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1.
Food Chem ; 338: 127796, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32805691

RESUMO

Trace detection of toxic chemicals in foodstuffs is of great concern in recent years. Surface-enhanced Raman scattering (SERS) has drawn significant attention in the monitoring of food safety due to its high sensitivity. This study synthesized signal optimized flower-like silver nanoparticle-(AgNP) with EF at 25 °C of 1.39 × 106 to extend the SERS application for pesticide sensing in foodstuffs. The synthesized AgNP was deployed as SERS based sensing platform to detect methomyl, acetamiprid-(AC) and 2,4-dichlorophenoxyacetic acid-(2,4-D) residue levels in green tea via solid-phase extraction. A linear correlation was twigged between the SERS signal and the concentration for methomyl, AC and 2,4-D with regression coefficient of 0.9974, 0.9956 and 0.9982 and limit of detection of 5.58 × 10-4, 1.88 × 10-4 and 4.72 × 10-3 µg/mL, respectively; the RSD value < 5% was recorded for accuracy and precision analysis suggesting that proposed method could be deployed for the monitoring of methomyl, AC and 2,4-D residue levels in green tea.


Assuntos
Contaminação de Alimentos/análise , Nanopartículas Metálicas/química , Resíduos de Praguicidas/análise , Análise Espectral Raman/métodos , Chá/química , Ácido 2,4-Diclorofenoxiacético/análise , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Metomil/análise , Neonicotinoides/análise , Prata/química , Extração em Fase Sólida
3.
Nat Commun ; 11(1): 4830, 2020 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-32973134

RESUMO

Non-invasively probing metabolites within single live cells is highly desired but challenging. Here we utilize Raman spectro-microscopy for spatial mapping of metabolites within single cells, with the specific goal of identifying druggable metabolic susceptibilities from a series of patient-derived melanoma cell lines. Each cell line represents a different characteristic level of cancer cell de-differentiation. First, with Raman spectroscopy, followed by stimulated Raman scattering (SRS) microscopy and transcriptomics analysis, we identify the fatty acid synthesis pathway as a druggable susceptibility for differentiated melanocytic cells. We then utilize hyperspectral-SRS imaging of intracellular lipid droplets to identify a previously unknown susceptibility of lipid mono-unsaturation within de-differentiated mesenchymal cells with innate resistance to BRAF inhibition. Drugging this target leads to cellular apoptosis accompanied by the formation of phase-separated intracellular membrane domains. The integration of subcellular Raman spectro-microscopy with lipidomics and transcriptomics suggests possible lipid regulatory mechanisms underlying this pharmacological treatment. Our method should provide a general approach in spatially-resolved single cell metabolomics studies.


Assuntos
Melanoma/metabolismo , Metabolômica/métodos , Microscopia/métodos , Análise Espectral Raman/métodos , Apoptose , Linhagem Celular Tumoral , Ácidos Graxos/metabolismo , Humanos , Gotículas Lipídicas , Metabolismo dos Lipídeos , Lipidômica , Lipídeos , Ácido Oleico , Estearoil-CoA Dessaturase/metabolismo , Transcriptoma
4.
Nat Commun ; 11(1): 4772, 2020 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-32973145

RESUMO

Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for vibrational spectroscopy as it provides several orders of magnitude higher sensitivity than inherently weak spontaneous Raman scattering by exciting localized surface plasmon resonance (LSPR) on metal substrates. However, SERS can be unreliable for biomedical use since it sacrifices reproducibility, uniformity, biocompatibility, and durability due to its strong dependence on "hot spots", large photothermal heat generation, and easy oxidization. Here, we demonstrate the design, fabrication, and use of a metal-free (i.e., LSPR-free), topologically tailored nanostructure composed of porous carbon nanowires in an array as a SERS substrate to overcome all these problems. Specifically, it offers not only high signal enhancement (~106) due to its strong broadband charge-transfer resonance, but also extraordinarily high reproducibility due to the absence of hot spots, high durability due to no oxidization, and high compatibility to biomolecules due to its fluorescence quenching capability.


