Repeated double cross-validation applied to the PCA-LDA classification of SERS spectra: a case study with serum samples
- PDF / 1,606,240 Bytes
- 10 Pages / 595.276 x 790.866 pts Page_size
- 109 Downloads / 152 Views
RESEARCH PAPER
Repeated double cross-validation applied to the PCA-LDA classification of SERS spectra: a case study with serum samples from hepatocellular carcinoma patients Elisa Gurian 1 & Alessia Di Silvestre 1 & Elisa Mitri 1 & Devis Pascut 2 & Claudio Tiribelli 2 & Mauro Giuffrè 2,3 & Lory Saveria Crocè 2,3 & Valter Sergo 1,4 & Alois Bonifacio 1 Received: 17 October 2020 / Revised: 19 November 2020 / Accepted: 23 November 2020 # The Author(s) 2020
Abstract Intense label-free surface-enhanced Raman scattering (SERS) spectra of serum samples were rapidly obtained on Ag plasmonic paper substrates upon 785 nm excitation. Spectra from the hepatocellular carcinoma (HCC) patients showed consistent differences with respect to those of the control group. In particular, uric acid was found to be relatively more abundant in patients, while hypoxanthine, ergothioneine, and glutathione were found as relatively more abundant in the control group. A repeated double cross-validation (RDCV) strategy was applied to optimize and validate principal component analysis-linear discriminant analysis (PCA-LDA) models. An analysis of the RDCV results indicated that a PCA-LDA model using up to the first four principal components has a good classification performance (average accuracy was 81%). The analysis also allowed confidence intervals to be calculated for the figures of merit, and the principal components used by the LDA to be interpreted in terms of metabolites, confirming that bands of uric acid, hypoxanthine, ergothioneine, and glutathione were indeed used by the PCA-LDA algorithm to classify the spectra. Keywords SERS . Double cross-validation . PCA-LDA . Serum . Hepatocellular carcinoma
Introduction Surface-enhanced Raman scattering (SERS) spectroscopy is an analytical technique based on the inelastic scattering of a laser by analytes adsorbed on nanostructured metal surfaces with adequate plasmonic properties [1, 2]. As for normal Raman spectroscopy, bands in SERS spectra are related to the different vibrational modes of the analyte molecules. Different molecular structures will yield different spectra, making vibrational spectroscopies as Raman and SERS very * Alois Bonifacio [email protected] 1
Raman Spectroscopy Lab, Dipartimento di Ingegneria e Architettura (DIA), University of Trieste, via Valerio 6, 34127 Trieste, TS, Italy
2
Fondazione Italiana Fegato – ONLUS, Area Science Park, SS14, km163.5, 34149, Basovizza, Trieste, TS, Italy
3
Department of Medical Sciences, University of Trieste, Strada di Fiume, 447, 34129 Trieste, Italy
4
Faculty of Health Sciences, University of Macau, Macau, SAR, People’s Republic of China
structure-specific. However, SERS benefits from a much greater sensitivity than Raman, due to the intensity enhancement granted by its interaction with the plasmonic surface. These characteristics, together with the availability of relatively inexpensive and portable instrumentation, as well as a fast analytical response, make SERS extremely appealing for bioanalytical applications, many of whi
Data Loading...
