Abstract: Wearable technologies for personalized monitoring require sensors that track biomarkers often present at low levels. Cortisol—a key stress biomarker—is present in sweat at low nanomolar concentrations. Previous wearable sensing systems are limited to analytes in the micromolar-millimolar ranges. To overcome these and other limitations, the present embodiments include a flexible field-effect transistor (FET) biosensor array that exploits a new cortisol aptamer coupled to nanometer-thin-film In2O3 FETs. Cortisol levels were determined via molecular recognition by aptamers where binding was transduced to electrical signals on FETs. The physiological relevance of cortisol as a stress biomarker was demonstrated by tracking salivary cortisol levels in participants in a Trier Social Stress Test and establishing correlations between cortisol in diurnal saliva and sweat samples.

Abstract: A robust and general fabrication/manufacturing method is described herein for the fabrication of periodic three-dimensional (3D) hierarchical nanostructures in a highly scalable and tunable manner. This nanofabrication technique exploits the selected and repeated etching of spherical particles that serve as resist material and that can be shaped in parallel for each processing step. The method enables the fabrication of periodic, vertically aligned nanotubes at the wafer scale with nanometer-scale control in three dimensions including outer/inner diameters, heights/hole-depths, and pitches. The method was utilized to construct 3D periodic hierarchical hybrid silicon and hybrid nanostructures such as multi-level solid/hollow nanotowers where the height and diameter of each level of each structure can be configured precisely as well as 3D concentric plasmonic supported metal nanodisk/nanorings with tunable optical properties on a variety of substrates.

Abstract: A robust and general fabrication/manufacturing method is described herein for the fabrication of periodic three-dimensional (3D) hierarchical nanostructures in a highly scalable and tunable manner. This nanofabrication technique exploits the selected and repeated etching of spherical particles that serve as resist material and that can be shaped in parallel for each processing step. The method enables the fabrication of periodic, vertically aligned nanotubes at the wafer scale with nanometer-scale control in three dimensions including outer/inner diameters, heights/hole-depths, and pitches. The method was utilized to construct 3D periodic hierarchical hybrid silicon and hybrid nanostructures such as multi-level solid/hollow nanotowers where the height and diameter of each level of each structure can be configured precisely as well as 3D concentric plasmonic supported metal nanodisk/nanorings with tunable optical properties on a variety of substrates.