Novel surface plasmon resonance biosensor that uses full-length Det7 phage tail protein for rapid and selective detection of Salmonella enterica serovar Typhimurium

摘要

We report a novel surface plasmon resonance (SPR) biosensor that uses the full-length Det7 phage tail protein (Det7T) to rapidly and selectively detect Salmonella enterica serovar Typhimurium (S. Typhimurium). Det7T, which was obtained using recombinant protein expression and purification in Escherichia coli, demonstrated a size of similar to 75 kDa upon SDS-PAGE and was homotrimeric in its native structure. Microagglutination and transmission electron microscopy (TEM) data revealed that the protein specifically bound to the host, S. Typhimurium, but not to nonhost E. coli K-12 cells. The observed protein agglutination occurred over a concentration range of 0.8-24.6 mu g/mL. The Det7T proteins were immobilized on gold-coated surfaces using amine-coupling to generate a novel Det7T-functionalized SPR biosensor, wherein the specific binding of these proteins with bacteria was detected by SPR. We observed rapid detection of (similar to 20 Min) and typical binding kinetics with S. Typhimurium in the range of 5 x 10(4)-5 x 10(7) CFU/mL, but not with E. coli at any tested concentration, indicating that the sensor exhibited recognition specificity. Similar binding was observed with 10% apple juice spiked with S. Typhimurium, suggesting that this strategy provides promise for the rapid, real-time, and selective monitoring of target microorganisms in the environment, and thus has great potential for supporting health by enabling early disease prevention.