18 research outputs found
MEMS ultrasonic transducers for safe, low-power and portable eye-blinking monitoring.
Eye blinking is closely related to human physiology and psychology. It is an effective method of communication among people and can be used in human-machine interactions. Existing blink monitoring methods include video-oculography, electro-oculograms and infrared oculography. However, these methods suffer from uncomfortable use, safety risks, limited reliability in strong light or dark environments, and infringed informational security. In this paper, we propose an ultrasound-based portable approach for eye-blinking activity monitoring. Low-power pulse-echo ultrasound featuring biosafety is transmitted and received by microelectromechanical system (MEMS) ultrasonic transducers seamlessly integrated on glasses. The size, weight and power consumption of the transducers are 2.5 mm by 2.5 mm, 23.3 mg and 71 μW, respectively, which provides better portability than conventional methods using wearable devices. Eye-blinking activities were characterized by open and closed eye states and validated by experiments on different volunteers. Finally, real-time eye-blinking monitoring was successfully demonstrated with a response time less than 1 ms. The proposed solution paves the way for ultrasound-based wearable eye-blinking monitoring and offers miniaturization, light weight, low power consumption, high informational security and biosafety
A Universal Biomolecular Concentrator To Enhance Biomolecular Surface Binding Based on Acoustic NEMS Resonator
In designing bioassay systems for
low-abundance biomolecule detection,
most research focuses on improving transduction mechanisms while ignoring
the intrinsically fundamental limitations in solution: mass transfer
and binding affinity. We demonstrate enhanced biomolecular surface
binding using an acoustic nano-electromechanical system (NEMS) resonator,
as an on-chip biomolecular concentrator which breaks both mass transfer
and binding affinity limitations. As a result, a concentration factor
of 10<sup>5</sup> has been obtained for various biomolecules. The
resultantly enhanced surface binding between probes on the absorption
surface and analytes in solution enables us to lower the limit of
detection for representative proteins. We also integrated the biomolecular
concentrator into an optoelectronic bioassay platform to demonstrate
delivery of proteins from buffer/serum to the absorption surface.
Since the manufacture of the resonator is CMOS-compatible, we expect
it to be readily applied to further analysis of biomolecular interactions
in molecular diagnostics