核酸适配体修饰金纳米散射探针检测金黄色葡萄球菌

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.