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1.
Nat Commun ; 12(1): 159, 2021 01 08.
Artículo en Inglés | MEDLINE | ID: mdl-33420035

RESUMEN

The quantitative label-free detection of neurotransmitters provides critical clues in understanding neurological functions or disorders. However, the identification of neurotransmitters remains challenging for surface-enhanced Raman spectroscopy (SERS) due to the presence of noise. Here, we report spread spectrum SERS (ss-SERS) detection for the rapid quantification of neurotransmitters at the attomolar level by encoding excited light and decoding SERS signals with peak autocorrelation and near-zero cross-correlation. Compared to conventional SERS measurements, the experimental result of ss-SERS shows an exceptional improvement in the signal-to-noise ratio of more than three orders of magnitude, thus achieving a high temporal resolution of over one hundred times. The ss-SERS measurement further allows the attomolar SERS detection of dopamine, serotonin, acetylcholine, γ-aminobutyric acid, and glutamate without Raman reporters. This approach opens up opportunities not only for investigating the early diagnostics of neurological disorders or highly sensitive biomedical SERS applications but also for developing low-cost spectroscopic biosensing applications.


Asunto(s)
Técnicas Biosensibles/métodos , Neurotransmisores/análisis , Espectrometría Raman/métodos , Estudios de Factibilidad , Oro/química , Nanopartículas del Metal/química
2.
Food Chem ; 346: 128956, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33418414

RESUMEN

In this study, the rice glutelin (RG)/sugar beet pectin (SBP) composite gels were prepared by laccase induced cross-linking and subsequent heat treatment, and the effects of different calcium ion concentrations (0-400 mM) on the gelation, structural properties and microstructure of the RG/SBP composite gels were investigated. The results showed that the addition of 200 mM calcium ion could improve the rheological, textural properties and water holding capacity of the RG/SBP composite gels. The addition of SBP and calcium ions enhanced the hydrophobic interaction between RG molecules, thereby increased the gel properties of RG. The changes in Raman spectroscopy reflected the positive effect of the addition of SBP and calcium ions on the formation of a denser and more homogeneous protein gel, as evidenced by the results of scanning electron microscopy. Overall, SBP and calcium ions could be applied to the plant protein gel systems as gel-strengthening agents.


Asunto(s)
Beta vulgaris/química , Geles/química , Glútenes/química , Oryza/química , Pectinas/química , Beta vulgaris/metabolismo , Lacasa/metabolismo , Microscopía Electrónica de Rastreo , Oryza/metabolismo , Concentración Osmolar , Reología , Solubilidad , Espectrometría de Fluorescencia , Espectrometría Raman , Agua/química
3.
Medicine (Baltimore) ; 100(1): e23900, 2021 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-33429751

RESUMEN

BACKGROUND: We aim to evaluate the efficiency of Raman spectroscopy (RS) in diagnosing suspected patients with intrahepatic cholangiocarcinoma (ICC), manifested by diagnostic sensitivity, specificity, and accuracy. METHODS: We will research widely the articles concerning the use of RS in ICC through authenticated database including PubMed/Medline, EMBASE, Web of Science, Ovid, Web of Knowledge, Cochrane Library, and CNKI between January 2012 and November 2020, retrieving at least 1500 spectra with strict criteria. This study will be carried out in accordance to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We are going to summarize the test performance using random effects models. RESULTS: Based on the pooled sensitivity, specificity, and diagnostic accuracy, we intend to provide the relative diagnostic efficiency in ICC through RS. CONCLUSION: Through this systematic review and meta-analysis, we intend to provide the pooled sensitivity, specificity and diagnostic accuracy of RS in the diagnosis of suspected ICC. Other parameters like positive likelihood ratios (LR), negative LR, diagnostic odds ratio (DOR), and area under curve (AUC) of the summary receiver operating characteristics (SROC) curve will also be calculated and related figures will be drawn to help illustrate the efficacy of RS in the diagnosis of ICC.


