Motivation:

The COVID-19 pandemic highlighted the urgent need for rapid, low-cost, and accessible diagnostic tools that can be deployed outside traditional laboratory settings. Conventional RT-PCR testing, though accurate, requires specialized equipment and trained personnel, limiting its use in resource-constrained environments. To address this challenge, we aimed to develop a colorimetric lateral flow sensor that provides reliable, real-time detection of viral antigens using simple, visual signals that can be quantified by a smartphone.

Method:

We designed a nitrocellulose-based lateral flow immunoassay incorporating gold nanoparticle (AuNP) conjugates for specific antigen recognition and colorimetric visualization. The test strip consists of sample, conjugate, and detection zones assembled on a paper substrate. Upon introduction of a sample, antigen–antibody binding induces AuNP aggregation, producing a visible color change. A smartphone-based image analysis module quantifies the intensity of the test line, enabling semi-quantitative readouts without the need for external instruments.

Team：Kexin Fan, Chenyu Yang, Chang (Holly) Liu.

Lab: Liu Lab.