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Oheim M, van 't Hoff M, Feltz A, Zamaleeva A, Mallet JM, Collot M. New red-fluorescent calcium indicators for optogenetics, photoactivation and multi-color imaging. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1843:2284-306. [PMID: 24681159 DOI: 10.1016/j.bbamcr.2014.03.010] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 03/09/2014] [Indexed: 01/15/2023]
Abstract
Most chemical and, with only a few exceptions, all genetically encoded fluorimetric calcium (Ca(2+)) indicators (GECIs) emit green fluorescence. Many of these probes are compatible with red-emitting cell- or organelle markers. But the bulk of available fluorescent-protein constructs and transgenic animals incorporate green or yellow fluorescent protein (GFP and YFP respectively). This is, in part, not only heritage from the tendency to aggregate of early-generation red-emitting FPs, and due to their complicated photochemistry, but also resulting from the compatibility of green-fluorescent probes with standard instrumentation readily available in most laboratories and core imaging facilities. Photochemical constraints like limited water solubility and low quantum yield have contributed to the relative paucity of red-emitting Ca(2+) probes compared to their green counterparts, too. The increasing use of GFP and GFP-based functional reporters, together with recent developments in optogenetics, photostimulation and super-resolution microscopies, has intensified the quest for red-emitting Ca(2+) probes. In response to this demand more red-emitting chemical and FP-based Ca(2+)-sensitive indicators have been developed since 2009 than in the thirty years before. In this topical review, we survey the physicochemical properties of these red-emitting Ca(2+) probes and discuss their utility for biological Ca(2+) imaging. Using the spectral separability index Xijk (Oheim M., 2010. Methods in Molecular Biology 591: 3-16) we evaluate their performance for multi-color excitation/emission experiments, involving the identification of morphological landmarks with GFP/YFP and detecting Ca(2+)-dependent fluorescence in the red spectral band. We also establish a catalog of criteria for evaluating Ca(2+) indicators that ideally should be made available for each probe. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.
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Affiliation(s)
- Martin Oheim
- CNRS, UMR 8154, Paris F-75006, France; INSERM, U603, Paris F-75006, France; University Paris Descartes, PRES Sorbonne Paris Cité, Laboratory of Neurophysiology and New Microscopies, 45 rue des Saints Pères, Paris F-75006, France.
| | - Marcel van 't Hoff
- CNRS, UMR 8154, Paris F-75006, France; INSERM, U603, Paris F-75006, France; University Paris Descartes, PRES Sorbonne Paris Cité, Laboratory of Neurophysiology and New Microscopies, 45 rue des Saints Pères, Paris F-75006, France; University of Florence, LENS - European Laboratory for Non-linear Spectroscopy, Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
| | - Anne Feltz
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), Paris F-75005, France; INSERM U1024, Paris F-75005, France; CNRS UMR 8197, Paris F-75005, France
| | - Alsu Zamaleeva
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), Paris F-75005, France; INSERM U1024, Paris F-75005, France; CNRS UMR 8197, Paris F-75005, France
| | - Jean-Maurice Mallet
- UPMC Université́ Paris 06, Ecole Normale Supérieure (ENS), 24 rue Lhomond, Paris F-75005, France; CNRS UMR 7203, Paris F-75005, France
| | - Mayeul Collot
- UPMC Université́ Paris 06, Ecole Normale Supérieure (ENS), 24 rue Lhomond, Paris F-75005, France; CNRS UMR 7203, Paris F-75005, France
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del Mercato LL, Ferraro MM, Baldassarre F, Mancarella S, Greco V, Rinaldi R, Leporatti S. Biological applications of LbL multilayer capsules: from drug delivery to sensing. Adv Colloid Interface Sci 2014; 207:139-54. [PMID: 24625331 DOI: 10.1016/j.cis.2014.02.014] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/15/2014] [Accepted: 02/15/2014] [Indexed: 11/24/2022]
Abstract
Polyelectrolyte multilayer (PEM) capsules engineered with active elements for targeting, labeling, sensing and delivery hold great promise for the controlled delivery of drugs and the development of new sensing platforms. PEM capsules composed of biodegradable polyelectrolytes are fabricated for intracellular delivery of encapsulated cargo (for example peptides, enzymes, DNA, and drugs) through gradual biodegradation of the shell components. PEM capsules with shells responsive to environmental or physical stimuli are exploited to control drug release. In the presence of appropriate triggers (e.g., pH variation or light irradiation) the pores of the multilayer shell are unlocked, leading to the controlled release of encapsulated cargos. By loading sensing elements in the capsules interior, PEM capsules sensitive to biological analytes, such as ions and metabolites, are assembled and used to detect analyte concentration changes in the surrounding environment. This Review aims to evaluate the current state of PEM capsules for drug delivery and sensing applications.
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