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Abstract
Lipids are essential cellular components forming membranes, serving as energy reserves, and acting as chemical messengers. Dysfunction in lipid metabolism and signaling is associated with a wide range of diseases including cancer and autoimmunity. Heterogeneity in cell behavior including lipid signaling is increasingly recognized as a driver of disease and drug resistance. This diversity in cellular responses as well as the roles of lipids in health and disease drive the need to quantify lipids within single cells. Single-cell lipid assays are challenging due to the small size of cells (∼1 pL) and the large numbers of lipid species present at concentrations spanning orders of magnitude. A growing number of methodologies enable assay of large numbers of lipid analytes, perform high-resolution spatial measurements, or permit highly sensitive lipid assays in single cells. Covered in this review are mass spectrometry, Raman imaging, and fluorescence-based assays including microscopy and microseparations.
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Affiliation(s)
- Ming Yao
- Department of Bioengineering, University of Washington, Seattle, Washington, USA; , ,
| | | | - Nancy L Allbritton
- Department of Bioengineering, University of Washington, Seattle, Washington, USA; , ,
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Wang Y, Yao M, Sims CE, Allbritton NL. Monolithic Silica Microbands Enable Thin-Layer Chromatography Analysis of Single Cells. Anal Chem 2022; 94:13489-13497. [PMID: 36121711 PMCID: PMC9789895 DOI: 10.1021/acs.analchem.2c02622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A picoliter thin-layer chromatography (pTLC) platform was developed for analyzing extremely miniature specimens, such as assay of the contents of a single cell of 1 picoliter volume. The pTLC chip consisted of an array of microscale bands made from highly porous monolithic silica designed to accept picoliter-scale volume samples. pTLC bands were fabricated by combining sol-gel chemistry and microfabrication technology. The width (60-80 μm) and depth (13 μm) of each band is comparable to the size of single cells and acted to reduce the lateral diffusion and confine the movement of compounds along the microbands. Ultrasmall volumes (tens of pL) of model fluorescent compounds were spotted onto the microband by a piezoelectric microdispenser and successfully separated by pTLC. The separation resolution and analyte migration were dependent on the macropore size (ranging from 0.3 to 2.3 μm), which was adjustable by changing the porogen concentration during the sol-gel process. For a 0.3 μm macropore size, attomoles of analyte were detectable by fluorescence using standard microscopy methods. The separation resolution, theoretical plate number, and separation times ranged from 1.3 to 2.1, 4 to 357, and 2 to 8 min, respectively, for the chosen model biological lipids. To demonstrate the capability of pTLC for separating analytes from single mammalian cells, cells loaded with fluorescent lipophilic dyes or sphingosine kinase reporter were spotted on microbands, and the single-cell contents separated by pTLC were detected from their fluorescence. These results demonstrate the potential of pTLC for applications in many areas where miniature specimens and high-throughput parallel analyses are needed.
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Affiliation(s)
- Yuli Wang
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Ming Yao
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Christopher E. Sims
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
- Department of Medicine, University of Washington, Seattle, WA, 98195, USA
| | - Nancy L. Allbritton
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
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Gallion LA, Wang Y, Massaro A, Yao M, Petersen BV, Zhang Q, Huang W, Carr AJ, Zhang Q, Allbritton NL. "Fix and Click" for Assay of Sphingolipid Signaling in Single Primary Human Intestinal Epithelial Cells. Anal Chem 2022; 94:1594-1600. [PMID: 35020354 PMCID: PMC8931668 DOI: 10.1021/acs.analchem.1c03503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Capillary electrophoresis with fluorescence detection (CE-F) is a powerful method to measure enzyme activation in single cells. However, cellular enzymatic assays used in CE-F routinely utilize reporter substrates that possess a bulky fluorophore that may impact enzyme kinetics. To address these challenges, we describe a "fix and click" method utilizing an alkyne-terminated enzyme activation reporter, aldehyde-based fixation, and a click chemistry reaction to attach a fluorophore prior to analysis by single-cell CE-F. The "fix and click" strategy was utilized to investigate sphingolipid signaling in both immortalized cell lines and primary human colonic epithelial cells. When the sphingosine alkyne reporter was loaded into cells, this reporter was metabolized to ceramide (31.6 ± 3.3% peak area) without the production of sphingosine-1-phosphate. In contrast, when the reporter sphingosine fluorescein was introduced into cells, sphingosine fluorescein was converted to sphingosine-1-phosphate and downstream products (32.8 ± 5.7% peak area) without the formation of ceramide. Sphingolipid metabolism was measured in single cells from both differentiated and stem/proliferative human colonic epithelium using "fix and click" paired with CE-F to highlight the diversity of sphingosine metabolism in single cells from primary human colonic epithelium. This novel method will find widespread utility for the performance of single-cell enzyme assays by virtue of its ability to temporally and spatially separate cellular reactions with alkyne-terminated reporters, followed by the assay of enzyme activation at a later time and place.
