Solid State Physics

Lund University

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Fluorescent nanodiamonds successfully injected into living cells


STED micrograph showing membrane pores at different closing stages after having been opened by electroporation.

Cell membrane recovery on nanostraws after the application of electroporation pulses. STED micrographs of the membrane of live A549 cells on top of nanostraws before, during, 5, 30, and 60 min after the application of low‐voltage EP through the nanostraws. The membrane pores start to close after 30 min and are completely closed 60 min after switching off the EP. From: Small, 17, 7, 2021, 2006421.

Elke Hebisch and Christelle Prinz from the Solid State Physics have succeeded in injecting a large number of nanodiamonds directly into the cell interior.

Diamonds are not only sought after for their beauty, but also for their uniquely luminescent properties, at least among scientists. Unlike other fluorescent materials, they do not bleach.

”We actually think of them as a dye. In addition, they are biocompatible”, says Elke Hebisch, researcher at solid state physics at Lund University.

Diamonds acting like reporters from inside the cell

Together with Professor Christelle Prinz, she has ”injected” fluorescent nano-sized diamonds into living cells.

As a researcher, having such a reporter from inside a cell has many advantages: gaining new knowledge about the cell, as well as monitoring what happens inside the cell over time.

”Especially the latter would be a great step forward, as it is currently possible to take snapshots of, for example, proteins in a cell, but difficult to follow changes over time”, explains Elke Hebisch.

Targeting and understanding disease

What would researchers want to know? It could be about separating healthy cells from diseased ones, targeting disease-causing proteins and other proteins within a specific cell, or monitoring variations in temperature and pH-levels. The knowledge gained could be pure basic research but can also be used to understand diseases and develop drugs.

Other researchers have previously tried to do the same thing, but the diamonds were then taken care of by the cell’s ”cleaners”, the so-called lysosomes, that quickly encapsulated the foreign substance.

Diamonds in a bottle

”In that scenario, they are not useful since they are trapped in lysosomes and unable to interact with the cell components. Others have managed to get the diamonds into the cell one cell at a time, but that is far too time-consuming to become a realistic alternative”, says Christelle Prinz.

The same technique could eventually be used to transport other molecules in order to alter cells or heal diseased cells.

On a final note: is using nanodiamonds expensive? No, Elke Hebisch explains – the quantities needed are extremely small. They are bought in a bottle where they are suspended around in water, and cost the same as regular antibodies.

Read the complete paper at the Journal's site (Open Access)

Nanostraw‐Assisted Cellular Injection of Fluorescent Nanodiamonds via Direct Membrane Opening.
Elke Hebisch, Martin Hjort, Diogo Volpati, Christelle N. Prinz. Small, Volume 17, Issue 7, February 18, 2021, 2006421.