Asunto(s)
Colangiocarcinoma/diagnóstico , Protocolos Clínicos , Espectrometría Raman/normas , Área Bajo la Curva , Colangiocarcinoma/diagnóstico por imagen , Humanos , Metaanálisis como Asunto , Curva ROC , Sensibilidad y Especificidad , Espectrometría Raman/métodos , Revisiones Sistemáticas como Asunto
4.
Nat Commun ; 12(1): 667, 2021 01 28.
Artículo en Inglés | MEDLINE | ID: mdl-33510173

RESUMEN

Biological organic-inorganic materials remain a popular source of inspiration for bioinspired materials design and engineering. Inspired by the self-assembling metal-reinforced mussel holdfast threads, we tested if metal-coordinate polymer networks can be utilized as simple composite scaffolds for direct in situ crosslink mineralization. Starting with aqueous solutions of polymers end-functionalized with metal-coordinating ligands of catechol or histidine, here we show that inter-molecular metal-ion coordination complexes can serve as mineral nucleation sites, whereby significant mechanical reinforcement is achieved upon nanoscale particle growth directly at the metal-coordinate network crosslink sites.


Asunto(s)
Bivalvos/química , Reactivos de Enlaces Cruzados/química , Hidrogeles/química , Metales/química , Minerales/química , Polímeros/química , Animales , Catecoles/química , Hierro/química , Microscopía Electrónica de Transmisión , Nanocompuestos/química , Nanocompuestos/ultraestructura , Dispersión del Ángulo Pequeño , Espectrometría Raman , Difracción de Rayos X
5.
Commun Biol ; 4(1): 70, 2021 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-33452375

RESUMEN

The proliferation and transmission of viruses has become a threat to worldwide biosecurity, as exemplified by the current COVID-19 pandemic. Early diagnosis of viral infection and disease control have always been critical. Virus detection can be achieved based on various plasmonic phenomena, including propagating surface plasmon resonance (SPR), localized SPR, surface-enhanced Raman scattering, surface-enhanced fluorescence and surface-enhanced infrared absorption spectroscopy. The present review covers all available information on plasmonic-based virus detection, and collected data on these sensors based on several parameters. These data will assist the audience in advancing research and development of a new generation of versatile virus biosensors.


Asunto(s)
/diagnóstico , Pandemias , Espectrometría Raman/métodos , Resonancia por Plasmón de Superficie/métodos , /virología , Humanos , Nanoestructuras/química , Espectrometría de Fluorescencia/métodos , Espectrofotometría Infrarroja/métodos
6.
Anal Chem ; 93(4): 2053-2061, 2021 02 02.
Artículo en Inglés | MEDLINE | ID: mdl-33406834

RESUMEN

Recurrent nasopharyngeal carcinoma (NPC) is the main cause of poor prognosis for NPC patients after chemo- and radiotherapies. Subsequent long-term follow-ups of post-treatment patients are crucial for the early discovery of tumor recurrence with timely intervention. Current clinical imaging methods based on tissue morphology encounter difficulties in differentiating recurrent tumors from post-treatment inflammation and fibrosis. In this work, we apply a unique fiberoptic Raman endoscopy technique to address the challenges for label-free follow-up surveying of post-treatment NPC patients and accurate detection of tumor recurrence. Significant Raman spectral differences can be observed among normal, NPC, and nonrecurring post-treatment patients. Raman endoscopy provides diagnostic accuracy of 100% for detecting recurrent NPC from early post-treatment inflammation and diagnostic accuracy of 98.21% for separating recurrent NPC from long-term post-treatment fibrosis. Further quantitative Raman modeling on in vivo nasopharyngeal tissue Raman data acquired unveils the changes of major tissue biochemicals (e.g., triolein, elastin, keratin, fibrillar collagen, and type IV collagen) associated with primary NPC and post-treatment recurrent NPC tissue compared to normal nasopharyngeal tissue. This work demonstrates that fiberoptic Raman endoscopy can be a clinically powerful diagnostic tool for rapid, label-free post-treatment surveying and recurrent tumor detection in NPC patients at the molecular level.