Assuntos
Carbono/química , Nanofios/química , Análise Espectral Raman/métodos , Fluorescência , Porosidade , Reprodutibilidade dos Testes , Ressonância de Plasmônio de Superfície/métodos , Propriedades de Superfície
5.
PLoS One ; 15(8): e0237070, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32822394

RESUMO

Bladder cancer (BCA) is relatively common and potentially recurrent/progressive disease. It is also costly to detect, treat, and control. Definitive diagnosis is made by examination of urine sediment, imaging, direct visualization (cystoscopy), and invasive biopsy of suspect bladder lesions. There are currently no widely-used BCA-specific biomarker urine screening tests for early BCA or for following patients during/after therapy. Urine metabolomic screening for biomarkers is costly and generally unavailable for clinical use. In response, we developed Raman spectroscopy-based chemometric urinalysis (Rametrix™) as a direct liquid urine screening method for detecting complex molecular signatures in urine associated with BCA and other genitourinary tract pathologies. In particular, the RametrixTM screen used principal components (PCs) of urine Raman spectra to build discriminant analysis models that indicate the presence/absence of disease. The number of PCs included was varied, and all models were cross-validated by leave-one-out analysis. In Study 1 reported here, we tested the Rametrix™ screen using urine specimens from 56 consented patients from a urology clinic. This proof-of-concept study contained 17 urine specimens with active BCA (BCA-positive), 32 urine specimens from patients with other genitourinary tract pathologies, seven specimens from healthy patients, and the urinalysis control SurineTM. Using a model built with 22 PCs, BCA was detected with 80.4% accuracy, 82.4% sensitivity, 79.5% specificity, 63.6% positive predictive value (PPV), and 91.2% negative predictive value (NPV). Based on the number of PCs included, we found the RametrixTM screen could be fine-tuned for either high sensitivity or specificity. In other studies reported here, RametrixTM was also able to differentiate between urine specimens from patients with BCA and other genitourinary pathologies and those obtained from patients with end-stage kidney disease (ESKD). While larger studies are needed to improve RametrixTM models and demonstrate clinical relevance, this study demonstrates the ability of the RametrixTM screen to differentiate urine of BCA-positive patients. Molecular signature variances in the urine metabolome of BCA patients included changes in: phosphatidylinositol, nucleic acids, protein (particularly collagen), aromatic amino acids, and carotenoids.


Assuntos
Detecção Precoce de Câncer/métodos , Análise Espectral Raman/métodos , Neoplasias da Bexiga Urinária/diagnóstico , Adulto , Idoso , Biomarcadores Tumorais/urina , Cistoscopia , Análise Discriminante , Feminino , Humanos , Masculino , Metaboloma , Metabolômica , Pessoa de Meia-Idade , Sensibilidade e Especificidade , Urinálise/métodos , Neoplasias da Bexiga Urinária/patologia
6.
Food Chem ; 333: 127454, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32679414

RESUMO

This study presents a method to determine adulteration of olive oil (obtained from Olea europea, i.e. olives) with rapeseed oil (obtained from Brassica napus) or with corn oil (also named maize oil, obtained from Zea mays, i.e. maize) using Raman spectroscopy and a mathematical method based on exponential equation fit. The samples were prepared by mixing olive oil with volume fractions (0-100%) of rapeseed or corn oil. The oils were differentiated spectroscopically using intensity ratio for specific Raman peaks; Raman spectroscopy is able to detect changes within a liquid molecular environment without the need for sample treatment. It was possible to determine rapeseed or corn oil volume fractions added into the olive oil using the method proposed. Thus, the potential of Raman spectroscopy as a technique for determining adulteration of olive oil was corroborated clearly, opening the potential to investigate adulteration of other liquid foods, without any need for sample preparation.


