cyanine-dye-3 and Necrosis

Accurate tracing of cell viability is critical for optimizing delivery methods and evaluating the efficacy and safety of cell therapeutics. A nanoparticle-based cell tracker is developed to image cell fate from live to dead. The particle is fabricated from two types of optically quenched polyelectrolytes, a life indicator and a death indicator, through electrostatic interactions. On incubation with cells, the fabricated bifunctional nanoprobes are taken up efficiently and the first colour is produced by normal intracellular proteolysis, reflecting the healthy status of the cells. Depending on the number of coated layers, the signal can persist for several replication cycles. However, as the cells begin dying, the second colour appears quickly to reflect the new cell status. Using this chameleon-like cell tracker, live cells can be distinguished from apoptotic and necrotic cells instantly and definitively.

Topics: Annexin A5; Apoptosis; Biotechnology; Carbocyanines; Cell Line, Tumor; Cell Lineage; Cell Survival; Electrolytes; HeLa Cells; Humans; Microscopy, Fluorescence; Molecular Probes; Molecular Weight; Nanoparticles; Necrosis; Reactive Oxygen Species; Signal Transduction; Static Electricity; Time Factors

Apoptosis, a mechanism of programmed cell death that removes superfluous and harmful cells, is important both during development and in tissue homeostasis. Although Zn2+ is believed to be critical in apoptosis, the precise details of its role have yet to be elucidated. The macrocyclic Zn2+ ligand dansylamidoethylcyclen [L1*(HCl)4*(H2O)2], which is found primarily in a diprotonated form (H2L1), is cell-permeable and forms a strongly fluorescent 1:1 Zn2+ complex when Zn2+ entry into cells is facilitated by the Zn2+ ionophore pyrithione. H2L1 can be used to readily identify HeLa cells undergoing the early stages of etoposide-induced apoptosis because of the increased level of free Zn2+ that occurs at this time. The selectivity of H2L1 for the detection of apoptotic cells was verified by a conventional probe for apoptosis, annexin V-Cy3. Here, we describe methods for detecting apoptotic cells with H2L1 and for comparing detection of apoptosis with H2L1 to detection with annexin V-Cy3 and Zinquin.

Topics: Annexin A5; Apoptosis; Carbocyanines; Cell Line, Tumor; Dansyl Compounds; DNA; DNA Fragmentation; Fluorescent Dyes; HeLa Cells; Heterocyclic Compounds, 1-Ring; Humans; Indicators and Reagents; Intercalating Agents; Ionophores; Necrosis; Propidium; Quinolones; Staining and Labeling; Tosyl Compounds; Zinc