Controllable Fabrication Of Surface-enhanced Raman Substrate For Gold Nanorods And Its Key Technology For Label-free Detection

In order to meet the needs of high-sensitivity on-site rapid detection of biochemicals such as Bacillus anthracis protective antigens and lung cancer markers,the paper carried out research on biochemical applications of the controllable preparation of gold nanorod SERS substrates and its label-free direct detection.（1）Based on the finite-difference time-domain（FDTD）algorithm,a structural optimization design method for the gold nanopillar SERS substrate was established,and a controllable preparation method for the gold nanopillar SERS substrate was established based on the inclination angle deposition method.The morphology was controlled by the process parameters to achieve the optimal SERS performance.The Finite Difference Time Domain algorithm was used to analyze the electromagnetic field enhancement characteristics of the gold nanopillar structure to obtain the optimal structural parameters.Realization of gold nanopillar structure substrates with different tilt anglesθ=80°,82°,84°,86°,88°and different evaporation rates v=1（?）/s,2（?）/s,3（?）/s Control equipment,through the analysis of the morphology,summarized the change law of the tilt angle,length and density with the deposition angle and evaporation rate,and mastered the morphology control method.Using trans-1,2-bis（4-pyridyl）ethylene（BPE）as a Raman labeled molecule to test the substrate SERS performance,the detection limit of BPE reached 10^-11 M,with excellent SERS enhancement performance.（2）The Raman spectrum of crystal and solution SERS spectrum set of L-amino acid based on the SERS substrate of gold nanorod were established.The test obtained 20 types of L-amino acid crystals with intrinsic Raman spectrum sets,which are basically consistent with those reported in the literature.Based on the optimized SERS substrate of the gold nanorod structure,the tests obtained 20 types of L-amino acid solutions with SERS spectrum sets.The differences in the Raman spectra of the solution states were discussed and analyzed in detail,which provided an important analytical basis for subsequent assignment of protein chemical bond vibration information.（3）Established label-free detection schemes based on gold nanorod SERS substrate for proteins and methamphetamine,and used the SERS substrate to achieve highly sensitive detection of Bacillus anthracis protective antigen,lung cancer marker cytokeratin 19,and methamphetamine.The feasibility of gold nanorod SERS substrate in high sensitivity and rapid biochemical sensing applications was verified.Based on the optimized gold nanocolumn SERS enhanced substrate,SERS non-standard direct detection was achieved for Bacillus anthracis protective antigen,human serum protein,a mixed solution of protective antigen in human serum protein,and lung cancer marker cytokeratin 19.Finally,the detection limit of the protective antigen in human serum albumin reached 100 pg/m L,which meets the clinical detection requirements.The detection limit of cytokeratin 19 reaches 20 ng/m L,which meets the threshold detection requirement of 21.4 ng/m L in non-small cell lung cancer.The detection limit of methamphetamine is 10^-7 M,which meets the requirements for rapid on-site detection of methamphetamine（500 ng/m L）in human urine,and is better than the detection limit of 10^-6 M of the more mature immunocolloid gold test strips.The whole detection is less than 5 minutes.