Kiwi‐Inspired Rational Nanoarchitecture with Intensified and Discrete Magneto‐Fluorescent Functionalities for Ultrasensitive Point‐of‐Care Immunoassay

Abstract Fluorescent lateral flow immunoassays (FLFIA) is a well‐established rapid detection technique for quantitative analysis. However, achieving accurate analysis of biomarkers at the pg mL −1 level using FLFIA still poses challenges. Herein, an ultrasensitive FLFIA platform is reported utilizing a kiwi‐type magneto‐fluorescent silica nanohybrid (designated as MFS) that serves as both a target‐enrichment substrate and an optical signal enhancement label. The spatially‐layered architecture comprises a Fe 3 O 4 core, an endocarp‐fibers like dendritic mesoporous silica, seed‐like quantum dots, and a kiwi‐flesh like silica matrix. The MFS demonstrates heightened fluorescence brightness, swift magnetic response, excellent size uniformity, and dispersibility in water. Through liquid‐phase capturing and fluorescence‐enhanced signal amplification, as well as magnetic‐enrichment sample amplification and magnetic‐separation noise reduction, the MFS‐based FLFIA is successfully applied to the detection of cardiac troponin I that achieved a limit of detection at 8.4 pg mL −1 , tens of times lower than those of previously published fluorescent and colorimetric lateral flow immunoassays. This work offers insights into the strategic design of magneto‐fluorescent synergetic signal amplification on LFIA platform and underscores their prospects in high‐sensitive rapid and on‐site diagnosis of biomarkers.