Title: Electrokinetically Altered Normal Saline Modulates Ion Channel Activity
Abstract: Normal saline (0.9% NaCl) was subjected to Taylor-Couette-Poiseuille (TCP) flow in the presence of oxygen in a mixing device that facilitates controlled turbulence and cavitation events. The resultant solution, RNS60, is proposed to contain charge-stabilized nanostructures consisting of a nanobubble core surrounded by an electrical double-layer at the liquid/gas interface. Through various methods (ICP, TOF mass spectroscopy, and UV-Vis, NMR, Raman spectroscopy) we find that RNS60 has no detectable contaminant species, and that the fluid is chemically equivalent to normal saline. Nanoparticle tracking analysis provides evidence for the presence of nanoscale structures in RNS60 bulk fluid, and tapping-mode AFM observations reveal differences in the nanobubbles formed on hydrophobic surfaces. Using whole-cell electrophysiology, we have detected bioactive interactions of RNS60 with the cell membrane. Transient receptor potential type V1 (TRPV1) current is strongly inhibited by physiological saline containing RNS60. Prolonged activation by capsaicin is significantly reduced (−85.9 +/− 7.0 %), while perfusion switch to RNS60 solution during acute application of capsaicin also shows rapid inhibition (−42.5 +/−14.7%). Further, with cys-loop protein family member 5HT3A, potentiation of serotonin-evoked current is observed (101.9 +/− 24.2%). These results suggest that a stable, chemically unaltered saline solution is able to interact strongly on the biological membrane to modulate activity of specific ion channels.