Assuntos
Óleo de Milho/química , Contaminação de Alimentos/análise , Azeite de Oliva/análise , Óleo de Brassica napus/química , Análise Espectral Raman/métodos , Análise de Alimentos/métodos , Azeite de Oliva/química
7.
Anal Chem ; 92(16): 11297-11304, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32683857

RESUMO

Viruses are infections species that infect a large spectrum of living systems. Although displaying a wide variety of shapes and sizes, they are all composed of nucleic acid encapsulated into a protein capsid. After virions enter the host cell, they replicate to produce multiple copies of themselves. They then lyse the host, releasing virions to infect new cells. The high proliferation rate of viruses is the underlying cause of their fast transmission among living species. Although many viruses are harmless, some of them are responsible for severe diseases such as AIDS, viral hepatitis, and flu. Traditionally, electron microscopy is used to identify and characterize viruses. This approach is time- and labor-consuming, which is problematic upon pandemic proliferation of previously unknown viruses, such as H1N1 and COVID-19. Herein, we demonstrate a novel diagnosis approach for label-free identification and structural characterization of individual viruses that is based on a combination of nanoscale Raman and infrared spectroscopy. Using atomic force microscopy-infrared (AFM-IR) spectroscopy, we were able to probe structural organization of the virions of Herpes Simplex Type 1 viruses and bacteriophage MS2. We also showed that tip-enhanced Raman spectroscopy (TERS) could be used to reveal protein secondary structure and amino acid composition of the virus surface. Our results show that AFM-IR and TERS provide different but complementary information about the structure of complex biological specimens. This structural information can be used for fast and reliable identification of viruses. This nanoscale bimodal imaging approach can be also used to investigate the origin of viral polymorphism and study mechanisms of virion assembly.


Assuntos
Microscopia de Força Atômica/métodos , Nanoestruturas/química , Análise Espectral Raman/métodos , Vírion/química , Animais , Betacoronavirus/isolamento & purificação , Betacoronavirus/fisiologia , Capsídeo/química , Chlorocebus aethiops , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Microscopia Crioeletrônica , Análise Discriminante , Herpesvirus Humano 1/fisiologia , Humanos , Vírus da Influenza A Subtipo H1N1/fisiologia , Análise dos Mínimos Quadrados , Levivirus/metabolismo , Pandemias , Pneumonia Viral/patologia , Pneumonia Viral/virologia , Estrutura Terciária de Proteína , Células Vero
8.
Nat Commun ; 11(1): 3452, 2020 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-32651381

RESUMO

The advent of image-activated cell sorting and imaging-based cell picking has advanced our knowledge and exploitation of biological systems in the last decade. Unfortunately, they generally rely on fluorescent labeling for cellular phenotyping, an indirect measure of the molecular landscape in the cell, which has critical limitations. Here we demonstrate Raman image-activated cell sorting by directly probing chemically specific intracellular molecular vibrations via ultrafast multicolor stimulated Raman scattering (SRS) microscopy for cellular phenotyping. Specifically, the technology enables real-time SRS-image-based sorting of single live cells with a throughput of up to ~100 events per second without the need for fluorescent labeling. To show the broad utility of the technology, we show its applicability to diverse cell types and sizes. The technology is highly versatile and holds promise for numerous applications that are previously difficult or undesirable with fluorescence-based technologies.


Assuntos
Separação Celular/métodos , Análise Espectral Raman/métodos , Animais , Humanos
9.
PLoS One ; 15(7): e0235214, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32614841

RESUMO

Placenta-derived extracellular vesicles (EVs) are involved in communication between the placenta and maternal immune cells possibly leading to a modulation of maternal T-cell signaling components. The ability to identify EVs in maternal blood may lead to the development of diagnostic and treatment tools for pregnancy complications. The objective of this work was to differentiate EVs from bovine placenta (trophoblast) and peripheral blood mononuclear cells (PBMC) by a label-free, non-invasive Raman spectroscopy technique. Extracellular vesicles were isolated by ultracentrifugation. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) were applied to verify the presence and the size distribution of EVs. Raman peaks at 728 cm-1 (collagen) and 1573 cm-1 (protein) were observed only in PBMC-derived EVs, while the peaks 702 cm-1 (cholesterol) and 1553 cm-1 (amide) appeared only in trophoblast-derived EVs. The discrimination of the Raman spectral fingerprints for both types of EVs from different animals was performed by principal component analysis (PCA) and linear discriminant analysis (LDA). The PCA and LDA results clearly segregated the spectral clusters between the two types of EVs. Moreover, the PBMC-derived EVs from different animals were indistinguishable, while the trophoblast-derived EVs from three placental samples of different gestational ages showed separate clusters. This study reports for the first time the Raman characteristic peaks for identification of PBMC and trophoblast-derived EVs. The development of this method also provides a potential tool for further studies investigating the causes and potential treatments for pregnancy complications.


