Self-Administrated Multiplex Radiation Indicator (SAMURAI) Kit for field triage biodosimetry

PROJECT SUMMARY After a mass-casualty radiological or nuclear accident, the first triage will need to distinguish exposed from non- exposed individuals to organize the countermeasure response. In this objective, there is a need to develop a bioassay that can screen tens or hundreds of thousands of individuals in a timely manner directly on field. Our team identified radiation responsive proteins and transcripts in leukocytes that can discriminate samples irradiated with dose < 2 Gy from ≥ 2 Gy. In this application, we propose to design, develop, and test a “sample- in-answer-out” radiation exposure assay, named Self-Administrated MUltiplex RAdiation Indicator (SAMURAI) kit. The SAMURAI kit is a self-administered, unpowered, and cost-efficient point-of-care paper-based vertical flow immunoassay (VFI) system based on a safe “tube and cap” user interface that allows the isolation and multiplex detection of both proteins and RNA from leukocytes. The handheld platform will consist of a sample preparation module (SPM) coupled to a detection (VFI) module and will be able to process sample from collection to data reporting in less than 30 min. To achieve this goal, we propose the following aims: #1) develop biodosimetry protein and transcript bioassays for paper-based format. This will involve the design and testing of sandwich immunodetection for proteins and the development of an assay chemistry allowing transcript detection using an amplification-free approach based on the detection of DNA:RNA hybrids; #2) design and test a SPM to extract proteins and gene transcripts from leukocytes. The SPM will be designed to load fingerstick-collected whole blood, lyse red blood cells, capture leucocytes by anti-CD45 antibodies and isolate RNA and proteins; #3) fabricate a VFI module to process sample directly from the SPM and generate a quantifiable signal on a multiplex paper membrane to assess irradiation status. A capillary-driven pre-existing VFI module will be adapted to fit to the SPM and transfer sample through the reaction pads and to the VFI multiplex membrane to generate a visible colorimetric signal that could ultimately be captured with commercial smartphones and analyzed by our VeriFAST software App. The ability to detect simultaneously protein and RNA biomarkers will make the SAMURAI kit useful, not only for the preliminary triage during radiobiological accident, but for a large variety of applications, broadening its appeal to industry partners.