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Di W, Clark HA. Optical Nanosensors for in vivo Physiological Chloride Detection for Monitoring Cystic Fibrosis Treatment. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2020; 12:1441-1448. [PMID: 32226484 PMCID: PMC7100910 DOI: 10.1039/c9ay02717c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Personalized approaches for continuous monitoring of chloride levels are potentially valuable for evaluating the efficacy of new treatments of genetic disorders such as cystic fibrosis. In this report, we validated optode-based nanosensors for real-time chloride monitoring in the interstitial fluid of living animals. These nanosensors take advantage of a ratiometric sensing scheme which demonstrates reversible and selective chloride detection in the physiological range. We further investigate how skin pigmentation affects the sensor performance during in vivo fluorescence imaging. We successfully monitored endogenous chloride changes using nanosensors during pharmacological treatment in a cystic fibrosis mouse model. We believe this platform is a valuable tool for chloride detection which could assess the efficacy of new treatments for cystic fibrosis.
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Affiliation(s)
- Wenjun Di
- Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Heather A Clark
- Department of Bioengineering, Northeastern University, Boston, Massachusetts 02115, United States
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
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2
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Live-Cell Imaging of Physiologically Relevant Metal Ions Using Genetically Encoded FRET-Based Probes. Cells 2019; 8:cells8050492. [PMID: 31121936 PMCID: PMC6562680 DOI: 10.3390/cells8050492] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/17/2019] [Accepted: 05/21/2019] [Indexed: 01/02/2023] Open
Abstract
Essential biochemical reactions and processes within living organisms are coupled to subcellular fluctuations of metal ions. Disturbances in cellular metal ion homeostasis are frequently associated with pathological alterations, including neurotoxicity causing neurodegeneration, as well as metabolic disorders or cancer. Considering these important aspects of the cellular metal ion homeostasis in health and disease, measurements of subcellular ion signals are of broad scientific interest. The investigation of the cellular ion homeostasis using classical biochemical methods is quite difficult, often even not feasible or requires large cell numbers. Here, we report of genetically encoded fluorescent probes that enable the visualization of metal ion dynamics within individual living cells and their organelles with high temporal and spatial resolution. Generally, these probes consist of specific ion binding domains fused to fluorescent protein(s), altering their fluorescent properties upon ion binding. This review focuses on the functionality and potential of these genetically encoded fluorescent tools which enable monitoring (sub)cellular concentrations of alkali metals such as K+, alkaline earth metals including Mg2+ and Ca2+, and transition metals including Cu+/Cu2+ and Zn2+. Moreover, we discuss possible approaches for the development and application of novel metal ion biosensors for Fe2+/Fe3+, Mn2+ and Na+.
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3
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Galyean AA, Behr MR, Cash KJ. Ionophore-based optical nanosensors incorporating hydrophobic carbon dots and a pH-sensitive quencher dye for sodium detection. Analyst 2017; 143:458-465. [PMID: 29226289 DOI: 10.1039/c7an01382e] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Nanosensors present a biological monitoring method that is biocompatible, reversible, and nano-scale, and they offer many advantages over traditional organic indicators. Typical ionophore-based nanosensors incorporate nile-blue derivative pH indicators but suffer from photobleaching while quantum dot alternatives pose a potential toxicity risk. In order to address this challenge, sodium selective nanosensors containing carbon dots and a pH-sensitive quencher molecule were developed based on an ion-exchange theory and a decoupled recognition element from the pH indicator. Carbon dots were synthesized and integrated into nanosensors containing a pH-indicator, an analyte-binding ligand (ionophore), and a charge-balancing additive. These nanosensors are ion-selective against potassium (selectivity coefficient of 0.4) and lithium (selectivity coefficient of 0.9). Reversible nanosensor response to sodium is also demonstrated. The carbon dot nanosensors are resistant to changes in optical properties for at least 12 h and display stable selectivity to physiologically-relevant sodium (alpha = 0.5 of 200 mM NaCl) for a minimum of 6 days.
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Affiliation(s)
- A A Galyean
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, Colorado 80401, USA.
