ELISA GURIAN - Academia.edu (original) (raw)

Papers by ELISA GURIAN

Lo scopo di questo progetto di dottorato \ue8 quello di utilizzare delle superfici metalliche nan... more Lo scopo di questo progetto di dottorato \ue8 quello di utilizzare delle superfici metalliche nanostrutturate come substrati per la spettroscopia Raman amplificata da superfici (SERS) per l\u2019analisi di biofluidi. Questa tecnica analitica restituisce l\u2019impronta digitale vibrazionale del campione grazie alla presenza della nanostruttura metallica. Queste caratteristiche anticipano le potenzialit\ue0 della spettroscopia SERS in campo bioanalitico che ha visto un aumento esponenziale delle sue applicazioni nell\u2019ultimo decennio. In particolare, la SERS richiede la fabbricazione di substrati metallici nanostrutturati che possano funzionare da sensori. Questo progetto si basa sullo sviluppo di un approccio privo di marcatura (label-free:): nessuna funzionalizzazione \ue8 presente sulla superficie metallica al fine di rilevare in modo aspecifico gli analiti presenti della matrice di interesse biologico. Il risultato del segnale SERS sar\ue0 un\u2019istantanea della soluzione i...

This dataset contains all the spectra used in the paper "Repeated double cross validation ap... more This dataset contains all the spectra used in the paper "Repeated double cross validation applied to the PCA-LDA classification of SERS spectra: a case study with serum samples from hepatocellular carcinoma patients", plus the R code to import the TXT (ASCII) files into a dataset, preprocess data, set-up and cross validate the PCA-LDA model and generate the figures shown in the paper. Data are available in 2 different formats: - 1 compressed archive ("dataset.zip") containing all the 144 TXT files (1 file = 1 spectrum) - 1 single CSV file ("dataset.csv") with all the 144 spectra in the form of a table. The data are structured as follow, with each row being 1 spectrum, preceded by metadata: "acquisition_date", "substrate_batch", "class", "sample_code". The code for R is available as a single file "Rcode.R".

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2021

Intense SERS spectra of the natural amino acid ergothioneine (ERG) are obtained on different subs... more Intense SERS spectra of the natural amino acid ergothioneine (ERG) are obtained on different substrates upon 785 nm excitation. A characteristic spectral pattern with a distinctive intense band at 480-486 cm −1 is conserved when substrates of different type and characteristics are used. On the basis of available literature, we propose ERG is adsorbed on the metal surface in its thiolate form via the sulphur and heterocyclic nitrogen. The same spectral pattern is obtained in SERS spectra of filtered erythrocytes lysates, confirming the presence of ERG in those cells. The occurrence of ERG bands in label-free SERS spectra of serum and plasma reported in literature by different authors is discussed, highlighting the importance of this amino acid for the interpretation of SERS spectra of these biofluids.

Analytica Chimica Acta, 2020

Label-free SERS has been successfully applied in the diagnosis of NAFLD. The analysis is non-inva... more Label-free SERS has been successfully applied in the diagnosis of NAFLD. The analysis is non-invasive and requires only a drop of plasma. Paper-based SERS substrates are potential reliable Point of Care tools. The detected relative concentration of uric acid and hypoxanthine is diagnostically relevant.

Talanta, 2019

In the present study, label-free SERS spectroscopy is applied as a useful analytical technique fo... more In the present study, label-free SERS spectroscopy is applied as a useful analytical technique for white wine characterization. 180 samples of three white wines varieties from northeastern Italy, Sauvignon Blanc, Ribolla Gialla and Friulano, collected from three different Italian producers from 2016 vintage, have been analyzed using Ag citrate-reduced colloids and a portable Raman instrument with a 785 nm laser. A PCA of SERS spectra showed that discrimination between wines and wineries is possible. Main spectral differences are due to adenine, carboxylic acids and glutathione, with their ratio changing among different wine types and producers. A robust version of the Soft Independent Modelling of Class Analogy (SIMCA) method was used to model the class space of each wine and to perform the classification among the different categories, yielding overall efficiencies between 87-93%. These results are extremely encouraging and open the way to the application of this SERS protocol as a wine identification assay.

