The electrical responses of vanadium pentoxide nanowires to helium gas and environmental pressures are demonstrated. The devices feature well-aligned nanowires that are oriented by electrophoresis technique in the submicron scale. The electrical conductance is found to increase and decrease upon exposure to helium gas and air, respectively. This electrical response to helium is due to physical adsorption of the helium atoms into the interlayer of vanadium pentoxide nanowires. Furthermore, we observe flow-rate-dependent conductance variations such that the conductance is increased with stepwise behavior to the increase of flow rate of helium. (c) 2005 American Institute of Physics.