1. INVESTIGATION AND OPTIMIZATION OF FUNCTIONAL GRAPHENE INKS
We are developing a facile way to directly pattern sprayed graphene materials for the fabrication of conductive path as well as detecting analytes using graphene patterns. If we prove its applicability for the fabrication of flexible electronic devices, electrochemical sensors can be fabricated by the highly conductive graphene electrodes.
By utilizing high surface-to-volume ratio of graphene patterns, we are able to design and build up the electro-chemical sensors such as lactate sensor, glucose sensor and calcium detecting sensor etc. Flexible sensors for E-health monitoring need to be fabricated on thin flexible substrate continuously in order to reduce materials used as well as process steps.
2. DEVELOPMENT AND OPTIMIZATION OF MECHANICALLY DURABLE DRY ADHESIVE
Conventional adhesive for medical skin patch is composed of acryl-based material. So it can be sensitive to skin and vulnerable to a prolonged exposure. Therefore, there are demands on less irritating, biocompatible medical bandage or tapes. Dry adhesive patch has been developed for repeatable and restorable adhesion of bio-medical sensors. It is less affected by surface contamination, oxidation, and other environmental stimuli.
Also, it has better characteristics than wet adhesive like better biocompatibility, which is associated with the fact that there is enough space for ventilation of air and skin residues. Mirco-hairs for dry adhesive surfaces have been designed to study scientific fundamentals of strongly enhanced adhesion and to use them for practical applications.
It has been known that micro-hair surfaces with high aspect ratio over three can be fabricated by top-down method, which has been applied to make the large surfaces of micro-hairs via two-step photolithographic patterning and silicon etching process for high aspect ratio patterning.
Although this method is very efficient to fabricate designed structures and precise fabrication of planned aspect ratio patterns, bottom-up method of easier fabrication is required for mass production of bio-medical sensor’s dry patch application. We recently create a bottom-up approach for large area dry adhesive for the project on a flexible substrate.
3. DEVELOPMENT OF MEASURABLE LACTATE SENSOR
Lactate depicts performance in connection to intensive and endurance-based activities. It is important analyte for muscle cells, which produce energy and lactate via glycolysis/lactate acidosis that increases lactate levels in the blood.
We are currently developing stretching conductor, which can be conformally attached to the skin surface.
The resulting lactate profiles from attached sensor reflect chances in the production of sweat lactate upon varying the exercise intensity. Such skin-worn metabolite bio-sensors could lead to useful insights into physical performance and overall physiological status.
4. DEVELOPMENT OF MEASURABLE GLUCOSE SENSOR
Continuous glucose monitoring is one of the representative E-Health sensor to avoid severe health conditions comes from hypoglycemia. Significant investment and intimate care are needed with professionally trained healthcare providers. Continuous glucose level monitoring with finger picking method is not actually available and inconvenient. Hence, continuous glucose monitoring from human tears using a glucose sensor embedded in a contact lens has been considered as a suitable option.
However, the glucose concentration in human tears is very low in comparison with the blood glucose level. We are developing a sensor that solves the problem in a new way, is flexible and conformal to the skin surface, and is constructed with stretchable electrodes developed both for lactate sensor as well as glucose sensor, by increasing the active electrode area by using silver nanowires for electrode. A new sensor will be low-cost, robust, biodegradable flexible biosensor.
5. INVESTIGATION OF WIRELESS SENSING USING LC CIRCUIT
Flexible and stretchable mechanical sensors for biomedical applications have been emerging to have extracorporeal sensing capability. These sensors have been developed to help disabled people in need and athletes in game. To achieve this goal, wireless communications such as the RFID is essential.
A system consisting of both electro-chemical sensors and RFID tags can be considered so that the mechanical strain is changed into electrical signals by the sensor and the electrical signals are transmitted to the reader by the RFID tag simultaneously.
However, this system is bulky for the attachable application to the body and it may restrict motion of the athletes. On the other hand, a stretchable RFID tag can perform both roles as the sensor and the antenna. Thus, a stretchable RFID tag can sense the mechanical strain and at the same time transmit the information wirelessly.
Therefore, the stretchable, passive and chipless RFID tag is well fitted into the sensing applications for real-time electro-chemical detection. We are using the mechanical strain detection induced from electro-chemical reaction on the sensor to use direct spraying of silver nano ink to fabricate a stretchable, passive and chipless RFID tag with a simple inductor-capacitor (LC) resonator antenna printed on flexible and stretchable substrates.
6. INTEGRATION OF WIRELESS EPIDERMAL SENSOR PATCHES
The final goal of Printed Attachable E-Health Sensor is to develop a fully functional wireless system, which can transmit, detected signals from electro-chemical reaction. All components are required to seamlessly integrated with the developed electro-chemical sensors and achieve wireless data capture, which is required for the system to send and receive data wirelessly.
Our optional development goal will be to connect multiple sensors to a single device. The sensors will be connected in a local wireless network to interact with each other. By doing this, the user will be able to monitor activity from all the electro-chemical sensors from a single device such as a mobile phone or a computer.
In 2015 CBHI laboratory will bring together scientists from the SFU, the UBC Research, University College London, Imperial College London and King’s College London. The strength of the Francis Crick Institute will spring from the synergy between these groups and new research directions in disciplines including mathematics, computing physics, chemistry and engineering which will be facilitated by the close interaction with university partners and by funding of additional research areas by the Wellcome Trust.
The grand scale of the Institute and its world-class research infrastructure, together with long-term core research funding from the partners, will allow its scientists to pursue cutting-edge research with ambitious objectives. The Crick will attract, train and develop the very best scientists to conduct bold research in innovative ways, and be the source of outstanding talent and expertise from which other UK academic and commercial biomedical institutions will draw.
The site for the new Institute is adjacent to the British Library at St. Pancras, central London’s main transport hub. This will allow excellent communications and networking with other UK research centres, and excellent interactions with continental Europe via the new High-Speed rail links.