Controlled fabrication of novel magneto-fluorescent encoded microspheres with host–guest structures for simultaneous detection of thyroxine and thyroid stimulating hormone

Abstract

Simultaneous detection of serum thyroxine (T4) and thyroid stimulating hormone (TSH) is essential for diagnosis and monitoring of congenital hypothyroidism (CH). Here, we reported a novel suspension array platform based on host–guest-structured magneto-fluorescent encoded beads (HGBs) for concurrent T4 and TSH detection. The foundation of HGBs lays in low-density polystyrene microsphere templates, ingeniously transformed into micron-scale host beads through the sequential deposition of iron oxide nanoparticles, quantum dots, and silica layers, resulting in good magnetism, satisfactory suspension ability and fluorescence stability. By combining micron-scale host beads exhibiting distinct red fluorescence intensities with nano-scale guest beads displaying varying green fluorescence intensities, we could repeatedly and accurately prepare 24 discriminable HGBs easily. Then, two representative HGBs were selected to construct a suspension arrays system for concurrent T4 and TSH detection. Under the optimal detection conditions, the suspension arrays we tested on T4 and TSH could be assayed in the ranges of 4 to 400 ng mL⁻¹, and 0.032 to 100 mIU L⁻¹ with limits of detection of 1.2 ng mL⁻¹, and 0.014 mIU L⁻¹, respectively. This innovative methodology not only exhibits commendable accuracy and precision but also demonstrates strong concordance with established chemiluminescence immunoassay results. Consequently, the suspension arrays based on HGB barcodes hold immense promise for enhancing the diagnostic efficiency in the realm of CH management.