Optimization of Measurement Setup in Bioimpedance-based Insulin Absorption Assessment

A measurement setup optimization was conducted to improve the sensitivity of a bioimpedance-based method for insulin absorption assessment. Specifically, the method identifies a customized parameter model linking the impedance magnitude variation to the quantity of drug injected. Then, the customized parameter model is used to predict the gradual absorption of the drug from the injection site. A Taguchi L9 fractional factorial plan was designed to analyze measurement setups on a healthy subject by varying electrode length, and electrode inter-distances. ANOM and ANOVA were carried out to find the optimal configuration and to assess the impact of each parameter on absolute sensitivity. Inter-electrode distances on the order of mm were explored by appropriately reshaping commercial electrodes. The electrode length resulted the most influencing factor on the absolute sensitivity. An absolute sensitivity variation of 14.7 Ω was obtained in the experimental configurations examined. The measurement setup with length = 7.0 mm, amperometric-voltmetric distance = 1.0 mm, and voltmetric-amperometric distance = 7.0 mm resulted the optimum measurement setup. In this configuration, an absolute sensitivity of 17.9 Ω by injecting 100 μl of saline solution was obtained. The new customized solution improved sensitivity by more than 5 times compared with the configuration obtained by keeping the parameters values unchanged from previous experimental works. typical measurement setup using intact commercial electrodes.