Development of a quantum, magnetic-imaging platform for biophysical measurements

Abstract

Single-molecule measurements help build up the fundamental understanding of many important biological functions. Due to the wide variety of molecules that have been studied, and the properties of these molecules that often make them difficult to directly image, many single-molecule experiments involve attaching a more-easily-observable object to the molecule in question. Whether that attached object is a fluorescent protein that a cell has been modified to attach to the desired target molecule or a immunofunctionalized sub-micron-scale bead, these probes can often only report on the position of the underlying molecule. This thesis presents the development of a sub-micron scale magnetic field imaging platform to allow for direct orientation measurements in single molecule, biological experiments. Following relevant background from the fields of single molecule experiment and quantum sensing, two experiments using this new imaging platform are presented. By combining the magnetic imaging platform with a novel quantum control system, video-rate magnetic imaging is possible. By combining the magnetic imaging platform with a magnetic tweezer system, a micro-magnetic torque balance is constructed, allowing for probing of single DNA strand bend stiffness. In both cases, statistical inference is applied to determine relevant magnetic particle parameters from magnetic field images to extract relevant information about the underlying system.