Amino-Acid/Protein-Engineered Zr/Ce-MOF Nanozyme for Dual-Channel Smart On-Site Detection of Tetracyclines and d-Penicillamine.

Abstract

The threat of drug residues drives an urgent demand for shifting from centralized laboratory testing to point-of-need intelligent diagnostics. Herein, we construct a smartphone-regulated sensing platform that integrates a wavelength-programmable dual-light source module with a custom-developed "FluoChroma X" App for parallel dual-channel monitoring of tetracycline antibiotics (TCs) and d-penicillamine (d-PA). The core of this system is a hierarchical bio-nanostructured sensor consisting of an arginine/histidine-modulated zirconium/cerium bimetallic organic framework conjugated with bovine serum albumin (BSA) and designated as ZCDA@Arg@His. TCs quench the intrinsic blue emission of ZCDA@Arg@His through inner filter effect and photoinduced electron transfer, while the BSA-confined microenvironment restricts the intramolecular rotation of TCs, triggering intense aggregation-induced green luminescence for high-fidelity ratiometric sensing. The ratiometric sensor array achieves 100% classification accuracy for structurally analogous TCs using machine learning algorithms. In addition, arginine and histidine cooperatively regulate the Ce4+/Ce3+ redox microenvironment by promoting substrate-active-site interactions and metal-site coordination, thereby enhancing the metalloenzyme-mimicking activity of ZCDA@Arg@His to catalyze the chromogenic cascade reaction, while d-PA acts as a radical scavenger to interrupt the colorimetric process. The sensing platform exhibits unprecedented analytical performance with limits of detection as low as 3.9 nmol·L-1 for TCs and 0.31 μmol·L-1 for d-PA. This work is validated across multiple food matrices and establishes a machine learning-assisted, structurally constrained biophotonic strategy for broad-scale, high-throughput monitoring.