Printing technologies for the fabrication of ion-selective electrodes

Abstract

The fabrication of ion-selective electrodes (ISEs) via printing technologies such as screen-printing, inkjet printing, and 3D printing is attracting increasing attention due to the superb reproducibility and scalability of these technologies. In contrast to traditional manual casting, coating, and assembling procedures often used in research labs, printing methods are much more compatible with manufacturing processes in industry and, therefore, are easier to scale up. In this paper, we first summarized and compared the printing mechanisms and ink requirements of screen printing, inkjet printing, and 3D printing technologies. Then we present an overview of how different printing technologies can create sensor components, such as electrical contact layers, ion-to-electron transduction layers, ion sensing membranes, reference electrode membranes, insulation layers, and microfluidic/detection housings. The printing protocol, ink material, and sensor performance are highlighted for a few selected ISEs. This review concludes with a summary of the advantages and drawbacks of various printing technologies.

Keywords: 3D printing; inkjet printing; ion-selective electrode; potentiometry; screen printing.

Fig. 1

Typical flatbed screen printing with planar substrates under the screen and squeegee for solution dispensing [21].

Fig. 2

Schematic diagram of (a) the piezoelectric inkjet head and (b) Electrohydrodynamic inkjet system [21].

Fig. 3

Schematic diagram of 3D printing technology [16].

Fig.4

A: 3D printing process and liquid- and solid-contact ISEs fabrication. B, C: Experimental setup and components of solid-contact and liquid-contact ISEs, respectively [57].

Fig. 5

Schematic illustration of the fabrication process of the fully inkjet-printed paper-based potentiometric devices [24].

Fig. 6

(a) Digital design of the pH sensor. (b) The final printed platform has nine indicator electrodes, one reference electrode, and a microscopic image of a printed electrode. (c) Detailed inkjet printing steps [29].