# Smartphone-assisted upconversion nanoparticle assay for rapid multiplex detection of H5, H7, and H10 avian influenza viruses

## TL;DR

A smartphone-connected test using nanoparticles can quickly detect three types of bird flu viruses in animal and human samples.

## Contribution

A novel smartphone-integrated immunoassay using upconversion nanoparticles for rapid, sensitive, and specific detection of H5, H7, and H10 avian influenza viruses.

## Key findings

- The assay detected H5, H7, and H10 avian influenza viruses with high sensitivity and no cross-reactivity.
- Validation with clinical samples showed complete agreement with real-time RT-PCR results.
- Integration with a smartphone platform enabled rapid results and cloud-based data sharing within 10 minutes.

## Abstract

Avian influenza viruses (AIVs) of the H5, H7, and H10 subtypes pose substantial threats to global public health owing to their high pathogenicity, cross-species transmissibility, and potential to spark epidemics. Rapid and accurate detection is essential for outbreak control and zoonotic risk mitigation. Here, we report the development of a multiplex lateral flow immunoassay (LFA) based on core-shell upconversion nanoparticles (UCNPs) conjugated with subtype-specific monoclonal antibodies targeting the haemagglutinin proteins of H5, H7, and H10 AIVs. The assay achieved limits of detection of 0.0313, 0.0156, and 0.0625 ng/mL for recombinant HA proteins and 2−4, 2−4, and 2−3 haemagglutination units for viral titres of H5, H7, and H10, respectively. No cross-reactivity was observed with other AIV subtypes or respiratory pathogens, and intra- and inter-assay variation remained below 6%, demonstrating high specificity and reproducibility. Validation with 135 avian and 125 human clinical samples showed complete concordance with real-time RT-PCR results. Integration with a smartphone-based analytical platform enabled rapid readout, automated quantification, and cloud-based data sharing, providing results within 10 min. This intelligent UCNPs-LFA system combines ultra sensitivity, multiplexing, and field-deployable usability, representing a significant advance over conventional methods. By enabling timely and reliable detection of H5, H7, and H10 AIVs in both animal and human samples, this platform offers a practical tool for early warning, surveillance, and control of emerging zoonotic influenza, thereby contributing to global preparedness against avian influenza outbreaks.