Dynamic Monitoring of the Oxidation Process of Phosphatidylcholine Using SERS Analysis

Abstract

Phosphatidylcholine oxidation is closely related to many neurodegenerative diseases. In this paper, Raman spectroscopy was proposed to continuously monitor the oxidation of phosphatidylcholine and provide deep understanding of this biochemical process. To increase the detection sensitivity, surface-enhanced Raman spectroscopy (SERS) with a micro−nanosilver-complex substrate was prepared by electrodeposition. The prepared SERS substrate had an enhancement factor as high as 7.8 × 10 7 , ensuring detection sensitivity in the phosphatidylcholine-oxidation process. It was illustrated that the oxidation of phosphatidylcholine in an ethanol−water solution under the experimental conditions could be monitored and well described by second-order kinetics by continuously measuring and analyzing the SERS spectra of phosphatidylcholine-oxidation intermediates in 20 days. Meanwhile, the oxidation products were confirmed by mass spectrometry, and the oxidation process was in good concordance with mass-spectrometry detection. The use of SERS in following a biochemical process has advantages, including simple instrumentation, a low cost, a short detection time, and no sample pretreatment. Therefore, as a kind of vibration spectrum, SERS is preferable to traditional detection approaches such as MS, HPLC, and MRI for the dynamic monitoring and analysis of complex biochemical processes.

Application of SERS in the Detection of Fungi, Bacteria and Viruses

“…Based on the continuous in-depth study of SERS spectral analysis theory, it was found that it not only has the basic characteristics of Raman spectral analysis, but also shows strong advantages in detection sensitivity, photobleaching resistance, and facilitates the easy realization of in-situ nondestructive testing, etc. Accordingly, SERS spectral analysis technology has been widely used for the detection of a variety of biochemical samples, such as phospholipid, glucose, glutathione, thrombin, and so on, which has been extended to bacteria and cells and other living organisms in recent years [ 8 ], making it possible to detect and diagnose fungi with efficient SERS [ 26 , 27 , 28 , 29 ]. Gussem et al [ 25 ] applied Raman spectroscopy to analyze the fungal folds of Lactarius ( Figure 1 b), analyzed their components, and compared the obtained fungal spectra with Raman spectra of reference substances known to exist in macrofungi, including saccharides.…”