FluidFM people: Leena Jaatinen

"With FluidFM I got statistical power"

Pablo Doerig

Interview with Leena Jaatinen

Leena Jaatinen is from the Tampere University of Technology in Finland, and is just finishing her PhD as a long-term guest in the Laboratory of Biosensors and Bioelectronics at ETH Zürich. There, she has been working with both a home-built FluidFM setup and the Nanosurf FlexAFM with FluidFM add-on (FlexFPM). Having more than 4 years of FluidFM experience she is an expert in measuring single cell adhesion.

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Ms. Jaatinen, could you please describe the research focus of your PhD?

I have been studying the effects of electric current on mammalian cells. A wide-spread method is to look at the adhesion of the exposed cells to an electrode substrate.

And that is where FluidFM comes in?

Right! Most studies in my field are based on qualitative methods, such as washing assays, to describe the changes in adhesion Thanks to FluidFM I could really quantify the adhesion, and see significant differences depending of the current density I applied to the cells. That was new and powerful. Ultimately it also gave my work a higher impact in the community.

Do you think you could have performed these quantitative studies with another method?

No, I do not think so. At least nothing that would have been so accessible.

So are you happy with the results you got thanks to FluidFM?

Yes, I am. I could measure 5 to 30 cells per current magnitude and condition, which allowed me to use the standard statistical tools in the field. This means that with FluidFM I got the same statistical power as the established, quantitative, methods. That was obviously very good for the acceptance of my research among my peers.

I am glad to hear that. Could you maybe tell us about the challenges you faced during your studies?

Most challenges were related to the cells and how to keep them alive while applying currents. For example finding the threshold of current where the induced changes were measurable without killing the cell. It was also crucial to keep everything sterile, clean and stable during the experiment and we invested a lot of time optimizing the corresponding protocols. For example we autoclaved the CO2 regulation circuit before each use, as it turned out to be a source of bacterial contamination.

A crucial point was the cleaning of the FluidFM probes; in the beginning they clogged after a few cells despite cleaning them with different solvents. Either I did not clean the cantilevers enough and they clogged or then I used too aggressive cleaning solutions, which destroyed the probeholder or caused leaks. Once we established the appropriate cleaning protocol with bleach that got much better.

The FluidFM probes themselves had some troubles in the early days but now when I open a new blister I am sure the probe works, so that is really good.

Do you think FluidFM is also interesting for other researchers?

Yes I do think it has a lot of potential. I could present my findings in some conferences about the effect of electric fields on mammalian cells, and my peers were intrigued about the possibilities. Many researchers, mostly biologists or medical doctors, are focused on qualitative methods to assess cell adhesion. To be able to actually quantify these effects on a single cell level was fascinating to them. Sometimes they had never heard of AFM before but they could still recognize the possibilities offered by the FluidFM.

In this context, what do you think about the FluidFM BOT?

I find the FluidFM BOT a really cool idea. For biologists a device has to be easy to use and also give them the large number of measurements to obtain statistically meaningful results. The FluidFM BOT can also automate the cleaning of the probes that is a critical and time-consuming step in my (manual) cell adhesion protocol. So I am looking forward to the device, I think people will like it.

If you now could start any research project with FluidFM, what would it be?

I think I would study the adhesion of stem cells, as there is very little (quantitative) data on stem cell adhesion around. Starting out with the basic stem cell it would be worth to quantify and monitor the adhesion as the stem cells differentiate towards more specialized cell types.

In a very similar fashion it would be interesting to study for example cancer cells. For example, could one quantify changes in adhesion forces when the cancer becomes metastatic?

Now that you finished your PhD what are your plans for the future?

For me, research in a company is an option but I am also looking at positions in technical consulting. Both could be equally interesting and I can apply the skills and background acquired during my thesis, I am thinking about areas such as tissue engineering among others.

Thanks a lot for your time Ms. Jaatinen!

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References 

(2016) L. Jaatinen, E. Young, J. Hyttinen, J. Vörös, T. Zambelli and L. Demkó. Quantifying the effect of electric current on cell adhesion studied by single-cell force spectroscopy. Biointerphases, 11(1), 011004. doi:10.1116/1.4940214 


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