Au/Fe3O4-based nanozymes with peroxidase-like activity integrated in immunochromatographic strips for highly-sensitive biomarker detection

Because of their simplicity, rapidity, and cost-effectiveness, immunochromatographic strips (ICTs) have been widely used as an effective tool in various fields. However, typical strips for the preliminary screening suffer from limited detection sensitivity, particularly in biomarker detection with trace concentration. Herein, to tackle this challenge, we integrated homemade gold-decorated Fe3O4 nanoparticles (Au/Fe3O4 NPs) with flexible strips, exploring the excellent peroxidase-like activity of this labeled material, and then enhancing the detection sensitivity via signal amplification. The limit of detection (LOD) of the strips is as low as 0.05 mIU mL(-1) when human chorionic gonadotropin (hCG) is as a biomarker model, which is 500 times lower than that of the traditional color-based strip. Overall, our results demonstrated the potential for Au/Fe3O4 NP based-ICTs for the rapid detection of the biomarker in an instrument-free and point-of-care testing format.

Automated summary

Immunochromatographic strips (ICTs) have been widely used in various fields due to their simplicity, rapidity, and cost-effectiveness. However, their limited detection sensitivity has been a challenge, especially for biomarker detection with trace concentration. To overcome this challenge, we integrated homemade gold-decorated Fe3O4 nanoparticles (Au/Fe3O4 NPs) with flexible strips, resulting in enhanced detection sensitivity through signal amplification. The Au/Fe3O4 NP-based ICTs demonstrated a low limit of detection (LOD) of 0.05 mIU mL(-1) for the biomarker model, which is 500 times lower than that of traditional color-based strips. This study showcases the potential of Au/Fe3O4 NP-based ICTs for rapid biomarker detection in an instrument-free and point-of-care testing format.