Zeitschrift für analytische und bioanalytische Techniken

Abstrakt

Electrochemical Biosensors Based on ZnO Nanostructures to Measure Intracellular Metal Ions and Glucose

Muhammad H. Asif, Fredrik Elinder and Magnus Willander

Zinc oxide (ZnO) nanostructures have attracted much interest for intracellular electrochemical measurements because of its large surface area, and its biocompatible properties. To design intracellular biosensors for metal ions and glucose, we grew ZnO nanorods on the tip of borosilicate glass capillaries (0.7µm in diameter) and characterized the nano-scale structure with field-emission scanning electron microscopy and high-resolution transmission electron microscopy. The ZnO nanorods were functionalized accordingly for intracellular free metal ions or glucose measurements. Selectivity was achieved by using a metal-ion selective plastic membrane or glucose oxidase enzyme for glucose measurements. These functionalized ZnO nanorods showed high sensitivity and good biocompatibility for intracellular environments. Human adipocytes and frog oocytes were used for determinations of intracellular free metal ions and glucose concentrations. In this review, we discuss the simple and direct approach for intracellular measurements using ZnO nanostructure-based potentiometric biosensors for clinical and nonclinical applications. The performance of ZnO nanostructure-based intracellular sensor can be improved through engineering of morphology, effective surface area, functionality, and adsorption/desorption capability. This study paves the way to find applications in biomedicine by using this simple and miniaturized biosensing device.