Dental Materials, 2017

Objective. Separately addressing the fatigue resistance (ISO 14801, evaluation of final product) ... more Objective. Separately addressing the fatigue resistance (ISO 14801, evaluation of final product) and aging behavior (ISO 13356, standardized sample) of oral implants made from yttriastabilized zirconia proved to be insufficient in verifying their long-term stability, since (1) implant processing is known to significantly influence transformation kinetics and (2) aging, up from a certain level, is liable to decrease fatigue resistance. Therefore, the aim of this investigation was to apply a new testing protocol considering environmental conditions adequately inducing aging during dynamic fatigue. Methods. Zirconia implants were dynamically loaded (10 7 cycles), hydrothermally aged (85 • , 60 days) or subjected to both treatments simultaneously. Subsequent, monoclinic intensity ratios (X m) were obtained by locally resolved X-ray microdiffraction (-XRD 2). Transformation propagation was monitored at cross-sections by-Raman spectroscopy and scanning electron microscopy (SEM). Finally, implants were statically loaded to fracture. Linear regression models (fracture load) and mixed models (X m) were used for statistical analyses. Results. All treatments resulted in increased fracture load (p ≤ 0.005), indicating the formation of transformation induced compressive stresses around surface defects during all treatment modalities. However, only hydrothermal and combinational treatment were found to increase X m (p < 0.001). No change in X m was observed for solely dynamically loaded samples (p ≥ 0.524). Depending on the variable observed, a monoclinic layer thickness of 1-2 m (SEM) or 6-8 m (Raman spectroscopy) was measured at surfaces exposed to water during treatments.

Journal of Thermal Analysis and Calorimetry, 2016

In this study, the isothermal dehydration of some biological substrates, i.e., cell monolayer, ha... more In this study, the isothermal dehydration of some biological substrates, i.e., cell monolayer, has been explored as an extension of the novel application of DSC for monitoring the dehydration changes in aqueous films of polysaccharide solutions and gels. Here we assess the possible correlation of the experimental calorimetric signal (heat flow) and changes in the water binding state using unperturbed or stressed cells as treated using hypotonic solutions or AgNO3 as aquaporin inhibitors. The experiments on unperturbed and stressed cells show the requirement for a proper setup in order to obtain reproducibility to highlight the cell dehydration patterns. The preliminary results and the analysis of the calorimetric curves proved the feasibility of the described measurements on cellular substrates and revealed a good sensitivity of the experimental response on the specific features of the system and on its actual hydration state.

Food Hydrocolloids, 2016

Abstract The isothermal dehydration of aqueous biosystems is a relevant topic in food, pharmaceut... more Abstract The isothermal dehydration of aqueous biosystems is a relevant topic in food, pharmaceutical and cosmetic industry and has been recently investigated for the assessment of a model calorimetric set-up and for the characterization of the parameters featuring the experimental calorimetric curve. In this study, the experimental Differential Scanning Calorimetry (DSC) data obtained under controlled conditions in isothermal mode have been collected on the dehydration of films consisting of solutions and gels of alginate, hydroxypropylmethylcellulose (HPMC), trehalose and mixtures thereof. Based on the proportionality between the calorimetric heat flow and water activity (aw) of solutions of known aw, the values calculated from calorimetry have been compared to those obtained with classic hygrometric measurements revealing a good consistency between the methods. Furthermore, the experimental data were mathematically turned into desorption isotherms, providing a continuous description of the water activity down to the low water activity limit. This experimental method represents an innovative approach to support other consolidated analytical techniques in the physico-chemical characterization of aqueous systems and, more importantly, a step forward in the determination of water activity as a continuous measurement in a timeframe far shorter than that necessary with other instruments (e.g., hygrometers).

Analytical and Bioanalytical Chemistry, 2020

Intense label-free surface-enhanced Raman scattering (SERS) spectra of serum samples were rapidly... more 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 metab...