Assuntos
Vesículas Extracelulares/química , Leucócitos Mononucleares/química , Trofoblastos/química , Animais , Bovinos , Células Cultivadas , Feminino , Placenta/química , Placenta/citologia , Gravidez , Análise Espectral Raman/métodos , Trofoblastos/citologia
10.
ACS Infect Dis ; 6(8): 1998-2016, 2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32677821

RESUMO

Since late December 2019, the coronavirus pandemic (COVID-19; previously known as 2019-nCoV) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been surging rapidly around the world. With more than 1,700,000 confirmed cases, the world faces an unprecedented economic, social, and health impact. The early, rapid, sensitive, and accurate diagnosis of viral infection provides rapid responses for public health surveillance, prevention, and control of contagious diffusion. More than 30% of the confirmed cases are asymptomatic, and the high false-negative rate (FNR) of a single assay requires the development of novel diagnostic techniques, combinative approaches, sampling from different locations, and consecutive detection. The recurrence of discharged patients indicates the need for long-term monitoring and tracking. Diagnostic and therapeutic methods are evolving with a deeper understanding of virus pathology and the potential for relapse. In this Review, a comprehensive summary and comparison of different SARS-CoV-2 diagnostic methods are provided for researchers and clinicians to develop appropriate strategies for the timely and effective detection of SARS-CoV-2. The survey of current biosensors and diagnostic devices for viral nucleic acids, proteins, and particles and chest tomography will provide insight into the development of novel perspective techniques for the diagnosis of COVID-19.


Assuntos
Betacoronavirus/química , Betacoronavirus/genética , Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , Betacoronavirus/isolamento & purificação , Sistemas CRISPR-Cas , Infecções por Coronavirus/virologia , Efeito Citopatogênico Viral , Transferência Ressonante de Energia de Fluorescência/métodos , Humanos , Imunoquímica/métodos , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Pandemias , Pneumonia Viral/virologia , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Análise Espectral Raman/métodos , Tomografia Computadorizada por Raios X/métodos , Sequenciamento Completo do Genoma/métodos
11.
Food Chem ; 332: 127431, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32645668

RESUMO

Illegal usage of ß-agonists as the animal growth promoters can lead to multiple harmful impacts to public health, thus detection of ß-agonists at trace level in complex sample matrixes is of great importance. In recent years, emergence of advanced nanomaterials greatly facilitates the advancement of sensors in terms of sensitivity, specificity and robustness. Plenty of nanoparticles-based sensors have been developed for ß-agonists determination. In this review, we comprehensively summarized the construction of emerging nanoparticles-based sensors (including colorimetric sensors, fluorescent sensors, chemiluminescent sensors, electrochemical sensors, electrochemiluminescent sensors, surface enhanced Raman scattering sensors, surface plasmon resonance sensors, quartz crystal microbalance sensors, etc.), and nanomaterial-based enzyme-linked immunosorbent assay (nano-ELISA). Impressively, the applications of nanoparticles-based sensors and nano-ELISAs in the detection of ß-agonists have also been summarized and discussed. In the end, future opportunities and challenges in the design construction of nanoparticles (NPs)-based sensors and their applications in ß-agonist assay are tentatively proposed.


Assuntos
Agonistas Adrenérgicos/análise , Nanoestruturas/química , Animais , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Colorimetria/instrumentação , Colorimetria/métodos , Humanos , Nanotecnologia/instrumentação , Nanotecnologia/métodos , Análise Espectral Raman/instrumentação , Análise Espectral Raman/métodos , Ressonância de Plasmônio de Superfície/instrumentação , Ressonância de Plasmônio de Superfície/métodos
12.
Proc Natl Acad Sci U S A ; 117(31): 18412-18423, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32694205

