Microfabricated devices for flexible sensing at the biointerface

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Sensors that are biocompatible and biodegradable and are mechanically flexible and conform to soft tissues and organs in the human body are highly desirable as they provide a means to measure and monitor activity. In this research, biodegradable silk will be engineered and fabricated for testing of measurement feasibility of biomarkers that are indicative of pathology. The project will investigate various electrochemical biosensor designs (1D wires, 2D sheets and 3D blocks) using biodegradable silk and conducting polymers in flexible and conformable formats for measuring such model biomarkers as acetylcholine, C-reactive protein, vascular endothelial growth factor (VEGF). The innovation proposed is the method of fabricating functional biosensors comprising the conducting polymer poly (3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and silk proteins (fibroin and sericin) via techniques developed by silk protein lithography. The structure-property relationships of fabricated biosensors will be investigated through the following specific aims. (1) Investigate the compositional relationships that enhance electrochemical response and mechanical properties, and enable their selective detection, and (2) Investigate sensor fabrication strategies for sensors in multi-scales and dimensions (1-D wires, 2D sheets, and 3D scaffold network) so that they can conform to soft tissue. Appropriate recognition elements (antibody and aptamers) will be immobilized on electrode surface against the target analyte. Sensor response and mechanical properties will be engineered for conformable attachment to the target soft tissue while minimizing cytotoxicity. Feasibility sensor experiments will be conducted in vitro using stock seeds of cells under physiological conditions. Reproducibility of sensor response will be characterized and sensor design will be modified to accommodate required sensitivity, selectivity, and reproducibility. Education and outreach activities are proposed. Haptic and 3D printed models of micro and nanoscale objects will be fabricated to give students a direct visualization and textural feel for the various kinds of sensor architectures. Sharing of these in annual outreach activities organized by the PI will help inspire young students into engineering and science careers.