Technology development for microfluidic multifunctional probe array dielectrophoretic force spectroscopy with wide loading rate

Abstract

The simultaneous investigation of a large number of events with different types of intermolecular interactions, from non-equilibrium high-force pulling assay to quasi-equilibrium unbinding events inside the same environment, is very important issues for fully understanding intermolecular bond rupture mechanism. Here, we describe a novel dielectrophoretic force spectroscopy technique that utilizes micro-sized beads as multifunctional probes for parallel measurement of intermolecular forces with an extremely wide force rate (10-4pN/s-104pN/s) inside a microfluidic device. In our experiments, various forces, which broadly form the basis of all molecular interactions in order to establish that our approach can be used for wide range of applications, were measured across a range of force loading rates by multifunctional probes with various diameters with about 600 events per mm2, simultaneously and under the same environment. Furthermore, the individual bond rupture forces, parameters for the characterization of entire energy landscapes, and the effective stiffness of the force spectroscopy were determined using the measured results. This method of determining intermolecular forces could be very useful for the precise and simultaneous examination of various molecular interactions as it can be easily and cost-effectively implemented within a micro-fluidic device for a range of applications including immunoassays, molecular mechanics, chemical and biological screening, and mechanobiology.