|Ph.D Thesis||Department of Civil and Environmental Engineering|
|Supervisor:||Assoc. Prof. Armon Robert|
Tissue-derived cells are anchorage dependent cells and require therefore attachment to a solid surface for viability, growth and spread over. The chemical characteristics of the substrate determine the behavior, function and shape of the attached cells.
The sol-gel process is a synthetic route by which metal alkoxide monomers (silane-alkoxides in particular) are converted to a glassy material by a sequence of hydrolysis and condensation-polymerization reactions. Being a room temperature glass-synthesis process, makes it possible to use sol-gel matrices to entrap various types of biological materials, from proteins to whole cells. Motivated by the demonstrated advantages of sol-gel materials for many bio-applications, a new family of films for tissue culture growth and for virus detection was developed, based on these special materials. A major advantage of sol-gel films is that they can be tailored to the specific growth-conditions requirements of various cells.
With the aim of finding the optimal hydrophobicity for cells growth, Buffalo Green Monkey Kidney (BGM) cells were grown on films that were prepared from various ratios of methyltrimethoxysilane (MTMOS)/tetraethoxysilane (TEOS), to achieve different hydrophobicities;. The morphology and the number of attached cells on the sol-gel surfaces was determined daily for a period of 1-7 days following initial inoculation. It was found that films with an intermediate hydrophobicity made from 25% MTMOS are optimal for BGM tissue culture growth. Notably, the sol-gel films are better than the commonly used tissue-culture polystyrene. In order to investigate the effect of positive charge density on cells growth, fully methylated thin films were doped with different concentrations of poly-L-lysine (PLL) or neutral red (NR). It was shown that PLL or NR doping under the standard conditions of 10% serum enhances cell attachment and growth, and that the enhancement improves with increase in PLL or NR concentration. The main important application of these doped films is the ability to reduce the amount of fetal calf serum required for growth. Thus, it was shown that good cell growth results were obtained after only one day of incubation in medium supplemented with only 2% serum (compared with the standard of 10%) on thin sol-gel films doped with 0.0142 % (PLL (moles lysine) / Si (moles) or 0.079 %NR (mole) / Si (mole).