Confocal images of a single cell under the magnetic micropen before and after turning on the external field
Single cell manipulation can provide insight into cell mechanics and adhesion, and has a crucial role in in vitro fertilization (IVF). Bartosz Grzybowski at Ulsan National Institute of Science and Technology in South Korea and his team’s new technique for this doesn’t need cells to be magnetically tagged beforehand. It also avoids the risks of heat- or stress-induced cell damage that can occur with other methods.
Grzybowski et al.’s method relies on an iron oxide nanoparticle medium in which cells are suspended. Applying an electromagnet to the magnetic medium through a micropen creates field gradients, which direct the cell to move in a certain direction. By varying how the micropen “tweezers” are positioned, cell movement can be manipulated in both 2 and 3 dimensions.
As well as controlling a single cell, the micropen can be used to pick up several cells together and guide them into regularly shaped clusters. Although it’s a long way off, this could one day be used to make IVF processes more efficient, reducing the number of potential embryos that need to be discarded. It could also be extended to manipulating bacteria and other single-celled organisms to conduct detailed studies on their behaviour.
Read abstract of this article:
Trapping, manipulation and crystallization of live cells using magnetofluidic tweezers J. V. I. Timonen, C. Raimondo, D. Pilans, P. P. Pillai and B. A. Grzybowski*
Nanoscale Horiz., 2017, 2, 50-54
Live mammalian cells are captured and manipulated in magnetofluidic traps created in a suspension of biocompatible, magnetic nanoparticles by a coaxial magnetic/non-magnetic “micropen”. Upon activation by an external electromagnet, the pen creates microscale gradients of magnetic field and nanoparticle concentration that translate into directional and confining forces acting on the cells. Both individual cells and cell collections can be trapped by this method, allowing, for instance, for the formation of regularly shaped cell assemblies. The method does not entail any local heating artifacts and does not require magnetic tagging of the cells.