A competitive dual-mode for tetracycline antibiotics sensing based on colorimetry and surface-enhanced Raman scattering.

Tetracycline antibiotics (TCs) are extensively used as broad-spectrum antimicrobials. However, their excessive use and misuse have led to serious accumulation in foods and environments, posing a significant threat to human health. To solve such public issue, we have designed a novel dual-mode detection method, integrating colorimetric sensing with surface-enhanced Raman scattering (SERS) technology, for sensitive and rapid evaluation on TCs. In this method, an Ag@NH-MIL-101(Al)-Ag nanoprobe that leverages the synergistic effect between silver nanoparticles (AgNPs) and NH-MIL-101(Al), resulting in remarkable peroxidase-like activity and enhanced SERS performance, was proposed. Moreover, for the instant colorimetric sensing, a competitive oxidative-reaction between TCs and 3,3',5,5'-tetramethylbenzidine (TMB) was developed based on the peroxidase-like activity of nanoprobe. Our innovative colorimetric-SERS dual-mode approach demonstrated high sensitivity accompanied by robust selectivity with limits of detection (LODs) for TCs of 10 ppm in colorimetric mode and 10 ppm in SERS mode. Furthermore, TCs can be reliably detected in honey samples with recoveries ranging from 87.69% to 120.49%. This dual-mode sensing strategy effectively combining the ease of colorimetric detection with high sensitivity of SERS provides significant values for rapid, direct, and multiplexed evaluation on various hazards in environment and food chains.