Study On SERS-based Microfluidic Biochemical Detection Chip And Its Application In Physiological Urine Detection

Combining microfluidic chip analysis with surface-enhanced Raman scattering spectroscopy technique has become a hotspot in biochemical detection.The combination of the two technologies not only brings the advantages of both technologies,but also brings new technical problems.Based on the microfluidic chip technology and SERS technique,the SERS microfluidics was fabricated with different kinds of SERS substrate,and the SERS detection of physiological urine was completed.The main work is as follows:1.Nanoparticle embedded nanohole arrays were prepared by nanosphere lithography,metal deposition,atomic layer deposition and vacuum annealing techniques.The electromagnetic characteristics of the substrate are simulated by finite difference time domain method?FDTD?.The results show that the main electromagnetic enhancement is focused on the contact area between the embedded particles and the bottom of the hole.The silver nanorod structure was fabricated by oblique evaporation method?And the electromagnetic properties of silver nanorod structure with different lengths various from 400nm to 1200nm were simulated by FDTD.The maximum electromagnetic enhancement of the 800nm silver nanorod structure is greater than other lengths of the silver nanorod structure.It is noted that the main electromagnetic enhancement is focused on the gap between the nanorods The SERS properties of the two different kinds of structures were tested.The results show that the SERS performance of the silver nanorod structure substrate is better than that of the nanoparticle embedded nanohole structure substrate.2.Au@AgNPs and AgNPs were prepared by chemical synthesis.The absorption properties and structural characteristics were characterized in this paper.BPE was used as the probe molecules to test the SERS performance of the two kinds of nanoparticles.The results show that the SERS performance of AgNPs is better than that of Au@AgNPs.3.The main research contents of fluid flow at the microscale are introduced,and the hydrodynamic characteristics of the microchannel are analyzed.According to the principle of fluid mechanics,two kinds of microchannel structures,semicircular bending and 90°bending,were designed.The flow characteristics were simulated by COMSOL.The results showed that the mixing performance of semicircular bending structure is better than that of 90°bending structure.4.The SU-8 ultraviolet photoresist mold was prepared by spin-coating,photo-lithography and developing.The SERS chip was fabricated by casting,curing and bonding.The influence of process parameters on the performance of the flow channel was studied,and the process parameters were optimized.At the same time,the realization of nano-structured embedded micro channel is introduced,and the preparation of microfluidic chip with SERS substrate is completed.5.A complete microfluidic SERS chip detection platform was set up,and the SERS detection of probe molecules and physiological urine was completed.The Raman peak of urea and creatinine are at 1000cm^-1 and 1410cm^-1,respectively.The SERS spectrum of uric acid is dominated by bands at 640cm^-1,862cm^-1 and 1233cm^-1.