Low-cost EGFET-based pH-sensor using encapsulated ITO/PET-electrodes

This paper presents a truly low-cost modular sensor using laser-micromachined Indium Tin Oxide (ITO) on Polyethylene Terephthalate (PET) as pH-sensitive material for a differential Extended Gate Field Effect Transistor (EGFET). In this method, the gate terminal of a commercially available MOSFET is connected to ITO/PET-electrodes providing an electrochemical measurement cell in combination with a reference electrode. Hence, a pH-variation of the solution in contact with the ITO/PET-electrode can be sensed by the MOSFET due to a surface potential change at its “liquid gate” terminal. A serial flow cell configuration has been designed to enable differential sensing, in order to overcome long-term drift and common mode disturbances and eliminate the need for a glass reference electrode. A special encapsulation method of the ITO/PET-foil conserves its pH-sensitivity. The whole sensor and its package are realized without any need for expensive cleanroom processes. The combination yields to a true low-cost modular flow-through-sensor with high precision and robustness to sense pH.

[1]  J. V. Spiegel,et al.  The extended gate chemically sensitive field effect transistor as multi-species microprobe☆ , 1983 .

[2]  Feng Yan,et al.  Organic Thin‐Film Transistors for Chemical and Biological Sensing , 2012, Advanced materials.

[3]  Peter Woias,et al.  An ISFET-FIA system for high precision pH recording , 1993 .

[4]  Yu-Lin Wang,et al.  A Package Technology for Miniaturized Field-Effect Transistor-Based Biosensors and the Sensor Array , 2017 .

[5]  P. Woias,et al.  Slow pH response effects of silicon nitride ISFET sensors , 1998 .

[6]  P. Woias,et al.  Protein detection with a novel ISFET-based zeta potential analyzer. , 1999, Biosensors & bioelectronics.

[7]  P. Woias,et al.  The Isfet-based Measurement Of The Streaming Potential As A Novel Biosensor Principle , 1995, Proceedings of the International Solid-State Sensors and Actuators Conference - TRANSDUCERS '95.

[8]  William Wang,et al.  pH sensing reliability of flexible ITO/PET electrodes on EGFETs prepared by a roll-to-roll process , 2012, Microelectron. Reliab..

[9]  M. Berggren,et al.  Biorecognition in Organic Field Effect Transistors Biosensors: The Role of the Density of States of the Organic Semiconductor. , 2016, Analytical chemistry.

[10]  Kyriaki Manoli,et al.  Printable Bioelectronics To Investigate Functional Biological Interfaces. , 2015, Angewandte Chemie.

[11]  Walter Gumbrecht,et al.  Online blood electrolyte monitoring with a ChemFET microcell system , 1990 .

[12]  Shizuo Tokito,et al.  Antibody- and Label-Free Phosphoprotein Sensor Device Based on an Organic Transistor. , 2016, Analytical chemistry.

[13]  Valtencir Zucolotto,et al.  Indium tin oxide synthesized by a low cost route as SEGFET pH sensor , 2013 .

[14]  Ying-Zong Juang,et al.  Extended-gate field-effect transistor packed in micro channel for glucose, urea and protein biomarker detection , 2015, Biomedical Microdevices.

[15]  N. Lee,et al.  Organic field-effect transistor with extended indium tin oxide gate structure for selective pH sensing , 2011 .