Acoustofluidic localization of sparse particles on a piezoelectric resonant sensor for nanogram-scale mass measurements

Abstract

The ability to weigh microsubstances present in low concentrations is an important tool for environmental monitoring and chemical analysis. For instance, developing a rapid analysis platform that identifies the material type of microplastics in seawater would help evaluate the potential toxicity to marine organisms. In this study, we demonstrate the integration of two different techniques that bring together the functions of sparse particle localization and miniaturized mass sensing on a microelectromechanical system (MEMS) chip for enhanced detection and minimization of negative measurements. The droplet sample for analysis is loaded onto the MEMS chip containing a resonant mass sensor. Through the coupling of a surface acoustic wave (SAW) from a SAW transducer into the chip, the initially dispersed microparticles in the droplet are localized over the detection area of the MEMS sensor, which is only 200 µm wide. The accreted mass of the particles is then calibrated against the resulting shift in resonant frequency of the sensor. The SAW device and MEMS chip are detachable after use, allowing the reuse of the SAW device part of the setup instead of the disposal of both parts. Our platform maintains the strengths of noncontact and label-free dual-chip acoustofluidic devices, demonstrating for the first time an integrated microparticle manipulation and real-time mass measurement platform useful for the analysis of sparse microsubstances.

Current development and future challenges in microplastic detection techniques: A bibliometrics-based analysis and review

“…Using a correlation between scanning electron microscopy (SEM) and μ-Raman, they identified nanoplastics in the 100 nm range in various environments. Qian et al 51 tried to combine sparse particle localization and miniaturized mass sensing functions on a microelectromechanical system (MEMS) chip to realize the analysis of sparse particles. The use of 4-dimethylamino-4′-nitrostilbene (DANS) fluorescent dyes for detecting microplastics was proposed by Sancataldo et al 52 DANS staining can provide access to different detection and analysis strategies based on fluorescence microscopy.…”

Fully differential higher order transverse mode piezoelectric membrane resonators for enhanced liquid-phase quality factors

“…interest for mass sensing applications [1][2][3][4], leveraging on several advantages such as small form factor, increased sensitivity through miniaturization, abundance of design permutations to explore different vibration modes, compatibility with complementary metal oxide semiconductor electronics for of the MEMS resonator is reduced due to increased damping in a liquid environment compared to oscillations in ambient conditions, leading to a significant reduction in signal output relative to the input drive signal. The reduction in the output resonant peak is further compounded for high dielectric constant fluids like water, which significantly increases the direct parasitic feedthrough between the input and output port of the MEMS resonator.…”

H-Shaped Radial Phononic Crystal for High-Quality Factor on Lamb Wave Resonators

“…In recent years, with the rapid development of the fifth-generation mobile communication network (5G), microelectromechanical system (MEMS) technology has shown good application prospects in wireless communication systems and sensor networks [ 1 , 2 ]. The Lamb wave resonator (LWR) is considered by most researchers to be the preferred choice for miniaturized, high-performance, and low-power integrated resonators due to its high operating frequency, high electromechanical coupling coefficient, and low power consumption [ 3 , 4 ]. LWRs are considered to be highly desirable in the 300–800 MHz range commonly used in the field of wireless communications [ 2 , 5 , 6 ].…”