PDDA electrostatic assembly of mesoporous MXene and AuNPs as a novel paper base SERS substrate for determination of CIP in milk
Abstract
In this study, a novel Surface Enhanced Raman Scattering (SERS) substrate was engineered by assembling mesoporous Ti3C2Tx (MesoTi3C2Tx) with gold nanoparticles (AuNPs) through cross-linking with poly (diallyl dimethyl ammonium chloride) (PDDA). MesoTi3C2Tx was first fabricated with a mesoporous structure and then modified with PDDA, after which the PDDA-coated MesoTi3C2Tx was applied to the rough surface of glass fiber filter paper. After drying, size-controlled AuNPs were dropped on the paper base PDDA-MesoTi3C2Tx substrate to form paper-based SERS substrate of PDDA-AuNPs/MesoTi3C2Tx. The adsorption capacity of MesoTi3C2Tx is 4.2-fold better than mono-few layer Ti3C2Tx, and the distribution of AuNPs on PDDA-MesoTi3C2Tx is more uniform than that on PDDA-Ti3C2Tx without mesoporous. After optimization, PDDA with the molecular weight of 100k - 200k can make paper-based PDDA-AuNPs/MesoTi3C2Tx substrate detect trace amount (10?ng/mL) of the methylene blue with significant Raman characteristic peak. The enhancement factor up to 2.09×106. The paper-based PDDA-AuNPs/MesoTi3C2Tx was used as SERS substrate to detect the ciprofloxacin. The result of detection is accurate, stable and sensitive especially in the application for milk detection. In conclusion, the novel paper-based PDDA-AuNPs/MesoTi3C2Tx constructed in this work as a SERS substrate can satisfy the needs of rapid SERS detection of veterinary drug residues in food.