A Paper-based Dual-mode Signal Output Detection Platform Incorporating Biomimetic Composites for the Detection of Benzophenone-3

Benzophenone-3（BP-3）is a widely used organic ultraviolet filter. Owing to its environmental contamina tion and potential toxicity to organisms，rapid and convenient detection of BP-3 is needed. Herein，a microfluidic paper-based analytical device（μPAD）has been developed by integrating biomimetic composites with paper chips. The biomimetic composite consists of nanozyme and molecularly imprinted polymer（MIP），which act as the catalyst for generating signals and the recognition unit of the μPAD， respectively. In particular， the nanozyme with peroxi dase activity is a dual-metal organic gel（Fe/Ru-MOG）synthesized in a simple and gentle manner and further doped with MIP via bulk polymerization. The obtained Fe/Ru-MOG@MIP-μPAD is employed for determination of BP-3 through a double-signal outputs including chemiluminescence（CL）and colorimetry. As the specific binding of BP-3 by the MIP weakens the catalytic ability of Fe/Ru-MOG towards H₂ O₂ ， CL intensities decrease together with the change of colorimetric signals. Both signals were recorded by in-situ taking photos of the detection region using a mo bile phone， followed by conversion to gray values for quantification. The dual signals demonstrate a good linearity within concentration ranges of 1×10⁻⁹-1×10⁻⁷ mol/L（CL）and 3×10⁻⁹-0. 9×10⁻⁷ mol/L（colorimetry）， and detection limits as low as 1. 63×10⁻¹⁰ mol/L（CL）and 1. 64×10⁻¹⁰ mol/L（colorimetry）. The novel μPAD exhibits admirable selectivity and reliability in analysis of real samples including soil，river water and tap water. It is fair to conclude that this platform，serving as a portable and cost-effective tool， will play an important role in fast and on-site detection of BP-3.