In the autumn of 2014, we presented new stains to conduct live cell imaging of Actin and Tubulin, which I covered in my post 2 new Actin and Tubulin live-cell imaging stains – without transfection!

Fig 1: Live MCF10A cells spheroid stained with SiR-DNA and imaged by confocal microscopy. Courtesy of C. Conrad and K. Jechow (Heidelberg).

SiR-Actin and SiR-Tubulin exhibit a number of benefits which have since then be experienced by a huge number of labs all over the world:

• No transfection
• No washing steps
• No toxic effects if used in the concentration range recommended
• Excellent brightness
• Far-red excitation & emission
• Deep tissue penetration and minimal background
• Multiple fluorescent stainings with other dyes possible
• Compatible with Superresolution microscopic techniques

Since then, Spirochrome has added another stain with the same benefits: SiR-DNA, a far-red, fluorogenic, cell permeable and highly specific probe for DNA (see Fig 1).

SLAS – High Content Screening Conference

From June 27th to June 29th, the SLAS – High Content Screening Conference took place in Dresden/Germany. The conference focussed on new essays and novel microscopy techniques.

Spirochrome and tebu-bio were selected to present a poster about the features of SiR-stains, which are excellent tools for phenotypic screening and high content screening (HCS) approaches.

If you are interested in learning more about these exciting live cell imaging tools, don’t hesitate to download our joint poster:

Fluorogenic probes for live-cell imaging of intracellular targets

Any questions or comments? Please feel free to contact me with the form below!

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Fig 1: 3D-SIM microscopy image of labeled Actin stress fibers in human primary dermal fibroblasts.

Launched just over a year ago,  SiR-Actin (Fig 1) and SiR-Tubulin (Fig 2) have been available on the market providing the most convenient tools to stain F-actin and Microtubules in living cells. In the meantime, Spirochrome  have launched a third stain based on the SiR-technology – SiR-DNA (Fig 3) to stain DNA in living cells.
These stains meet the central requirements for live cell imaging tools:

Fig 2: 3D-SIM microscopy image of labeled microtubules in primary rat cortex neuron body.

• high selectivity
• minimal toxicity
• fluorogenic for wash-free imaging
• applicable in different cell types and tissues
• excited by far-red light
• suitable for super-resolution microscopy

For one year now,  SiR-Actin and SiR-Tubulin, the second generation of tools to stain actin and tubulin in living cells, have been available on the market – and although it may sound like an overstatement, these stains have changed the world of Live Cell Imaging.

Actin serves as one of the major cytoskeleton structures. It is a crucial component involved in a plethora of processes in cell biology:  stabilizing the cell shape, cell movements (e.g. cell migration)  and intracellular movements and transport mechanisms.

Actin is a 43 kDa protein that is very highly conserved between species. Actin has three main isotypes (α-actin, β-actin and γ-actin), which show >90% amino-acid (aa) homology between isotypes and >98% homology within members of a particular isotypic group.