RESUMO

Stem cells with the capability to self-renew and differentiate into multiple cell derivatives provide platforms for drug screening and promising treatment options for a wide variety of neural diseases. Nevertheless, clinical applications of stem cells have been hindered partly owing to a lack of standardized techniques to characterize cell molecular profiles noninvasively and comprehensively. Here, we demonstrate that a label-free and noninvasive single-cell Raman microspectroscopy (SCRM) platform was able to identify neural cell lineages derived from clinically relevant human induced pluripotent stem cells (hiPSCs). By analyzing the intrinsic biochemical profiles of single cells at a large scale (8,774 Raman spectra in total), iPSCs and iPSC-derived neural cells can be distinguished by their intrinsic phenotypic Raman spectra. We identified a Raman biomarker from glycogen to distinguish iPSCs from their neural derivatives, and the result was verified by the conventional glycogen detection assays. Further analysis with a machine learning classification model, utilizing t-distributed stochastic neighbor embedding (t-SNE)-enhanced ensemble stacking, clearly categorized hiPSCs in different developmental stages with 97.5% accuracy. The present study demonstrates the capability of the SCRM-based platform to monitor cell development using high content screening with a noninvasive and label-free approach. This platform as well as our identified biomarker could be extensible to other cell types and can potentially have a high impact on neural stem cell therapy.


Assuntos
Células-Tronco Pluripotentes Induzidas/citologia , Neurônios/citologia , Análise de Célula Única/métodos , Análise Espectral Raman/métodos , Diferenciação Celular , Humanos
13.
Food Chem ; 328: 127106, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32485584

RESUMO

In this work, based on the strawberry-like SiO2/Ag nanocomposites (SANC) immersed filter paper, a newly surface-enhanced Raman scattering (SERS) substrate was constructed for the detection of acrylamide (AAm) in food products. To construct filter paper-based SANC (F-SANC) SERS substrates, SiO2 nanoparticles (SNP) were firstly synthesized and acted as carriers. After that, the in-situ preparation of silver nanoparticles (Ag NP) on SNP surface was carried out to form the strawberry-like three-dimensional (3D) structure of SANC. Finally, SANC were entangled into the filter paper to produce nanoarchitecture, thus providing enhanced plasmon resonance between SANC with strong SERS signal. Under the optimized conditions, the method exhibited good performance toward AAm with a vast linear response from 0.1 nM to 50 µM (R = 0.9935), limit of detection (LOD) of 0.02 nM (S/N = 3), and the recoveries of 80.5%~105.6% for practical samples. This strategy showed good robustness in the rapid and sensitive detection of AAm, which could be a promising strategy in food analysis and verification.


Assuntos
Acrilamida/análise , Análise de Alimentos/métodos , Nanopartículas Metálicas/química , Nanocompostos/química , Análise Espectral Raman/métodos , Filtração/instrumentação , Análise de Alimentos/instrumentação , Fragaria/química , Limite de Detecção , Dióxido de Silício/química , Prata/química
14.
Ecotoxicol Environ Saf ; 200: 110780, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32470683

RESUMO

A green synthesis method for nanoscale silver using ß-cyclodextrin as both reducing agent and stabilizer was developed. ß-cyclodextrin was used not only as a reducing agent but also a stabilizing agent for nano-silver, and is also an excellent detection substrate due to its special structure (inner hydrophobic and outer hydrophilic ring structure). Then, the green synthesized silver nanoparticles were used as Surface-enhanced Raman spectroscopy (SERS) enhanced substrates to detect polycyclic aromatic hydrocarbons, such as: anthracene, pyrene, chrysene and triphenylene. The SERS substrate can be used for both quantitative detection of the four polycyclic aromatic hydrocarbons and qualitative identification of mixtures of these hydrocarbons. This synthesis method is simple and convenient, having great potential in simultaneous and rapid detection of environmental organic pollutants.


