A robust sensing technology, suitable for wearable devices, will be developed for continuous monitoring of molecules secreted by the human body. Electrically active polymers will be combined with molecularly selective polymers to sense a range of molecules in a sensitive and selective way. The sensor fabrication process will take advantage of the same technology developed to fabricate microprocessors, thus giving access to a wide range of sensor sizes and shapes in order to determine the optimum sensor geometry. Furthermore, the electrical response of the sensor will be modeled mathematically in order to predict the best sensor design. Finally, several sensors will be arrayed to demonstrate the simultaneous detection of several molecules of interest. The development of a general sensing technology based on plastics has the potential to produce a substantial impact in the world of low-cost wearable sensors suitable for non-hospital based applications. Furthermore, the workforce trained with these funds will have an interdisciplinary outlook, being equally comfortable with electronics and with biomedical applications in the realm of analytical chemistry.
Enzyme-based sensing is not robust for wearables or measurements in non-controlled environments. A new transduction method is proposed where an organic electrochemical transistor (OECT) is functionalized with a robust molecularly imprinted polymer (MIP) incorporated in a membrane. The MIP acts as an artificial receptor and selectively binds to the molecule that was imprinted in it during the fabrication phase. This is an entirely new sensor device concept, which incorporates selectivity (from the membrane) and sensitivity (thanks to the gain given by the transistor). This approach works in a cortisol sensor, which is compatible with wearable electronics as it is sensitive (thanks to the electronic gain of the transistor), operates at low voltages and can be fabricated on flexible substrates. Device scaling studies will demonstrate that sensitivity and range can be controlled with device geometry. The effect of processing on the selectivity and sensitivity of the membrane will be studied as well. Ultimately these experimental data will be used to build and validate a complete device model, which will give insights into the device physics of the sensor and will be used for a priori design of sensors with arbitrary architectures. Because the concept of OECT and artificial receptor membranes is general, the model will be a useful design tool for this entire family of novel sensors. Finally, the MIP-functionalization approach is quite general as will be demonstrated by building a multiplexed sensor array that will sense two hormones (cortisol and adrenaline) in addition to other electrolytes in a single sample. A high-school teacher will be involved in the project with the goal of using the materials investigated to fabricate a ?visible? transistor, i.e. a device where the switching process can be viewed by naked eye. The goal is to provide a simple demonstration for high-school students helping them understand the basic functionality of the device that is at the heart of the IT revolution.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
