Project Details
Projekt
Living Plasmonics: Distributed environmental sensing with photoluminescent sensor ELM through enzymatic coupling of bacterial sensing with nanoplasmonics
Subject Area
Synthesis and Properties of Functional Materials
Biochemistry
Biochemistry
Term
since 2024
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 541297978
Bacterial sensors with programmed genetic circuitry detect environmental pollutants such as antibiotics with high selectivity and sensitivity. They are suitable for efficient monitoring of large areas or secluded areas because the bacteria do not require electrical power or maintenance and a simple biofilm contains all elements required for detection. Today, these highly attractive, renewable sensors are often not used because the evaluation of bacterial sensor responses requires sophisticated infrastructure that is not available in the field. On the other hand, hybrid sensor materials for environmental analysis based on nanoplasmonics and photoluminescence (PL) have been developed in recent years. Their optical properties depend on the concentration of certain analytes. They can be efficiently excited with laser diodes and evaluated with simple CCD cameras. Sensor materials based on inorganic materials and polymers are robust and can be read by drones, for example. However, they react less specifically and sensitively than established electrochemical or chromatographic methods, which limits their application areas. In this project, we combine bacterial sensing with plasmon resonance and photon up-conversion in living sensing materials (ELM). We couple the sensitivity and specificity of bacteria with the robustness and intensity of optically active particles. The central link is the enzyme gold reductase GoIR, which was recently been described in bacteria for the first time. We engineer E. coli that produce GoIR only when the bacteria detect contaminants such as tetracyclines or arsenic. A biofilm of these bacteria is then integrated into a multilayer ELM. When the analyte reaches the biofilm, GoIR reduces a gold complex and forms nanoparticles with strong surface plasmon resonance inside the bacteria. By selectively segregating and agglomerating the particles, we achieve the formation of resonant plasmonic superstructures that dramatically increase the optical density of the bacterial microfilm. This modulates the emission of a photoluminescent film upon read-out and generates a strong PL signal that depends on the concentration of the detected analyte. By ratiometrically evaluating the emission at two wavelengths, we can thus quickly and remotely determine the presence of the analyte. The approach of this project is modular because the genetic circuits responsible for detection can be exchanged independently of the optical system. The results not only create a hybrid of bio- and plasmonic sensor. They can be used in other SPP projects to indicate the state of other ELMs.
DFG Programme
Priority Programmes
