Femtosecond lasers weld neurons back together
Researchers used a near-infrared femtosecond laser to perform "hemifusion" of healthy soma and axons.
Intact neuronal cells consisting of soma (the main cell body), dendrites (structures that branch off the soma), and the axon (a long extension from the cell body that connects to other soma, dendrites, or axons) process and transfer information via electrical impulses and chemical signals. Of course, when these neuronal pathways are disrupted, communication is broken, causing the muscles normally innervated by these synaptic pathways to atrophy and/or die.
Until now, it was not possible to reconnect neuronal tissue. But thanks to ongoing applications development for ultrafast lasers, researchers at the University of Alberta (Edmonton, AB, Canada) have used a near-infrared femtosecond laser with 1.7 (± 0.08) × 1012 W/cm2 intensity and ± 0.5 μm aiming accuracy to perform "hemifusion" of healthy soma and axons. Through ultrafast multiphoton and avalanche ionization processes, the laser pulses induce molecular rearrangement of the phospholipid bilayers, allowing photo-induced ions and electrons to cross over to the central nonpolar region of the phospholipid bilayer and break the bonds of the fatty acid tails, after which the ionized phospholipid molecules seek an equilibrium state and form new bonds with nearby ions. This cross-linking process forms a strong, shared phospholipid bilayer or hemifused membrane-an important implication for potential studies into neuronal regeneration and repair. Reference: N. Katchinskiy et al., Sci. Rep., 6, 20529 (Feb. 5, 2016).