Hydrodynamic assisted multiparametric particle spectrometry

Abstract

The real-time analysis of single analytes in flow is becoming increasingly relevant in cell biology. In this work, we theoretically predict and experimentally demonstrate hydrodynamic focusing with hollow nanomechanical resonators by using an interferometric system which allows the optical probing of flowing particles and tracking of the fundamental mechanical mode of the resonator. We have characterized the hydrodynamic forces acting on the particles, which will determine their velocity depending on their diameter. By using the parameters simultaneously acquired: frequency shift, velocity and reflectivity, we can unambiguously classify flowing particles in real-time, allowing the measurement of the mass density: 1.35 ± 0.07 g·mL-1 for PMMA and 1.7 ± 0.2 g·mL-1 for silica particles, which perfectly agrees with the nominal values. Once we have tested our technique, MCF-7 human breast adenocarcinoma cells are characterized (1.11 ± 0.08 g·mL-1) with high throughput (300 cells/minute) observing a dependency with their size, opening the door for individual cell cycle studies. ; This work was supported by the European Union's Horizon 2020 research and innovation program under European Research Council Grant 681275-LIQUIDMASS-ERC-CoG-2015, project CELLTANGLE reference RTI2018-099369-B-I00, project MOMPs reference TEC2017-89765-R, Asociación Elena Torres (contract OTR04893) and FERO Foundation (Grant OTR06145). The service from the Micro and Nanofabrication Laboratory (MiNa) and X-SEM Laboratory, is funded by MCIU (CSIC13-4E-1794) and EU (FEDER, FSE). ; Peer reviewed