface topography, self-assembly is more versatile and could enable mass-production of nano-roughness on a wide range of substrates at a lower cost. Therefore, we focus on discussion of different self-assembly methods, including sol–gel processes, microphase separation, templating, and nanoparticle assembly, to create transparent, superhydrophobic surfaces. The review concludes with perspectives on future directions and challenges in manipulation of surface nanoroughness, specifically, using nanoparticles, for both high transparency and superhydrophobicity and their potential applications.

Fructose Enhanced Reduction of Bacterial Growth on Nanorough Surfaces

ABSTRACTBiofilms are a major source of medical device-associated infections, due to their persistent growth and antibiotic resistance. Recent studies have shown that engineering surface nanoroughness has great potential to create antibacterial surfaces. In addition, stimulation of bacterial metabolism increases the efficacy of antibacterial agents to eradicate biofilms. In this study, we combined the antibacterial effects of nanorough topographies with metabolic stimulation (i.e., fructose metabolites) to further decrease bacterial growth on polyvinyl chloride (PVC) surfaces, without using antibiotics. We showed for the first time that the presence of fructose on nanorough PVC surfaces decreased planktonic bacteria growth and biofilm formation after 24 hours. Most importantly, a 60% decrease was observed on nanorough PVC surfaces soaked in a 10 mM fructose solution compared to conventional PVC surfaces. In this manner, this study demonstrated that bacteria growth can be significantly decreased through the combined use of fructose and nanorough surfaces and thus should be further studied for a wide range of antibacterial applications.

Using mathematical models to understand the effect of nanoscale roughness on protein adsorption for improving medical devices

Surface roughness and energy significantly influence protein adsorption on to biomaterials, which, in turn, controls select cellular adhesion to determine the success and longevity of an implant. To understand these relationships at a fundamental level, a model was originally proposed by Khang et al to correlate nanoscale surface properties (specifically, nanoscale roughness and energy) to protein adsorption, which explained the greater cellular responses on nanostructured surfaces commonly reported in the literature today. To test this model for different surfaces from what was previously used to develop that model, in this study we synthesized highly ordered poly(lactic-co-glycolic acid) surfaces of identical chemistry but altered nanoscale surface roughness and energy using poly(dimethylsiloxane) molds of polystyrene beads. Fibronectin and collagen type IV adsorption studies showed a linear adsorption behavior as the surface nanoroughness increased. This supported the general trends observed by Khang et al. However, when fitting such data to the mathematical model established by Khang et al, a strong correlation did not result. Thus, this study demonstrated that the equation proposed by Khang et al to predict protein adsorption should be modified to accommodate for additional nanoscale surface property contributions (ie, surface charge) to make the model more accurate. In summary, results from this study provided an important step in developing future mathematical models that can correlate surface properties (such as nanoscale roughness and surface energy) to initial protein adsorption events important to promote select cellular adhesion. These criteria are critical for the fundamental understanding of the now well-documented increased tissue growth on nanoscale materials.

Resistance to Degradation of Resin-Dentin Bonds Produced by One-Step Self-Etch Adhesives

The objective of this article is to evaluate the resistance to degradation of resin-dentin bonds formed with three one-step adhesives. Flat, mid-coronal dentin surfaces were bonded with the self-etching adhesives [Tokuyama Bond Force (TBF), One Up Bond F Plus (OUB), and G-Bond (GB)]. The bonded teeth were subjected to fatigue loading, chemical degradation, and stored in distilled water for four time periods (up to 12 months). Specimens were tested for microtensile bond strength and microleakage. Fractographic analysis was performed by scanning electron microscopy. Bonded interfaces were examined by light microscopy using Masson's trichrome staining. An atomic force microscope was employed to analyze phase separation and surface nanoroughness (Ra) at the polymers. Vickers microhardness and the degree of the conversion (DC) were also determined. ANOVA and multiple comparisons tests were performed. Bond strength significantly decreased after the chemical challenge, but not after load cycling. Aging decreased bond strength after 6 months in TBF and GB, in OUB after 12 months. An increase of the nonresin protected collagen zone occurred in all groups, after storing. TBF showed the highest roughness, microhardness, and DC values, and GB showed the lowest. Mild self-etch one-step adhesives (TBF/OUB) showed a higher degree of cure, lower hydrophilicity, and major resistance to degradation of resin-dentin bonds when compared to highly acidic self-etching adhesive (GB).

