An acoustofluidic sputum liquefierElectronic supplementary information (ESI) available: Video1-mixing of two fluids when a piezoelectric transducer was alternately switched on and off. See DOI: 10.1039/c5lc00539f

We demonstrate the first microfluidic-based on-chip liquefaction device for human sputum samples. Our device is based on an acoustofluidic micromixer using oscillating sharp edges. This acoustofluidic sputum liquefier can effectively and uniformly liquefy sputum samples at a throughput of 30 μL min −1 . Cell viability and integrity are maintained during the sputum liquefaction process. Our acoustofluidic sputum liquefier can be conveniently integrated with other microfluidic units to enable automated on-chip sputum processing and analysis. The first microfluidic-based on-chip sputum-liquefaction device is demonstrated via an acoustofluidic micromixer.