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Nanoscale Stress Imaging with Imperfect Diamonds

Periodic Reporting for period 2 - Stress Imaging (Nanoscale Stress Imaging with Imperfect Diamonds)

Reporting period: 2018-09-01 to 2020-02-29

"Free radicals play a role in several processes in healthy individuals including how we defend ourselfes against bacteria or viruses, how cells talk to one another or how our cells age. But they are also present, when a cell responds to stress for instance when a cancer cell is killed by a drug. However, depite their importance it is currently not possible to measure both their identity and locationin living cells.In the ERC project we aim to change this with the help of quantum physics. In the first half on the ERC project we have already succeeded to bring tiny diamonds into cells. These diamonds interact with the radicals in their surrounding. By measuring how these special diamonds change their brightness we can extract information that is similar to an MRI. With the difference, that we can see much smaller signals. Using this method we can for instance differentiate between young and old cells or how much of these radicals our immune cells generate when we are stimulating them. These measurements could be used to get a better understanding on the many processes they are involved in. Apart from that the fact that they are part of the working mechanism of many drugs this information could be used to predict wether or not a drug candidate could work. While we have so far mainly proven that the technique works at all and answered the question ""How many radicals are there?"" we will now also start to answer the question ""Which ones are created?"""
The first part of the project was dominated by equipment building as well as optimization of samples. However, we were also already able to obtain first results on biological samples.
So far we have performed T1 measurements on yeasts and macrophages as well as reference samples. In macrophages we were able to follow nitric oxide signaling. There we are able to measure triggering and inhibition of free radical production. We also have already achieved to gain some control over the particle location within the cell by attaching antibodies to the diamond surface. So far co-localisation with the nucleus or with mitochondria has been shown.
In yeast cells we were able to improve diamond uptake and to diffententiate between young and old cells, between different knock-out strains. Additionally, we compared cells that were aged in presence or absence of an antioxidant.
The measurements on test samples helped us to identify which particles and which data analysis method are best to use . Additionally, we could learn from this data what our signals mean.
We have implemented 3D particle tracking was essential record a signal at all from a particle that is moving. However, particle trajectories give interesting additional insights. How fast a particle is moving inside the cell can for instance indicate where within a cell it is. Additionally, one can use the natural movement to obtain information on different parts of the cell. On our way to differentiating between radicals we have adapted the measuring program for pulsing and upgraded the equipment in the group.
For all the experiments that we have done with our technique we have also compared with the closest standard techniques.
While diamond magnetometry has already had some success in the fields of physics, it is rather new in biology. When it comes to work in cells, the only work that has been done before is measuring a cell sample that has been marked with spin labels. In addition to that a different way to use diamond magnetometry has been used to measure temperatures inside cells. Measuring free radicals (or any metabolic activity from a cell) is entirely new. In the remaining time of the project we aim to provide a tool which can at least to some extend differentiate between different radicals. We also plan to found a company which will make the technology more broadly avalable.