Asunto(s)
Endoscopía/instrumentación , Endoscopía/métodos , Tecnología de Fibra Óptica , Carcinoma Nasofaríngeo/terapia , Neoplasias Nasofaríngeas/terapia , Espectrometría Raman , Estudios de Casos y Controles , Estudios de Seguimiento , Humanos , Carcinoma Nasofaríngeo/patología , Neoplasias Nasofaríngeas/patología
8.
Anal Chem ; 93(4): 1951-1956, 2021 02 02.
Artículo en Inglés | MEDLINE | ID: mdl-33464044

RESUMEN

Recent developments in molecular spectroscopy have widened the scope of surface-enhanced Raman spectroscopy (SERS) for detection of nucleic acids. In order to solve the interference of impurity signals in SERS analysis that hamper the reliable detection of DNA, Ag nanoparticles modified with thiosulfate ions were used to obtain SERS signals of DNA molecules in aqueous solutions, which showed good reproducibility. By using thiosulfate ions and calcium ions as aggregating agents, this method not only eliminated the influence of citrate on DNA signals completely but also obtained the signals for all bases indiscriminately, including the T base that was considered to have low Raman activity. Subsequently, the base stacking rule was used to identify mutations arising from C/T transition. It further identified the mutation sites of single-base C/T transition using this platform for the first time. This method has wide application prospects in DNA analysis, DNA sequencing, and genetic testing.


Asunto(s)
ADN/química , Nanopartículas del Metal/química , Plata/química , Espectrometría Raman/métodos , Tiosulfatos/química , Mutación
9.
Spectrochim Acta A Mol Biomol Spectrosc ; 244: 118825, 2021 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-32866803

RESUMEN

Novel antiviral active molecule 2- [(4,6-diaminopyrimidin-2-yl)sulfanyl]-N-(4-fluoro- phenyl)acetamide has been synthesised and characterized by FT-IR and FT-Raman spectra. The equilibrium geometry, natural bond orbital calculations and vibrational assignments have been carried out using density functional B3LYP method with the 6-311G++(d,p) basis set. The complete vibrational assignments for all the vibrational modes have been supported by normal coordinate analysis, force constants and potential energy distributions. A detailed analysis of the intermolecular interactions has been performed based on the Hirshfeld surfaces. Drug likeness has been carried out based on Lipinski's rule and the absorption, distribution, metabolism, excretion and toxicity of the title molecule has been calculated. Antiviral potency of 2- [(4,6-diaminopyrimidin-2-yl)sulfanyl]-N-(4-fluoro-phenyl) acetamide has been investigated by docking against SARS-CoV-2 protein. The optimized geometry shows near-planarity between the phenyl ring and the pyrimidine ring. Differences in the geometries due to the substitution of the most electronegative fluorine atom and intermolecular contacts due to amino pyrimidine were analyzed. NBO analysis reveals the formation of two strong stable hydrogen bonded N-H···N intermolecular interactions and weak intramolecular interactions C-H···O and N-H···O. The Hirshfeld surfaces and consequently the 2D-fingerprint confirm the nature of intermolecular interactions and their quantitative contributions towards the crystal packing. The red shift in N-H stretching frequency exposed from IR substantiate the formation of N-H···N intermolecular hydrogen bond. Drug likeness and absorption, distribution, metabolism, excretion and toxicity properties analysis gives an idea about the pharmacokinetic properties of the title molecule. The binding energy -8.7 kcal/mol of the nonbonding interaction present a clear view that 2- [(4,6-diaminopyrimidin-2-yl)sulfanyl]-N-(4-fluoro- phenyl) acetamide can irreversibly interact with SARS-CoV-2 protease.


Asunto(s)
Acetamidas/química , Antivirales/química , Betacoronavirus/efectos de los fármacos , Infecciones por Coronavirus/tratamiento farmacológico , Pandemias , Neumonía Viral/tratamiento farmacológico , Inhibidores de Proteasas/química , Pirimidinas/química , Proteínas no Estructurales Virales/antagonistas & inhibidores , Acetamidas/farmacocinética , Antivirales/farmacocinética , Betacoronavirus/enzimología , Cristalografía por Rayos X , Cisteína Endopeptidasas , Humanos , Modelos Moleculares , Simulación del Acoplamiento Molecular , Estructura Molecular , Dinámicas no Lineales , Inhibidores de Proteasas/farmacocinética , Conformación Proteica , Pirimidinas/farmacocinética , Teoría Cuántica , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría Raman , Termodinámica , Vibración
10.
Food Chem ; 339: 127843, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-32889134

