Postdoctoral Associate: Nanopore Spectroscopy for Single-Molecule Biodosimetry

About the role

The Biophysical and Biomedical Measurement Group at NIST (Gaithersburg, MD) is seeking a postdoctoral research associate to develop nanopore spectroscopy measurements of ionizing-radiation damage to polymers and nucleic acids. This project builds on recent NIST work demonstrating single-molecule biodosimetry using resistive-pulse nanopore measurements of radiation-induced DNA fragmentation. The next stage will expand this approach to quantify chain scission and molecular damage in standard polymers, including cellulose, and in nucleic acids such as DNA and RNA. Measurements will be performed as a function of absorbed dose and radiation quality, including radiation type, linear energy transfer (LET), dose rate, and related conditions. The broader goal is to connect molecular damage to absorbed dose (Gy), radiation chemistry, and relative biological effectiveness (RBE), providing a complementary molecular measurement approach for radiation dosimetry, cancer-therapy response assessment, and radiological emergency response.

This position is within the Biophysical Metrology and Inference program at NIST, which develops measurement approaches, physical models, and data-analysis methods that connect biological signals to quantitative mechanism and uncertainty.

Responsibilities

• Design and execute research on measuring ionizing-radiation dose using polymer chain scission reactions.
• Prepare and characterize standard polymers (e.g., cellulose) and nucleic acids (DNA/RNA) for irradiation, nanopore measurement, and quantitative analysis.
• Measure radiation-induced molecular damage using nanopore spectroscopy, resistive-pulse sensing, nanopipettes, and related single-molecule measurement approaches.
• Develop and validate dose-response curves as a function of radiation quality, including radiation type, LET, dose rate, and related experimental conditions.
• Analyze nanopore signals to quantify fragment-length distributions, chain scission, capture statistics, dose response, uncertainty, and reproducibility.
• Develop physical, statistical, and computational models linking radiation chemistry, direct/indirect molecular damage, absorbed dose (Gy), and RBE-relevant response.
• Collaborate with NIST teams in nanopore sensing, radiation dosimetry, radiation biology/chemistry, and biophysical measurement.
• Report results through internal and external presentations and peer-reviewed publications.

Requirements

• Ph.D. in chemistry, biochemistry, biophysics, analytical chemistry, radiation chemistry, radiation biology, biomedical engineering, physics, or a closely related field.
• Demonstrated experience in one or more of the following: nucleic acid chemistry, resistive-pulse sensing, nanopore spectroscopy, radiation chemistry, radiation biology, polymer/biopolymer damage, or single-molecule measurement.
• Strong experimental skills and ability to develop, troubleshoot, and validate measurement workflows.
• Strong data-analysis skills using Python, MATLAB, R, Origin, or similar tools.
• Strong written and oral communication skills.

Skills

• Experience with nanopores, nanopipettes, ionic-current measurements, resistive-pulse sensing, electrophysiology, or electrochemical sensing.
• Experience with DNA/RNA sample preparation, nucleic-acid damage assays, polymer chain scission, fragmentation analysis, or molecular-length/molecular-weight characterization.
• Experience with ionizing radiation, dosimetry, LET/radiation quality, radiation chemistry, radiation biology, RBE, or radiotherapy-relevant measurements.
• Experience with statistical analysis, dose-response modeling, signal processing, internal standards/calibration, and uncertainty quantification.
• Experience with spectroscopy, chromatography, electrophoresis, fluorescence methods, or complementary molecular characterization techniques.
• Ability to work effectively in a multidisciplinary environment spanning chemistry, biophysics, radiation science, nanopore measurement, and biomedical metrology.

U.S. citizenship is preferred; for some appointment mechanisms, eligibility depends on citizenship.