Lo scopo di questo progetto di dottorato \ue8 quello di utilizzare delle superfici metalliche nan... more Lo scopo di questo progetto di dottorato \ue8 quello di utilizzare delle superfici metalliche nanostrutturate come substrati per la spettroscopia Raman amplificata da superfici (SERS) per l\u2019analisi di biofluidi. Questa tecnica analitica restituisce l\u2019impronta digitale vibrazionale del campione grazie alla presenza della nanostruttura metallica. Queste caratteristiche anticipano le potenzialit\ue0 della spettroscopia SERS in campo bioanalitico che ha visto un aumento esponenziale delle sue applicazioni nell\u2019ultimo decennio. In particolare, la SERS richiede la fabbricazione di substrati metallici nanostrutturati che possano funzionare da sensori. Questo progetto si basa sullo sviluppo di un approccio privo di marcatura (label-free:): nessuna funzionalizzazione \ue8 presente sulla superficie metallica al fine di rilevare in modo aspecifico gli analiti presenti della matrice di interesse biologico. Il risultato del segnale SERS sar\ue0 un\u2019istantanea della soluzione i...

This dataset contains all the spectra used in the paper "Repeated double cross validation ap... more This dataset contains all the spectra used in the paper "Repeated double cross validation applied to the PCA-LDA classification of SERS spectra: a case study with serum samples from hepatocellular carcinoma patients", plus the R code to import the TXT (ASCII) files into a dataset, preprocess data, set-up and cross validate the PCA-LDA model and generate the figures shown in the paper. Data are available in 2 different formats: - 1 compressed archive ("dataset.zip") containing all the 144 TXT files (1 file = 1 spectrum) - 1 single CSV file ("dataset.csv") with all the 144 spectra in the form of a table. The data are structured as follow, with each row being 1 spectrum, preceded by metadata: "acquisition_date", "substrate_batch", "class", "sample_code". The code for R is available as a single file "Rcode.R".

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2021

Intense SERS spectra of the natural amino acid ergothioneine (ERG) are obtained on different subs... more Intense SERS spectra of the natural amino acid ergothioneine (ERG) are obtained on different substrates upon 785 nm excitation. A characteristic spectral pattern with a distinctive intense band at 480-486 cm −1 is conserved when substrates of different type and characteristics are used. On the basis of available literature, we propose ERG is adsorbed on the metal surface in its thiolate form via the sulphur and heterocyclic nitrogen. The same spectral pattern is obtained in SERS spectra of filtered erythrocytes lysates, confirming the presence of ERG in those cells. The occurrence of ERG bands in label-free SERS spectra of serum and plasma reported in literature by different authors is discussed, highlighting the importance of this amino acid for the interpretation of SERS spectra of these biofluids.

Analytica Chimica Acta, 2020

Label-free SERS has been successfully applied in the diagnosis of NAFLD. The analysis is non-inva... more Label-free SERS has been successfully applied in the diagnosis of NAFLD. The analysis is non-invasive and requires only a drop of plasma. Paper-based SERS substrates are potential reliable Point of Care tools. The detected relative concentration of uric acid and hypoxanthine is diagnostically relevant.

Talanta, 2019

In the present study, label-free SERS spectroscopy is applied as a useful analytical technique fo... more In the present study, label-free SERS spectroscopy is applied as a useful analytical technique for white wine characterization. 180 samples of three white wines varieties from northeastern Italy, Sauvignon Blanc, Ribolla Gialla and Friulano, collected from three different Italian producers from 2016 vintage, have been analyzed using Ag citrate-reduced colloids and a portable Raman instrument with a 785 nm laser. A PCA of SERS spectra showed that discrimination between wines and wineries is possible. Main spectral differences are due to adenine, carboxylic acids and glutathione, with their ratio changing among different wine types and producers. A robust version of the Soft Independent Modelling of Class Analogy (SIMCA) method was used to model the class space of each wine and to perform the classification among the different categories, yielding overall efficiencies between 87-93%. These results are extremely encouraging and open the way to the application of this SERS protocol as a wine identification assay.

