Intracellular protein determination using droplet-based immunoassays


This paper describes the implementation of a sensitive, on-chip immunoassay for the analysis of intracellular proteins, developed using microdroplet technology. The system offers a number of analytical functionalities, enabling the lysis of low cell numbers, as well as protein detection and quantification, integrated within a single process flow. Cells were introduced into the device in suspension and were electrically lysed in situ. The cell lysate was subsequently encapsulated together with antibody-functionalized beads into stable, water-in-oil droplets, which were stored on-chip. The binding of intracellular proteins to the beads was monitored fluorescently. By analyzing many individual droplets and quantifying the data obtained against standard additions, we measured the level of two intracellular proteins, namely, HRas-mCitrine, expressed within HEK-293 cells, and actin-EGFP, expressed within MCF-7 cells. We determined the concentrations of these proteins over 5 orders of magnitude, from ~50 pM to 1 µM. The results from this semiautomated method were compared to those for determinations made using Western blots, and were found not only to be faster, but required a smaller number of cells.

Publication DOI:
Divisions: Life & Health Sciences > Pharmacy
Life & Health Sciences
Life & Health Sciences > Cellular and Molecular Biomedicine
Additional Information: Copyright © 2011 American Chemical Society
Uncontrolled Keywords: Western blotting,calibration,cell line,humans,immunoassay,proteins
Full Text Link: https://strathp ...
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2011-05-16
Authors: Martino, Chiara
Zagnoni, Michele
Sandison, Mairi E.
Chanasakulniyom, Mayuree
Pitt, Andrew ( 0000-0003-3619-6503)
Cooper, Jonathan M.

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