Advancing human biodosimetry with solid-state nanopore analyses

Project Summary In the event of a radiological emergency, the ability to measure acute radiation exposure will be paramount. While several potential direct molecular markers of radiation damage have been identified, there are currently no tools available with the necessary speed and sensitivity to mace their deployable assessment feasible. However, the developments in nanotechnology provide a potential solution to this significant national challenge in the form of solid-state (SS-) nanopores: nanometer-scale holes fabricated in thin, insulating membranes that can facilitate the electrical translocation and measurement of single molecules. SS-nanopore sensors operate on the simple principle of resistive pulse sensing in which key signals are carried via an ionic current that can be measured with simple and readily-miniaturized transimpedance amplifiers and used to determine molecular size. In this proposal, we will wise this unique capacity to probe three related but independent DNA-based biomarkers of radiation exposure. We select DNA as the critical biomarker because it is (1) the most thoroughly characterized biopolymer in nature and (2) has high chemical stability, enabling reliable physical models to be built for determining how ionizing radiation interacts with DNA in vivo. In this project, we propose a panel of DNA biomarkers that will support mass casualty assessment, including direct fragmentation of mitochondrial DNA (Aim 1), shifts in the characteristic length of cell-free DNA (Aim 2), and changes in the abundance of oxidative lesions in genomic DNA (Aim 3). When measured independently and considered jointly, these markers will provide high precision (uncertainty < 0.5 Gy) in determining the exposure range from 0-10 Gy as well as the radiation source modality. The resulting technology will address the catastrophic measurement gaps that currently exist and offer a clear path towards a tool for on-site radiological triage.