Nanozymes featuring a mesoporous silica shell for rapid enrichment and ultrasensitive lateral flow immunoassay of influenza A.

Background: Respiratory illnesses stemming from influenza A viruses represent a significant worldwide health concern. There is an immediate need for a rapid and sensitive method to detect influenza A viruses early, without requiring extra equipment.

Results: Here, we established a lateral flow immunoassay (LFIA) for the detection of influenza A (Flu A) using a "three-in-one" multifunctional mesoporous FeO@SiO@Pt nanozymes (FeO@MSiO@Pt NZs) with excellent magnetic separation properties, colorimetric, and peroxidase-like (POD-like) activities. Effective enrichment of target Flu A in complex samples as well as greater loading of Pt particles by mesoporous structures with large specific surface area to enhance POD-like activity can significantly improve the detection sensitivity of the LFIA. After colorimetric amplification by FeO@MSiO@Pt tags catalysis, the qualitative and quantitative results of detection for Flu A nucleoprotein (Flu A-NP) were 0.01 and 0.0089 ng mL, respectively. This indicated a sensitivity approximately 100 times greater than commercially available colloidal Au nanoparticle (AuNP)-based LFIA strips. For detection of inactivated H1N1 virus, quantification can be as low as 33 copies mL. Moreover, it demonstrated high accuracy in pharyngeal swab sample simulation experiments.

Significance: Therefore, the proposed platform based on FeO@MSiO@Pt NZs-LFIA offered a promising approach for point-of-care testing (POCT), enabling rapid and ultrasensitive diagnosis of Flu A.