RESUMEN

Thiabendazole (TBZ) is extensively used in agriculture to control molds; residue of TBZ may pose a threat to humans. Herein, surface-enhanced Raman spectroscopy (SERS) coupled variable selected regression methods have been proposed as simple and rapid TBZ quantification technique. The nonlinear correlation between the TBZ and SERS data was first diagnosed by augmented partial residual plots method and calculated by runs test. Au@Ag NPs with strong enhancement factor (EF = 4.07 × 106) of Raman signal was used as SERS active material to collect spectra from TBZ. Subsequently, three nonlinear regression models were comparatively investigated and the competitive adaptive reweighted sampling-extreme learning machine (CARS-ELM) achieved a higher correlation coefficient (Rp2 = 0.9406) and the lower root-mean-square-error of prediction (RMSEP = 0.5233 mg/L). Finally, recoveries of TBZ in apple samples were 83.02-93.54% with relative standard deviation (RSD) value < 10%. Therefore, SERS coupled CARS-ELM could be employed as a rapid and sensitive approach for TBZ detection in Fuji apples.


Asunto(s)
Algoritmos , Análisis de los Alimentos/métodos , Malus/química , Espectrometría Raman/métodos , Tiabendazol/análisis , Análisis de los Alimentos/estadística & datos numéricos , Contaminación de Alimentos/análisis , Fungicidas Industriales/análisis , Humanos , Nanopartículas del Metal/química
11.
Food Chem ; 338: 128115, 2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33092006

RESUMEN

Citrus flavonoids consist of diverse analogs and possess various health-promoting effects dramatically depending on their chemical structures. Since different flavonoids usually co-exist in real samples, it's necessary to develop rapid and efficient methods for simultaneous determination of multiple flavonoids. Thin layer chromatography combined with surface enhanced Raman spectroscopy (TLC-SERS) was established to simultaneously separate and detect 14 citrus flavonoids for the first time. These target compounds could be characterized and discriminated when paired with SERS at 6-500 times greater the sensitivity than TLC alone. TLC-SERS exhibited high recovery rates (91.5-121.7%) with relative standard deviation lower than 20.8%. Moreover, the established TLC-SERS method was successfully used to simultaneously detect multiple flavonoids in real samples, which exhibited comparable accuracy to high performance liquid chromatography with shorter analytical time (10 vs 45 min). All the results demonstrated that this could be a promising method for simultaneous, rapid, sensitive and accurate detection of flavonoids.


Asunto(s)
Cromatografía en Capa Delgada/métodos , Citrus/química , Flavonoides/análisis , Análisis de los Alimentos/métodos , Espectrometría Raman/métodos , Cromatografía Líquida de Alta Presión , Propiedades de Superficie , Factores de Tiempo
12.
Food Chem ; 339: 128085, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33152876

RESUMEN

Due to the excessive use of fungicides, pesticide residues have become a growing concern in recent years. Herein, we demonstrated an easy-prepared and low-cost surface enhanced Raman Scattering (SERS) chip composed of 3D silver microspheres (AgMSs) pattern for the quantitative testing of carbendazim in Chinese tea. Compared with the common monolayer SERS substrate, the 3D patterns formed by self-assembly AgMSs with fine nanostructure can offer much more aggregation-induced hotspots and generate strong 3D synergetic effects. Furthermore, when the thickness of the 3D pattern exceeded 6 µm, we replaced the conductive supporting coatings using the glass slides to reduce the cost without any impact on SERS properties. The prepared 3D chips achieved the determination of carbendazim within the linear range of 0.1-10 mg/L and the detection limit of 0.01 mg/L. It is simple and sensitive enough for the detection of most pesticide residues or other harmful organic molecules in our food or environment.


Asunto(s)
Bencimidazoles/análisis , Carbamatos/análisis , Contaminación de Alimentos/análisis , Microesferas , Residuos de Plaguicidas/análisis , Plata/química , Espectrometría Raman , Té/química , Bencimidazoles/química , Carbamatos/química , Color , Humanos , Límite de Detección , Residuos de Plaguicidas/química , Factores de Tiempo
13.
J Environ Sci (China) ; 100: 11-17, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33279023

RESUMEN

Monolayer-ordered gold nanoring arrays were prepared by ion-sputtering method and used as surface enhanced Raman spectroscopy (SERS) substrates to test the individual atmospheric aerosols particle. Compared to other methods used for testing atmospheric aerosols particles, the collection and subsequent detection in our work is performed directly on the gold nanoring SERS substrate without any treatment of the analyte. The SERS performance can be tuned by changing the depth of the gold nanoring cavity as originating from coupling of dipolar modes at the inner and outer surfaces of the nanorings. The electric field exhibits uniform enhancement and polarization in the ordered Au nanoring substrate, which can improve the accuracy for detecting atmospheric aerosol particles. Combined with Raman mapping, the information about chemical composition of individual atmospheric aerosols particle and distribution of specific components can be presented visually. The results show the potential of SERS in enabling improved analysis of aerosol particle chemical composition, mixing state, and other related physicochemical properties.


