A 3-D-printed acoustofluidic device for Raman spectroscopy Free

The development of technologies capable of determining direct information about cell status is highly required. Confocal Raman microscopy offers a singular pathway to monitoring chemical “fingerprints” of intracellular components via radiation-complex biomolecules interactions. Nevertheless, Raman spectroscopy's biological applications are still challenging due to the small probability of spontaneous light scattering events with bio-micromolecules. As a consequence, the signal-to-noise ratio is low. Acoustofluidic devices offer an ingenious solution to enhance the Raman signal by levitating the biological sample. In this work, we present a cheap 3-D-printed acoustofluidic device for confocal Raman spectroscopy. The device comprises a cylindrical cavity with a 750 μm-height and 4 mm-diameter, which operates around 1 MHz. Raman spectra of polystyrene microparticles (10 μm-diameter), levitating at 300 μm in water, were obtained by using a 785 nm excitation laser focused through a 40x objective lens. In another set of careful experiments, the device efficiently trapped 20-μm macrophages (cell line j774.A1), of which the preliminary Raman spectra will be presented. Finally, we will discuss Raman spectroscopy's trends as an optoacoustofluidic technique, as well as its applications in biotechnology and microbiology.