Bilayer Actuator Film for Urea Biosensing with Dual Responsiveness: Bending Actuation and Photonic Color Change

초록

A noninvasive sweat-based biosensor was developed forurea detectionusing a photonic bilayer actuator film (BAF) consisting of an interpenetratingpolymer network (IPN) as the active layer and a flexible poly(ethyleneterephthalate) (PET) substrate as the passive layer (IPN/PET). Theactive IPN layer comprises intertwined solid-state cholesteric liquidcrystal and poly(acrylic acid) (PAA) networks. Urease was immobilizedin the PAA network in the IPN layer of the photonic BAF. The interactionwith aqueous urea altered the curvature and photonic color of thephotonic urease-immobilized IPN/PET (IPNurease/PET) BAF.The curvature (and wavelength of the photonic color) of the IPNurease/PET BAF increased linearly with urea concentration (C (urea)) in the range of C (urea) = 20-65 (and 30-65) mM with a limit of detectionvalue of 1.42 (and 1.34) mM. The developed photonic IPNurease/PET BAF exhibited high selectivity toward urea and excellent spiketest results with real human sweat. This novel IPNurease/PET BAF is promising because it enables battery-free, cost-effective,and visual detection-based analysis without the use of sophisticatedinstruments. Furthermore, the application of this photonic IPN/PETBAF can be easily extended to other biosensors by immobilizing otherreceptors on the IPN.

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