Fig. 4: Wireless smartphone actuation and lateral flow protein labeling.

a A green fluorescent protein (GFP) reservoir drop (green) and Alexa Fluor-594 reservoir drop (red) were mixed using 25 parallel channels after applying 3.5 V_RMS. Conglomerates of GFP were extruded from the GFP reservoir into individual OMEF channels and were labeled red by the Alexa dye after mixing using amine chemistry. b Alexa fluorescence intensity in the GFP reservoir is plotted versus time (red) and normalized to its source-reservoir fluorescence at the same time point. Similarly, GFP fluorescence inside the Alexa reservoir is also plotted versus time (green). An exchange in reservoir material is observed for both solutions. Source data are provided as a Source Data file. c Schematic demonstrating wireless inductive coupling of magnetic fields to actuate liquid. d Demonstration of wireless smartphone actuation of PBS using an NFC signal. Images are from before (left) and after (right) smartphone-powered actuation was applied, where the solution was pulled an additional ~200 µm beyond the capillary action while increasing the channel width throughout its entire length. The electrode edge is outlined in white for reference. Scale bar is 25 µm. Below is an example of a resonant wireless power-transfer circuit using a primary inductor (L_P), capacitor (C_P), and resistor (R_P) (LCR) circuit to transfer power to a secondary LCR with an inductance (L_S), resistance (R_S), and circuit capacitance of our device, C_DEP.