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Affiliation(s)
- Luke A. Gallion
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina, 27514, United States of America,Department of Bioengineering, University of Washington, Seattle, Washington, 98105, United States of America
| | - Yuli Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, 98105, United States of America
| | - Angelo Massaro
- Department of Bioengineering, University of Washington, Seattle, Washington, 98105, United States of America
| | - Ming Yao
- Department of Bioengineering, University of Washington, Seattle, Washington, 98105, United States of America
| | - Brae V. Petersen
- Department of Bioengineering, University of Washington, Seattle, Washington, 98105, United States of America
| | - Quanzheng Zhang
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, Chapel Hill, North Carolina, 27514, United States of America
| | - Weigang Huang
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, Chapel Hill, North Carolina, 27514, United States of America
| | - Adam J. Carr
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, Chapel Hill, North Carolina, 27514, United States of America
| | - Qisheng Zhang
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, Chapel Hill, North Carolina, 27514, United States of America
| | - Nancy L. Allbritton
- Department of Bioengineering, University of Washington, Seattle, Washington, 98105, United States of America,Correspondence: Nancy L. Allbritton, Department of Bioengineering, University of Washington, Seattle, Washington, 98105, United States of America;
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Kawai T. Recent Advances in Trace Bioanalysis by Capillary Electrophoresis. ANAL SCI 2021; 37:27-36. [PMID: 33041311 DOI: 10.2116/analsci.20sar12] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 09/29/2020] [Indexed: 07/25/2024]
Abstract
Recently, single cell analysis is becoming more and more important to elucidate cellular heterogeneity. Except for nucleic acid that can be amplified by PCR, the required technical level for single cell analysis is extremely high and the appropriate design of sample preparation and a sensitive analytical system is necessary. Capillary/microchip electrophoresis (CE/MCE) can separate biomolecules in nL-scale solution with high resolution, and it is highly compatible with trace samples like a single cell. Coupled with highly sensitive detectors such as laser-induced fluorescence and nano-electrospray ionization-mass spectrometry, zmol level analytes can be detected. For further enhancing sensitivity, online sample preconcentration techniques can be employed. By integrating these high-sensitive techniques, single cell analysis of metabolites, proteins, and lipids have been achieved. This review paper highlights successful research on CE/MCE-based trace bioanalysis in recent 10 years. Firstly, an overview of basic knowledge on CE/MCE including sensitivity enhancement techniques is provided. Applications to trace bioanalysis are then introduced with discussion on current issues and future prospects.
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Affiliation(s)
- Takayuki Kawai
- RIKEN Center for Biosystems Dynamics Research
- Graduate School of Frontier Biosciences, Osaka University
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Kristoff CJ, Bwanali L, Veltri LM, Gautam GP, Rutto PK, Newton EO, Holland LA. Challenging Bioanalyses with Capillary Electrophoresis. Anal Chem 2020; 92:49-66. [PMID: 31698907 PMCID: PMC6995690 DOI: 10.1021/acs.analchem.9b04718] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Courtney J. Kristoff
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Lloyd Bwanali
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Lindsay M. Veltri
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Gayatri P. Gautam
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Patrick K. Rutto
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Ebenezer O. Newton
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Lisa A. Holland
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
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Gallion LA, Anttila MM, Abraham DH, Proctor A, Allbritton NL. Preserving Single Cells in Space and Time for Analytical Assays. Trends Analyt Chem 2020; 122:115723. [PMID: 32153309 PMCID: PMC7061724 DOI: 10.1016/j.trac.2019.115723] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Analytical assays performed within clinical laboratories influence roughly 70% of all medical decisions by facilitating disease detection, diagnosis, and management. Both in clinical and academic research laboratories, single-cell assays permit measurement of cell diversity and identification of rare cells, both of which are important in the understanding of disease pathogenesis. For clinically utility, the single-cell assays must be compatible with the clinical workflow steps of sample collection, sample transportation, pre-analysis processing, and single-cell assay; therefore, it is paramount to preserve cells in a state that resembles that in vivo rather than measuring signaling behaviors initiated in response to stressors such as sample collection and processing. To address these challenges, novel cell fixation (and more broadly, cell preservation) techniques incorporate programmable fixation times, reversible bond formation and cleavage, chemoselective reactions, and improved analyte recovery. These technologies will further the development of individualized, precision therapies for patients to yield improved clinical outcomes.
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Affiliation(s)
- Luke A. Gallion
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Matthew M. Anttila
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
| | - David H. Abraham
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Angela Proctor
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Nancy L. Allbritton
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
- Joint Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC 27599, USA and North Carolina State University, Raleigh, NC 27695, USA
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Abraham DH, Anttila MM, Gallion LA, Petersen BV, Proctor A, Allbritton NL. Design of an automated capillary electrophoresis platform for single-cell analysis. Methods Enzymol 2019; 628:191-221. [PMID: 31668230 DOI: 10.1016/bs.mie.2019.06.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Single-cell analysis of cellular contents by highly sensitive analytical instruments is known as chemical cytometry. A chemical cytometer typically samples one cell at a time, quantifies the cellular contents of interest, and then processes and reports that data. Automation adds the potential to perform this entire sequence of events with minimal intervention, increasing throughput and repeatability. In this chapter, we discuss the design considerations for an automated capillary electrophoresis-based instrument for assay of enzymatic activity within single cells. We describe the key requirements of the microscope base and capillary electrophoresis platforms. We also provide detailed protocols and schematic designs of our cell isolation, lysis, sampling, and detection strategies. Additionally, we describe our signal processing and instrument automation workflows. The described automated system has demonstrated single-cell throughput at rates above 100cells/h and analyte limits of detection as low as 10-20mol.
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Affiliation(s)
- David H Abraham
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, United States
| | - Matthew M Anttila
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, United States
| | - Luke A Gallion
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, United States
| | - Brae V Petersen
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, United States
| | - Angela Proctor
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, United States
| | - Nancy L Allbritton
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, United States; Joint Department of Biomedical Engineering, University of North Carolina, Chapel and North Carolina State University, Raleigh, NC, USA.
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