Single Molecule Detection of Binding Kinetics

University Of Southern California, Los Angeles CA

Investigators

Abstract

The ability to understand and to manipulate protein-protein interactions will contribute to improvements in biological imaging and methods for drug discovery and delivery. One crucial component of protein interactions is the binding site. The strength of the interaction determines the utility of the two proteins, which could be an antibody-antigen or an enzyme-substrate pair. Different methods have been developed to characterize this interaction, yet these techniques require either high protein pair concentrations or imaging of the interaction. High concentrations often cause blurring in the final data. Therefore, to accurately determine the interaction between two proteins, it is important to perform both types of measurements. The primary focus of this project is to develop and to demonstrate an optical sensor capable of characterizing antibody-antigen binding at the single molecule level without relying on images. This instrument is based on an optical sensor that relies on resonance, somewhat like an acoustic tuning fork. The optical sensor is capable of single molecule detection, because as molecules bind to the sensor, the sensor?s resonant frequency changes, resulting in a fast response time (100ns) and improved sensitivity. This technique will enable new types of measurements that will have immediate impact on the fields of cell biology and biochemistry, with longer-term benefits to systems biology. Training future scientists and engineers at all age levels is an integral component of this project. In addition to the involvement of a graduate student and a post-doctorate scholar, several undergraduate researchers whose stipends are provided through USC?s Undergraduate Research Fund will be involved in different aspects of this project. They will have the opportunity to learn state-of-the-art instrumentation and fabrication methods in USC?s Class 10 cleanroom and electron microscopy center. Results will be presented at professional conferences and the equipment will be demonstrated to middle school and high school visitors to the laboratory.