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4
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Ruckh TT, Skipwith CG, Chang W, Bulovic V, Anikeeva P, Clark HA. Ion-Switchable Quantum Dot Förster Resonance Energy Transfer Rates in Ratiometric Potassium Sensors. ACS NANO 2016; 10:4020-30. [PMID: 27089024 PMCID: PMC5270641 DOI: 10.1021/acsnano.5b05396] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The tools for optically imaging cellular potassium concentrations in real-time are currently limited to a small set of molecular indicator dyes. Quantum dot-based nanosensors are more photostable and tunable than organic indicators, but previous designs have fallen short in size, sensitivity, and selectivity. Here, we introduce a small, sensitive, and selective nanosensor for potassium measurements. A dynamic quencher modulates the fluorescence emitted by two different quantum dot species to produce a ratiometric signal. We characterized the potassium-modulated sensor properties and investigated the photonic interactions within the sensors. The quencher's protonation changes in response to potassium, which modulates its Förster radiative energy transfer rate and the corresponding interaction radii with each quantum dot species. The nanosensors respond to changes in potassium concentrations typical of the cellular environment and thus provide a promising tool for imaging potassium fluxes during biological events.
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Affiliation(s)
- Timothy T. Ruckh
- Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Ave, Boston, MA 02115
| | - Christopher G. Skipwith
- Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Ave, Boston, MA 02115
| | - Wendi Chang
- Department of Electrical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139
| | - Vladimir Bulovic
- Department of Electrical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139
| | - Polina Anikeeva
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139
| | - Heather A. Clark
- Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Ave, Boston, MA 02115
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5
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Sahari A, Ruckh T, Hutchings R, Clark H. Development of an Optical Nanosensor Incorporating a pH-Sensitive Quencher Dye for Potassium Imaging. Anal Chem 2015; 87:10684-7. [PMID: 26444247 PMCID: PMC5241046 DOI: 10.1021/acs.analchem.5b03080] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
One of the key challenges in the design of a sensor for measuring extracellular changes in potassium concentration is selectivity against the competing cation, sodium. Here, we present an optode-based nanosensor selective to potassium ions, owing to the addition of a pH-sensitive quencher molecule paired with a static fluorophore. The nanosensor was fabricated using emulsification and characterized in solution by absorbance and fluorescence spectroscopy. The resulting nanosensor detected potassium with nearly 1 order of magnitude higher selectivity compared to our chromoionophore-based optode nanosensors. In addition to the improved selectivity, the nanosensor has the following properties required for measurements in a biological environment: (1) a physiologically relevant dynamic range, (2) response to potassium ions at a physiological ionic strength, and (3) response to serum potassium in the presence of fouling biological components. The potassium nanosensor described in this study is envisioned to have application in cellular imaging and drug screening.
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Affiliation(s)
- Ali Sahari
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115
| | - Tim Ruckh
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115
| | | | - Heather Clark
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115
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6
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Ion selective optodes: from the bulk to the nanoscale. Anal Bioanal Chem 2015; 407:3899-910. [DOI: 10.1007/s00216-014-8413-4] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 12/08/2014] [Accepted: 12/13/2014] [Indexed: 01/06/2023]
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7
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Awqatty B, Samaddar S, Cash KJ, Clark HA, Dubach JM. Fluorescent sensors for the basic metabolic panel enable measurement with a smart phone device over the physiological range. Analyst 2014; 139:5230-8. [DOI: 10.1039/c4an00999a] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Mistlberger G, Crespo GA, Bakker E. Ionophore-based optical sensors. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2014; 7:483-512. [PMID: 25014348 DOI: 10.1146/annurev-anchem-071213-020307] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This review provides an overview of the key aspects of designing ionophore-based optical sensors (IBOS). Exact response functions are developed and compared with a simplified, generalized equation. We also provide a brief introduction into less established but promising working principles, namely dynamic response and exhaustive exchange. Absorbance and fluorescence are the main optical readout strategies used in the evaluation of a sensor response, but they usually require a robust referencing technique for real-world applications. Established referencing schemes using IBOS as well as those from other optical sensors are also discussed. Finally, the power of recently developed photoresponsive ion extraction/release systems is outlined and discussed in view of dynamically switchable IBOS or regenerative exhaustive exchange IBOS.
