@article{Tan2025, 
author = {Xiaotian Tan and Yujuan Chai and Ruihan Li and Binmao Zhang and Hao Li and Jie Zhang and Tianen Zhu and Weishu Wu and Lixiang An and Shi Hu and Bin Yang and Li Wang and Zhenqiu Cao and Hongjiu Zhang and Peng Wang and Lingling Yu and Shan Yin and Xingyu Li and Fei Shao and Jianheng Huang and Jinze Li and Fan Yang and Chao Zhao and Jiajia Guo and Lin Zeng and Dong Liang and Zhengting Zou and Hairong Zheng and Xudong Fan and Liangzhi Xie and Yunlong Cao and Hui Yang},
title = {Tip optofluidic immunoassay: Evaluating COVID-19 antibody protection with 1 μL fingertip blood},
year = {2025},
journal = {hLife},
volume = {3},
number = {7},
pages = {338-356},
keywords = {fingertip blood, optofluidic immunoassay, antibody protection assessment, coronavirus disease 2019 (COVID-19), biosensing},
url = {https://www.sciopen.com/article/10.1016/j.hlife.2025.04.005},
doi = {10.1016/j.hlife.2025.04.005},
abstract = {Infectious diseases such as coronavirus disease 2019 (COVID-19) continue to pose significant global health challenges. Effective management of reinfection risks depends on sustained levels of binding and neutralizing antibodies. However, conventional methods—such as enzyme-linked immunosorbent assays (ELISA) and virus neutralization tests (VNT)—are limited by complex workflows, long assay durations, and high sample volume requirements, making them less suitable for routine, decentralized, or time-sensitive surveillance. This study presents a custom-developed tip optofluidic immunoassay (TOI) platform that enables rapid, multiplexed antibody profiling using only 1 μL of fingertip blood. The system integrates batch-fabricated microfluidic immunoreactors with a portable chemiluminescent imaging station, completing both binding and neutralization capability assessments within 40 min. TOI achieves a broad dynamic range (3–4 orders of magnitude), high signal-to-noise ratio (~10,000), and excellent sensitivity for immunoglobulin G (IgG) detection. A renovated version of the rapid in vitro inhibition assay (RIVIA) is incorporated to evaluate neutralizing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with greater speed and cost-efficiency. In clinical studies, TOI successfully quantified antibody protection against multiple variants, identifying individuals with broad-spectrum immunity to both wild-type and XBB strains. With its high-precision, rapid turnaround, and minimal sample requirement, TOI offers a valuable tool for decentralized immune surveillance and personalized immunization strategy development.}
}