Bottom-up engineering of the surface roughness of nanostructured cubic zirconia to control cell adhesion

Nanostructured cubic zirconia is a strategic material for biomedical applications since it combines superior structural and optical properties with a nanoscale morphology able to control cell adhesion and proliferation. We produced nanostructured cubic zirconia thin films at room temperature by supersonic cluster beam deposition of nanoparticles produced in the gas phase. Precise control of film roughness at the nanoscale is obtained by operating in a ballistic deposition regime. This allows one to study the influence of nanoroughness on cell adhesion, while keeping the surface chemistry constant. We evaluated cell adhesion on nanostructured zirconia with an osteoblast-like cell line using confocal laser scanning microscopy for detailed morphological and cytoskeleton studies. We demonstrated that the organization of cytoskeleton and focal adhesion formation can be controlled by varying the evolution of surface nanoroughness.

Novel injectable biomimetic hydrogels with carbon nanofibers and self assembled rosette nanotubes for myocardial applications

The objective of the present in vitro study was to investigate cardiomyocyte functions, specifically their adhesion and proliferation, on injectable scaffolds containing RNT (rosette nanotubes) and CNF (carbon nanofibers) in a pHEMA (poly(2-hydroxyethyl methacrylate)) hydrogel to determine their potential for myocardial tissue engineering applications. RNTs are novel biocompatible nanomaterials assembled from synthetic analogs of DNA bases guanine and cytosine that self-assemble within minutes when placed in aqueous solutions at body temperatures. These materials could potentially improve cardiomyocyte functions and solidification time of pHEMA and CNF composites. Because heart tissue is conductive, CNFs were added to pHEMA to increase the composite's conductivity. Our results showed that cardiomyocyte density increased after 4 h, 1 day, and 3 days with greater amounts of CNFs and greater amounts of RNTs in pHEMA (up to 10 mg mL(-1) CNFs and 0.05 mg mL(-1) RNTs). Factors that may have increased cardiomyocyte functions include greater wettability, conductivity, and an increase in surface nanoroughness with greater amounts of CNFs and RNTs. In effect, contact angles measured on the surface of the composites decreased while the conductivity and surface roughness increased as CNFs and RNTs content increased. Lastly, the ultimate tensile modulus decreased for composites with greater amounts of CNFs. In summary, the properties of these injectable composites make them promising candidates for myocardial tissue engineering applications and should be further studied.

Nanoroughness Impact on Liquid–Liquid Displacement

The influence of surface nanoroughness on the static and dynamic behavior of a solid–water–dodecane contact line is investigated. Surface roughness is found to affect the substrate static and dynamic wettability for root-mean-square roughnesses below 7 nm. The kinetics of liquid–liquid displacement is slowed down drastically by the nanoroughness. Nevertheless, contact line motion is found to be governed by a thermally activated process. This process is not based on a pure molecular adsorption–desorption mechanism. Instead, two different nanoscale local displacements mechanisms occurring in the vicinity of the contact line may account for the thermally activated dynamics: we suggest that both molecular adsorption–desorption processes and contact line pinning on nanodefects play significant roles in controlling water displacement by dodecane on surfaces which are rough at the nanoscale.

Effect of different surface nanoroughness of titanium dioxide films on the growth of human osteoblast‐like MG63 cells

