Multi-immunoreaction-based dual-color capillary electrophoresis for enhanced diagnostic reliability of thyroid gland...

Thyroid-stimulating hormone (TSH) secretion plays a critical role in regulating thyroid gland function and circulating thyroid hormones (i.e., thyroxine (T4) and triiodothyronine (T3)). A novel multi-immunoreaction-based dual-color capillary electrophoresis (CE) technique was investigated in this study to assess its reliability in diagnosing thyroid gland disease via simultaneous detection of TSH, T3, and T4 in a single run of CE. Compared to the conventional immunoreaction technique, multi-immunoreaction of biotinylated streptavidin antibodies increased the selectivity and sensitivity for individual hormones in human blood samples. Dual-color laser-induced fluorescence (LIF) detection-based CE performed in a running buffer of 25mM Na₂B₄O₇-NaOH (pH 9.3) allowed for fast, simultaneous quantitative analysis of three target thyroid hormones using different excited wavelengths within 3.2min. This process had excellent sensitivity and detection limits of 0.05-5.32 fM. The results showed 1000-100,000 times higher detection sensitivity than previous methods. Method validation with enzyme linked immunosorbent assay for application with human blood samples showed that the CE method was not significantly different at the 98% confidence level. Therefore, the developed CE-LIF method has the advantages of high detection sensitivity, faster analysis time, and smaller sample amount compared to the conventional methods The combined multi-immunoreaction and dual-color CE-LIF method should have increased diagnostic reliability for thyroid gland disease compared to conventional methods based on its highly sensitive detection of thyroid hormones using a single injection and high-throughput screening.