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.

称量低浓度微量物质的能力是环境监测和化学分析的重要工具。例如，开发一个快速分析平台来识别海水中微塑料的材料类型，将有助于评估对海洋生物的潜在毒性。在这项研究中，我们展示了两种不同技术的集成，这些技术将稀疏粒子定位和微型质量传感功能结合到微机电系统 (MEMS) 芯片上，以增强检测和最小化负测量。用于分析的液滴样品加载到包含共振质量传感器的 MEMS 芯片上。通过将声表面波 (SAW) 从 SAW 换能器耦合到芯片中，最初分散在液滴中的微粒位于 MEMS 传感器的检测区域上，该区域只有 200 µm 宽。然后根据传感器谐振频率的最终偏移校准粒子的吸积质量。SAW 器件和 MEMS 芯片在使用后是可拆卸的，允许重复使用设置的 SAW 器件部分，而不是丢弃这两个部分。我们的平台保持了非接触式和无标签双芯片声流体设备的优势，首次展示了一个集成的微粒操作和实时质量测量平台，可用于分析稀疏的微量物质。SAW 器件和 MEMS 芯片在使用后是可拆卸的，允许重复使用设置的 SAW 器件部分，而不是丢弃这两个部分。我们的平台保持了非接触式和无标签双芯片声流体设备的优势，首次展示了一个集成的微粒操作和实时质量测量平台，可用于分析稀疏的微量物质。SAW 器件和 MEMS 芯片在使用后是可拆卸的，允许重复使用设置的 SAW 器件部分，而不是丢弃这两个部分。我们的平台保持了非接触式和无标签双芯片声流体设备的优势，首次展示了一个集成的微粒操作和实时质量测量平台，可用于分析稀疏的微量物质。