Fig. 2: Conceptual framework for bioresorbable wireless environmental sensors.
a–c Deployment strategies for environmental sensors. a Autorotating flier, inspired by Tristellateia seeds, utilizing leading-edge vortex (LEV) stabilization. Reused with permission from Kim et al.8 b Parachuting flier, inspired by dandelion seeds, stabilized by separated vortex rings (SVR). c Drifting floater, inspired by cranberry seeds, serving as a buoyant vortex tracer (BVT). Insets show images of natural seeds as inspiration for these designs, along with schematic illustrations of patterns of the flow of air and water that occur during deployment. d, e Wireless communications strategies, comprising (d) optical methods and (e) radio-frequency (RF) approaches (TX IC Trasmitter Integrated Circuit, RX IC Receiver Integrated Circuit). Optical strategies include passive (e.g., absorption, fluorescence/phosphorescence) and active modes (e.g., chemiluminescence, electroluminescence). RF approaches can be categorized similarly, as passive backscatter (e.g., monostatic, bistatic) and active emission (e.g., direct active, relay). f–h Power supply strategies, classified into (f) power transfer (e.g., RF wireless transfer), (g) power harvesting (mechanical and optical), and (h) power storage (fuel cells and galvanic cells). (D: maximum linear dimension of the antenna, \(\lambda\): wavelength of operation).
