Carbon dots (CDs) are intrinsically luminescent nanomaterials that have many potential applications in biosensing technologies due in part to their high photostability and fluorescent properties. However, attempts to integrate CDs into immunosorbent assays have been deterred by challenges preventing quantum yield augmentation and surface functionalization. To address these issues, we fabricated carbon dot-encapsulated silica nanospheres (CSNs) using a facile one-pot synthesis method. The enclosing silica matrix rendered extensive material stability to the nanospheres and abated quenching by nonradiative decay to cause considerable signal amplification. Nanosphere hybridization to antibodies permitted their use in solid-phase immunoassays as tracers. Here, we demonstrate the suitability of CSN-based immunosorbent assays as a point-of-care technique for the detection of foodborne pathogens through E. coli O157:H7 quantitation experiments. After optimization, detection limit of E. coli O157:H7 was determined to be 2.4 CFU mL⁻¹. The estimated recoveries were in the range of 91.7–110.5% in spiked samples, which indicated that the developed method is capable for detecting E. coli O157:H7 in food samples. The nanosphere tracers described herein, and the methods used to create them, may be beneficial tools for the development of new pathogen biosensing strategies.

碳点 (CD) 是本质上发光的纳米材料，由于其高光稳定性和荧光特性，在生物传感技术中具有许多潜在的应用。然而，阻止量子产率增加和表面功能化的挑战阻碍了将 CD 整合到免疫吸附测定中的尝试。为了解决这些问题，我们使用简便的一锅法合成了碳点封装的二氧化硅纳米球（CSN）。封闭的二氧化硅基质为纳米球提供了广泛的材料稳定性，并减弱了非辐射衰减引起的猝灭，从而导致相当大的信号放大。纳米球与抗体的杂交允许它们在固相免疫测定中用作示踪剂。这里，大肠杆菌O157:H7 定量实验。优化后，大肠杆菌O157:H7 的检测限确定为2.4 CFU mL ^-1。加标样品的估计回收率在 91.7-110.5% 的范围内，这表明所开发的方法能够检测食品样品中的大肠杆菌O157:H7。本文所述的纳米球示踪剂以及用于创建它们的方法可能是开发新病原体生物传感策略的有益工具。