Researchers at the Laboratoire Adaptation Biologique et Vieillissement and the Centre de Recherche Cardiovasculaire de Paris have successfully created cellular magnetic “Legos.” The team incorporated magnetic nanoparticles in cells and developed a system that uses miniaturized magnets. They were able to aggregate cells using only magnets, without an external supporting matrix, then forming a tissue that can be deformed at will. This could prove to be a powerful tool for biophysical studies and the regenerative medicine of tomorrow.
Nanotechnology has swept across the medical field by proposing sometimes unprecedented solutions at the furthest limits of current treatments. This is becoming central to diagnosis and therapy, especially for the regeneration of tissue. A current challenge for regenerative medicine is to create a cohesive and organized cellular assembly without using an external supporting matrix. This is a challenge when it involves synthesizing thick and/or large-size tissue or when the tissues must be stimulated their in vivo counterparts in order to improve functionality.
The researchers met the challenge by using magnetism to act on the cells at a distance, in order to assemble, organize and stimulate them. Cells are magnetized in advance through the incorporation of magnetic nanoparticles and become true cellular magnetic “Legos” that can be moved and stacked using external magnets. In the new system acting as a magnetic tissue stretcher, the magnetized cells are trapped on the first micro magnet before a second, mobile magnet traps the aggregate formed by the cells. The movement of the two magnets can stretch or compress the resulting tissue at will.
Researchers first used embryonic stem cells to test this system. They started by showing the incorporation of nanoparticles had no impact on either the functioning of the stem cell or its capacity for differentiation. These functional magnetic stem cells were tested in the stretcher where they were remarkably differentiated toward cardiac cell precursors when stimulation imposed “magnetic beating” imitating the contraction of the heart. The results demonstrate the role that purely mechanical factors can play in cell differentiation.
The “all-in-one” approach makes it possible to build and manipulate tissue within the same system and could prove to be a powerful tool for biophysical studies and tissue engineering.