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The microscopic world of cells and bacteria is incredibly important to understand, but it is difficult to study in detail, especially without harm to the subjects. Researchers from EPFL have developed a new microscopy technique that combines two existing ones, which allows scientists to create three-dimensional images of cells inside and outside with high resolution.

Scientists have access to many different methods of obtaining images using a microscope, but all have their pros and cons. Electron microscopy can reveal complex details of the sample surface, but it cannot be used on living cells because the intensity of the electron beam destroys the sample. Other methods, such as fluorescence microscopy, do not damage the sample, but it lacks resolution.

So, for the new study, scientists from EPFL started by developing their own visualization technique. It is based on an existing technique called scanning probe microscopy, in which the tip of the probe penetrates into the sample to display its surface.

However, this is aggressive for cells, so the EPFL team replaced this probe with a glass nanopore that measures the flow of ions without having to touch the sample. They called this method ion conduction scanning microscopy (SICM).

Scientists have combined this new SICM technique with an existing one called stochastic optical fluctuation imaging (SOFI), which can look inside cells to observe various molecules and processes occurring in them.

These two methods together allow scientists to simultaneously obtain high-resolution three-dimensional images of the inner and outer surfaces of cells.

"The cell membrane is the place where it interacts with the environment," says Samuel Mendes Leitau, author of the study.

"Many biological processes and morphological changes occur here, for example, when cells are infected. Our system allows researchers to analyze the molecular structures inside the cell and determine how they relate to the dynamics of the membrane."

Perhaps most importantly, they can track processes over time on a scale from a second to several days. During the tests, the team of scientists was able to observe how mammalian cells move, communicate, differentiate, absorb molecules through their membranes and become infected with bacteria.

The researchers say the new technology will be a very useful tool for infection biology, immunology and neuroscience, but could also find applications in other fields such as energy.

PHOTO: A new combination of microscopy techniques allows scientists to obtain images of cells inside and outside in high resolution and 3D. © LBNI-LBEN

ab-news.ru (Maria Samsonova)