Aptamer Modified Gold Nano-scattering Probe for Sensing of S.aureus

• 1、Food science and technology School, Jiangnan University, Wuxi 214122
• 2、Food science and technology School, Jiangnan University, Wuxi 214122
• 3、Suzhou Quality and Technical Supervision and Comprehensive Testing Center, Suzhou 215000

Abstract：In this paper, coupling dark-field imaging with aptamer-modified gold nanoparticles, a new method for qualitative detection of Staphylococcus aureus (S. aureus) was proposed. First, the gold nanoparticles were modified with aptamer which against S. aureus; then the functionized nanoparticles were used as scattering probes under a dark-field microscope which converted from a basic monocular microscope to identify the target pathogens with direct microscopy and qualitatively detect them with indirect microscopy. A mass of botryoid light spots with diameter of 1 μm were observed in direct microscopy inferring the existing of S. aureus; Further more, in indirect microscopy, the scattering signal can be detected with a concentration as low as 10^5 CFU/mL. A positive definition was newly set in order to reduce the chances of false positive tests, and then applied in real sample tests which showed a reliable recovery rate of 100% in high concentration groups(10^7 CFU/mL) and a minimum positive limit of 10^6 CFU/mL.

Keywords： Foodborne microbe detection Aptamer Nano scattering probe dark-field microscope Staphylococcus aureus