Integrated CRISPR/Cas12a-activated liposomal SERS amplification in microfluidic chips for ultrasensitive ampicillin...

The misuse of antibiotics has created a vicious cycle: from excessive use in livestock breeding to elevated residue levels in food products, ultimately leading to heightened antibiotic resistance in humans, a phenomenon with significant public health consequences. Food-based antibiotic testing is crucial for preventing antibiotic misuse and protecting human health. However, traditional analytical methods exhibit high equipment dependency, restricting on-site detection in hills, plateaus, and other regions with inconvenient transportation. This study developed an integrated CRISPR/Cas12a-activated liposomal Surface-enhanced Raman scattering (SERS) amplification system within a microfluidic chip for ultrasensitive ampicillin detection. The method achieves primary signal amplification by converting ampicillin concentration into a DNA signal through catalytic hairpin assembly (CHA), followed by secondary signal amplification using an Au@Ag substrate coupled with SERS technology for 4-MPBA@liposome marker detection. The platform demonstrated a linear detection range of 1 fM-1 nM with a limit of detection as low as 740 aM. Notably, the method exhibited excellent stability, selectivity, and sensitivity, successfully detecting ampicillin residues in environmental water and milk samples. It provides a technological approach for environmental monitoring and food safety, demonstrating significant practical application value.