Acoustofluidics Lab on a Chip System for size-based Nanoparticle Separation

Abstract Despite the growing demand for nanoscale biomolecule analysis in point-of-care (POC) applications, nanoparticle separation remains a significant challenge. This is due to issues like high sample loss, low throughput, large-scale material requirements, and the complexity of current technologies. Given that separation efficiency directly impacts subsequent sample processing and analysis, there is a clear need for a robust and reliable size-based separation technique. This study introduces a novel acoustofluidics lab-on-a-chip system designed to overcome current separation barriers. It combines simple polymer prototyping with integrated ultrasonic agitation. The system features two key components: (1) a microfluidic network embedded with membrane filters of varying pore-size cut-offs, and (2) an ultrasonic transmitter that induces acoustic agitation. Using this novel system, we successfully demonstrate the fractionation of 60 nm Au nanoparticles from a polydisperse solution under ultrasonic waves (28–40 kHz) generated by the transducer integrated into the microfluidic platform. Ultrasonic irradiation not only prevents cake formation but also reverses the fouling process through acoustic agitation. This significantly increases the flow rate during separation and improves the recovery of target-size nanoparticles. This microfluidic platform holds great potential as a powerful tool for sample preparation and analytical methodologies in POC applications.