Chemical delivery microsystem for single-molecule analysis using multilaminar continuous flow

The fluidic operations, such as chemical delivery, hydrodynamic force control, solutions exchange, etc., to a desired location in a microfluidic channel are one of the most important technical aspects to progress single-molecule studies in microfluidic devices. This paper experimentally demonstrates multilaminar flow-based fluidic operations to supply and remove chemicals to an immobilized single-molecule on an inner surface of a microchannel to develop a future platform microfluidic device for single-molecule analysis. The microfluidic device, having multiple inlets and single outlet embedded with a micropump for each inlet, can generate continuous multiple laminar flow inside of the microchannel. The multiple laminar flow control capabilities were experimentally evaluated to deliver any single laminar flow to a desired location and to control flow speed to minimize hydrodynamic force to the target single-molecule. As a demonstration of single-molecule analysis using this format, ATP dependent rotation of F1-ATPase was investigated. As a result, the rotation of F1-ATPase was successfully investigated. This format showed many advantages and flexibility to realize the future platform of single-molecule studies.