Leveraging coffee‐ring effect on plasmonic paper substrate for sensitive analyte detection using Raman spectroscopy

Raman spectroscopy has demonstrated immense promise as a molecular fingerprinting tool in biomedical diagnostics. However, the utility of conventional Raman scattering for ultrasensitive measurements of biofluids is limited by intrinsically weak signals and has spurred advances in and wider applications of plasmon‐enhanced measurements. Here, we propose a label‐free methodology that leverages drop coating deposition on a silver ink‐based plasmonic paper substrate with tunable hydrophobic attributes to combine two distinct sources of enhancement, namely, solute preconcentration and excitation of localized surface plasmons. The facile modulation of the hydrophobicity of the plasmonic silver paper facilitates investigations into the coffee‐ring effect that results from the interplay of contact line pinning, solvent evaporation, and capillary flow. We show that the Raman spectra acquired from the hydrated ring deposits show clear enhancement beyond that obtained from surface‐enhancement owing to the presence of the silver nanofilm. In light of the superior sensitivity and lack of substantive sample preparation requirements, our findings open the door for a complementary low‐cost paper‐based analytical device for molecular sensing.We propose a label‐free analytical tool that leverages drop coating deposition on a silver ink‐based plasmonic paper substrate to combine two distinct sources of enhancement for Raman scattering signals. The facile modulation of the hydrophobicity of the plasmonic silver paper facilitates investigations into the coffee‐ring effect that results from the interplay of contact line pinning, solvent evaporation, and capillary flow. Raman spectra acquired show clear enhancement beyond that obtained from surface‐enhancement owing to the presence of the silver nanofilm.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146368/1/jrs5415_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146368/2/jrs5415.pd

Análisis de la espectroscopia Raman para la detección de la diabetes

Trabajo de investigaciónEl objetivo de este trabajo de grado es proporcionar información sobre una técnica ya implementada en la literatura para diagnosticar la diabetes. Para lograr esto lo primero que se realiza es recopilar información sobre las técnicas convencionales empleadas para dicho diagnóstico, seguidamente se expone la técnica espectroscopia Raman, teniendo en cuenta su definición, antecedentes, etapas del sistema y protocolos empleados en las muestras de sangre.INTRODUCCIÓN 1. GENERALIDADES 2. TÉCNICAS PARA REALIZAR DIAGNÓSTICO DE DIABETES MEDIANTE ANÁLISIS DE SANGRE 3. ETAPAS DE LA ESPECTROSCOPIA RAMAN PARA EL DIAGNÓSTICO DE DIABETES 4. IMPLEMENTACIÓN DE LA ESPECTROSCOPIA DE RAMAN PARA EL DIAGNÓSTICO DE DIABETES 5. COMPARAR LAS PRUEBAS REALIZADAS DE LA ESPECTROSCOPIA RAMAN CON LA BASE TEÓRICA REFERENTE A LA ESPECTROSCOPIA RAMAN DIVULGADA EN LA LITERATURA SOBRE EL ANÁLISIS DE LAS CÉLULAS DE LOS GLÓBULOS ROJOS DE LA SANGRE 6. CONCLUSIONES 7. TRABAJO A FUTURO 8. ESTRATEGIAS DE COMUNICACIÓN PARA LA TRANSFERENCIA DE RESULTADOS BIBLIOGRAFÍA ANEXOSPregradoIngeniero Electrónic

Characterization of flavour and volatile compounds of fermented squid using electronic nose and HPMS in combination with GC-MS

The present study investigated the flavour characteristics and key volatile components of fermented squid (Dosidicus gigas) as well as their formation mechanism by three different starter cultures of lactic acid bacteria (LAB) and natural squid. The sensory assessment, volatile compounds, as well as the amino acids of the mixed fermented squid were detected using pickled brine as samples of fermented squid. A total 88 types of volatile compounds were found in four samples by 0–72 h of fermentation. After fermentation by LAB, the volatile compounds of squid showed that the fermented squid with different started cultures differed mainly in terms of numbers of alcohols, ketones, and esters. Furthermore, the amounts of volatile compounds among three starter cultures were also obviously different. Gas Chromatography-Mass Spectrometer (GC-MS) analysis indicated that the mixed fermentation process contained relatively higher (+)-limonene (11.71%) (lemon scent) and 3-hydroxy-2-butanone (5.72%) (creamy taste). These compounds were not detected in the control group. The main flavour compounds of nonanal and 2, 4-decadienal were gradually reduced. Meanwhile, 2, 3-butanedione, 2-heptanone, 2-pentylfuran, and nonanoic acid are the key flavour components. The total principal component is 94.01%, which were clarified by electronic nose in combination with principal components analysis. After mixed fermentation by LAB, the total amino acid (TAA) content reached 85.36 g/100 g, which was almost twice the amount of the control, especially in aspartate, glutamate, and threonine. Our results indicated that LAB has obvious effects on deodorization and flavour promotion during the fermentation of squid. This study provided an important basis for the further development and utilization of squid

