Acid-catalyzed preparation of silicon-based imprinted polymers on the surface of SERS sensors for selective detection of L-tryptophan

Tryptophan is a potential biomarker for a variety of diseases, so rapid and accurate detection of tryptophan levels in the human body is essential. In this work, surface-enhanced Raman scattering (SERS) detection was combined with acid-catalyzed silicon-based molecularly imprinted polymers to synthesize Cu 2 O@Ag-MIPs (CA-MIPs) for selective detection of L-tryptophan(L-Trp). Compared with traditional detection methods, SERS detection has the advantages of being sensitive, fast and nondestructive. Here, Ag nanoparticles are uniformly loaded on {100} surface-dominated Cu 2 O sub-microcubes to excite strong localized surface plasmon resonance, which exhibits good SERS performance. Considering the complexity of practical detection, an acid-catalyzed method was adopted to load silicon-based imprinted polymers with high biocompatibility on the Cu 2 O@Ag surface, which improved the drawbacks of the common silicon-based imprinting method, such as loose structure and long reaction time. The thickness of the imprinted layer can be controlled to ensure selectivity while ensuring superior SERS sensitivity. The prepared CA-MIPs were shown good linearity with L-Trp concentration in the range of 10 −3 –10 −10 mol L −1 , and the sensor also exhibited excellent selectivity for the determination of L-Trp in the presence of other interfering amino acids. In addition, the method was shown good recoveries in spiked recovery tests of simulated urine samples and was expected to be practically applied to the detection of clinical disease markers.