Consolidated Microscale Interferon-γ Release Assay with Tip Optofluidic Immunoassay for Dynamic Parallel Diagnosis of Tuberculosis Infection.

Abstract

Interferon-γ release assay (IGRA) is one of the most important diagnostic tools for tuberculosis (TB) infection. Despite its high accuracy, conventional IGRA has several drawbacks, including complicated procedures, large blood volume requirements, lengthy incubation times, and difficulties in parallel testing. Efforts have been made to develop miniaturized and highly sensitive biosensors for interferon-γ or to evaluate the specific immune response through microfluidic platforms. However, the need for sophisticated consumables and equipment, as well as the partial experimental design, has limited the application of these advanced techniques in TB diagnosis and disease control. Here, we report the development of a tip optofluidic immunoassay (TOI)-based consolidated microscale IGRA (CM-IGRA) for the dynamic and parallel evaluation of TB infection, refining both the blood incubation and interferon-γ quantification processes. The TOI system comprises 12 microfluidic immuno-reactors and a portable chemiluminescent imaging station, capable of quantifying interferon-γ with high sensitivity (8.00 pg/mL in plasma) and a wide detection range (∼10⁴). The results generated with CM-IGRA achieved 98.39% agreement with the standard IGRA while reducing blood sample consumption to 50 μL per assay (20-fold reduction) and significantly shortening the incubation time from 20 to 10 h. This diagnostic method simplifies operations and improves efficiency for the parallel assays required in IGRA, providing a promising solution for TB screening in patients for whom current methods are inconvenient, such as children and older adults.