Cell behavior depends strongly on the physical and chemical properties of the material surface, for example, its chemistry and topography. The authors have therefore assessed the influence of materials of different chemical composition (i.e., glass substrates with and without TiO(2) films in anatase form) and different surface roughness (R(a) = 0, 40, 100, or 170 nm) on the adhesion, proliferation, and osteogenic differentiation of human osteoblast-like MG63 cells. On day 1 after seeding, the largest cell spreading area was found on flat TiO(2) films (R(a) = 0 nm). On TiO(2) films with R(a) = 170 nm, the cell spreading area was larger and the number of initially adhering cells was higher than the values on the corresponding uncoated glass. On day 3 after seeding, the cell number was higher on the TiO(2) films (R(a) = 0 and 40 nm) than on the corresponding glass substrates and the standard polystyrene dishes. On day 7, all TiO(2) films contained higher cell numbers than the corresponding glass substrates, and the cells on the TiO(2) films with R(a) = 40 and 100 nm also contained a higher concentration of β-actin. These results indicate that TiO(2) coating had a positive influence on the adhesion and subsequent proliferation of MG63 cells. In addition, on all investigated materials, the cell population density achieved on day 7 decreased with increasing surface roughness. The concentration of osteocalcin, measured per mg of protein, was significantly lower in the cells on rougher TiO(2) films (R(a) = 100 and 170 nm) than in the cells on the polystyrene dishes. Thus, it can be concluded that the adhesion, growth, and phenotypic maturation of MG63 cells were controlled by the interplay between the material chemistry and surface topography, and were usually better on smoother and TiO(2)-coated surfaces than on rougher and uncoated glass substrates.

Modulating cellular behaviors through surface nanoroughness

Download options Please wait... Supplementary files Supplementary information PDF (665K) Article information DOI https://doi.org/10.1039/C2JM32007J Article type Paper Submitted 30 Mar 2012 Accepted 01 Jun 2012 First published 07 Jun 2012 Download Citation J. Mater. Chem., 2012,22, 15654-15664 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Modulating cellular behaviors through surface nanoroughness C. Luo, L. Li, J. Li, G. Yang, S. Ding, W. Zhi, J. Weng and S. Zhou, J. Mater. Chem., 2012, 22, 15654 DOI: 10.1039/C2JM32007J To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author Chao Luo Long Li Jinrong Li Guang Yang Shan Ding Wei Zhi Jie Weng Shaobing Zhou

Characterization of Thin ZnO Films by Vacuum Ultra-Violet Reflectometry

ABSTRACTZnO has a huge potential and is already a crucial material in a range of key technologies from photovoltaics to opto and printed electronics. ZnO is being characterized by versatile metrologies to reveal electrical, optical, structural and other parameters with the aim of process optimization for best device performance. The aim of the present work is to reveal the capabilities of vacuum ultra-violet (VUV) reflectometry for the characterization of ZnO films of nominally 50 nm, doped by Ga and In. Optical metrologies have already shown to be able to sensitively measure the gap energy, the exciton strength, the density, the surface nanoroughness and a range of technologically important structural and material parameters. It has also been shown that these optical properties closely correlate with the most important electrical properties like the carrier density and hence the specific resistance of the film. We show that VUV reflectometry is a highly sensitive optical method that is capable of the characterization of crucial film properties. Our results have been cross-checked by reference methods such as ellipsometry and X-ray fluorescence.

Relationships between structure and activity of carbon as a multifunctional support for electrocatalysts

We report on new insights into the relationships between structure and activity of glassy carbon (GC), as a model material for electrocatalyst support, during its anodization in acid solution. Our investigation strongly confirms the role of CFGs in promotion of Pt activity by the "spill-over" effect related to CO(ads) for methanol electrooxidation (MEO) on a carbon-supported Pt catalyst. Combined analysis of voltammetric and impedance behaviour as well as changes in GC surface morphology induced by intensification of anodizing conditions reveal an intrinsic influence of the carbon functionalization and the structure of a graphene oxide (GO) layer on the electrical and electrocatalytic properties of activated GC. Although GO continuously grows during anodization, it structurally changes from being a graphite inter-layer within graphite ribbons toward a continuous GO surface layer that deteriorates the native structure of GC. As a consequence of the increased distance between GO-spaced graphite layers, the GC conductivity decreases until the case of profound GO exfoliation under drastic anodizing conditions. This exposes the native, yet abundantly functionalized, GC texture. While GC capacitance continuously increases with intensification of anodizing conditions, the surface nano-roughness and GO resistance reach the highest values at modest anodizing conditions, and then decrease upon drastic anodization due to the onset of GO exfoliation. We found for the first time that the activity of a GC-supported Pt catalyst in MEO, as one of the promising half-reactions in polymer electrolyte fuel cells, strictly follows the changes in GC nano-roughness and GO-induced GC resistance. The highest GC/Pt MEO activity is reached when optimal distance between graphite layers and optimal degree of GC functionalization bring the highest amount of CFGs into intimate contact with the Pt surface. This confirms the promoting role of CFGs in MEO catalysis.

