Rare earth elements—particularly lanthanides like terbium, thulium, and dysprosium—are essential to technologies underpinning renewable energy, electrified transportation, high-performance magnets, and medical imaging. As demand accelerates, sustainable extraction and recycling processes require precise monitoring of these valuable metals, especially within complex waste streams such as acid mine drainage and industrial effluents. Efficient, on-site sensing tools are critical for optimizing recovery operations, minimizing environmental impact, and supporting a resilient rare earth supply chain.
Current methods for lanthanide detection, such as inductively coupled plasma mass spectrometry (ICP–MS), offer excellent sensitivity but are expensive, labor-intensive, and restricted to centralized laboratories, rendering them impractical for field applications. Fluorescent and luminescent assays, though portable, often saturate at high metal concentrations and are vulnerable to interference from abundant co-occurring ions like aluminum and iron. Chemical extraction techniques rely on harsh solvents and multi-step workflows that generate hazardous waste and are unsuitable for real-time bioprocess monitoring.
This technology introduces supercharged yellow and green fluorescent proteins engineered to selectively detect terbium, thulium, and dysprosium over a dynamic concentration range of 10 µM to 5 mM. By strategically adding acidic residues to the protein surfaces, arrays of negative charges are created that chelate lanthanide ions, enabling nonradiative energy transfer upon UV excitation and thereby producing a fluorescent signal proportional to ion concentration.
Unlike traditional systems that saturate at low concentrations, these biosensors are tuned for the elevated metal levels found in mining and recycling streams. Their design minimizes interference from common contaminants such as aluminum, and pH adjustment mitigates iron-related noise. The proteins are genetically encodable, allowing integration into living microbial systems for real-time monitoring, and can also be assembled into supramolecular structures for targeted lanthanide capture.
Compatibility with standard fluorescence microscopy, minimal sample preparation, and scalable expression make the platform ideal for sustainable rare earth element recovery and environmental monitoring.