Nie, Z; (2017) Assessment of bioprocess shear stress as a tool to enhance osteogenic induction of mesenchymal cells. Masters thesis , UCL (University College London).

Preview

Text Nie_Zi_Thesis Z.pdf Download (4MB) | Preview

Abstract

Shear stress is an unavoidable bioprocess force encountered during routine cell culture and large scale cell manufacture. It is generally considered as harmful for cells in bio-manufacturing, as it affects cell viability and function. Thus, reducing cell loss, maintaining cell integrity and function during processing are important for cell therapy. Also, based on the fact that mechanical cues can increase bone formation in vivo, we hypothesized that the capillary shear stress could enhance osteogenic differentiation and maturation of cells. This study assessed the effect of capillary shear stress on survival and osteogenic differentiation using rat bone marrow derived mesenchymal stromal cells (MSCs), human MG63 cells and human MSCs. Cells were exposed to defined shear stress by passing through a capillary device. Three key parameters were tested: capillary internal diameters (e.g. 0.254 mm, 0.203 mm), flow rates (e.g. 13, 20, 28 ml/min) and number of passes (e.g. 10, 20, 40 passes). Cell recovery and viability were measured immediately after exposure to shear stress and after 24 and 72 hours cell culture. A small decline in immediate recovery and viability at 24 hrs was evident for MSCs passed through capillaries compared to controls. High flow rates and hence higher shear stress (e.g. 258 Pa) resulted in greater cell loss and reduced cell viability after culture for 24 hrs (p < 0.05). Using the capillary diameters and flow rates we reported here, cell growth is permissible in spite of an initial reduction in viable cell growth, but cells recover from this rapidly in culture. Although longer exposure durations to shear stress lead to more osteogenic differentiation, the increasing trend of mineralization was not linear to the increase of shear stress exposure time. Alizarin red S staining of both MSCs and MG63 cells revealed that appropriate capillary wall shear stress has potential to enhance osteogenic differentiation. In conclusion, sub-lethal fluid shear stress that cells experience during bioprocessing can be used as a mechanical cue for osteogenesis.

Download activity - last month

Export as CSVXMLJSON

Download activity - last 12 months

Export as JSONCSVXML

Downloads by country - last 12 months

Export as JSONXMLCSV

Archive Staff Only

View Item