Controlling the lateral distribution and alignment of human gingival fibroblasts by micropatterned polysaccharide surfaces

Effect of Modified Pectin Molecules on the Growth of Bone Cells

The aim of this study was to investigate molecular candidates for bone implant nanocoatings, which could improve biocompatibility of implant materials. Primary rat bone cells and murine preosteoblastic MC3T3-E1 cells were cultured on enzymatically modified hairy regions (MHR-A and MHR-B) of apple pectins. MHRs were covalently attached to tissue culture polystyrene (TCPS) or glass. Uncoated substrata or bone slices were used as controls. Cell attachment, proliferation, and differentiation were investigated with fluorescence and confocal microscopy. Bone cells seem to prefer MHR-B coating to MHR-A coating. On MHR-A samples, the overall numbers as well as proportions of active osteoclasts were diminished compared to those on MHR-B, TCPS, or bone. Focal adhesions indicating attachment of the osteoblastic cells were detected on MHR-B and uncoated controls but not on MHR-A. These results demonstrate the possibility to modify surfaces with pectin nanocoatings.

Human fibroblast migration in three-dimensional collagen gel in response to noninvasive electrical stimulus. I. Characterization of induced three-dimensional cell movement

Cell adhesion and motility is one of the important biological processes involved in cell growth, differentiation, inflammatory response, and wound healing, and in engineered tissue constructs. Because cellular behaviors can be influenced by the local electrical environment within tissues, induced cell orientation, adhesion, and migration by exogenous electrical stimulus have been extensively examined on two-dimensional (2D) substrates. Similar cellular responses in 3D matrix have not been well documented, however. We have therefore used the 3D collagen gel as a model to characterize human fibroblast movement in response to noninvasive DC electrical stimulus. Cell movements were compared by plating the cells on 2D substrates and embedding them into the reconstituted 3D collagen gel. Our results indicate that 3D cell movement is regulated by both electrical stimulus strength and collagen concentration. For example, a small noninvasive electrical stimulus (0.1 V/cm) was found to be sufficient to induce 3D cell migration, and a collagen concentration of 0.58 mg/mL appeared to represent the optimal scaffold network environment. The same electrical stimulus did not induce significant 2D cell movement, however. Typical cell migration was best analyzed by assuming both directed and random movement and that, in response to an electrical stimulus of 0.1 V/cm, the cell migration rate was 0.23 microm/min and the random motility coefficient was 0.07 microm2/min. Because regulation of cell adhesion and migration is often desired in tissue engineering, the ability to apply physical stimulus and to control 3D cell movement may provide an alternative methodology for regulation of engineered tissue constructs.

Cellular alignment by grafted adhesion peptide surface density gradients

The extracellular matrix and extracellular matrix-associated proteins play a major role in growth and differentiation of tissues and organs. To date, few methods have been developed that allow researchers to examine the affect of surface density gradients of adhesion molecules in a controlled manner. Fibroblasts cultured on surfaces with a surface density gradient of RGD peptide aligned parallel to the gradient while fibroblasts on constant density RGD surfaces spread but did not align as has been shown in numerous earlier studies. Not only did fibroblasts align on the gradient surfaces, but they also showed significantly greater elongation than on constant density peptide surfaces or on control surfaces. This type of method is easy to replicate and can be used by laboratories interested in investigating alignment of various cell types without mechanical force or other stimulation, and without cell-cell interaction or for investigation of affects of surface density gradients of molecules on cellular biochemistry and biophysics. This method also has potential applications for developing scaffolds for tissue engineering applications where cellular alignment is necessary.