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Affiliation(s)
- Günter Mistlberger
- Department of Inorganic and Analytical Chemistry, University of Geneva, CH-1211 Geneva 4, Switzerland; , ,
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9
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Asselin J, Roy C, Boudreau D, Messaddeq Y, Bouchareb R, Mathieu P. Supported core–shell nanobiosensors for quantitative fluorescence imaging of extracellular pH. Chem Commun (Camb) 2014; 50:13746-9. [DOI: 10.1039/c4cc06075j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
“Click” chemistry was used to functionalize silica substrates with pH-sensitive nanoparticles, thus producing uniform and highly luminescent ion-sensitive surfaces for quantitative and spatially-resolved extracellular measurements on live cells.
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Affiliation(s)
- Jérémie Asselin
- Département de chimie
- Faculté de Sciences et Génie
- Université Laval
- Québec (QC), Canada G1V 0A6
- Centre d'optique photonique et laser (COPL)
| | - Carl Roy
- Département de chimie
- Faculté de Sciences et Génie
- Université Laval
- Québec (QC), Canada G1V 0A6
- Centre d'optique photonique et laser (COPL)
| | - Denis Boudreau
- Département de chimie
- Faculté de Sciences et Génie
- Université Laval
- Québec (QC), Canada G1V 0A6
- Centre d'optique photonique et laser (COPL)
| | - Younès Messaddeq
- Centre d'optique photonique et laser (COPL)
- Université Laval
- Québec (QC), Canada G1V 0A6
| | - Rihab Bouchareb
- Laboratoire d'études moléculaires des valvulopathies
- Institut universitaire de cardiologie et de pneumologie de Québec
- Université Laval
- Québec (QC), Canada G1V 4G5
| | - Patrick Mathieu
- Laboratoire d'études moléculaires des valvulopathies
- Institut universitaire de cardiologie et de pneumologie de Québec
- Université Laval
- Québec (QC), Canada G1V 4G5
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Ruckh TT, Mehta AA, Dubach JM, Clark HA. Polymer-free optode nanosensors for dynamic, reversible, and ratiometric sodium imaging in the physiological range. Sci Rep 2013; 3:3366. [PMID: 24284431 PMCID: PMC3842545 DOI: 10.1038/srep03366] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 11/12/2013] [Indexed: 11/10/2022] Open
Abstract
This work introduces a polymer-free optode nanosensor for ratiometric sodium imaging. Transmembrane ion dynamics are often captured by electrophysiology and calcium imaging, but sodium dyes suffer from short excitation wavelengths and poor selectivity. Optodes, optical sensors composed of a polymer matrix with embedded sensing chemistry, have been translated into nanosensors that selectively image ion concentrations. Polymer-free nanosensors were fabricated by emulsification and were stable by diameter and sensitivity for at least one week. Ratiometric fluorescent measurements demonstrated that the nanosensors are selective for sodium over potassium by ~1.4 orders of magnitude, have a dynamic range centered at 20 mM, and are fully reversible. The ratiometric signal changes by 70% between 10 and 100 mM sodium, showing that they are sensitive to changes in sodium concentration. These nanosensors will provide a new tool for sensitive and quantitative ion imaging.