Assuntos
Química Verde/métodos , Nanopartículas Metálicas/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Prata/química , Análise Espectral Raman/métodos , beta-Ciclodextrinas/química , Antracenos/análise , Crisenos/análise , Interações Hidrofóbicas e Hidrofílicas , Pirenos/análise
15.
Food Chem ; 328: 127105, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32464556

RESUMO

Synthetic dyes have been widely applied to food processing, but abuse of colourants in food may pose risks to human health. To analyze new coccine (NC) and orange II (OII) in food, a versatile surface-enhanced Raman scattering (SERS) platform was proposed. A metal-organic framework (MOF, UiO-66(NH2)) with octahedral crystal structure was synthesized and gold nanoparticles were grown on the MOF surface to fabricate UiO-66(NH2)@Au versatile SERS platform. The UiO-66(NH2)@Au displayed much better SERS performance than gold nanoparticles with high R2 of 0.9684 for NC and 0.9912 for OII and low LOD of 0.4015 mg/L for NC and 0.0546 mg/L for OII. The recoveries of NC and OII in Mirinda soft drink and paprika ranged from 82.92 to 109.63%. This study provided a sensitive and rapid method for determination of NC and OII through UiO-66(NH2)@Au, and the proposed SERS platform revealed great potential for analyzing synthetic colourants in food samples.


Assuntos
Compostos Azo/análise , Benzenossulfonatos/análise , Análise de Alimentos/métodos , Nanopartículas Metálicas/química , Estruturas Metalorgânicas/química , Naftalenossulfonatos/análise , Análise Espectral Raman/métodos , Adsorção , Corantes/análise , Ouro/química , Limite de Detecção
16.
Clin Hemorheol Microcirc ; 75(4): 489-498, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32444535

RESUMO

 Cell metabolism decides the state of cells in division, differentiation and growth, maintaining intracellular balance. Monitoring the metabolic behavior of cells is of great significance to study the development of diseases in cell levels. Surface-enhanced Raman spectroscopy (SERS) is a powerful technique to detect and quantify analytes in extremely low concentration. Combined with SRES technology, we can monitor the concentration of metabolites in live cells and thus study the biological behavior of cells. In this work, Raman-tag labelled Au@ZIF-8 nanoparticles were used to monitor the distribution of reactive oxygen species (ROS) in SKOV3 cells. With the help of the ultrasensitive Raman enhancement material, the distribution of ROS in SKOV3 cells was mapped, the results were further confirmed in the fluorescent images. The SERS platform provides an ultrasensitive monitoring method of ROS distribution, which may offer an opportunity for real-time monitoring the cell metabolism in the cell biology applications.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Análise Espectral Raman/métodos , Humanos
17.
Muscle Nerve ; 62(1): 137-142, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32304246

RESUMO

BACKGROUND: Conventional processing of nerve for histomorphometry is resource-intensive, precluding use in intraoperative assessment of nerve quality during nerve transfer procedures. Stimulated Raman scattering (SRS) microscopy is a label-free technique that enables rapid and high-resolution histology. METHODS: Segments of healthy murine sciatic nerve, healthy human obturator nerve, and human cross-facial nerve autografts were imaged on a custom SRS microscope. Myelinated axon quantification was performed through segmentation using a random forest machine learning algorithm in commercial software. RESULTS: High contrast, high-resolution imaging of nerve morphology was obtained with SRS imaging. Automated myelinated axon quantification from cross-sections of healthy human nerve imaged using SRS was achieved. CONCLUSIONS: Herein, we demonstrate the use of a label-free technique for rapid imaging of murine and human peripheral nerve cryosections. We illustrate the potential of this technique to inform intraoperative decision-making through rapid automated quantification of myelinated axons using a machine learning algorithm.


Assuntos
Nervo Facial/química , Nervo Obturador/química , Nervo Isquiático/química , Análise Espectral Raman/métodos , Animais , Nervo Facial/anatomia & histologia , Humanos , Camundongos , Microscopia Confocal/métodos , Nervo Obturador/anatomia & histologia , Nervo Isquiático/anatomia & histologia
18.
Int J Nanomedicine ; 15: 2303-2314, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32280222

