Cell growth as a sheet on three-dimensional sharp-tip nanostructures (original) (raw)

Influence of Systematically Varied Nano-Scale Topography on Cell Morphology and Adhesion

Cell Communication & Adhesion, 2007

The types of cell-matrix adhesions and the signals they transduce strongly affect the cellphenotype. We hypothesized that cells sense and respond to the three-dimensionality of their environment, which could be modulated by nano-structures on silicon surfaces. Human foreskin fibroblasts were cultured on nano-structures with different patterns (nano-post and nano-grate) and heights for 3 days. The presence of integrin α 5 ,β 1 , β 3 , paxillin and phosphorylated FAK (pFAK) were detected by western blot and immunofluorescence. Integrin β 3 exhibited stronger signals on nano-grates. pFAK and paxillin were observed as small dot-like patterns on the cellperiphery on nano-posts and as elongated and aligned patterns on nano-grates. Collectively, our observations highlighted the presence of focal (integrin β 1 , β 3 , pFAK, paxillin), fibrillar (integrin α 5 , β 1) and 3-D matrix (integrin α 5 , β 1 , paxillin) adhesions on nano-structures. The presented nano-structures offer interesting opportunities to study the interaction of cells with topographical features comparable to the size of extracellular matrix components.

Cell interaction with three-dimensional sharp-tip nanotopography

Biomaterials, 2007

Cells in their native microenvironment interact with three-dimensional (3D) nanofeatures. Despite many reports on the effects of substrate nanotopography on cells, the independent effect of 3D parameters has not been investigated. Recent advances in nanofabrication for precise control of nanostructure pattern, periodicity, shape, and height enabled this systematic study of cell interactions with 3D nanotopographies. Two distinct nanopatterns (posts and grates) with varying three-dimensionalities (50-600 nm in nanostructure height) were created, while maintaining the pattern periodicity (230 nm in pitch) and tip shape (needle-or blade-like sharp tips). Human foreskin fibroblasts exhibited significantly smaller cell size and lower proliferation on needle-like nanoposts, and enhanced elongation with alignment on blade-like nanogrates. These phenomena became more pronounced as the nanotopographical three-dimensionality (structural height) increased. The nanopost and nanograte architectures provided the distinct contact guidance for both filopodia extension and the formation of adhesion molecules complex, which was believed to lead to the unique cell behaviors observed.

Nanoscale engineering of biomimetic surfaces: cues from the extracellular matrix

Cell and Tissue Research, 2010

The ultimate goal in the design of biomimetic materials for use in tissue engineering as permanent or resorbable tissue implants is to generate biocompatible scaffolds with appropriate biomechanical and chemical properties to allow the adhesion, ingrowth, and survival of cells. Recent efforts have therefore focused on the construction and modification of biomimetic surfaces targeted to support tissue-specific cell functions including adhesion, growth, differentiation, motility, and the expression of tissue-specific genes. Four decades of extensive research on the structure and biological influence of the extracellular matrix (ECM) on cell behavior and cell fate have shown that three types of information from the ECM are relevant for the design of biomimetic surfaces: (1) physical properties (elasticity, stiffness, resilience of the cellular environment), (2) specific chemical signals from peptide epitopes contained in a wide variety of extracelluar matrix molecules, and (3) the nanoscale topography of microenvironmental adhesive sites. Initial physical and chemical approaches aimed at improving the adhesiveness of biomaterial surfaces by sandblasting, particle coating, or etching have been supplemented by attempts to increase the bioactivity of biomaterials by coating them with ECM macromolecules, such as fibronectin, elastin, laminin, and collagens, or their integrin-binding epitopes including RGD, YIGSR, and GFOGER. Recently, the development of new nanotechnologies such as photo-or electron-beam nanolithography, polymer demixing, nano-imprinting, compression molding, or the generation of TiO 2 nanotubes of defined diameters (15-200 nm), has opened up the possibility of constructing biomimetic surfaces with a defined nanopattern, eliciting tissue-specific cellular responses by stimulating integrin clustering. This development has provided new input into the design of novel biomaterials. The new technologies allowing the construction of a geometrically defined microenvironment for cells at the nanoscale should facilitate the investigation of nanotopography-dependent mechanisms of integrin-mediated cell signaling.

Nanoscale tissue engineering: spatial control over cell-materials interactions

Nanotechnology, 2011

Cells interact with the surrounding environment by making tens to hundreds of thousands of nanoscale interactions with extracellular signals and features. The goal of nanoscale tissue engineering is to harness the interactions through nanoscale biomaterials engineering in order to study and direct cellular behaviors. Here, we review the nanoscale tissue engineering technologies for both two-and three-dimensional studies (2-and 3D), and provide a holistic overview of the field. Techniques that can control the average spacing and clustering of cell adhesion ligands are well established and have been highly successful in describing cell adhesion and migration in 2D. Extension of these engineering tools to 3D biomaterials has created many new hydrogel and nanofiber scaffolds technologies that are being used to design in vitro experiments with more physiologically relevant conditions. Researchers are beginning to study complex cell functions in 3D, however, there is a need for biomaterials systems that provide fine control over the nanoscale presentation of bioactive ligands in 3D. Additionally, there is a need for 2-and 3D techniques that can control the nanoscale presentation of multiple bioactive ligands and the temporal changes in cellular microenvironment. † Corresponding

Cell Adhesions on Nanoturf Surfaces

19th IEEE International Conference on Micro Electro Mechanical Systems, 2006

We report on various aspects of cell adhesion of fibrolasts over densely-populated sharp-tip nano-post structures, which we term "NanoTurf". The ability to control the size, shape, and aspect ratio of the nanostructures enabled the study on the effect of surface three-dimensionality of the cell-matrix adhesion in detail. To our best knowledge, this is the first systematic investigation of the nanometric three-dimensional surface topography effect on cell adhesions.

Altered nanofeature size dictates stem cell differentiation

Journal of Cell Science, 2012

The differentiation of stem cells can be modulated by physical factors such as the micro-and nano-topography of the extracellular matrix. One important goal in stem cell research is to understand the concept that directs differentiation into a specific cell lineage in the nanoscale environment. Here, we demonstrate that such paths exist by controlling only the micro-and nano-topography of polymer surfaces. Altering the depth (on a nanometric scale) of micro-patterned surface structures allowed increased adhesion of human mesenchymal stem cells (hMSCs) with specific differentiation into osteoblasts, in the absence of osteogenic medium. Small (10 nm) depth patterns promoted cell adhesion without noticeable differentiation, whereas larger depth patterns (100 nm) elicited a collective cell organization, which induced selective differentiation into osteoblast-like cells. This latter response was dictated by stress through focal-adhesion-induced reorganization of F-actin filaments. The results have significant implications for understanding the architectural effects of the in vivo microenvironment and also for the therapeutic use of stem cells.

Fibroblast response to a controlled nanoenvironment produced by colloidal lithography

Journal of Biomedical Materials Research, 2004

It is thought that by understanding how cells respond to topography, that better tissue engineering may be achievable. An important consideration in the cellular environment is topography. The effects of microtopography have been well documented, but the effects of nanotopography are less well known. Previously, methods of nanofabrication have been costly and time-consuming, but research by engineers, physicists, and chemists is starting to allow the production of nanostructures using low-cost techniques. In this report, nanotopography is specifically considered. Con-trolled patterns of 160 nm high nanocolumns were produced for in vitro cell culture using colloidal lithography. By studying cell adhesion with time and cytoskeletal (actin, tubulin, and vimentin) maturity, insight has been gained as to how fibroblasts adhere to these nanofeatures.