Focusing of mammalian cells under an ultrahigh pH gradient created by unidirectional electropulsation in a confined microchamber

Despina Nelie Loufakis, Zhenning Cao, Sai Ma, David Mittelman, Chang Lu

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The transport and manipulation of cells in microfluidic structures are often critically required in cellular analysis. Cells typically make consistent movement in a dc electric field in a single direction, due to their electrophoretic mobility or electroosmotic flow or the combination of the two. Here we demonstrate that mammalian cells focus to the middle of a closed microfluidic chamber under the application of unidirectional direct current pulses. With experimental and computational data, we show that under the pulses electrochemical reactions take place in the confined microscale space and create an ultrahigh and nonlinear pH gradient (∼2 orders of magnitude higher than the ones in protein isoelectric focusing) at the middle of the chamber. The varying local pH affects the cell surface charge and the electrophoretic mobility, leading to focusing in free solution. Our approach provides a new and simple method for focusing and concentrating mammalian cells at the microscale.

Original languageEnglish
Pages (from-to)3331-3337
Number of pages7
JournalChemical Science
Volume5
Issue number8
DOIs
StatePublished - Aug 2014
Externally publishedYes

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