Resistive Analysis of Hydrogen Peroxide in One Axon of Single Neuron with Nanopipets

Electrochemical analysis of intracellular hydrogen peroxide in submicrometer scaled cellular protrusion is challenging and requires a highly sensitive nanoelectrode and advanced electrochemical detection system. In this technical note, a resistive analysis based on acrylic acid polymerization in the nanopipets is established to measure hydrogen peroxide in one axon of single neuron. Upon the position of nanopipet tip inside the axon, hydrogen peroxide is electrokinetically loaded into the pipet to react with ferrous ions generating hydroperoxyl radicals. These radicals initial the polymerization of acrylic acid for the elevation of capillary resistance, as reflected by the drop of the ion current. A 0.3-0.5 nA of current drop is observed supporting the successful analysis of intracellular hydrogen peroxide in the axon. Similar current drops are observed at the body and the axon after the physical loading or physiological stimulation, which suggests even distribution of hydrogen peroxide in the neuron. As compared with the classical amperometric analysis using nanoelectrodes, this new strategy avoids the complexity in the electrode fabrication and the measurement that should facilitate electrochemical analysis of the intracellular molecule at the subcellular level.