Flow stabilization in wearable microfluidic sensors enables noise suppression

• DOI: 10.1039/c9lc00842j
• Publication Date: 2019-10-15T22:27:08Z
• Authors: I. Emre Araci; Sevda Agaoglu; Ju Young Lee; Laura Rivas Yepes; Priscilla Diep; Matthew Martini; Andrew Schmidt
• Keywords: SIGNAL (programming language); Time constant

Dilatometric strain sensors (DSS) that work based on detection of volume change in microfluidic channels; i) are highly sensitive to biaxial strain, ii) can be fabricated using only soft and transparent materials, iii) easy integrate with smart-phones. These features especially attractive for contact lens intraocular pressure (IOP) sensing applications. The inherent flow stabilization the systems is an additional advantage suitable filtering out rapid fluctuations. Here, we have demonstrated low-pass improves signal-to-noise-ratio ophthalmic We devices a time constant range 1-200 seconds. device architecture working liquid viscosity (10-866 cSt) two independent factors determine sensor constant. developed equivalent circuit model DSS accurately represents experimental results thus used as computational design development sensors. For 4 s, report signal IOP monitoring applications suppress fluctuations (i.e., noise due ocular pulsation, blinking etc.) by 9 dB without need electronic components.