A critical unmet need in the diagnosis of bacterial infections, which remain a major cause of human morbidity and mortality, is the detection of scarce bacterial pathogens in a variety of samples in a rapid and quantitative manner. Herein, we demonstrate smartphone-based detection of Staphylococcus aureus in a culture-free, rapid, quantitative manner from minimally processed liquid samples using aptamer-functionalized fluorescent magnetic nanoparticles. The tagged S. aureus cells were magnetically captured in a detection cassette, and then fluorescence was imaged using a smartphone camera with a light-emitting diode as the excitation source. Our results showed quantitative detection capability with a minimum detectable concentration as low as 10 cfu/ml by counting individual bacteria cells, efficiently capturing S. aureus cells directly from a peanut milk sample within 10 min. When the selectivity of detection was investigated using samples spiked with other pathogenic bacteria, no significant non-specific detection occurred. Furthermore, strains of S. aureus from various origins showed comparable results, ensuring that the approach can be widely adopted. Therefore, the quantitative fluorescence imaging platform on a smartphone could allow on-site detection of bacteria, providing great potential assistance during major infectious disease outbreaks in remote and resource-limited settings.

仍然是人类发病和死亡的主要原因的诊断细菌感染的关键未满足需求是以快速和定量的方式检测各种样品中稀缺的细菌病原体。在本文中，我们演示了使用适体功能化的荧光磁性纳米颗粒，从最少处理的液体样品中以无培养物，快速，定量的方式，基于智能手机的金黄色葡萄球菌检测。标记的金黄色葡萄球菌将细胞磁性捕获在检测盒中，然后使用智能手机相机以发光二极管作为激发源对荧光成像。我们的结果表明，通过对单个细菌细胞进行计数，定量检测能力最低可检测浓度低至10 cfu / ml，可在10分钟内直接从花生奶样品中有效捕获金黄色葡萄球菌细胞。当使用掺有其他病原细菌的样品调查检测的选择性时，没有发生明显的非特异性检测。此外，金黄色葡萄球菌的菌株来自不同来源的数据显示出可比的结果，从而确保该方法可以被广泛采用。因此，智能手机上的定量荧光成像平台可以对细菌进行现场检测，从而在偏远和资源有限的环境中，在重大传染病暴发期间提供了巨大的潜在帮助。