Miniature and flexible oxygen sensors for healthcare

Lead Research Organisation: University College London
Department Name: Electronic and Electrical Engineering


Progress in soft materials and manufacturing technologies is enabling unprecedented and exciting growth of gas and chemical sensors for internet of things, body area networks, big data and health care applications. One example is oxygen sensors, which offer critical information regarding the physiology of a person. Thus, wearable oxygen sensors are nowadays common place in hospitals and also form an integral part of wearable devices such as the apple watch. In this project, we seek to investigate a new class of high-resolution and small form factor oxygen sensors for healthcare applications.

Realizing a high resolution and wireless monitoring system of oxygen using arrays of miniature (< 1 sq. mm) sensors will unlock opportunities for exploiting these systems in implantable medical devices. This will minimise the cost of monitoring patients who need such devices for life saving restoration or augmentation of bodily functions and will also play a vital role delivering next generation of health and care practices. Example applications include new artificial organs, prosthetic devices from cardio vascular to orthopaedic applications and bionic devices for new developments in medical robotics, where oxygen sensing is required. In addition, miniature sensors can also be employed to monitor oxygen in tumours, thereby facilitating early cancer detection and development of new therapeutics.

The underpinning sensing mechanism will comprise of spectroscopic analysis of blood flow using arrays of organic light emitting diodes (OLEDs) and organic photodiodes (OPDs). The overarching goal of the project is to design and fabricate low cost miniature sensors (devices, electronics and signal processing and software) with excellent oxygen sensitivity and specificity (i.e. ability to distinguish O2 from other gas species), high signal-to-noise ratio and long term operational stability.

This multidisciplinary research project will combine the capabilities in the supervisors' groups in high-resolution 3D printing, photonics and electronic and signal processing circuit design and soft material manufacturing. Special emphasis will be placed on design of novel electronics hardware for noise stable sensing and sensor drift minimisation. The project will also offer an opportunity to extend to a PhD with ultimate goal to integrate a full-scale sensor system into implantable medical devices and characterize them in vivo with the help of our clinical collaborators.

Relevance to EPSRC Thematic Areas:

1. Healthcare Technologies
2. Information and Communications Technologies (ICT)
3. Manufacturing the Future


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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/R512400/1 01/10/2017 31/03/2022
1926362 Studentship EP/R512400/1 25/09/2017 30/12/2021 Nikolaos Salaris
Description The contribution of this research project that is hoped to be achieved and has been partially achieved up to now focuses on the improvement of oxygen sensing for healthcare applications. The main goals evolve around the development of a robust but reliable sensor capable of monitoring the oxygen content in highly dynamic envoronments, such as invasive clinical procedures. This will be achieved through the use of oxygen dependent phosphorescence via the straightforward chemical fabrication of sensitive indicators along with the development of optoelectronic devices that can acquire and transmit the data in real time. These devices should be designed such that miniaturisation is possible.
Exploitation Route It would be pivotal that such an oxygen sensitive device is developed in order for it to be used invasively and with a seamless integration by clinicians in surgical procedures. In addition, one of the goals of the project is the development of a protocol so that the cell cultures for tissue engineering are monitored from their initiation to their implantation.
Sectors Electronics,Healthcare,Manufacturing, including Industrial Biotechology

Title Stting up of an oxygen calibration methodology 
Description An inhouse oxygen calibration setup was configured in order to test the characteristics of the oxygen sensors developed. This included both air and water measurements with the use of PID controllers, heater - coolers, pressure based enclosures, a signal generator, an oscilloscope, mass flow controllers for nitrogen and oxygen and oxygen and nitrogen tanks. These were all incorporated alongside a purchased calibrated oxygen sensing device via labview in order to have a fully automated system available. 
Type Of Material Improvements to research infrastructure 
Year Produced 2019 
Provided To Others? No  
Impact By developing such a procedure it was possbile for us to continue to the main part of the research involving the improvement of existing oxygen sensing methods utilizing a robust optoelectronic device. 
Title Oxygen photosensitive chemical Indicators and their behaviour with specific LEDs and Photodiodes 
Description Used a specific setup involving LEDs and photodiodes connected to a signal generator and an oscilloscope respectively. This was done in an enclosure whose gas contents was controlled with the use of two mass flow controllers and the data taken was used to characterise the system of the particular LEDs and PDs according to their oxygen sensing capabilities based on the specific chamical indicators used. The oxygen sensing was performed on the grounds of oxygen sensitive phosphorescence emission. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? No  
Impact This could allow future personallized robust oxygen sensors that wil be miniaturised and easily accessible and implementable both by the patient and the clinician. 
Description Dr Paulo Di Coppi's group 
Organisation University College London
Department Institute of Child Health
Country United Kingdom 
Sector Academic/University 
PI Contribution This is a two way collaboration due to the fact that we provide them the necesasry insight of the challenges faced in terms of optoelectronics for oxygen sensing in the desired environment they are looking at, such as cell cultures and later on invasively record the oxygen content of a the bioengineered organ inside the body.
Collaborator Contribution They helped us by providing a better understanding of their requirements towards monitoring the oxygen content in cell cultures for tissue engineering, thus made them more identifiable to address them in the future. This also helped in the provision of a clearer pathway towards achieving our research goal via the description of clinical procedures in theis particular filed. They also provided some demos for the enclosures where cell cultures are devloped.
Impact The outcomes up to now for both sides have been towards the understanding of the challenges on both sides which lead to the carving of clear pathways for future research goals. However, the future implications of such a collaboration can be expected to be of vital importance in developing methods of tissue engineering with high impact. This is a highly multidisciplinary effort since there are: medical practitioners, engineers, biophysicists and bio chemists involved in the particular project.
Start Year 2018
Title Software for signal processing of square waves after oxygen sensitive phosphorescent emission from simple PD - LED setup 
Description Matlab code based detection of decay profiles to investigate differences depending on the content of oxygen as well as the surrounding environment monitored. Data was recorded through an oscilloscope connected to labview and the sensor was a silicone photodiode. 
Type Of Technology New/Improved Technique/Technology 
Year Produced 2020 
Impact Future impacts would involve the development of a robust oxygen sensing device 
Description Science of Surgery - Charles Bell House 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact A large group of school pupils along with their parents or guardians attended an open day at the research organisation building which involved live demonstrations and sparked questions and discussion with the parents showing an interest in the research related subject areas presented on that day.
Year(s) Of Engagement Activity 2018