Differential nanofiller cluster formations in dental adhesive systems

Nanofillers are added to dental adhesives to improve mechanical properties of the hybrid layer. Ethanol or water added to the demineralized dentin to improve adhesive infiltration may produce filler aggregation. To assess the effect of 5 vol% water or ethanol addition on nanoparticles distribution in dental adhesives. Six available commercial adhesives systems were selected: Clearfil SE Bond (CSE), Clearfil Protect Bond (CPB), FL-Bond (FLB), Clearfil S3 (CS3), Bond Force (BF), One Up Bond F plus (OUB), and an experimental adhesive system without filler (EXP). Polymer films were obtained by adding 0 (control) or 5 vol% water or ethanol into the bonding resins. Preparations were light-cured (40 s). Three specimens were analyzed for each mixture. Three phases and 3D images were taken from each specimen by means of an atomic force microscope in taping mode (TM/AFM). Cluster sizes and surface nanoroughness were assessed. Control specimens from CSE, FLB, OUB, and BF presented clusters. The addition of solvents lead to particles aggregation in tested bonding resins. Ethanol addition produced more aggregates, particularly in adhesives containing fluoraluminosilicate as fillers. Nanofillers aggregation occurred in all adhesive systems in presence of additional solvents. In general, aggregate sizes were higher after the addition of ethanol. Formed clusters size values are always above the dimensions of the spaces existing between the demineralized collagen fibers.

Surface modification of high-performance polymeric fibers by an oxygen plasma. A comparative study of poly( p-phenylene terephthalamide) and poly( p-phenylene benzobisoxazole)

Poly( p-phenylene terephthalamide) (PPTA) and poly( p-phenylene benzobisoxazole) (PBO) fibers were exposed to an oxygen plasma under equivalent conditions. The resulting changes in the surface properties of PPTA and PBO were comparatively investigated using inverse gas chromatography (IGC) and atomic force microscopy (AFM). Both non-polar ( n-alkanes) and polar probes of different acid–base characteristics were used in IGC adsorption experiments. Following plasma exposure, size-exclusion phenomena, probably associated to the formation of pores (nanoroughness), were detected with the largest n-alkanes (C 9 and C 10). From the adsorption of polar probes, an increase in the number or strength of the acidic and basic sites present at the fiber surfaces following plasma treatment was detected. The effects of the oxygen plasma treatments were similar for PPTA and PBO. In both cases, oxygen plasma introduces polar groups onto the surfaces, involving an increase in the degree of surface nanoroughness. AFM measurements evidenced substantial changes in the surface morphology at the nanometer scale, especially after plasma exposure for a long time. For the PBO fibers, the outermost layer – contaminant substances – was removed thanks to the plasma treatment, which indicates that this agent had a surface cleaning effect.

TOPOGRAPHICAL EFFECTS OF O2- AND NH3-PLASMA TREATMENT ON WOVEN PLAIN POLYESTER FABRIC IN ADJUSTING HYDROPHILICITY

Abstract Hydrophilisation of polyester textile materials has been investigated over the last twenty years using low-pressure and atmospheric plasmas. According to these studies, wettability and capillarity of fabrics can be significantly improved depending on the process gas used. In the present study, the effects of low pressure O2- and NH3- plasma on the morphology and topometry of fabrics on four different length scales, as well as the influence of the topographical changes of textile structures on the resulting water spreading and absorption rates were investigated. The results of the topographic characterisation using two non-contact optical methods and wettability measurements indicate that the modification of filament nano-topography cannot satisfactorily explain the drastic changes observed in wettability. Dimensional changes (relaxation and shrinkage) as well as changes in warp morphology and inter-yarn spaces are more decisive for inducing hydrophilicity in polyester woven plain fabrics than an increase in the surface nano-roughness of their filaments.