In Vitro Imaging of Thyroid Tissues Using Two-Photon Excited Fluorescence and Second Harmonic Generation

National Natural Science Foundation of China [60778046]; Scientific Program of the Scientific Hall of Fujian Province [2008I0015]; Natural Science Foundation of Fujian Province of China [2008J0016]Objective: To evaluate the feasibility of two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) imaging to discriminate the normal, nodular goiter and papillary cancerous thyroid tissue. Materials and Methods: In total, 45 fresh thyroid specimens (normal, 15; nodular goiter, 12; and papillary cancerous, 18) from 31 subjects were directly imaged by the TPEF and SHG combination method. Results: The microstructure of follicle and collagen structure in thyroid tissue were clearly identified, morphologic changes between normal, nodular goiter, and papillary cancerous thyroid tissue were well characterized by using two-photon excitation fluorescence. SHG imaging of the collagen matrix also revealed the differences between normal and abnormal. Conclusions: Our preliminary study suggests that the TPEF and SHG combination method might be a useful tool in revealing pathologic changes in thyroid tissue

Micro-Raman Analysis of Sperm Cells on Glass Slide: Potential Label-Free Assessment of Sperm DNA toward Clinical Applications

Routine assessment of sperm DNA integrity involves the time-consuming and complex process of staining sperm chromatin. Here, we report a Raman spectroscopy method combined with extended multiplicative signal correction (EMSC) for the extraction of characteristic fingerprints of DNA-intact and DNA-damaged sperm cells directly on glass slides. Raman results of sperm cell DNA integrity on glass substrates were validated one-to-one with clinical sperm cell staining. Although the overall Raman spectral pattern showed considerable similarity between DNA-damaged and DNA-intact sperm cells, differences in specific Raman spectral responses were observed. We then employed and compared multivariate statistical analysis based on principal component analysis-linear discriminant analysis (PCA-LDA) and partial least-squares-discriminant analysis (PLS-DA), and the classifications were validated by leave-one-out-cross-validation (LOOCV) and k-fold cross-validation methods. In comparison, the PLS-DA model showed relatively better results in terms of diagnostic sensitivity, specificity, and the classification rate between the sperm DNA damaged group and the DNA intact group. Our results demonstrate the potential of Raman based label-free DNA assessment of sperm cell on glass substrates as a simple method toward clinical applications

Highly Efficient Blood Protein Analysis Using Membrane Purification Technique and Super-Hydrophobic SERS Platform for Precise Screening and Staging of Nasopharyngeal Carcinoma

Early screening and precise staging are crucial for reducing mortality in patients with nasopharyngeal carcinoma (NPC). This study aimed to assess the performance of blood protein surface-enhanced Raman scattering (SERS) spectroscopy, combined with deep learning, for the precise detection of NPC. A highly efficient protein SERS analysis, based on a membrane purification technique and super-hydrophobic platform, was developed and applied to blood samples from 1164 subjects, including 225 healthy volunteers, 120 stage I, 249 stage II, 291 stage III, and 279 stage IV NPC patients. The proteins were rapidly purified from only 10 µL of blood plasma using the membrane purification technique. Then, the super-hydrophobic platform was prepared to pre-concentrate tiny amounts of proteins by forming a uniform deposition to provide repeatable SERS spectra. A total of 1164 high-quality protein SERS spectra were rapidly collected using a self-developed macro-Raman system. A convolutional neural network-based deep-learning algorithm was used to classify the spectra. An accuracy of 100% was achieved for distinguishing between the healthy and NPC groups, and accuracies of 96%, 96%, 100%, and 100% were found for the differential classification among the four NPC stages. This study demonstrated the great promise of SERS- and deep-learning-based blood protein testing for rapid, non-invasive, and precise screening and staging of NPC