Detachment of Cells from Surface in Biosensitive Media by Surface-Level Bubble Generation

Biofouling and uncontrolled cell-adhesion are critical concerns in a wide range of industries and applications with bio-sensitive media such as pharmaceuticals, biomedicine, food processing, energy as well as many others. In this work, we demonstrate a gentle method of detaching cells from substrates using surface-level bubble generation. A mini-fluidic imaging platform with a chloride-free electrolyte is created to study the interactions between departing bubbles and fouled cells on the surface. Chlorella Vulgaris micro-algae are used as a model cell. We hypothesize a new mechanism of foulant removal, namely shear stress on the wall generated beneath a departing bubble. We furthermore create an analytical model to predict the shear stress beneath a departing bubble. The model is validated with experimental results showing great overlap between measurements and predictions. Finally, we apply our knowledge to build a lab-scale defouling set-up where we show robust fouling removal of both micro-algae and cultured human cells while maintaining high viability. This approach can work for both seawater and fresh-water algae, mammalian cell culturing, sensors in the food industry, and other applications with sensitive media.