Combined and rapid detection of anti-Brucella IgG/IgM in clinical samples based on surface-enhanced Raman scattering-lateral flow immunochromatography.

Brucellosis is a bacterial infectious disease caused mainly by Brucella. Transmission is mainly by contact with infected domestic or wild animals or their excreta. Clinical diagnosis of brucellosis is usually based on qualitative total antibody tests, which make it difficult to differentiate between acute and pre-existing infections. In this study, for the simultaneous detection of anti-brucellosis IgG and IgM, we innovatively developed a surface-enhanced Raman scattering (SERS)-lateral flow immunoassay (LFIA) detection system, and evaluated its performance and diagnostic effect by using clinical serum samples. The key design of this biosensor involves the preparation of two immunoprobes using two Raman spheres (R-Sphere) with distinct signals conjugated to mouse anti-human IgG and IgM, respectively. In this design, brucellosis-specific antigens are embedded in the T-line, allowing simultaneous capture of anti-brucellosis IgG and IgM in a specific binding reaction. A portable Raman instrument is used to detect the characteristic signal intensities generated by IgM and IgG on the T-line, which can then be used to analyze the target IgM and IgG antibodies. Based on the analysis of 40 clinical samples, the method has a sensitivity and specificity of 100%, and the detection time is only 15 min. The advantages of this technology are fast speed, convenient use, high sensitivity, and it can distinguish the disease course to achieve precise treatment. These features make it an ideal solution for large-scale brucellosis testing in remote and nomadic areas, where it can play a crucial role in improving public health protection.