Issue 9, 2017

Near-infrared luminescent metallacrowns for combined in vitro cell fixation and counter staining

Abstract

Cell fixation is an essential approach for preserving cell morphology, allowing the targeting and labelling of biomolecules with fluorescent probes. One of the key requirements for more efficient fluorescent labelling is the preservation of cell morphology, which usually requires a combination of several fixation techniques. In addition, the use of a counter stain is often essential to improve the contrast of the fluorescent probes. Current agents possess significant limitations, such as low resistance toward photobleaching and sensitivity to changes in the microenvironment. Luminescent Ln3+ ‘encapsulated sandwich’ metallacrowns (MCs) overcome these drawbacks and offer complementary advantages. In particular, they emit sharp emission bands, possess a large difference between excitation and emission wavelengths and do not photobleach. Herein, MCs formed with pyrazinehydroxamic acid (Ln3+[Zn(II)MCpyzHA], Ln3+ = Yb, Nd) were used, combined with near-infrared (NIR) counter staining and fixation agents for HeLa cells upon an initial five minute exposure to UV-A light. The validity and quality of the cell fixation were assessed with Raman spectroscopy. Analysis of the NIR luminescence properties of these MCs was performed under different experimental conditions, including in a suspension of stained cells. Moreover, the high emission intensity of Ln3+[Zn(II)MCpyzHA] in the NIR region allows these MCs to be used for imaging with standard CCD cameras installed on routine fluorescence microscopes. Finally, the NIR-emitting Ln3+[Zn(II)MCpyzHA] compounds combine, within a single molecule, features such as cell fixation and staining abilities, good photostability and minimal sensitivity of the emission bands to the local microenvironment, and they are highly promising for establishing the next generation of imaging agents with a single biodistribution.

Graphical abstract: Near-infrared luminescent metallacrowns for combined in vitro cell fixation and counter staining

Supplementary files

Article information

Article type
Edge Article
Submitted
26 Apr 2017
Accepted
21 Jun 2017
First published
08 Aug 2017
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2017,8, 6042-6050

Near-infrared luminescent metallacrowns for combined in vitro cell fixation and counter staining

I. Martinić, S. V. Eliseeva, T. N. Nguyen, F. Foucher, D. Gosset, F. Westall, V. L. Pecoraro and S. Petoud, Chem. Sci., 2017, 8, 6042 DOI: 10.1039/C7SC01872J

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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