A Three-Dimensional Printed Aptasensor Array for Simultaneous Detection of Bioactive Components and Three Coexisting Mycotoxins Based on the MXene/ZnO@Ag@Au Nanoarchitecture with Synergistic Surface-Enhanced Raman Scattering Enhancement

The increasing demand for quality control of natural products necessitates innovative methods that enable the simultaneous detection of bioactive components and hazardous contaminants. This study introduces a three-dimensional (3D) printed aptasensor array utilizing MXene/ZnO@Ag@Au nanocomposites for rapid and concurrent detection of berberine (BBR), aflatoxin B1 (AFB1), ochratoxin A (OTA), and chloramphenicol (CAP) in medicinal herbs. The nanocomposite achieves enhanced surface-enhanced Raman scattering (SERS) performance through the synergistic effects of Ag@Au local surface plasmon resonance (electromagnetic enhancement), ZnO charge transfer (chemical enhancement), and the optimized electromagnetic field distribution enabled by the MXene scaffold. A hydrogel microarray fabricated via 3D printing incorporates 4-nitrobenzenethiol (4-NTP)-labeled SERS nanoprobes and specific aptamers, delivering an enhancement factor of 4.97 × 107, excellent reproducibility (RSD < 3%), and high specificity against structural analogs. Detection limits were 0.45 μg/mL for BBR, 0.46 ng/mL for AFB1, 0.95 ng/mL for OTA, and 0.86 ng/mL for CAP. Principal component analysis confirms that signal variations originate predominantly from specific 4-NTP–aptamer interactions. Recovery rates of 80–120% for 36 real samples were validated by thin-layer chromatography with ultraviolet/fluorescence detection, meeting quality control standards. The portable platform enables on-site analysis within 5 min.