Combined Detection of C-Reactive Protein and Serum Amyloid A Based on Up-Conversion Luminescent System for Internet of Medical Things Application

The combined detection of C-reactive protein (CRP) and serum amyloid A (SAA) is of great value in early diagnosis of infantile infectious diseases and the differentiation of bacterial and viral infections; however, conventional detection methods, such as electrochemical immunoassay, are costly and time-consuming, and not conducive to the application. In this paper, we report a miniature up-conversion luminescent system that exploits up-conversion nanoparticles (UCNPs) as fluorescent markers and uses the principle of lateral flow immunochromatography to detect CRP and SAA. The concentrations of CRP and SAA were obtained by analyzing the luminescence intensity of up-conversion luminescence excited by UCNPs. Using this system, the detection limit of CRP and SAA reached 0.05 ng/mL and 0.05 ng/mL, respectively, with high sensitivity and stability. In addition, the system can also interconnect with cloud-enabled smartphones through Bluetooth to realize Internet of medical things applications. The up-conversion luminescent system has the advantages of portability, rapid analysis, accuracy, and low cost. Thus, there is great potential for the monitoring of inflammatory diseases and mobile health management in point-of-care testing.