Dental Materials, 2017

Objective. Separately addressing the fatigue resistance (ISO 14801, evaluation of final product) ... more Objective. Separately addressing the fatigue resistance (ISO 14801, evaluation of final product) and aging behavior (ISO 13356, standardized sample) of oral implants made from yttriastabilized zirconia proved to be insufficient in verifying their long-term stability, since (1) implant processing is known to significantly influence transformation kinetics and (2) aging, up from a certain level, is liable to decrease fatigue resistance. Therefore, the aim of this investigation was to apply a new testing protocol considering environmental conditions adequately inducing aging during dynamic fatigue. Methods. Zirconia implants were dynamically loaded (10 7 cycles), hydrothermally aged (85 • , 60 days) or subjected to both treatments simultaneously. Subsequent, monoclinic intensity ratios (X m) were obtained by locally resolved X-ray microdiffraction (-XRD 2). Transformation propagation was monitored at cross-sections by-Raman spectroscopy and scanning electron microscopy (SEM). Finally, implants were statically loaded to fracture. Linear regression models (fracture load) and mixed models (X m) were used for statistical analyses. Results. All treatments resulted in increased fracture load (p ≤ 0.005), indicating the formation of transformation induced compressive stresses around surface defects during all treatment modalities. However, only hydrothermal and combinational treatment were found to increase X m (p < 0.001). No change in X m was observed for solely dynamically loaded samples (p ≥ 0.524). Depending on the variable observed, a monoclinic layer thickness of 1-2 m (SEM) or 6-8 m (Raman spectroscopy) was measured at surfaces exposed to water during treatments.

Journal of Thermal Analysis and Calorimetry, 2016

In this study, the isothermal dehydration of some biological substrates, i.e., cell monolayer, ha... more In this study, the isothermal dehydration of some biological substrates, i.e., cell monolayer, has been explored as an extension of the novel application of DSC for monitoring the dehydration changes in aqueous films of polysaccharide solutions and gels. Here we assess the possible correlation of the experimental calorimetric signal (heat flow) and changes in the water binding state using unperturbed or stressed cells as treated using hypotonic solutions or AgNO3 as aquaporin inhibitors. The experiments on unperturbed and stressed cells show the requirement for a proper setup in order to obtain reproducibility to highlight the cell dehydration patterns. The preliminary results and the analysis of the calorimetric curves proved the feasibility of the described measurements on cellular substrates and revealed a good sensitivity of the experimental response on the specific features of the system and on its actual hydration state.

Food Hydrocolloids, 2016

Abstract The isothermal dehydration of aqueous biosystems is a relevant topic in food, pharmaceut... more Abstract The isothermal dehydration of aqueous biosystems is a relevant topic in food, pharmaceutical and cosmetic industry and has been recently investigated for the assessment of a model calorimetric set-up and for the characterization of the parameters featuring the experimental calorimetric curve. In this study, the experimental Differential Scanning Calorimetry (DSC) data obtained under controlled conditions in isothermal mode have been collected on the dehydration of films consisting of solutions and gels of alginate, hydroxypropylmethylcellulose (HPMC), trehalose and mixtures thereof. Based on the proportionality between the calorimetric heat flow and water activity (aw) of solutions of known aw, the values calculated from calorimetry have been compared to those obtained with classic hygrometric measurements revealing a good consistency between the methods. Furthermore, the experimental data were mathematically turned into desorption isotherms, providing a continuous description of the water activity down to the low water activity limit. This experimental method represents an innovative approach to support other consolidated analytical techniques in the physico-chemical characterization of aqueous systems and, more importantly, a step forward in the determination of water activity as a continuous measurement in a timeframe far shorter than that necessary with other instruments (e.g., hygrometers).

Analytical and Bioanalytical Chemistry, 2020

Intense label-free surface-enhanced Raman scattering (SERS) spectra of serum samples were rapidly... more 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 metab...