Molecularly imprinted polymers-coated gold iron nanoparticles for sensitive detection of ketamine via surface-enhanced Raman spectroscopy

Fan Yang^1*Jinjing Hu²

• ¹Neijiang Academy of Agricultural Sciences, Neijiang, China
• ²Irradiation Preservation and Effect Key Laboratory of Sichuan Province, School of Bioscience and Technology, Chengdu Medical College, Chengdu, China

Broad application of drug detection using surface-enhanced Raman spectroscopy (SERS) technique is limited because of complex human body fluid systems. In this study, molecularly imprinted polymers (MIPs) coated AuFe nanoparticles (AuFe@MIPs) with 19.9±0.3 nm of polymer shell and 100.3±1.4 nm of AuFe core were prepared by applying ketamine molecule as template. AuFe nanoparticles were fabricated via the pulsed laser ablation in solutions. By systematically evaluating sorption kinetic, isotherm and thermodynamic, ketamine could be captured by AuFe@MIPs with a fast kinetic (20.0 min), efficient maximum sorption capacity (209.9 mg/g at T 298 K and pH 7.0), excellent selectivity against the interference of coexisting drugs, and favorable recycling usage (16.9% decline of pristine capacity after 6 cycles). Moreover, ketamine could be efficiently detected with a SERS enhancement factor of 1.24×103 from deionized water (100 ppb) and human urine (500 ppb) by applying AuFe@MIPs as the SERS substrate. The detection presented an excellent spatial uniformity of typical peak at 1001 cm-1 (8.4% of relative standard deviation for 50 measurements of the same substrate batch and 5.3% of relative standard deviation for 50 batches of SERS substrate). This study provided a valuable reference to combine laser-ablated magnetic-plasmonic NPs with drug-template MIPs for selective capture and effective SERS detection of drugs.