Influence of Surface Nano-roughness of Dental Alumina Ceramic on Bond Strength to Dual-Cure Resin Cements

The goal of this research is to evaluate the effect of sandblasting and silica coating on the nano-roughness and on the microtensile bond strength (MTBS) of glass-infiltrated alumina bonded to different resin cements. Six slabs of In-Ceram Alumina (Vita) were randomly treated according to the following groups: (1) no treatment; (2) sandblasting (125 μm Al2O3-particles); and (3) tribochemical silica-coating (50 μm silanated silica particles). Nano-roughness (Ra) was assessed under an atomic force microscope (AFM). Such surface treatments were also applied to nine In-Ceram Alumina CAD/CAM blocks. Ceramic blocks were duplicated in composite resin, and composite samples were bonded to the conditioned surfaces. Each pre-treatment group was divided into three subgroups depending on the resin cement system: (1) Clearfil Ceramic Primer plus Clearfil Esthetic Cement (CEC, Kuraray); (2) RelyX Unicem (RXU, 3M); and (3) Calibra Silane plus Calibra Resin Cement (CAL, Dentsply). After 24 h, the bonded specimens were cut into 1±0.2 mm2 sticks. The MTBS values (MPa) were obtained using a universal testing machine (crosshead speed: 0.5 mm/min). Failure modes were recorded using a scanning electron microscope (SEM). Nano-roughness and MTBS data were analyzed by ANOVA and Student–Newman–Keuls tests (α =0.05). No significant changes in nano-roughness occurred after conditioning. The MTBS of CEC and RXU were comparable despite the surface treatment. All CAL-sticks debonded prematurely. Ceramic pre-treatments, such as sandblasting or silica coating, do not affect the alumina's surface nano-roughness or bond strength. The MDP monomers dissolved in the CEC Primer and the functional dimethacrylate monomers present in the self-adhesive RXU may be the key to successful bonds to alumina.

Prediction of Inter-particle Adhesion Force from Surface Energy and Surface Roughness

Fine powder flow is a topic of great interest to industry, in particular for the pharmaceutical industry; a major concern being their poor flow behavior due to high cohesion. In this study, cohesion reduction, produced via surface modification, at the particle scale as well as bulk scale is addressed. The adhesion force model of Derjaguin–Muller–Toporov (DMT) was utilized to quantify the inter-particle adhesion force of both pure and surface modified fine aluminum powders (∼8 μm in size). Inverse Gas Chromatography (IGC) was utilized for the determination of surface energy of the samples, and Atomic Force Microscopy (AFM) was utilized to evaluate surface roughness of the powders. Surface modification of the original aluminum powders was done for the purpose of reduction in cohesiveness and improvement in flowability, employing either silane surface treatment or dry mechanical coating of nano-particles on the surface of original powders. For selected samples, the AFM was utilized for direct evaluation of the particle pull-off force. The results indicated that surface modification reduced the surface energy and altered the surface nano-roughness, resulting in drastic reduction of the inter-particle adhesion force. The particle bond number values were computed based on either the inter-particle adhesion force from the DMT model or the inter-particle pull-off force obtained from direct AFM measurements. Surface modification resulted in two to three fold reductions in the Bond number. In order to examine the influence of the particle scale property such as the Bond number on the bulk-scale flow characterization, Angle of Repose (AOR) measurements were done and showed good qualitative agreements with the Bond number and acid/base surface characteristics of the powders. The results indicate a promising method that may be used to predict flow behavior of original (cohesive) and surface modified (previously cohesive) powders utilizing very small samples, and that the surface modification can drastically improve the powder flow for industrially relevant materials.

Signal enhancement in a protein chip array using a 3-D nanosurface

A silica based 3-D nanosurface was developed to enhance the signal intensity of a protein chip by increasing the surface density and reducing the aggregation of captured proteins immobilized on the nanosurface. The 3-D nanosurface was composed of silica nanopillar bundles formed from a nanoporous alumina template using the sol–gel method. The signal intensity of a protein spot increased exponentially when the capture probe was immobilized on a nanosurface with higher roughness and the amount of protein immobilized on the surface was proportional to the roughness of the nanosurface. To further investigate this nanosurface effect, changes in the nanosurface roughness before and after protein immobilization were investigated by AFM. The surface roughness was shown to increase after protein immobilization when the nanosurface initially had a relatively low surface roughness (Rq: 30–40 nm); however, the surface roughness decreased after protein immobilization when it initially had a high roughness (Rq: 60–130 nm). These results imply that a high nanosurface roughness decreases the overall aggregation of proteins on the surface. These findings were also confirmed by comparing the level of protein aggregation on nanosurfaces with high roughness and low roughness using AFM.

