Surface-enhanced Resonance Raman Spectroscopy Detection Of Catecholamine Acupuncture Substances In Complex System

Catecholamine(CA)is a class of acupuncture substances,including dopamine(DA),norepinephrine(NE)and epinephrine(EP).They play an important role in life and health in spite of the low content of the body.Therefore,rapid and sensitive detection of CA molecules have become an interest of research.In recent years,surface-enhanced Raman spectroscopy(SERS)technology has been widely concerned for its advantages of fingerprint recognition,rapid,in situ detection and so on.However,the content of CA in biofluids,such as serum and tissue fluid is low,and Raman cross section of CA molecule is small,so it is particularly important to realize sensitive and selective detection of CA molecules in complex systems.Herein,surface-enhanced resonance Raman spectroscopy(SERRS)strategy was applied to detect CA molecules in complex system were carried out by the following several parts:(1)PVP stabilized gold nanoparticles(PVP-Au NPs)were prepared by seed growth method,and a serious of active substrates were constructed by modifying the Fe(?)complexes on the surface of PVP-Au NPs.The SERRS enhancement was attributed to the process of charge transfer between metal and ligands under irradiation of 633 nm laser.Meanwhile,DA molecule was trapped by active substrates selectively.The optimal Raman label was determined through experimental characterizations.(2)Detection of DA,NE and EP selectively and sensitively by the functionalized substrate which was modified Fe(NTA)on the surface of PVP-Au NPs.Combined with principal component analysis(PCA),we have realized multicomponent detection of these three CA molecules in the serum.Furthermore,the independent Raman signals of Au-0 band of PVP-Au NPs can be used as the internal reference for quantitative SERS detection of target molecules.(3)In order to further improve the sensitivity of DA,Fe3O4/Au nanostructure was synthesized as active substrate.The detection limit of DA was greatly reduced by the irradiation with 633 nm He-Ne laser.Based on this sensitivity,we have explored enhancement mechanism of the active substrate.In order to investigate the application of the detection strategy in the complex system,serum and bio fluid were selected in further study.The detection limit of DA in serum was significantly decreased by optimizing the pretreatment method of serum.In addition,we successful realize the SERS measurements of DA in biofluids by the same pretreatment method.