Cell Attachment Efficiency Research Articles

Effects of cell adhesion to the substratum on the growth of chick embryo fibroblasts

Chick embryo fibroblasts were plated on Petri dishes that had not been treated for use in tissue culture (bacteriological dishes). On these dishes the cells grow at the same exponential rate as cells plated on tissue culture dishes, but their growth becomes inhibited sooner after plating, and therefore at a lower cell number per dish. The inhibition of cell growth on bacteriological dishes is correlated with the formation of cell clumps. Clump formation is reversible by mechanical transfer of the clumps to a tissue culture dish: the cells migrate out of the clumps, form a monolayer, and cell growth resumes. Clump formation was studied by time-lapse cinematography, and was found to be due to reduced adhesion of the cells to the bacteriological dish surface. This reduced adhesiveness of the substratum is due to a lower number of negatively-charged residues on the bacteriological dish surface, which can be measured by the binding of crystal violet. The number of negatively-charged residues, and therefore the adhesiveness of the substratum can be altered by treatment of the dishes with sulfuric acid. Serum components of the medium were found to affect cell adhesion to the bacteriological dishes, consequently altering the efficiency of cell attachment, the extent of cell growth and the pattern of clump formation. The cells in clumps were compared with those in confluent monolayers on tissue culture dishes. Growth-inhibited cells on both types of dish were found to be equally viable. Cells in clumps on bacteriological dishes were found to be inhibited in the G1 phase of the cell cycle, as are cells in density-inhibited monolayers. Infection by the oncogenic virus, Rous sarcoma virus, can release the cells from growth-inhibition on both types of dish. Cell-induced alterations of the medium are not involved in the growth inhibition of cells on bacteriological dishes.

Electron spin resonance spectroscopy for flame research

Bioreactor design is a challenging endeavour that aims to provide the most ideal environment in which cells can grow and biological reactions can occur. The emergence of regenerative medicine and stem cell therapies has led to the need for more diverse environmental requirements in the bioreactor design space.The study presented uses an additive manufacturing approach for the initial design phase of a packed/fluidized bed bioreactor for mesenchymal stem cell expansion. Combining 3D-printing with CFD for precision control over the bioreactor flow dynamics. Novel flow distributors were developed to engender swirling particle fluidization. The design was simulated and optimised using CFD, demonstrating an increase from 0.01 m/s to 0.02 m/s in the radial velocity of 3.0 mm macrocarriers (1080 kg/m3) at the minimum fluidization velocity. An autoclavable prototype was constructed to illustrate proof-of-concept in the use of swirling flow distribution to enhance cell attachment efficiency (compared to static culture system). Commercial Cytodex 1 carriers were tested: an improvement in attachment efficiency after 24 h from 50 % to 95 % was induced by the swirling flow distributor, with subsequent expansion of 2.4-fold after 6 days of culture.The computational design, modelling and 3D-printing of complex geometric architecture that control the flow dynamics within a bioreactor, provides a novel approach to bioprocess unit operation development for manufacturing novel ATMPs.