Development of a Patch-Type Flexible Oxygen Partial Pressure Sensor.

Yuta Katayama,Yuta Fujioka,Kosuke Tsukada

doi:10.1109/jtehm.2020.3005477

Yuta Katayama, Yuta Fujioka + Show 1 more

Open Access

https://doi.org/10.1109/jtehm.2020.3005477

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Abstract

Oxygen concentration in living organisms is one of the important vital indicators in emergency care and bedside medical settings. However, the oximetry method has limitations: the measurement site is limited to the tissue containing blood and the absolute value of oxygen concentration cannot be measured. To overcome these limitations, in this work, we develop a new oxygen sensor that can directly measure the oxygen particle pressure (n}{}ptext{O}_{2}n) on the surface of the body and organs. A light emitting diode (LED) and a photodiode (PD) were embedded in a dimethylpolysiloxane substrate mixed with carbon nanotubes. The effectiveness of the device was evaluated using calibration, bending strain tests, time and frequency response, and finally in vivo assessments. The results reveal that the calibration experiment of the fabricated oxygen sensor device showed high sensitivity. The carbon nanotube electrode has a sufficient bending resistance and does not affect the response characteristics of the LED and PD, that is, it does not affect the oxygen measurement. In vivo assessment shows that the developed patch-type flexible oxygen sensor can accurately measure n}{}ptext{O}_{2}n by attaching it to tissues or organs having irregularities or curved surfaces and actual measurements on rat liver surface demonstrated its feasibility.

Highlights

In the medical field, oxygen concentration is one of the vital signs from living organisms, especially in bedside and emergency medical settings
PO2 CALIBRATION AND RESPONSE EXPERIMENTS Figure 3(a) shows an oxygen sensor that was installed in the gas-tight chamber, and the oxygen concentration inside the chamber was changed stepwise from 0 to 159 mmHg in steps of 40 mmHg
In the oxygen measurement method that is based on the oxygen quenching effect of phosphorescence in principle, the quenching by oxygen molecules reduces the phosphorescence intensity and shortens the lifetime; this leads to decrease in accuracy as the oxygen concentration increases, At 120 and 159 mmHg, the lifetime intensity change of the decay is small and noisy

Summary

Introduction

Oxygen concentration is one of the vital signs from living organisms, especially in bedside and emergency medical settings. Pulse oximetry has the advantage of non-invasive measurement, which has found widespread application for humans It has some disadvantages; for example, the measurement site is limited to tissues containing sufficient blood and the absolute value of oxygen concentration cannot be measured. The measurement of oxygen partial pressure (pO2) by the phosphorescence lifetime method [7], [8], which is based on the oxygen quenching effect of phosphorescence (where pO2 is calculated from the intensity or lifetime of the luminescence emitted depending on oxygen), has been applied to various organs [9]–[12] It is relatively minimally invasive because the excitation light is applied to the site where the phosphorescence dye exists. It is limited to animal use and it is difficult to administer the dye to humans because of its phototoxicity of its energized singlet oxygen. [15], [16]

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