Aptamer-functionalized localized surface plasmon resonance sensor for the rapid and affordable detection of <i>Staphylococcus aureus</i> alpha-toxin

Abstract

The present study aimed to design a novel technique for detection of Staphylococcus aureus Alpha-toxin based on the aptamer-localized surface plasmon resonance (LSPR) to eliminate or reduce existing limitations. For this purpose, gold nanoparticles (GNPs) and the alpha-toxin-specific probe and aptamer were prepared. Nanoparticles were modified with optimal concentrations the aptamer and the performance of the aptasensor in the detection of different alpha-toxin concentrations was studied. Ultimately, spiked real samples with known concentrations of alpha-toxin were used to assess the analytical performance of the sensor. The results demonstrated that GNPs were synthesized and distributed equally. In concentrations of 40 nM and 5 pM, the performance of the probe and aptamer were optimized, respectively. Furthermore, the results regarding the linear range of detection (0-1400 nM), the limit of detection (LOD, 22 nM), and the limit of quantification (LOQ, 68 nM) demonstrated desired performance of the aptasensor. Additionally, the percent recovery between 98 and 106 and the relative standard deviation (RSD) between 0.51 and 1.35 were obtained. Taking together, the results achieved by the present aptamer-functionalized LSPR biosensor suggested a valid, simple, cost-effective, rapid, and reliable detection strategy to quantify alpha-toxin in human samples which is comparative with traditional S. aureus detection strategies.