Reconfigurable surface acoustic wave platform for particle concentration, sorting and in situ Raman identification on a single lithium niobate chip
Year: 2026
Type: article
Abstract: Environmental microplastics occur predominantly as irregular fragments and fibers, whose acoustic manipulation is complicated by shape-dependent radiation forces and torques. We report a reconfigurable acoustofluidic platform fabricated on a 128 ∘ Y -cut LiNbO 3 substrate that provides three surface acoustic wave (SAW) operating configurations on a single chip without device modification: traveling SAW for pre-concentration and size-dependent sorting, standing SAW for positioning particles into pressure nodes, and a focused standing-wave configuration generated by opposing curved interdigital transducers for localized trapping. The individual functions were characterized separately; continuous sorting of polydisperse polyethylene microspheres achieved a mean large-fraction deflection of 91.8% ( n = 3 ). Focused acoustic gradients retain irregular polyethylene terephthalate (PET) fragments of 20–60 μ m within the Raman focal region under continuous flow at 1 μ l min − 1 , despite residual rotation. Retention is sustained for at least 30 s, sufficient for in situ Raman identification of trapped polyethylene, polystyrene and PET; diagnostic PET bands were also recovered from pond water spiked with fragments. The results show that concentration, sorting and spectroscopic identification can each be performed on a single micromachined device, providing a basis for label-free sample preparation.
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,325
Awards: G1454965787, G469635607, G7384073382
OpenAlex ID: W7223288331