Microsphere‐Based Real‐Time Calcium Sensing

Abstract

Nachweis in der Zelle: Mikrokügelchen (2 μm), die kovalent mit Calciumsensoren beladen sind, können effizient in lebende Zellen eingebracht werden, um die intrazellulären Änderungen der Ca2+‐Konzentration in Echtzeit zu analysieren. Das Bild zeigt die ratiometrische Fluoreszenzanalyse (Verhältnis 400/475 nm) der Freisetzung von Ca2+‐Ionen in mit den Mikrokügelchen beladenen Zellen in Echtzeit.

Highly Sensitive and Fast Responsive Fluorescence Turn‐On Chemodosimeter for Cu2+ and Its Application in Live Cell Imaging

“…A widely used strategy is to closely link the metal recognition portion to a fluorophore as the signal generation moiety and then a selective metal ion binding process could induce the fluorescence increase. In this way, several "turn-on" fluorescent probes in living cells for sensing main Group II metal ions (such as Ca 2 + and Mg 2 + ) [10] and transition-metal ions (such as Zn 2 + , [11,12] Abstract: A rhodamine B derivative 4 containing a highly electron-rich S atom has been synthesized as a fluorescence turn-on chemodosimeter for Cu 2 + . Following Cu 2 + -promoted ringopening, redox and hydrolysis reactions, comparable amplifications of absorption and fluorescence signals were observed upon addition of Cu 2 + ; this suggests that chemodosimeter 4 effectively avoided the fluorescence quenching caused by the paramagnetic nature of Cu 2 + .…”

Fluoreszenzbildgebung mit chemischen Sensoren

“…[97] Durch eine nachträgliche Reaktion mit reaktiven Oberflächengruppen kçnnen Fluorophore auch kovalent auf der Partikeloberfläche gebunden werden. [104] Der Einschluss von 2',7'-Dichlordihydrofluoresceindiacetat in Ormosil-NPs führt zu Sonden, mit denen H 2 O 2 hoch selektiv gegenüber anderen reaktiven Sauerstoffspezies in lebenden Zellen bestimmt werden kann. [94b] Nanosonden werden hauptsächlich für die Bestimmung von Sauerstoff, pH-Wert und Ionen (z.…”

“…Prinzipiell kçnnen Lumineszenzsonden und Nanopartikel direkt in biologischen Umgebungen wie Geweben appliziert werden, um so beispielsweise die Verteilung von Calcium, [116] Magnesium, [59] pH-Wert [104,117] oder Wasserstoffperoxid aufzunehmen. [118] Genetisch kodierte Sonden, die an fluoreszierende Proteine konjugiert sind, spielen eine große Rolle für die In-vivo-Bildgebung.…”

Microsphere‐Mediated Protein Delivery into Cells

“…[9][10] These beads have been used for cellular "encoding" as well as for intracellular calcium sensing and pH monitoring; in these cases attachment to the bead avoids the dilution and cellular degradation observed with other, more conventional sensors. [11][12] Recently we have also described the use of streptavidin-loaded microspheres for the delivery of various biotinylated molecules, such as DNA, into cells. We have successfully silenced green fluorescent protein (GFP), which is expressed in human ovarian cancer (HeLa) cells, by using siRNA linked to microspheres through cleavable and noncleavable linkers.…”

“…As expected, cellular uptake was lower compared to microspheres loaded with smaller cargos such as a sensor (Indo-1), while the degree of cellular uptake was influenced by cell type (see the Supporting Information for flow cytometry analysis). [11][12] To further validate beadification as an effective tool for protein delivery, we tested the ability of microspheres to deliver a functional protein (b-galactosidase) into cells. This is a robust model system due to the number of well-known and defined protocols and techniques to analyse its activity in mammalian cells.…”