Gold Magnetic Nanoparticle Conjugate-based Lateral Flow Assay For Detection Of TORCH IgM-class Antibodies

TORCH is an acronym of a group of diseases during perinatal, including Toxoplasma, Rubella virus (RV), Cytomegalovirus (CMV), and Herpes Simplex virus (HSV). These diseases are common causes of congenital infections which have serious effect on fetal or neonatal. Primary infections with TORCH pathogens, including those in pregnant women, are usually subclinical and, even if symptomatic, lack specificity in their symptoms and signs. On the other hand, specific IgM has been shown to be an indicator of acute and recent pathogen infection as IgM antibody can be detected within 2 weeks of infection. Therefore, detection of TORCH specific IgM antibody can achieve early detection of TORCH pathogens with high clinical value.In this paper, GoldMag(?) nanoparticles were used as a carrier and modified with poly styrene sulfonate (PSS) and poly(methyl methacrylate) (PMAA). After been modified, the GoldMag(?) nanoparticles could conjugate with mouse anti-human IgM (μ-chain specific) antibody to construct a probe and a lateral immunochromatographic system for detection of TORCH specific IgM antibodies based on GoldMag(?) nanoparticles was established.The result shows that after been modified with PMAA, the size of GoldMag(?) nanoparticles become smaller and distribute uniformly. What is more, this method exhibited good repeatability, high sensitivity and specificity. No interference was found with triglycerides, hemoglobin and bilirubin and no cross-reactivity was found among the four pathogens. Compared to commercial colloidal gold based LFIA strips, our method exhibited higher sensitivity.