Asunto(s)
Nanopartículas del Metal , Espectrometría Raman , Aerosoles , Oro
14.
Med Hypotheses ; 146: 110356, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33342643

RESUMEN

Corona Virus Disease 19 (COVID-19) pandemic has created an alarming situation across the globe. Varieties of diagnostic protocols are being developed for the diagnosis of COVID-19. Many of these diagnostic protocols however, have limitations such as for example unacceptable no of false-positive and false-negative cases, particularly during the early stages of infection. At present, the real-time (quantitative) reverse transcriptase-polymerase chain reaction (RT-PCR) is considered the gold standard for COVID-19 diagnosis. However, RT-PCR based tests are complex, expensive, time consuming and involve pre-processing of samples. A swift, sensitive, inexpensive protocol for mass screening is urgently needed to contain this pandemic. There is urgent need to harness new powerful technologies for accurate detection not only of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) but also combating the emergence of pandemics of new viruses as well. To overcome the current challenges, the authors propose a diagnostic protocol based on Surface-enhanced Raman Spectroscopy (SERS) coupled with microfluidic devices containing integrated microchannels functionalized either with vertically aligned Au/Ag coated carbon nanotubes or with disposable electrospun micro/nano-filter membranes. These devices have the potential to successfully trap viruses from diverse biological fluids/secretions including saliva, nasopharyngeal, tear etc. These can thus enrich the viral titre and enable accurate identification of the viruses from their respective Raman signatures. If the device is successfully developed and proven to detect target viruses, it would facilitate rapid screening of symptomatic as well as asymptomatic individuals of COVID-19. This would be a valuable diagnostic tool not only for mass screening of current COVID-19 pandemic but also in viral pandemic outbreaks of future.


Asunto(s)
/instrumentación , Dispositivos Laboratorio en un Chip , Espectrometría Raman/métodos , /métodos , Dimetilpolisiloxanos , Diseño de Equipo , Humanos , Nanopartículas del Metal , Nanotubos de Carbono , Pandemias , /aislamiento & purificación
15.
Anal Chem ; 93(3): 1326-1332, 2021 01 26.
Artículo en Inglés | MEDLINE | ID: mdl-33347264

RESUMEN

Conventional paper lateral flow assays have low sensitivity and suffer from severe interference from complex human fluid sample matrices, which prevents their practical application in the testing of whole blood samples in the point-of-care settings. To solve this problem, gold nanostar@Raman reporter@silica-sandwiched nanoparticles have been developed as the surface-enhanced Raman scattering (SERS) probes for sensing transduction; and a functionalized filter membrane assembly has been designed and constructed in the paper-based lateral flow strip (PLFS) as a built-in plasma separation unit. In this "on-strip" plasma separation unit, three layers of filter membranes are stacked and surface-modified to maximize the separation efficiency and the plasma yield. As a result, the integrated PLFS has been successfully used for the detection of carcinoembryonic antigen (CEA) in 30 µL of whole blood with the assistance of a portable Raman reader, achieving a limit of detection of 1.0 ng mL-1. In short, this report presents an inexpensive, disposable, portable, and field-deployable paper-based device as a general point-of-care testing tool for protein biomarker detection in a drop of whole blood.


Asunto(s)
Antígeno Carcinoembrionario/sangre , Tiras Reactivas/química , Oro/química , Humanos , Nanopartículas del Metal/química , Papel , Dióxido de Silicio/química , Espectrometría Raman
16.
Anal Chem ; 93(3): 1466-1471, 2021 01 26.
Artículo en Inglés | MEDLINE | ID: mdl-33347282

