# Functionalized AgFeO2 Particles as Fluorescent Platforms for the Detection of Salmonella spp

## TL;DR

A new biosensor using AgFeO2 nanoparticles can detect Salmonella DNA quickly and accurately, with potential uses in food safety and diagnostics.

## Contribution

A novel AgFeO2-based biosensing platform with ultrafast detection and high selectivity for Salmonella DNA is introduced.

## Key findings

- The sensor reaches signal saturation in under 10 minutes with a detection limit of 73 pmol L–1.
- It distinguishes fully complementary DNA from mismatched sequences with high selectivity.
- SYBR Green I dye enables dual fluorescence detection and dsDNA on–off sensing.

## Abstract

Rapid and accurate pathogen detection remains a major
challenge
in public health, particularly in food safety and biomedical diagnostics.
Here, we present a highly sensitive biosensing platform based on silver
ferrite (AgFeO2) nanoparticles functionalized with 3-mercaptopropionic
acid (3-MPA) and single-stranded DNA (ssDNA). The sensor enables ultrafast
detection, with signal saturation reached in under 10 min, and achieves
an analytical limit of detection (LoD) of 73 pmol L–1 for Salmonella spp. DNA sequences. The platform also exhibits excellent
selectivity, clearly distinguishing fully complementary targets from
sequences containing base mismatches. Its versatility is further enhanced
by the incorporation of SYBR Green I dye, enabling dual fluorescence-based
detection and on–off sensing of double-stranded DNA (dsDNA).
By combining high sensitivity, selectivity, and operational simplicity,
the AgFeO2@MPA/ssDNA biosensor demonstrates strong potential
for applications in biotechnology, diagnostics, and food safety, with
performance comparable to state-of-the-art biosensing technologies.