Acoustofluidic harvesting of microalgae on a single chip

We present an on-chip acoustofluidic platform for harvesting a target microalgal species from a heterogeneous population of cells and particles based on their size, density, and compressibility in a rapid, non-invasive, energy-efficient, continuously running, and automated manner. For our proof-of-principle demonstration, we use Euglena gracilis as a target species. Specifically, we show the simultaneous separation and enrichment of E. gracilis from a mixed population of E. gracilis in pond water (consisting of other microalgae and various kinds of particles as contaminants) on a single acoustofluidic chip with a recovery ratio of 92.6%, a target separation ratio of 90.1%, a concentration factor of 3.43, an enrichment factor of 12.76, and a cell viability rate of 98.3% at a high volume rate of 500 μl/min. Our results indicate that the on-chip acoustofluidic platform is an effective tool for harvesting target microalgae from mixed populations of microalgae and other contaminants.