Showing papers by "Bei Peng published in 2022"

Electrokinetically induced concentration of diluted sample by liquid metal embedded microfluidic chip

Abstract: Microfluidic devices have been demonstrated to be able to concentrate low-abundance analytes and to be integrated in point of care (POC) devices for the purpose of reducing equipment size and cost; however, the complications involved in the fabrication of microfluidic chips or microelectrodes can be challenging. Here, we present a simple and effective microfluidic device monolithically integrated with liquid metal-based microelectrodes for the transportation and concentration of molecules in dilute solutions. Numerical and experimental studies were combined to validate and optimize the performance of the presented co-designing microfluidic chip featured by a double T-shaped manifold microchannel, in which the electrokinetically induced pressure-driven flow and concentration process were fully characterized. The microfluidic chip was used in a fluorimetric assay based on fluorescence resonance energy transfer between the fluorophore labeled aptamer and molybdenum disulfide nanosheets for the detection of cortisol, a stress biomarker of humans. Both experimental and numerical results show that a concentration factor up to 83-fold can be achieved within 5 min. By avoiding cumbersome fabrication processes and mechanical equipment, the proposed co-designing concentrating strategy provides insights for the fabrication of compact microfluidic chips that facilitate the miniaturization of POC devices with enhanced detection limit and sensitivity.

A Piezoelectric Water Skating Microrobot Steers Through Ripple Interference

Abstract: This work reports a 4-cm-long piezoelectric microrobot with agile steering abilities on water surface. Two unique accomplishments are demonstrated: (1) A 0.88g soft robot uses two pairs of flapping hydrofoils (equal frequency but with phase offsets) to generate adjustable thrusts that cause smoothly steering on water surface (first in published papers). The robot's angular velocity ranges from -6°/s (clockwise) to +6°/s (counterclockwise), and the turning resolution is 0.4°/s; (2) The soft robot that made of fully flexible structures has a forward skating speed up to 2cm/s, and carries loads of three times its weight with the speed of 4mm/s. As such, the new method could open up new opportunities for microrobots working on water surface.