Cell culture is a crucial part of biomedical research in both academia and industry. In vitro cell culture models allow biological systems to be studied and drugs to be developed while reducing the need for animal models. Sterile technique is necessary to ensure that only the cells of interest are growing in the cultures. Contamination, however, is still a relatively common occurrence in cell culture laboratories. Typical contaminants include bacteria, yeast, and mold. These microorganisms can affect the way cells behave in culture and alter the culture conditions by changing the pH or by competing with the cells for resources. Dead cells can also contaminate cultures by distorting cell counts or signaling other cells to die. Contaminants typically have different buoyant densities from the cultured cells. We exploited this difference and developed a method to separate cultured mammalian cells from contaminants on the basis of density using aqueous two-phase systems (ATPS). We tuned the properties of a 7% w/w polyethylene glycol (PEG)−11% w/w Ficoll ATPS to prepare a biocompatible system that removes contaminants and isolates desired cells at the liquid-liquid interface with little to no adverse effects on the viability or growth of the cultured cells. This system can be used to enrich cell culture populations for viable cells and to reduce the number of microorganism contaminants in a culture, which increases the chances of subsequent antibiotic treatments being successful. We tested the effectiveness of our method in model contaminated cultures of both adherent (HeLa) and suspension (HL-60 II) mammalian cells contaminated with bacteria (E. coli), yeast (S. cerevisiae), and nonviable cells.

Enrichment and recovery of mammalian cells from contaminated cultures using aqueous two-phase systems

256th National Meeting (2018)

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