Miniaturized surface plasmon resonance biosensor for odorant and pheromone detection using odorant binding protein

The use of protein as a sensing substrate represents a tremendous achievement in biosensing technology. It has been demonstrated that protein-based biosensors could potentially replace the conventional methodology in analyzing the interactions between proteins and analytes through different types of sensing approaches. In the study presented here, we used a type of odorant binding protein (OBP) obtained from Drosophila, LUSH, as a biosensing substrate and a miniaturized surface plasmon resonance (SPR) sensor to detect the presence of odorants and a pheromone. The LUSH used in the study was induced for expression in Escherichia coli. Subsequently, the protein expressed was purified and then immobilized onto the gold sensor chip of the SPR biosensor. The saturated concentration of LUSH was first determined prior to the detection of alcohols and 11-cis vaccenyl acetate (cVA) at various concentrations. The results showed that the LUSH was saturated at ≥1000 μg/ml on the gold sensor chip. The resonance unit of detection for LUSH was observed at higher concentrations of two alcohols and cVA. LUSH detected ethanol at concentrations ≥50%; propanol was detected at ≥25% whereas cVA was detected at ≥6.25 μg/μl. Although the sensitivity of detection was insufficient, these results suggest that LUSH has the potential to be used as a simple and easy OBP-based biosensor for detecting volatile compounds such as odorants and pheromones in the near future.