Electrically controlled nicotine delivery through Carbon nanotube membranes via electrochemical oxidation and nanofluidically enhanced electroosmotic flow.

Abstract

A promising tool for nicotine addiction treatment is a programmable nicotine delivery device coupled to smart phone-assisted behavioral therapies. Key metrics for such a device are delivery of adjustable nicotine doses tailored to individual needs, compact size and power efficiency. Reported here is a detailed optimization of carbon nanotube (CNT) membrane fabrication based on electrochemical oxidation, to improve its electrically driven performance for nicotine fluxes and switching ON (-1.5\xa0V)-OFF (0\xa0V) flux ratio. ON- state nicotine flux of\u2009~\u20096 µmoles/cm2/h at -1.5\xa0V applied bias was achieved allowing\u2009~\u20096-folds decrease in the size of device (4 cm2) to attain flux equivalent to high dose nicotine gum (1.1 µmoles/cm2/h). Application of\u2009+\u20091.5\xa0V bias in OFF state reduced diffusional background flux, giving an ON (-1.5\xa0V)/OFF (+\u20091.5\xa0V) flux ratio of 68 that enabled device to deliver between the highest nicotine gum (1.1 µmoles/cm2/h) and lowest nicotine patch (0.08 µmoles/cm2/h) doses, as well as taper off nicotine doses for long term addiction treatment. The nicotine transport mechanism was studied as a function of pH and applied bias, using neutral tracer molecule, showing a mechanism of both electroosmosis and electrophoresis in the atomically smooth nanofluidic pores of CNTs. Optimal power consumption/flux efficiency of 111(µW/cm2)/µmoles/cm2/h was achieved allowing watch-battery lifetimes of 7-62\xa0days for conventional treatment dosing regimens. Bluetooth-enabled, remotely controlled CNT membrane system has potential for treatments of nicotine, opioid and alcohol addictions that needs dose adjustment with precise temporal control.