Design Of Multi-enhanced SERS Paper-based Chip And Fast Analysis Of Food Contaminants

In recent years,with the gradual improvement of the requirements on the performance of sensors,SERS sensors,which are simple,convenient and low-cost and can realize real-time monitoring,have been widely used.Although SERS technology has advantages other than traditional analytical technology,it still faces challenges when applied to the analysis of complex samples.Recent advance in the application of SERS technology focuses on the development of SERS substrates with high enhancement effect and the preparation of selective substrates.Meanwhile,based on the advantages of cellulosic paper such as biodegradability,low cost,good flexibility,easy molding,large specific surface area,easy modification and good biocompatibility,the construction of paper-based SERS chip will provide a reliable way for the sensitive and rapid detection in complex food samples.The cellulose paper was used as substrate in this work,the working zone was designed on the surface based on the past experience of our laboratory.Noble metal nanomaterials with different morphologies and structures were functionally modified in chip work zone,combined with functional modification of specific identification materials on chip substrate.The multiple signal amplification strategy of was adjusted and the paper-based SERS chip with high sensitivity and rapid monitoring effect of contaminants in food was constructed.The main research has been carried out as follows:(1)Paper substrates were first installed with a dense silver layer and then molecularly imprinted polymer(MIP)was attached upon the Ag paper as specific identification device through electropolymerization.Finally,silver nanoparticles was decorated on the surface of MIP layer through in-situ growth method to form a sandwich structure.Based on the synergistic enhancement effect via double layers of silver-based materials and the specific selectivity/enrichment capacity of MIP,a multiple signal enhancement strategy for the highly sensitive detection of tartrazine was designed.(2)Three-dimensional(3D)dendritic noble metal nano materials were prepared on the surface of cellulose paper by in-situ method.Such structure can get the efficient utilization of3 D laser excitation volume and efficient 3D plasma hot spot to achieve optimal SERS performance.Moreover,the structure of 3D substrates can increase the tolerance to the misfocus along the z-plane,which overcomes the limitations of two-dimensional SERS platform.Based on UV photo-polymerization to achieve the in-situ polymerization of recognition materials on the surface of the base,the urchin-like nanoparticles with rich cutting-edge structure were decorated in the recognition materials to provide sufficient “hot spots”.This structure ensures the synergistic enhancement of two metal structures,the highly sensitive detection of thiram and the simplicity of the detection process.