Three-dimensional chemical sensors based on rolled-up hybrid nanomembranes

Moving towards the realization of ultra-compact diagnostic systems, we demonstrate the design, realization and characterization of rolled-up nanomembrane-based chemical sensing elements operating at room temperature. The tube-shaped devices with a final diameter of ∼15 μm rely on a fabrication process which combines top-down and bottom-up approaches and is compatible with standard processing technologies. Arrays of sensors are created in parallel on-a-chip, consequently, the integration of such elements into lab-in-a-tube devices as sensing units certainly seems feasible. The sensing properties of the devices are created by the selective incorporation of thin organic active layers in the inner wall of the microtubes. While the sensitivity towards volatile organic compounds is observed to be similar to previously reported sensors, indicating that the integration of the organic layer is efficiently achieved, the occupied footprint area of the tube-shaped devices is at least one order of magnitude smaller than its planar counterpart. This particular feature makes this procedure an attractive pathway to condense sensing elements for ultra-compact devices.