RESUMEN

The expression of microRNAs (miRNAs) is critical in gene regulation and has been counted into disease diagnosis marks. Precise imaging and quantification of miRNAs could afford the important information for clinical diagnosis. Here, two smart binary star ratio (BSR) probes were designed and constructed, and miRNA triggered the connection of the binary star probes and the reciprocal changes of dual signals in living cells. This multifunctional probe integrates fluorescence and surface enhanced Raman scattering (SERS) imaging, with enzyme-free numerator signal amplification for dual-mode imaging and dual-signal quantitative analysis of miRNA. First, compared with the single-mode ratio imaging method, using fluorescence-SERS complementary ratio imaging, this probe enables more accurate imaging contrast for direct visualization signal changes in living cells. Multiscale information about the dynamic behavior of miRNA and the probe is acquired. Next, via SERS reverse signal ratio response and a novel enzyme-free numerator signal amplification, the amplified signal and reduced black value were achieved in the quantification of miRNA. More importantly, BSR probes showed good stability in cells and were successfully used for accurate tracing and quantification of miR-203 from MCF-7 cells. Therefore, the reported BSR probe is a potential tool for the reliable monitoring of biomolecule dynamics in living cells.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Colorantes Fluorescentes/química , MicroARNs/análisis , Humanos , Células MCF-7 , Imagen Óptica , Espectrometría Raman
17.
Anal Chem ; 93(3): 1443-1450, 2021 01 26.
Artículo en Inglés | MEDLINE | ID: mdl-33369381

RESUMEN

A prophage comprises a bacteriophage genome that has integrated into a host bacterium's DNA, which generally permits the cell to grow and divide normally. However, the prophage can be induced by various stresses, or induction can occur spontaneously. After prophage induction, viral replication and production of endolysins begin until the cell lyses and phage particles are released. However, the heterogeneity of prophage induction and lysis of individual cells in a population and the dynamics of a cell undergoing lysis by prophage induction have not been fully characterized. Here, we used Raman tweezers and live-cell phase-contrast microscopy to characterize the Raman spectral and cell length changes that occur during the lysis of individual Bacillus subtilis cells from spores that carry PBSX prophage during spores' germination, outgrowth, and then vegetative growth. Major findings of this work are as follows: (i) After addition of xylose to trigger prophage induction, the intensities of Raman spectral bands associated with nucleic acids of single cells in induced cultures gradually fell to zero, in contrast to the much smaller changes in protein band intensities and no changes in nucleic acid bands in uninduced cultures; (ii) the nucleic acid band intensities from an individual induced cell exhibited a rapid decrease, following a long lag period; (iii) after the addition of nutrient-rich medium with xylose, single spores underwent a long period (228 ± 41.4 min) for germination, outgrowth, and vegetative growth, followed by a short period of cell burst in 1.5 ± 0.8 min at a cell length of 8.2 ± 5.5 µm; (iv) the latent time (Tlatent) between the addition of xylose and the start of cell burst was heterogeneous in cell populations; however, the period (ΔTburst) from the latent time to the completion of cell lysis was quite small; (v) in a poor medium with l-alanine alone, addition of xylose caused prophage induction following spore germination but with longer Tlatent and ΔTburst times and without cell elongation; (vi) spontaneous prophage induction and lysis of individual cells from spores in a minimal nutrient medium were observed without xylose addition, and cell length prior to cell lysis was ∼4.1 µm, but spontaneous prophage induction was not observed in a rich medium; (vii) in a rich medium, addition of xylose at a time well after spore germination and outgrowth significantly shortened the average Tlatent time. The results of this study provide new insights into the heterogeneity and dynamics of lysis of individual B. subtilis cells derived from spores upon prophage induction.


Asunto(s)
Bacillus subtilis/citología , Análisis de la Célula Individual , Esporas Bacterianas/crecimiento & desarrollo , Bacillus subtilis/metabolismo , Microscopía de Contraste de Fase , Pinzas Ópticas , Espectrometría Raman , Esporas Bacterianas/química , Esporas Bacterianas/metabolismo
18.
Anal Chem ; 93(3): 1569-1577, 2021 01 26.
Artículo en Inglés | MEDLINE | ID: mdl-33369400

RESUMEN

Herein, an interference-free surface-enhanced Raman scattering (SERS) platform with a "sandwich" structure has been developed for reliable detection and photothermal killing of bacteria with whole blood as the real sample. The multifunctional platform comprised a plasmonic gold film (pAu) functionalized with bacteria-capturing units of 4-mercaptophenylboronic acid and internal reference of 4-mercaptobenzonitrile as the SERS substrate and vancomycin-modified core (gold)-shell (Prussian blue) nanoparticles (Au@PB@Van NPs) as the SERS tag. The detected SERS signals were from the Raman-silent region where no background signals occurred from biological sources, eliminating the interference and improving the detection sensitivity and accuracy. As a proof-of-concept, model bacterial strain, Staphylococcus aureus, was captured and detected in the whole blood samples. Furthermore, high antibacterial efficiency of approximately 100% was reached under the synergistic photothermal effect from pAu and Au@PB@Van NPs. This study provides a new avenue for bacteria detection in real samples and their subsequent in situ elimination.


