There is increasing interest in the utilisation of medical gases, such as ozone, for the treatment of herniated disks, peripheral artery diseases, and chronic wounds, and for dentistry. Currently, the in situ measurement of the dissolved ozone concentration during the medical procedures in human bodily liquids and tissues is not possible. Further research is necessary to enable the integration of ozone sensors in medical and bioanalytical devices. In the present review, we report selected recent developments in ozone sensor technology (2016–2020). The sensors are subdivided into ozone gas sensors and dissolved ozone sensors. The focus thereby lies upon amperometric and impedimetric as well as optical measurement methods. The progress made in various areas—such as measurement temperature, measurement range, response time, and recovery time—is presented. As inkjet-printing is a new promising technology for embedding sensors in medical and bioanalytical devices, the present review includes a brief overview of the current approaches of inkjet-printed ozone sensors.
Ozone therapy is established in clinical applications since many decades, such as treatment of infections or herniated discs. However, in-line monitoring of ozone concentrations is challenging and therefore not performed by default. We developed an experimental setup to measure the inline ozone concentration in water in real-time with a spectroscopic sensor. Thereby, the experimental setup enables the calibration and evaluation of newly evolved ozone sensors. The results for ozone concentration measurement with the spectroscopic sensor and the colorimetric photometer show a very good correlation. Furthermore, the ozone decay curves measured with our experimental setup highly correlate with those of previous research.
The biocompatibility of medical sensors is of great importance. In order to prevent harm of the patient during measurement, this aspect must be considered throughout the entire design process. Biocompatibility can be achieved by various methods. For example, the sensor can be encapsulated, only biocompatible materials can be used for the sensor, or anti-inflammatory agents can be applied to the surface of the sensor. In this paper the focus is on sensors fully fabricated from biocompatible materials. Two exemplary inkjet-printed amperometric and impedimetric sensors are systematically assessed regarding their biocompatibility. Both sensors can be used for the measurement of dissolved ozone during oxygen-ozone injection therapy. For the sensors each material is evaluated with respect to the international standard ISO 10993. Overall, many amperometric and impedimetric sensors are fabricated from a small set of materials. The assessment reveals that for this specific application an amperometric sensor consisting of gold and silver nanoparticle inks, inkjet-printed on a polydimethylsiloxane membrane, and passivated with SU-8 ink offers the highest biocompatibility and reaches a good compliance with other important requirements. In addition, biological characterization tests are required for the specific medical application to validate the biocompatibility. From this study, it can be concluded that the findings on biocompatibility can also be transferred to other sensors that are made of the same set of materials but are for other applications. This applies to oxygen, glucose, pH, hydrogen peroxide, sweat lactate, and acetone sensors.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.