Effects of surface topography on organization of cells and extracellular matrix

• Main Author: Glass-Brudzinski, Jeanette
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/10622

The long-term success of an implant is governed to a large extent by its surface properties that will influence cell behaviour reflected in their migration, attachment, morphology, and proliferation. Also, the integration of the surrounding tissue around the implant is dependent on the reorganization of the surrounding E C M in a morphogenetic manner. It is of great importance to understand the interactions of cells with the implant surface, with the E C M , and with other cells so that failure of implanted devices can be avoided. This thesis examined the in vitro process of connective tissue reorganization and how it was affected by the topography of substratum using the following techniques: substrata micromachining, collagen gels as substrata, Light Microscopy, Polarized Light Microscopy (PSR stained collagen), Confocal Laser Scanning Microscopy (PI stained nuclei), and Time Lapse Video Microscopy. This thesis measured the cell orientation on 6 types of surfaces: T C dish, smooth titanium, 30IP175S, 3G30P, 30G40P, and 30G175P grooved titanium. The effect of collagen matrix on cell orientation under three conditions (Control, CellGel, and Gel) was determined. Also, the effects of cell distribution within a gel on the gel contraction was examined. The distribution of cells between collagen and titanium surface under the CellGel and Gel conditions was compared. Gel penetration into grooves was determined. The following observations and conclusions were made. It appeared that collagen gel did not penetrate into the grooves of a grooved surface. In the absence of collagen gel, cells formed patchworks of parallel arrays on TC dish, smooth, and pitted surfaces. Cells aligned with the grooves on grooved surfaces. The presence of collagen matrix atop a stable culture (CellGel) disrupted the orientation of cells leading to a lesser alignment. The presence of collagen matrix around the cells (Gel), resulted in lowest level of alignment. The collagen fibers seemed to conform with the orientation of cells and also become aligned with the grooves. Orientation of cells within the three dimensional matrix was not affected by either the surface topography or the collagen fibers. Cells were found to be essential for the gel contraction. When most cells were found at the bottom of the gel throughout the experiments (CellGel) a thin sheet of "orthogonally" arranged fibers was formed after a period of 3-4 weeks. When cells were distributed throughout a matrix (Gel) a "Ring" of fibers was created. Cells were not only able to leave titanium surface and make new attachments with the overlaying matrix (CellGel) but also to leave a collagenous matrix and settle on titanium surface (Gel). The CellGel condition that leads to a production of a continuous sheet of "tissue" can be used to coat a device prior to implantation to improve a long term success of such a device.