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Affiliation(s)
- Timothy T. Ruckh
- Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Avenue, Boston, MA 02115
- These authors contributed equally to this work
| | - Ankeeta A. Mehta
- Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Avenue, Boston, MA 02115
- These authors contributed equally to this work
| | - J. Matthew Dubach
- Department of Bioengineering, Northeastern University, 360 Huntington Avenue, Boston, MA 02115
| | - Heather A. Clark
- Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Avenue, Boston, MA 02115
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11
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Development of a potassium-selective optode for hydroponic nutrient solution monitoring. Anal Chim Acta 2012; 737:72-82. [DOI: 10.1016/j.aca.2012.05.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 05/15/2012] [Accepted: 05/16/2012] [Indexed: 11/23/2022]
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12
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Xie L, Qin Y, Chen HY. Polymeric optodes based on upconverting nanorods for fluorescent measurements of pH and metal ions in blood samples. Anal Chem 2012; 84:1969-74. [PMID: 22320710 DOI: 10.1021/ac203003w] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Optical thin films incorporating NaYF(4):Er,Yb upconverting nanorods and chromoionophore ETH 5418 in hydrophobic polymer matrixes have been developed for the first time to measure pH and metal ions based on the ion-exchange mechanism. The absorption spectra of protonated and unprotonated ETH 5418 overlap the two emission peaks of upconverting material, respectively, which makes the inert nanorods ion-sensitive. Optodes for pH and metal ions (Na(+), K(+), Ca(2+), and Cu(2+)) were investigated and exhibited excellent sensitivity, selectivity, and reproducibility. Because of excitation by the 980 nm laser source, detection in the near-infrared region at 656 nm, and high quantum yield of the nanorods in hydrophobic membrane, the proposed sensors have been successfully used in whole blood measurements with minimized background absorption and sample autofluorescence.
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Affiliation(s)
- Liangxia Xie
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
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13
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Dubach JM, Balaconis MK, Clark HA. Fluorescent nanoparticles for the measurement of ion concentration in biological systems. J Vis Exp 2011:2896. [PMID: 21750495 PMCID: PMC3196184 DOI: 10.3791/2896] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Tightly regulated ion homeostasis throughout the body is necessary for the prevention of such debilitating states as dehydration.1 In contrast, rapid ion fluxes at the cellular level are required for initiating action potentials in excitable cells.2 Sodium regulation plays an important role in both of these cases; however, no method currently exists for continuously monitoring sodium levels in vivo3 and intracellular sodium probes 4 do not provide similar detailed results as calcium probes. In an effort to fill both of these voids, fluorescent nanosensors have been developed that can monitor sodium concentrations in vitro and in vivo.5,6 These sensors are based on ion-selective optode technology and consist of plasticized polymeric particles in which sodium specific recognition elements, pH-sensitive fluorophores, and additives are embedded.7-9 Mechanistically, the sodium recognition element extracts sodium into the sensor. 10 This extraction causes the pH-sensitive fluorophore to release a hydrogen ion to maintain charge neutrality within the sensor which causes a change in fluorescence. The sodium sensors are reversible and selective for sodium over potassium even at high intracellular concentrations.6 They are approximately 120 nm in diameter and are coated with polyethylene glycol to impart biocompatibility. Using microinjection techniques, the sensors can be delivered into the cytoplasm of cells where they have been shown to monitor the temporal and spatial sodium dynamics of beating cardiac myocytes.11 Additionally, they have also tracked real-time changes in sodium concentrations in vivo when injected subcutaneously into mice.3 Herein, we explain in detail and demonstrate the methodology for fabricating fluorescent sodium nanosensors and briefly demonstrate the biological applications our lab uses the nanosensors for: the microinjection of the sensors into cells; and the subcutaneous injection of the sensors into mice.
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Dubach JM, Lim E, Zhang N, Francis KP, Clark H. In vivo sodium concentration continuously monitored with fluorescent sensors. Integr Biol (Camb) 2010; 3:142-8. [PMID: 21088796 DOI: 10.1039/c0ib00020e] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sodium balance is vital to maintaining normal physiological function. Imbalances can occur in a variety of diseases, during certain surgical operations or during rigorous exercise. There is currently no method to continuously monitor sodium concentration in patients who may be susceptible to hyponatremia. Our approach was to design sodium specific fluorescent sensors capable of measuring physiological fluctuations in sodium concentration. The sensors are submicron plasticized polymer particles containing sodium recognition components that are coated with biocompatible poly(ethylene) glycol. Here, the sensors were brought up in saline and placed in the subcutaneous area of the skin of mice by simple injection. The fluorescence was monitored in real time using a whole animal imager to track changes in sodium concentrations. This technology could be used to monitor certain disease states or warn against dangerously low levels of sodium during exercise.
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Affiliation(s)
- J Matthew Dubach
- Department of Bioengineering, Northeastern University, 360 Huntington Ave., Boston, MA 02115, USA
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