Simple and fast method for fabrication of endoscopic implantable sensor arrays.

I Tahirbegi,Margarita Alvira,Mònica Mir,Josep Samitier

doi:10.3390/s140711416

Abstract

Here we have developed a simple method for the fabrication of disposable implantable all-solid-state ion-selective electrodes (ISE) in an array format without using complex fabrication equipment or clean room facilities. The electrodes were designed in a needle shape instead of planar electrodes for a full contact with the tissue. The needle-shape platform comprises 12 metallic pins which were functionalized with conductive inks and ISE membranes. The modified microelectrodes were characterized with cyclic voltammetry, scanning electron microscope (SEM), and optical interferometry. The surface area and roughness factor of each microelectrode were determined and reproducible values were obtained for all the microelectrodes on the array. In this work, the microelectrodes were modified with membranes for the detection of pH and nitrate ions to prove the reliability of the fabricated sensor array platform adapted to an endoscope.

Highlights

The development of miniaturized, implantable chemical sensors to monitor different diseases in organs or blood-gas measuring pH, glucose, lactate and electrolytes such as Na+, K+ and Ca2+ remain one of the great challenges in analytical science
Scanning electron microscope (SEM) images were performed with a Nova NANOSEM
The ion-selective electrodes (ISE) membrane for nitrate detection was prepared with a mixture of 7.2 wt% nitrate ionophore Tetradodecylammonium nitrate (TDAN), 63.8 wt% nitrophenyl octyl ether (NPOE), and 29 wt% polyvinyl chloride (PVC)

Summary

Introduction

The development of miniaturized, implantable chemical sensors to monitor different diseases in organs or blood-gas measuring pH, glucose, lactate and electrolytes such as Na+, K+ and Ca2+ remain one of the great challenges in analytical science. Ion-selective electrodes (ISEs) are a very promising approach to fabricate implantable chemical sensors to detect analytes for their low cost and easy miniaturization. They have been used in a wide variety of applications, ranging from environmental analysis [2,3] to biomedical procedures [4,5]. We describe a reliable, reproducible, low cost and easy method for the simple fabrication of a miniaturized multi-electrode array, which does not require expensive equipment and clean room facilities. This work is still in its embryonic stage and preliminary optimization of in vitro detection of pH and nitrate are reported in this work

Reagents and Materials

Instruments and Measurements

Fabrication of Microelectrodes on an Array

Characterization of the Fabricated Array