Surface-enhanced Raman Spectroscopy For The Clinical Detection Of Primary Liver Cancer

ObjectiveRaman spectroscopy technology is proved to be a kind of material molecular analysis technology,which can reflect the internal structure and composition information of the sample.The present study used the Simple template nanocomb(STN)surface-enhanced Raman spectroscopy(SERS)substrate to explore the characteristic of SERS spectra of the serum of patients with Primary liver cancer(PLC).The study also evaluated the diagnostic efficacy of AFP negative liver cancer,and analyze the SERS spectra from different stages of liver cancer,providing a new method for the diagnosis of liver cancer based on serum.MethodAfter preparing the STN SERS substrate,the study investigated its apparent enhancement factor and reproducibility,and used it to collect SERS spectras of serum samples.A total of serum samples from 50 patients with liver cancer(including 25 patients with AFP negative liver cancer and 25 patients with AFP positive liver cancer),25 patients with LC and 25 healthy controls were collected.The samples were used for Raman detection by InVia+Plus laser confocal microRaman spectrometer.By analyzing the SERS spectra of each group of samples,the differences of spectral peaks were compared using statistical algorithms,and OPLS was used to evaluate the application value of diagnosing liver cancer from LC group and health control group.Finally,the accuracy of classification was evaluated by drawing the ROC curve of each group and calculating the AUC.ResultThe apparent enhancement factor and reproducibility relative standard value of STN SERS substrate were 3.14 × 106 and 6.37%.The Raman spectra of serum samples from different groups were collected,and the vibration mode and spectral peak assignment of the main spectral peaks were analyzed.1.Compared with healthy control group and LC group,the liver cancer group spectra were characterized by stronger intensity at 636 cm-1(Tyrosine).728 cm-1(Purine),864 cm-1(Phosphatidic acid),917 cm-1(Glycogen,Lactic acid),1062 cm-1(C-N and C-C stretching vibration),1098 cm-1(D-Mannose)and 1478 cm-1(Nucleic acid)(P<0.001).2.Compared with healthy control group and LC group,the AFP negative liver cancer group spectra were characterized by stronger intensity at 636 cm-1(Tyrosine),728 cm-1(Purine),864 cm-1(Phosphatidic acid),917 cm-1(Glycogen,Lactic acid),1062 cm-1(C-N and C-C stretching vibration),1098 cm-1(D-Mannose)and 1478 cm-1(Nucleic acid)(P<0.05).3.After data analysis by SERS combined with OPLS-DA,ROC curves were drawn for liver cancer-LC group/healthy control group,liver cancer group-LC group,liver cancer group-healthy control group,respectively,with AUC of 0.793,0.904 and 1.000.ROC curves were also drawn for AFP negative liver cancer groupLC group/healthy control group.AFP negative liver cancer group-LC group,and AFP negative liver cancer group-healthy control group,with AUC of 0.979,1.000 and 0.966,respectively.Conclusion1.STN SERS detection substrate has good reproducibility and enhancement on serum.2.Using SERS can detect significant differences in the levels of metabolites such as tyrosine and purine in the serum of liver cancer group,healthy control group and LC group.The combination of OPLS-DA and SERS can effectively diagnose liver cancer.3.The combination of OPLS-DA and SERS can serve as a supplementary diagnosis method for AFP negative liver cancer.