|
1
|
Hong S, Dechaumphai E, Green CR, Lal R, Murphy AN, Metallo CM, Chen R. Sub-nanowatt microfluidic single-cell calorimetry. Nat Commun 2020; 11:2982. [PMID: 32532969 PMCID: PMC7292832 DOI: 10.1038/s41467-020-16697-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 05/18/2020] [Indexed: 12/02/2022] Open
Abstract
Non-invasive and label-free calorimetry could become a disruptive technique to study single cell metabolic heat production without altering the cell behavior, but it is currently limited by insufficient sensitivity. Here, we demonstrate microfluidic single-cell calorimetry with 0.2-nW sensitivity, representing more than ten-fold enhancement over previous record, which is enabled by (i) a low-noise thermometry platform with ultralow long-term (10-h) temperature noise (80 μK) and (ii) a microfluidic channel-in-vacuum design allowing cell flow and nutrient delivery while maintaining a low thermal conductance of 2.5 μW K−1. Using Tetrahymena thermophila as an example, we demonstrate on-chip single-cell calorimetry measurement with metabolic heat rates ranging from 1 to 4 nW, which are found to correlate well with the cell size. Finally, we perform real-time monitoring of metabolic rate stimulation by introducing a mitochondrial uncoupling agent to the microchannel, enabling determination of the spare respiratory capacity of the cells. Calorimetrically measuring the heat of single cells is currently not possible due to the sensitivity of existing calorimeters. Here the authors present on-chip single cell calorimetry, with a sensitivity over ten-fold greater than the current gold-standard.
Collapse
Affiliation(s)
- Sahngki Hong
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, 92093, USA.,Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Edward Dechaumphai
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Courtney R Green
- Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Ratneshwar Lal
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, 92093, USA.,Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, 92093, USA.,Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Anne N Murphy
- Department of Pharmacology, University of California San Diego, La Jolla, CA, 92093, USA
| | - Christian M Metallo
- Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Renkun Chen
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, 92093, USA. .,Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, 92093, USA.
| |
Collapse
|
|
2
|
Effect of resveratrol on oxygen consumption by Philasterides dicentrarchi, a scuticociliate parasite of turbot. Protist 2012; 164:206-17. [PMID: 22951214 DOI: 10.1016/j.protis.2012.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 07/11/2012] [Accepted: 07/14/2012] [Indexed: 11/22/2022]
Abstract
The phytoalexin resveratrol (RESV) displays antiparasitic activity against Philasterides dicentrarchi, a scuticociliate pathogen of turbot, and causes oxidative stress, inhibition of antioxidant enzyme activity and morphological alterations in the parasite mitochondria. In this study, we analysed the mitochondrial biology of P. dicentrarchi and assessed the effect of RESV on mitochondrial metabolism. We found that RESV caused dose-dependent inhibition of mitochondrial electron transport and O₂ consumption in ciliates permeabilized with digitonin. Although the RESV molecule has a high capacity for antiradical and antioxidant activity, it induced a high level of pro-oxidant activity against the ciliate, thus causing a significant increase in intracellular ROS production. The increased ROS production was accompanied by mitochondrial collapse and dysfunction of mitochondrial membrane potential (ΔΨm) and by a significant increase in intracellular Ca⁺² levels. RESV inhibited parasite growth in a similar way to antimycin A, an inhibitor of mitochondrial electron transport and ROS generator. The findings confirm the mitochondria as a target in the potential development of effective antiparasitic treatments.
Collapse
|