Culture of oesophageal smooth muscle cells in a bioreactor.
Date of Issue2009
School of Chemical and Biomedical Engineering
Many health problems in humans lead to the loss and damage of tissues in the body. Solutions currently being employed include organ transplantation and artificial implants. However, problems like graft rejection and allergic reactions arise. A new promising therapy concept for medical application is tissue engineering. One area of investigation is the production of smooth muscle cells (SMCs) such as those in the oesophagus, which is prone to diseases like oesophageal cancer. A three-dimensional tensegrity model of a cell was developed to visualize how a cell responds to strain. When small strains were applied, some components remained in their equilibrium position while others reoriented themselves. This suggests that critical elements of the cell cytoskeleton may need to be stimulated to elicit desired cellular responses. For quantifying purposes, a further simplified model was built and the response when different magnitudes of strain were externally applied was measured. The result was a linear relationship between the strains externally applied and actually experienced by the cell suggesting that in vivo the cells also follow a quantifiable relationship to the strain applied. Previous research proved that many cells in vivo only experience small strain magnitudes. Thus, SMCs were stimulated with small uni-axial cyclic strains (0.3%, 0.6%, 0.9%). Though, standard deviation of cell orientation decreased slightly with increasing strain (from 47.35 to 38.92), no visible alignment of cells was observed. Possible reasons for this lack of response could be because the strain applied was not enough for the SMCs and because there were losses in the bioreactor system so that membrane deformation is insufficient to elicit any cellular response. However, when higher strains (1.8%, 2.4%, 3.1%) were applied, the cells preferred to align 90° away from the direction of stimulation. This result was expected and is thought to be a cellular response to reduce internal stress. In fact, 67% of the cells subjected to 3.1% strain followed this behaviour and their mean angle of orientation was 90.2°. Their standard deviation also greatly decreased from 41.47 to 4.63 with increasing strain.
Final Year Project (FYP)
Nanyang Technological University