Confinement of high-loading probes within silica film for paper-based sensor with enhanced imidacloprid sensitivity application

In order to solve the problem of limited sensitivity of paper-based colorimetric sensors in the face of trace analyte, we verified the feasibility of improving the sensitivity by establishing a signal amplification method with high-abundance binding agent and confined nanopores/nanochannels through silica sol-gel treated paper fiber. The elevated abundance of agent serves to increase the absorption efficiency, and the silica nanopores/nanochannels generated on the fiber surface provide confined transport for molecules. By continuously flowing a large volume of sample vertically through the paper-based sensing membrane, the target could be enriched, increasing the signal accumulation, and realizing the sensitive paper-based sensing detection of target analyte. At the same time, we first proposed a novel pesticide detecting protocol based on nanozyme-catalyzed degradation. The chemical sensing of stable pesticides could be realized under the catalysis of nanozymes, and pesticides were degraded into easily detectable active small molecules. The limit of detection of imidacloprid was determined to be as low as 50 ppb with good selectivity. This novel paper-based pesticide sensor with high sensitivity holds great promise for future practical applications.