Construction Of Highly Efficient And Recyclable Copper Mesh SERS Substrate And Its Research On Uric Acid Detection In Complex Systems

Objective:The occurrence of urinary stones is closely related to the body’s metabolic disorders,the long-term and excessive accumulation of common metabolites such as uric acid in body fluids is an important driving force for the formation and development of stones.The development of methods that can monitor uric acid quickly,sensitively and at low cost is a research hotspot in clinical and scientific research.Based on the rapid,efficient and fingerprint recognition characteristics of surface-enhanced Raman spectroscopy（SERS）technology,this study explored the CM substrate construction method with dense nanostructure（hot spot）on the surface using copper mesh（CM）as the substrate,and then tested the SERS detection effect of the substrate on trace uric acid in complex systems such as urine and blood.Methods:As a large-area,tailorable,two-dimensional（2D）flexible substrate,CM can synthesize large-area ordered Cu（OH）₂nanowire arrays on its surface by simple and mature alkali oxidation.The key to SERS substrate preparation is how to reduce the spacing between nanostructures,increase the number of hot spots,and improve the ability of analytes to enter hot spots.In order to solve the above problems,this study uses natural solvent evaporation to induce the aggregation of ordered Cu（OH）₂nanowire arrays into nanowire clusters,and then couples silver nanoparticles（Ag-NPs）in the nanowire cluster structure by in situ chemical displacement to prepare the SERS substrate.Then we chose SEM,XRD,FDTD simulation,two-dimensional SERS MAPPING and other characterization and analysis methods,studied the substrate preparation method,enhancement principle and SERS detection effect from experiments and theories.Results:The SERS substrate shows the detection limit of 1 p M for beacon molecule CV and enables sensitive detection of uric acid at a low concentration of 50 n M.In addition,the substrate can be recycled after simple cleaning and exhibit signal stability over a long period of time.When SERS detection of target molecules in biological samples such as urine and blood,the complex composition of biological samples often interferes with the final test results.We tested the selectivity of uric acid molecules during SERS-based detection in different hybrid systems.The SERS substrate enables specific identification and analysis of trace uric acid molecules in mixed systems of different metabolites and in real urine and blood samples.Conclusion:In this research,we synthesized a novel SERS substrate that can be used as a rapid,low-cost,label-free platform for the immediate diagnosis of uric acid in body fluids.The high selectivity of this substrate for the detection of uric acid molecules in urine without pretreatment and serum proves the feasibility of substrate in real sample detection.The rapid identification and analysis capability of this platform can detect the formation and recurrence of uric acid stones from the etiological perspective,which has important clinical significance for the early prevention and treatment of uric acid stones.The clinical application of this method is expected to provide guidance for clinical prevention and treatment of uric acid stones,and ultimately avoid unnecessary surgical treatment.