Hybrid capillary-microfluidic device for the separation, lysis, and electrochemical detection of vesicles

Donna M. Omiatek, Michael F. Santillo, Michael L. Heien, Andrew G. Ewing

Research output: Contribution to journalArticlepeer-review

57 Scopus citations


The primary method for neuronal communication involves the extracellular release of small molecules that are packaged in secretory vesicles. We have developed a platform to separate, lyse, and electrochemically measure the contents of single vesicles using a hybrid capillary-microfluidic device. This device incorporates a sheath-flow design at the outlet of the capillary for chemical lysis of vesicles and subsequent electrochemical detection. The effect of sheath-flow on analyte dispersion was characterized using confocal fluorescence microscopy and electro-chemical detection. At increased flow rates, dispersion was minimized, leading to higher separation efficiencies but lower detected amounts. Large unilamellar vesicles (diameter ̃ 200 nm), a model for secretory vesicles, were prepared by extrusion and loaded with an electroactive molecule. They were then separated and detected using the hybrid capillary-microfluidic device. Determination of size from internalized analyte concentration provides a method to characterize the liposomal suspension. These results were compared to an orthogonal size measurement using dynamic light scattering to validate the detection platform.

Original languageEnglish (US)
Pages (from-to)2294-2302
Number of pages9
JournalAnalytical Chemistry
Issue number6
StatePublished - Mar 15 2009
Externally publishedYes

ASJC Scopus subject areas

  • Analytical Chemistry


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