RESUMO

Objective: The objective of this study is to evaluate the performance and feasibility of surface-enhanced Raman spectroscopy coupled with a filter membrane and advanced multivariate data analysis on identifying and differentiating benign and malignant thyroid tumors from blood plasma. Patients and Methods: We proposed a membrane filter SERS technology for the differentiation between benign thyroid tumor and thyroid cancer. That is to say, by using filter membranes with optimal pore size, the blood plasma samples from thyroid tumor patients were pretreated with the macromolecular proteins being filtered out prior to SERS measurement. The SERS spectra of blood plasma ultrafiltrate obtained using filter membranes from 102 patients with thyroid tumors (70 thyroid cancers and 32 benign thyroid tumors) were then analyzed and compared. Two multivariate statistical analyses, principal component analysis-linear discriminate analysis (PCA-LDA) and Lasso-partial least squares-discriminant analysis (Lasso-PLS-DA), were performed on the SERS spectral data after background subtraction and normalization, as well as the first derivative processing, to analyze and compare the differential diagnosis of benign thyroid tumors and thyroid cancer. Results: SERS measurements were performed in blood plasma acquired from a total of 102 thyroid tumor patients (benign thyroid tumor N=32; thyroid cancer N=70). By using filter membranes, the macromolecular proteins in blood plasma were effectively filtered out to yield high-quality SERS spectra. 84.3% discrimination accuracy between benign and malignant thyroid tumor was achieved using PCA-LDA method, while Lasso-PLS-DA yields a discrimination accuracy of 90.2%. Conclusion: Our results demonstrate that SERS spectroscopy, coupled with ultrafiltration and multivariate analysis has the potential of providing a non-invasive, rapid, and objective detection and differentiation of benign and malignant thyroid tumors.


Assuntos
Plasma/química , Análise Espectral Raman/métodos , Neoplasias da Glândula Tireoide/sangue , Ultrafiltração/métodos , Adulto , Diagnóstico Diferencial , Análise Discriminante , Humanos , Membranas Artificiais , Nanopartículas Metálicas/química , Pessoa de Meia-Idade , Análise Multivariada , Análise de Componente Principal , Estudo de Prova de Conceito , Prata/química , Neoplasias da Glândula Tireoide/diagnóstico , Neoplasias da Glândula Tireoide/patologia , Ultrafiltração/instrumentação
19.
Meat Sci ; 165: 108136, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32272341

RESUMO

In this study, pH, meat color analysis, microbial counts and Raman spectroscopic data were obtained from beef steaks stored at 4 °C for up to 21 days using two different packaging methods: vacuum (VP) and modified atmosphere packaging (MAP). Models using partial least square regression (PLSR), indicated that Raman spectroscopy was able to predict total viable counts (TVC) and lactic acid bacteria (LAB) measured at 21d post mortem (TVC in VP: R2cv = 0.99, RMSEP = 0.61; TVC in MAP: R2cv = 0.90, RMSEP = 0.38; LAB in VP: R2cv = 0.99, RMSEP = 0.54; LAB in MAP: R2cv = 0.75, RMSEP = 0.60). The results of this study demonstrate that Raman spectroscopy may have potential for the rapid determination of meat spoilage.


Assuntos
Embalagem de Alimentos/métodos , Carne Vermelha/análise , Análise Espectral Raman/métodos , Animais , Bovinos , Contagem de Colônia Microbiana , Cor , Armazenamento de Alimentos/métodos , Concentração de Íons de Hidrogênio , Lactobacillales/crescimento & desenvolvimento , Músculo Esquelético , Carne Vermelha/microbiologia , Vácuo
20.
J Phys Chem Lett ; 11(8): 2864-2869, 2020 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-32212699

RESUMO

A complete understanding of a photochemical reaction dynamics begins with real-time measurements of both electronic and vibrational structures of photoexcited molecules. Time-resolved impulsive stimulated Raman spectroscopy (TR-ISRS) with femtosecond actinic pump, Raman pump, and Raman probe pulses is one of the incisive techniques enabling one to investigate the structural changes of photoexcited molecules. Herein, we demonstrate that such femtosecond TR-ISRS is feasible with synchronized triple mode-locked lasers without using any time-delay devices. Taking advantage of precise control of the three repetition rates independently, we could achieve automatic scanning of two delay times between the three pulses, which makes both rapid data acquisition and wide dynamic range measurement of the fifth-order TR-ISRS signal achievable. We thus anticipate that the present triple mode-locked laser-based TR-ISRS technique will be of critical use for long-term monitoring of photochemical reaction dynamics in condensed phases and biological systems.


Assuntos
Lasers , Análise Espectral Raman/métodos , Análise Espectral Raman/instrumentação , Fatores de Tempo
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