1
|
Konz T, Monnard C, Restrepo MR, Laval J, Sizzano F, Girotra M, Dammone G, Palini A, Coukos G, Rezzi S, Godin JP, Vannini N. Multielemental Analysis of Low-Volume Samples Reveals Cancer-Specific Profile in Serum and Sorted Immune Cells. Anal Chem 2020; 92:8750-8758. [PMID: 32460479 DOI: 10.1021/acs.analchem.9b05643] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We developed and validated a reliable, robust, and easy-to-implement quantitative method for multielemental analysis of low-volume samples. Our ICP-MS-based method comprises the analysis of 20 elements (Mg, P, S, K, Ca, V, Cr, Mn, Fe, Co, Cu, Zn, Se, Br, Rb, Sr, Mo, I, Cs, and Ba) in 10 μL of serum and 12 elements (Mg, S, Mn, Fe, Co, Cu, Zn Se, Br, Rb, Mo, and Cs) in less than 250 000 cells. As a proof-of-concept, we analyzed the elemental profiles of serum and sorted immune T cells derived from naı̈ve and tumor-bearing mice. The results indicate a tumor systemic effect on the elemental profiles of both serum and T cells. Our approach highlights promising applications of multielemental analysis in precious samples such as rare cell populations or limited volumes of biofluids that could provide a deeper understanding of the essential role of elements as cofactors in biological and pathological processes.
Collapse
Affiliation(s)
- Tobias Konz
- Nestlé Research, Vers-chez-les-Blanc, Lausanne 1000, Switzerland
| | - Caroline Monnard
- Nestlé Research, Vers-chez-les-Blanc, Lausanne 1000, Switzerland
| | - Marcela Rincon Restrepo
- Laboratory of Immunosenscence and Stem Cell Metabolism, Department of Oncology UNIL CHUV, Ludwig Institute for Cancer Research Lausanne, University of Lausanne, Epalinges 1066, Switzerland
| | - Julie Laval
- Nestlé Research, Vers-chez-les-Blanc, Lausanne 1000, Switzerland
| | - Federico Sizzano
- Nestlé Research, EPFL Innovation Park, Lausanne 1015, Switzerland
| | - Mukul Girotra
- Laboratory of Immunosenscence and Stem Cell Metabolism, Department of Oncology UNIL CHUV, Ludwig Institute for Cancer Research Lausanne, University of Lausanne, Epalinges 1066, Switzerland
| | - Gabriele Dammone
- Nestlé Research, EPFL Innovation Park, Lausanne 1015, Switzerland
| | - Alessio Palini
- Nestlé Research, EPFL Innovation Park, Lausanne 1015, Switzerland
| | - George Coukos
- Human Integrated Tumor Immunology Discovery Engine, Department of Oncology UNIL CHUV, Ludwig Institute for Cancer Research Lausanne, University of Lausanne, Epalinges 1066, Switzerland
| | - Serge Rezzi
- Nestlé Research, Vers-chez-les-Blanc, Lausanne 1000, Switzerland
| | | | - Nicola Vannini
- Laboratory of Immunosenscence and Stem Cell Metabolism, Department of Oncology UNIL CHUV, Ludwig Institute for Cancer Research Lausanne, University of Lausanne, Epalinges 1066, Switzerland
| |
Collapse
|
2
|
Abstract
Detection of chemical processes on a single molecule scale is the ultimate goal of sensitive analytical assays. We recently reported the possibility to detect chemical modifications on individual molecules by monitoring a change in the single ion channel conductance of derivatives of gramicidin A (gA) upon reaction with analytes in solution. These peptide-based nanosensors detect reaction-induced changes in the charge of gA derivatives that were engineered to carry specific functional groups near their C-terminus.1 Here, we discuss five key design parameters to optimize the performance of such chemomodulated ion channel sensors. In order to realize an effective sensor that measures changes in charge of groups attached to the C-terminus of a gA pore, the following conditions should be fulfilled: (1) the change in charge should occur as close to the entrance of the pore as possible; (2) the charge before and after reaction should be well-defined within the operational pH range; (3) the ionic strength of the recording buffer should be as low as possible while maintaining a detectable flow of ions through the pore; (4) the applied transmembrane voltage should be as high as possible while maintaining a stable membrane; (5) the lipids in the supporting membrane should either be zwitterionic or charged differently than the derivative of gA. We show that under the condition of high applied transmembrane potential (>100 mV) and low ionic strength of the recording buffer (< or =0.10 M), a change in charge at the entrance of the pore is the dominant requirement to distinguish between two differently charged derivatives of gA; the conductance of the heterodimeric gA pore reported here does not depend on a difference in charge at the exit of the pore. We provide a simple explanation for this asymmetric characteristic based on charge-induced local changes in the concentration of cations near the lipid bilayer membrane. Charge-based ion channel sensors offer tremendous potential for ultrasensitive functional detection since a single chemical modification of each individual sensing element can lead to readily detectable changes in channel conductance.
Collapse
Affiliation(s)
- Ricardo Capone
- Department of Chemical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, Michigan 48109-2099, USA
| | | | | | | | | |
Collapse
|