Preparing A Silver-Dendrite Decorated Microneedle SERS Substrate For Mechanism Of Plasmon Driven Catalysis

In order to improve the detection efficiency,it is particularly important to omit the complicated sample pretreatment and realize the“sampling and sample detection”integration in the analysis process.Among the existing detection methods,"Surface Enhanced Raman spectroscopy(SERS)"has the advantages of real-time detection and no damage to samples.It can be used in many fields such environmental detection,food safety,health care and so on.In this paper,a new type of"sampling,sample detection"integrated acupuncture needle microneedle was prepared by controlling and optimizing the experimental conditions.It was applied as the active substrate of SERS detection in chemical reaction mechanism research and actual sample detection.Electrochemical reduction method was used to grow dendritic silver nanoparticles on the surface of acupuncture needles.Self-assembly of p-aminothiophenol molecule as a probe molecule and"microneedle substrate"was used to detect the SERS signal.The applicability of the"microneedle substrate"as a SERS substrate was evaluated by examining the authenticity,accuracy,repeatability,and detection limit of the signal.Using the“microneedle substrate”to collect the SERS spectra,matrix-assisted laser desorption ionization mass spectrometry and other signals,the“microneedle substrate”showed excellent compatibility;the“microneedle substrate”was used to study the aminothiophenol isomers.The factor of Raman enhancement from two point,on the one hand is the molecules density in substrate,on the other hand is the laser induced charge transfer.The experimental results showed that the analytical mechanism is reliable.The“microneedle substrate”was used to detect the solution of vitamin B12 and ampicillin.The minimum detection limits were 10~-55 mol/L and 10~-77 mol/L,respectively.The calculated enhancement coefficient was in the range of 10~3-10~4.The“microneedle substrate”was used to detect the complex of cysteine modified TNT,and the minimum detection limit was 10~-55 mol/L.The reduced TNT was detected by“microneedle substrate”.In the reduction process,the“microneedle substrate”was not only the catalyst the reduction process,but also the active substrate of SERS.The minimum detection limit of TNT after detection was 10~-77 mol/L.The experimental results show that the“microneedle substrate”has low cost,simple preparation and use,and the average preparation time is 1 hour.The detection signal is accurate and the signal reproducibility is 2.9%.The enhancement factor is reproducible.During the detection process,the microneedle substrate can be used not only as an active substrate of SERS,but also as a catalyst for studying the mechanism of chemical reaction.It indicates that the“microneedle substrate”has great potential in the diagnosis and treatment of no damage,and it has great value in simple catalytic reduction.