(A) Schematic illustration of the one-step gold deposition-induced signal amplification process for detecting anti-interferon-γ autoantibodies, highlighting the time-sequenced fluid flow and automated reagent release. (B) 3D-osPAD and colorimetric results shows the layout of the control and test wells on the 3D printed holder. (C) Real testing results with verified positive and negative. (D) Clinical validation using patient serum samples demonstrated 100% sensitivity and 100% specificity. Credit: National Taiwan University

A 3D paper-based analytical device (3D-osPAD) with in situ gold signal amplification enables one-step, highly sensitive detection of anti-IFN-γ autoantibodies within 10 minutes, showing 10-fold improved sensitivity and high clinical accuracy for adult-onset immunodeficiency.

Researchers at National Taiwan University have developed a fast, low-cost paper-based test to detect hidden immune defects that make patients prone to severe, persistent infections. The device targets harmful autoantibodies that block interferon-gamma, a key immune molecule, leaving patients vulnerable to difficult-to-diagnose diseases. The study is published in Biosensors and Bioelectronics.

The test features a 3D folded paper structure integrated with gold nanoparticle signal amplification. All required reagents are preloaded in layered compartments, enabling the assay to start automatically when just a small drop of diluted blood serum is added—delivering results in only 10 minutes.

This one-step design not only streamlines the process but also improves sensitivity tenfold compared to conventional methods, detecting even trace levels of these autoantibodies in the early stages of illness.

In clinical validation, the device showed 100% sensitivity and specificity, accurately identifying patients with immune-related conditions. Portable and user-friendly, it holds great promise for rapid diagnosis, treatment guidance, and recovery monitoring in both hospitals and remote clinics.

"Our goal is to create user-friendly and highly sensitive analytical tools that can be used on-site without the need for expensive laboratory equipment, " says Prof. Chien-Fu Chen, the corresponding author of the study.

More information: Yuh-Shiuan Chien et al, One-step gold nanoparticle signal amplification in a 3D paper-based device for rapid detection of anti-interferon-γ autoantibodies, Biosensors and Bioelectronics (2025). DOI: 10.1016/j.bios.2025.117724  Journal information: Biosensors and Bioelectronics