# An Enhanced Electrochemiluminescence Immunoassay Platform via Optimized Magnetic Bead Uniformity for Reliable Thyroid-Stimulating Hormone Monitoring

## TL;DR

This paper introduces an improved electrochemiluminescence immunoassay platform that enhances thyroid-stimulating hormone detection through better magnetic bead distribution.

## Contribution

A quantitative method for optimizing magnetic bead uniformity in ECLIA systems is introduced, improving signal performance.

## Key findings

- Optimizing flow rate improved bead distribution uniformity and increased luminescence intensity by 26.32%.
- The system showed a linear TSH detection range of 0.016–120 µIU·mL−1 with high correlation to a commercial analyzer.

## Abstract

Electrochemiluminescence immunoassay (ECLIA) is widely used in clinical diagnostics owing to its high sensitivity, broad dynamic range, and excellent analytical stability. However, the influence of magnetic bead deposition behavior on electrochemiluminescence (ECL) signal performance remains insufficiently characterized. In this study, a quantitative evaluation method for magnetic bead distribution uniformity on the electrode surface was established and applied to optimize fluidic parameters in an ECLIA measurement system. By combining microscopic imaging with image analysis, magnetic bead spreading behavior under different flow conditions was systematically characterized and correlated with luminescence signal intensity. Optimization of the flow rate (18.46 µL·s−1) improved bead distribution uniformity and resulted in a 26.32% increase in luminescence intensity without altering bead coverage or assay chemistry. The optimized system was further validated using thyroid-stimulating hormone (TSH) detection, showing a linear response over 0.016–120 µIU·mL−1 (R2 > 0.996) and high consistency with a commercial analyzer (R2 = 0.998) from Roche. These results demonstrate that quantitative control of magnetic bead distribution provides an effective strategy for improving ECLIA performance and offers a general optimization framework for bead-based electrochemiluminescence systems.