Motion of submicrometer particles dominated by Brownian motion near cell and microfabricated surfaces

Control of submicrometer particles is essential for microfluidic devices. In microfluids, the current approach for achieving particle control relies on interaction between particles and patterned obstructions and requires complex manufacturing and purified samples. Here, we report how the rigid, silica frustules of diatoms, microscopic protists, control submicrometer particle movement on their open surfaces. This provides insight into how diatoms function in a particle-laden environment and suggests potentially useful open-channel principles and designs in microfluidics.