Nien-Hsuan Chou

All Solid-State Potentiometric Biosensors for Creatinine Determination Based on pH and Ammonium Electrodes

This work investigates a disposable creatinine potentiometric biosensor based on a pH-sensitive electrode and an ammonium ion-selective electrode. An enzyme, creatinine iminohydrolase (CIH) was immobilized directly onto the surface of the electrodes by the entrapment method. According to the experimental results, the creatinine biosensors based on the pH-sensitive electrode and ammonium ion-selective electrode show a rapid response time (t95 < 30 s) and a linear dynamic response range for creatinine determination between 40 muM and 140 muM. Furthermore, the ammonium ion-selective electrode-based biosensors exhibited good operational stability (over 14 times) and storage stability (over 40 days). By discussing the reproducibility and pH effects of the creatinine biosensors, features of creatinine biosensors based on ammonium ion-selective electrodes are described. Moreover, development of a low-cost, solid-state, disposable potentiometric creatinine biosensor based on pH-sensitive electrodes and ammonium ion-selective electrodes is discussed.

Differential Structure Solid-State Array Biosensors for Creatinine Detection

This work presents a differential structure of solid-state creatinine array biosensor based on an ion-selective membrane. The creatinine enzyme is chemically immobilized by a physical immobilization method onto an ammonium ion-selective membrane. Moreover, the solid-state creatinine biosensors based on ammonium ion-selective membrane respond rapidly, stably and linearly in the range of creatinine concentrations between 15 muM and 140 muM. An array sensing system is designed to enhance the precision of the solid-state creatinine biosensor, which comprises four parts, the creatinine biosensors, the input buffer circuit, the differential circuit and the weighted sum circuit. As indicated in the experimental results of the array sensing structure, the sensing characteristic of the array sensing structure is similar to the mean sensing characteristic from four solid-state creatinine biosensors.