1
|
Saboktakin Rizi B, Braasch K, Salimi E, Butler M, Bridges GE, Thomson DJ. Monitoring the dielectric response of single cells following mitochondrial adenosine triphosphate synthase inhibition by oligomycin using a dielectrophoretic cytometer. BIOMICROFLUIDICS 2014; 8:064114. [PMID: 25553191 PMCID: PMC4257975 DOI: 10.1063/1.4903221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/18/2014] [Indexed: 06/04/2023]
Abstract
One of the main uses of adenosine triphosphate (ATP) within mammalian cells is powering the Na(+)/K(+) ATPase pumps used to maintain ion concentrations within the cell. Since ion concentrations determine the cytoplasm conductivity, ATP concentration is expected to play a key role in controlling the cytoplasm conductivity. The two major ATP production pathways within cells are via glycolysis within the cytoplasm and via the electron transport chain within the mitochondria. In this work, a differential detector combined with dielectrophoretic (DEP) translation in a microfluidic channel was employed to observe single cell changes in the cytoplasm conductivity. The DEP response was made sensitive to changes in cytoplasm conductivity by measuring DEP response versus media conductivity and using double shell models to choose appropriate frequencies and media conductivity. Dielectric response of Chinese hamster ovary (CHO) cells was monitored following inhibition of the mitochondria ATP production by treatment with oligomycin. We show that in CHO cells following exposure to oligomycin (8 μg/ml) the cytoplasm conductivity drops, with the majority of the change occurring within 50 min. This work demonstrates that dielectric effects due to changes in ATP production can be observed at the single cell level.
Collapse
Affiliation(s)
- B Saboktakin Rizi
- Department of Electrical and Computer Engineering, University of Manitoba , Winnipeg, Manitoba R3T5V6, Canada
| | - K Braasch
- Department of Microbiology, University of Manitoba , Winnipeg, Manitoba R3T5V6, Canada
| | - E Salimi
- Department of Electrical and Computer Engineering, University of Manitoba , Winnipeg, Manitoba R3T5V6, Canada
| | - M Butler
- Department of Microbiology, University of Manitoba , Winnipeg, Manitoba R3T5V6, Canada
| | - G E Bridges
- Department of Electrical and Computer Engineering, University of Manitoba , Winnipeg, Manitoba R3T5V6, Canada
| | - D J Thomson
- Department of Electrical and Computer Engineering, University of Manitoba , Winnipeg, Manitoba R3T5V6, Canada
| |
Collapse
|
2
|
Nikolic-Jaric M, Cabel T, Salimi E, Bhide A, Braasch K, Butler M, Bridges GE, Thomson DJ. Differential electronic detector to monitor apoptosis using dielectrophoresis-induced translation of flowing cells (dielectrophoresis cytometry). BIOMICROFLUIDICS 2013; 7:24101. [PMID: 24404007 PMCID: PMC3598809 DOI: 10.1063/1.4793223] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 02/01/2013] [Indexed: 05/26/2023]
Abstract
The instrument described here is an all-electronic dielectrophoresis (DEP) cytometer sensitive to changes in polarizability of single cells. The important novel feature of this work is the differential electrode array that allows independent detection and actuation of single cells within a short section ([Formula: see text]) of the microfluidic channel. DEP actuation modifies the altitude of the cells flowing between two altitude detection sites in proportion to cell polarizability; changes in altitude smaller than 0.25 μm can be detected electronically. Analysis of individual experimental signatures allows us to make a simple connection between the Clausius-Mossotti factor (CMF) and the amount of vertical cell deflection during actuation. This results in an all-electronic, label-free differential detector that monitors changes in physiological properties of the living cells and can be fully automated and miniaturized in order to be used in various online and offline probes and point-of-care medical applications. High sensitivity of the DEP cytometer facilitates observations of delicate changes in cell polarization that occur at the onset of apoptosis. We illustrate the application of this concept on a population of Chinese hamster ovary (CHO) cells that were followed in their rapid transition from a healthy viable to an early apoptotic state. DEP cytometer viability estimates closely match an Annexin V assay (an early apoptosis marker) on the same population of cells.
Collapse
Affiliation(s)
- Marija Nikolic-Jaric
- Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada
| | - Tim Cabel
- Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada
| | - Elham Salimi
- Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada
| | - Ashlesha Bhide
- Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada
| | - Katrin Braasch
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Michael Butler
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Greg E Bridges
- Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada
| | - Douglas J Thomson
- Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada
| |
Collapse
|