A chamber for biomechanical, electrochemical and electrophysiological measurements in functional segments of peripheral nerves

Abstract

The aim of the work was to develop the chamber to be used in biomechanical, electrochemical and electrophysiological measurements in functional segments of peripheral nerves, when electrical stimulating pulses are selectively applied to preselected locations along the nerve and neural responses are measured.The main part of the chamber is the silicone multi-electrode spiral cuff system (cuff). It includes a spirally rolled matrix of 99 platinum electrodes, arranged in eleven longitudinal spiral configurations of nine electrodes for establishing electrical contact with specific sites on the peripheral nerve.The chamber is constructed to enable simulation of various mechanical actions which could occur when the spiral cuff is installed on the nerve. For this purpose the chamber is equipped with sensors for measurement of stretching forces, spiral cuff diameter/radial pressure and stretching elongation. Nevertheless, the chamber is equipped also with a 3D micro-manipulator for precise positioning of various stimulating or recording microelectrodes.To perform electrochemical measurements using the method of cyclic voltammetry, the chamber is instrumented also with a Ag/AgCl reference electrode.To maintain appropriate thermal conditions, the chamber body was machined out from Plexiglas using a CNC milling machine and is instrumented with a water bath circulator and with a precision temperature probe for precise temperature regulation.A functionality of both, the developed experimental chamber and a single-part cuff was tested on the isolated and functional segment of the left vagus nerve of a pig at simulated physiological conditions.