Biomarkers Detection Based On SERS Chips

Surface enhanced Raman scattering（SERS）technology is widely used in the field of life sciences due to its high sensitivity,fingerprint spectrum,and rapid non-destructive testing.With the improvement of process level,coupled with miniaturization and integration,Lab of Chip（Lo C）has developed rapidly in the fields of life sciences and analytical chemistry.Based on the development of SERS technology and Lo C technology,combining the advantages of the two,the functionalized SERS substrate is integrated into the microfluidic chip,and the detection chip based on Lo C-SERS with high sensitivity,high throughput,miniaturization and easy operation is developed,It is of great significance to realize highly sensitive portable detection.In this paper,combined with Lo C technology and SERS technology,a microfluidic chip with SERS activity was prepared to achieve SERS detection of biomarkers.The main contents of this article are as follows:（1）The SERS active microfluidic channel was prepared.Silver glue and gold glue were prepared separately,and then the surface of PDMS was modified,and metal nanoparticles were assembled on PDMS by layer-by-layer self-assembly method to form a solid SERS substrate.The prepared solid SERS substrate has good uniformity,repeatability and detection sensitivity.The solid SERS substrate is bonded to a PDMS cover slip with a straight channel to form a SERS active microchannel.Compared with the open solid-state SERS substrate,integrating the solid-state SERS substrate into the microfluidic chip solves the problems of large reagent consumption and high requirements on the cleanliness of the detection environment.（2）A temperature-controlled micro-reactor was prepared to achieve highly sensitive SERS detection of malondialdehyde（MDA）.A carbon black doped polydimethylsiloxane（C-PDMS）conductive composite material was prepared,and the SERS active microchannel was heated.Subsequently,a temperature control circuit was built to control the heating temperature of the C-PDMS,and the temperature control error was within 1°C,and the construction of the temperature controlled microreactor with SERS activity was completed.Carry out the reaction of thiobarbituric acid（TBA）and MDA in a temperature-controlled microreactor,and amplify the SERS signal through the reaction product to realize the highly sensitive SERS detection of MDA.The linear detection range is 10^-6 M-10^-9 M,the detection limit is 10^-9 M.（3）The detection of superoxide dismutase（SOD）activity is achieved based on two methods.Inhibition of pyrogallol autoxidation by SOD,monitoring changes in absorption intensity of pyrogallol autoxidation products,to achieve detection of low activity SOD,linear detection range is 0.375 U/m L-4 U/m L,detection limit is 0.375 U/m L.It inhibits the catalytic oxidation of 4-aminothiophenol（4-ATP）to dimercaptoazobenzene（DMAB）by SOD,monitors the yield of DMAB,and realizes the detection of highly active SOD.The linear detection range is 25 U/m L-100 U/m L,the detection limit is 25U/m L.The two methods have different linear detection ranges,which complement each other and can be applied to different occasions.