Understanding the role of microbial nanowires as a biosensing tool for peptide detection

The National Science Foundation Division of Chemical, Bioengineering, Environmental, and Transport Systems awarded South Dakota School of Mines & Technology $450,000 on September 1, 2026, under the Engineering program (CFDA 47.041) to develop a biosensing platform using bacterial nanowires for peptide detection and insulin level monitoring.

The project will create a noninvasive biosensing approach that harvests nanowires from genetically modified bacteria and uses artificial intelligence and machine learning to design recognition elements that detect target molecules in human saliva indicating insulin levels, eliminating the need for blood draws. The team will integrate the nanowire biosensors onto portable sensor chips to monitor electrical readouts generated when nanowires bind to salivary biomarkers. The platform aims to benefit millions of people with insulin-related medical conditions and establish foundational concepts applicable to public health monitoring, water quality assessment, and detection of harmful substances.

The award also includes educational and professional development activities providing undergraduate and graduate students hands-on experience in systems biology, machine learning, and bioelectronics, along with community interaction activities raising awareness about microbial electrical signal generation.

Period of performance runs from September 1, 2026, through August 31, 2029. Work is performed in Rapid City, South Dakota.

Abstract

Electron transfer is the foundation of life and is central to all abiotic reactions. This project will develop a new biosensing approach inspired by bacteria that use their hair-like structures to facilitate electron transfer. These hair-like structures, called nanowires, are nearly 1000 times thinner than a bacterium. Powerful microscopes are required to visualize them. Current detection techniques often rely on expensive tools and chemical labels; however, bacterial nanowires offer an environmentally friendly, inexpensive alternative. The project will monitor electrical readouts generated when a bacterial nanowire binds to a target molecule in human saliva that indicates an individual?s insulin level. This approach will eliminate the need for painful blood draws. To develop a highly efficient biosensing platform, artificial intelligence and machine learning models will be used to design recognition elements. These recognition elements will SIT at the top of the tailor-made nanowires harvested from a genetically modified bacterium. Ultimately, the entire setup of nanowires will be integrated onto portable sensor chips to monitor the electrical readout resulting from specific binding to the salivary molecule. The project's outcomes could benefit millions of people who struggle with insulin-related medical condition. In addition, the core ideas demonstrated in the project could advance future technologies to monitor public health and water quality and detect harmful substances. The project will provide educational and professional development opportunities, enabling undergraduate and graduate students to gain hands-on experience in systems biology, machine learning, and bioelectronics. The project team will lead community interaction activities to raise awareness about how microbes generate electrical signals. This project will investigate a fundamental question: whether natural proteins can serve as a conductive biomaterial for monitoring electron transfer rates and sensing molecular interactions at the nanometer scale. The project team will engineer bacterial structural extrusions called nanowires. The nanowires are considered quasi-one-dimensional (1D) biological nanomaterials. They are composed of a special protein and have exceptionally high extracellular electron transfer (EET) rate to metal oxides. To validate nanowires as sensors at the nanometer scale, the team will deploy them on a unified bioelectronic platform and quantify a key salivary biomarker that reflects human insulin levels. The research will combine (i) bacterial nanowires as a core conductive material, (II) an engineered short peptide called a binder for precise recognition of the biomarker, and (III) a reconfigurable microfluidic system that detects extremely low-frequency electrical stimuli resulting from ?binder-biomarker? Interactions. To achieve a higher yield of nanowires, the team will use the crispr approach to manipulate the genome of the model bacterium. Using artificial intelligence and machine learning (ML), the team will design the next generation of binders to enhance the specificity of the conductive protein core for electrical readout of the targeted biomarker in saliva. Following three-dimensional conformation validation, non-canonical binders will be fused with the nanowires to generate electrical readouts. Ultimately, binder-biomarker duplexes will be characterized using state-of-the-art microfluidics before being assembled into thick sheets for salivary biomarker detection. The project will deliver tailor-made nanowires, non-canonical probes, and a unified bioelectronics platform capable of detecting extremely low concentrations of biological molecules in real time. The theme of the project is highly versatile and can be adopted for biosensing critical minerals, including lithium, and environmental contaminants such as forever chemicals (PFAS). This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the foundation's intellectual merit and broader impacts review criteria.- subawards are not planned for this award.