Experimental investigation of the effect of polymer matrices on polymer fibre optic oxygen sensors and their time response characteristics using a vacuum testing chamber and a liquid flow apparatus

Abstract

Very fast sensors that are able to track rapid changes in oxygen partial pressure (PO2) in the gas and liquid phases are increasingly required in scientific research – particularly in the life sciences. Recent interest in monitoring very fast changes in the PO2 of arterial blood in some respiratory failure conditions is one such example. Previous attempts to design fast intravascular electrochemical oxygen sensors for use in physiology and medicine have failed to meet the criteria that are now required in modern investigations. However, miniature photonic devices are capable of meeting this need. In this article, we present an inexpensive polymer type fibre-optic, oxygen sensor that is two orders of magnitude faster than conventional electrochemical oxygen sensors. It is constructed with biologically inert polymer materials and is both sufficiently small and robust for direct insertion in to a human artery. The sensors were tested and evaluated in both a gas testing chamber and in a flowing liquid test system. The results showed a very fast T90 response time, typically circa 20 ms when tested in the gas phase, and circa 100 ms in flowing liquid.

Intravascular oxygen sensors with novel applications for bedside respiratory monitoring

“…Schematic of sensor design (see text for details). Modified from [17] *Correction added on 6 January 2017, after first online publication on 3 January 2017. Figure 1c has been replaced due to some red arrows appearing outside the boundaries of the figure. light may be retransmitted back down the fibre, but this depends of the nature of the blood in which it sits (i.e.…”

“…However, for such small sensors, the amount of luminophore that can be accommodated on the blunt tip end, and the amount of light that can be launched, is limited, thereby limiting the signal‐to‐noise ratio. The sensor design from shown in Fig. c overcomes this limitation to some extent by using a tapered tip design.…”

“…Consequently, this would give a very slow signal response. These opposing requirements and properties have been reconciled by the use of blends of copolymers with large pendant side chains , which have a higher intrinsic diffusivity, and by the addition of novel nanostructures into the matrix which increase the diffusivity and allow oxygen to remain at least partly in the gas phase as it enters and leaves the sensing matrix (rather than dissolving in the polymer and forming a reservoir). As a result, the sensors are capable of tracking very rapid changes in PO 2 in the liquid phase, as shown in Fig.…”

Respiratory oscillations in alveolar oxygen tension measured in arterial blood

“…We developed a fibre optic oxygen sensor 16 , optimized its response time and linearity 17 – 20 , tested it in vitro 21 , showed it to be resistant to clotting, and demonstrated it to be capable of detecting rapid PaO 2 changes in an animal model of ARDS 18 , 34 . With this new technique to study gas exchange dynamically, we explore here PaO 2 responses to mechanical ventilation in a porcine model.…”

Fiber-optic fluorescence-quenching oxygen partial pressure sensor using platinum octaethylporphyrin

“…Both coated the tips of the optical fibre in oxygen sensitive fluorescent materials developed in house. Chen et al [18] developed a sensor using PtOEP coated onto an optical fibre with a tapered tip, demonstrating very rapid measurement times of 20 ms. Jiang et al [19] developed a sensor using plastic optical fibres within a catheter tube for measuring pO2 in the artieral blood of rabits.…”