Effect of titanium implant surface nanoroughness and calcium phosphate low impregnation on bone cell activity in vitro

In the field of bone implant surfaces, the effects of nanoscale modifications have received significant attention. In the present study, bone cell activity on 2 implant surfaces with similar microtopography but distinct chemistry and nanotopography (sandblasted/acid-etched surface as control group, and calcium phosphate (CaP) low impregnated surface (Ossean) as test group, both from Intra-Lock, Boca Raton, FL) were evaluated. The 2 surfaces were characterized by X-ray photoelectronic spectroscopy (XPS) and scanning electron microscopy (SEM) up to x200,000 magnification. The micrometer level roughness profiles were evaluated by means of computer software. Cell adhesion, proliferation, and alkaline phosphatase activity were assessed with human SaOS-2 osteoblasts and bone mesenchymal stem cells in nonosteogenic culture conditions. The XPS and SEM results showed that the Ossean surface presented low levels of CaP impregnation within the titanium oxide layer and texturization at the nanometer scale (nanoroughness) compared with the control surface. Moreover Ossean surface induced significantly higher cell differentiation levels than the control (P < .01). This study showed that both homogeneous nanoroughness and CaP low impregnation differently affected in vitro bone cell behavior compared with the control moderately rough surface with less texturing in the nanometer scale. However, the relative importance of nanotopography and surface chemistry in cell reactions is yet to be determined.

Tip profile estimation of scanned probe microscopy for micro and nano surface roughness measurement

Tip profile estimation is essential for tracing and calibrating surface roughness measurements either for conventional surface roughness measurement or for scanning probe microscopy (SPM), especially atomic force microscopy (AFM). This paper presents a tip profile estimation method, called the stylus tip reconstruction method (STRM), which is based on set‐theory and the convolution method, which determines the calibrated grating gage for nano surface roughness measurement. A micro‐STRM has been implemented first on a surface roughness analyzer with a tip of radius 5 μm for measuring a traced roughness gage having a step height of 10 μm and a razor blade with the ISO 5436 standard. Experimental results in the micro scale tests show that the residual of the micro‐STRM with the step gage and razor blade measurement is around 4%. Then in a nano scale test, AFM was configured to verify the developed nano‐STRM. The tip profile calculated by the nano‐STRM was obtained and verified by a scanning electron microscopy (SEM) image. The developed STRM has been verified for micro and nano surface roughness measurement for tip profile estimation. Further application of the developed STRM can be used in compensating for measured images in micro and nano surface roughness measurements.

Responses of fibroblasts and glial cells to nanostructured platinum surfaces

The chronic performance of implantable neural prostheses is affected by the growth ofencapsulation tissue onto the stimulation electrodes. Encapsulation is associated withactivation of connective tissue cells at the electrode’s metallic contacts, usually made ofplatinum. Since surface nanotopography can modulate the cellular responses to materials,the aim of the present work was to evaluate the ‘in vitro’ responses of connective tissuecells to platinum strictly by modulating its surface nanoroughness. Using molecular beamepitaxy combined with sputtering, we produced platinum nanostructured substratesconsisting of irregularly distributed nanopyramids and investigated their effect on theproliferation, cytoskeletal organization and cellular morphology of primary fibroblasts andtransformed glial cells. Cells were cultured on these substrates and their responses tosurface roughness were studied. After one day in culture, the fibroblasts were moreelongated and their cytoskeleton less mature when cultured on rough substrates. This effectincreased as the roughness of the surface increased and was associated with reduced cellproliferation throughout the observation period (4 days). Morphological changesalso occurred in glial cells, but they were triggered by a different roughness scaleand did not affect cellular proliferation. In conclusion, surface nanotopographymodulates the responses of fibroblasts and glial cells to platinum, which may be animportant factor in optimizing the tissue response to implanted neural electrodes.