Asunto(s)
Antibacterianos/química , Bacillus subtilis/aislamiento & purificación , Escherichia coli/aislamiento & purificación , Salmonella typhimurium/aislamiento & purificación , Staphylococcus aureus/aislamiento & purificación , Vancomicina/química , Antibacterianos/farmacología , Bacillus subtilis/efectos de los fármacos , Ácidos Borónicos/química , Escherichia coli/efectos de los fármacos , Oro/química , Humanos , Nitrilos/química , Tamaño de la Partícula , Procesos Fotoquímicos , Salmonella typhimurium/efectos de los fármacos , Espectrometría Raman , Staphylococcus aureus/efectos de los fármacos , Compuestos de Sulfhidrilo/química , Propiedades de Superficie , Temperatura , Vancomicina/farmacología
19.
Food Chem ; 340: 127930, 2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-32871357

RESUMEN

It has been remained a challenge to detect trace formaldehyde in complex samples, such as rice flour and duck blood products. In this study, a purge-trap device was designed and used for volatile target detection, which avoided interference adsorptions on enhanced particle surfaces during subsequent surface-enhanced Raman spectroscopy (SERS) analysis. The device produced a low detection limit for formaldehyde of 1 × 10-4 µg/mL in the concentration ranges of 4 × 10-3-4 µg/mL and 1 × 10-4-3 × 10-3 µg/mL. In the process of the detection of duck blood and rice flour, partial least squares regression (PLSR) was adopted for sample analysis. The formaldehyde concentration was calculated and compared to the actual value from the above model with R2 of 0.97, which indicated high accuracy and stability. These results suggested that the proposed method was reliable and suitable for rapid analysis of trace formaldehyde in real products.


Asunto(s)
Análisis de los Alimentos/métodos , Formaldehído/análisis , Espectrometría Raman/métodos , Adsorción , Animales , Patos , Harina , Análisis de los Alimentos/estadística & datos numéricos , Contaminación de Alimentos , Análisis de los Mínimos Cuadrados , Límite de Detección , Nanopartículas del Metal/química , Productos Avícolas/análisis
20.
Food Chem ; 336: 127707, 2021 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-32763737

RESUMEN

Anthocyanins (ACNs) are naturally derived colorants and antioxidants added to manufactured foods. ACNs were encapsulated in nanocomplexes with chitosan hydrochloride (CHC), carboxymethyl chitosan (CMC) and whey protein isolate (WPI). The ACN-loaded CHC/CMC-WPI nanocomplexes (ACN-CHC/CMC-WPI) showed a preferred particle size (332.20 nm) and zeta potential (+23.65 mV) and a high encapsulation efficiency (60.70%). ACN-CHC/CMC-WPI nanocomplexes exhibited a smooth spherical shape by transmission electron microscopy. Fourier transform infrared (FT-IR) and Raman spectroscopy confirmed interactions between the ACNs and the encapsulation materials (CHC/CMC-WPI). The nanocomplexes or the nanocomplexes incorporated into coffee beverage better protected ACNs at high temperature compared to the unencapsulated ACNs. In simulated gastrointestinal fluids, the ACNs in the ACN-CHC/CMC-WPI were more stable and more slower released over time. The nanocomplexes maintained high DPPH and hydroxyl free radical scavenging activities. This study indicated that CHC/CMC-WPI nanocomplexes can improve the thermal stability and slow the release of ACNs added to food products.


Asunto(s)
Antocianinas/farmacocinética , Quitosano/química , Café/química , Nanoestructuras/química , Proteína de Suero de Leche/química , Antioxidantes/química , Quitosano/análogos & derivados , Digestión , Humanos , Microscopía Electrónica de Transmisión , Tamaño de la Partícula , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría Raman , Temperatura
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