Glass microspargers as effective frit spargers in single use bioreactors.

For multiple-use bench scale and larger bioreactors, sintered stainless steel frit spargers are commonly used as microspargers. For bench-scale single-use bioreactors (SUBs), existing microspargers are sintered plastics, such as polyethylene. However, though plastics are readily sterilized by irradiation making them convenient for single use, these designs overlook surface energy properties of the materials of construction.

Transient Electric Birefringence of Linear and Circular DNA: A Comparison of Kinetic Theory Predictions.

The use of monodisperse DNA and restriction enzyme modification allows the preparation of model samples of polymer rings and linear chains with a precision that is not possible by conventional synthetic routes. These samples allow direct comparisons of the predictions of polymer kinetic theories. Transient electric birefringence allows rapid imposition or forces (∼100 ns) and monitoring of conformational changes (∼0.

A comprehensive comparison of mixing, mass transfer, Chinese hamster ovary cell growth, and antibody production using Rushton turbine and marine impellers.

Large scale production of monoclonal antibodies has been accomplished using bioreactors with different length to diameter ratios, and diverse impeller and sparger designs. The differences in these physical attributes often result in dissimilar mass transfer, mechanical stresses due to turbulence and mixing inside the bioreactor that may lead to disparities in cell growth and antibody production. A rational analysis of impeller design parameters on cell growth, protein expression levels and subsequent antibody production is needed to understand such differences.