Study On Raman Spectroscopy And Raman Mapping In The Detection For Intracellular Zinc Ions

Zinc,an essential trace element in human body,exits mainly in the form of ions and plays a critical role in many processes including promoting organism growth,wound healing,the absorption and the metabolism of vitamin A and enhancing human immunity.Besides,zinc ions are involved in many biological processes,such as the transfer of gene and the transmission of neural signal.It can also act as the cofactor and catalysis site of some proteins.The studies have shown that the metabolic disorder of zinc ions is related to neurological diseases,such as Alzheimer's disease,epilepsy and ischemic stroke,so it is significant for clinical research to establish a rapid and sensitive method for detecting zinc ions in organism.In this study,a novel Au-peptide probe was synthesized to detect zinc ions based on Raman spectroscopy and Raman mapping.Raman reporter(4-MBA)and peptide(CCALNNHPHGHW)were decorated on the surface of gold nanoparticles through Au-S bond.The zinc ions can conjugate with the histidine to cause the aggregation of probes.As a result,the red shift of UV-vis absorption peak and the enhancement of Raman signals were observed.Based on the mechanism,the detection of zinc ions in vitro was operated by UV-vis and Raman spectroscopy and the intracellular distribution of zinc ions was investigated by Raman mapping.The results showed that the optimal amount of Raman reporter was 2.5 ?mol/L and the amount of peptide modified on the nanoparticle surface was about 1.36×10-8mol/cm2.Moreover,the linear range of UV-vis spectroscopy was 5-80?mol/L and the detection limit was 1 ?mol/L with the correlation coefficient R2=0.9912.However,the linear range of Raman spectroscopy was 1-160 ?mol/L and the detection limit was 0.1 ?mol/L with the correlation coefficient R2=0.9807,which confirmed that the latter has a wider linear range and lower detection limit.The detection of zinc ions in vitro and in vivo was achieved based on Raman spectroscopy and Raman mapping.The strategy proposed in this study is attractive for its high sensitivity,selectivity and easy operation,which provides a new approach for zinc ions detection and theoretical guidance for its application in food safety detection,biomedical and clinical monitoring.