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Biomedical subjects

G N Stephanopoulos

Publications and source records attributed to G N Stephanopoulos.

4 recordsLinked to original sources

Engineering cell shape and function.

An elastomeric stamp, containing defined features on the micrometer scale, was used to imprint gold surfaces with specific patterns of self-assembled monolayers of alkanethiols and, thereby, to create islands of defined shape and size that support extracellular matrix protein adsorption and cell attachment. Through this technique, it was possible to place cells in predetermined locations and arrays, separated by defined distances, and to dictate their shape. Limiting the degree of cell extension provided control over cell growth and protein secretion. This method is experimentally simple and highly adaptable. It should be useful for applications in biotechnology that require analysis of individual cells cultured at high density or repeated access to cells placed in specified locations.

Albumins

Use of regulated secretion in protein production from animal cells: an overview.

Traditional industrial cell culture processes require extensive downstream product refining due to low product titer and purity in the spent growth medium. A controlled secretion process incorporating cells derived from endocrine or exocrine organs could potentially alleviate this processing burden by dynamically decoupling product recovery from cell growth and product biosynthesis. In addition, such specialized secretory cells may be uniquely capable of performing desirable post-translational processing of the secretory product. We briefly review the biology of regulated protein secretion as well as the biology and biochemistry of the signal transduction mechanisms by which regulated systems respond to environmental stimuli. Drawing on these and other basic principles from cell biology and bioengineering, we describe the important features of a controlled secretion process. Among other issues we discuss the choice of cell lines, expression systems, cell culture methods, and bioreactor configurations. We extensively analyze the kinetics of regulated secretion in the context of a controlled secretion process. This discussion is illustrated with experimental results from two model cell lines, recombinant AtT-20 and beta TC3, expressing recombinant human endocrine hormones or native murine insulin respectively.

Animals