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1.
J Cell Sci ; 135(5)2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33975358

RESUMO

Lipid droplets (LDs) are lipid-rich organelles universally found in most cells. They serve as a key energy reservoir, actively participate in signal transduction and dynamically communicate with other organelles. LD dysfunction has been associated with a variety of diseases. The content level, composition and mobility of LDs are crucial for their physiological and pathological functions, and these different parameters of LDs are subject to regulation by genetic factors and environmental inputs. Coherent Raman scattering (CRS) microscopy utilizes optical nonlinear processes to probe the intrinsic chemical bond vibration, offering label-free, quantitative imaging of lipids in vivo with high chemical specificity and spatiotemporal resolution. In this Review, we provide an overview over the principle of CRS microscopy and its application in tracking different parameters of LDs in live cells and organisms. We also discuss the use of CRS microscopy in genetic screens to discover lipid regulatory mechanisms and in understanding disease-related lipid pathology.


Assuntos
Microscopia , Análise Espectral Raman , Biologia , Gotículas Lipídicas , Lipídeos
2.
Anal Chim Acta ; 1178: 338800, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34482860

RESUMO

Accurate quantification of multiple miRNAs biomarkers in body fluid is still a challenge for early screening of cancer. Herein, by catalytic hairpin assembly as a signal amplification strategy, we designed a novel surface-enhanced Raman scattering (SERS)-lateral flow assay (LFA) strip for ultrasensitive detection of miR-21 and miR-196a-5p in non-small cell lung cancer (NSCLC) urine on a single test (T) line. 4-mercaptobenzoic acid or 5,5'-dithiobis-2-nitrobenzoic acid as Raman molecules was labeled and two hairpin DNA sequence was modified gold nanocages (GNCs) were designed as two SERS tags. Through target miRNA-triggered catalytic hairpin assembly (CHA), the double-stranded DNAs (H1-H2 complex) formed by SERS tags and the related hairpin-structured DNA sequence 2 (H2) were immobilized on a single T line of SERS-LFA strip. This generated abundant "hot spots" because of the formation of numerous H1-H2 complex thus facilitated the SERS measurement. Through this method, two kinds of miRNAs were analyzed, resulting in limits of detection of 2.08 pM and 3.31 pM for miR-21 in PBS buffer and human urine, 1.77 pM and 2.18 pM for miR-196a-5p in PBS buffer and human urine. Significantly, the SERS-LFA strip exhibited high specificity and good repeatability toward miRNAs. The whole detection time was only 30 min, which means that the high detection efficiency of the strip. The clinical feasibility of the proposed method was also evaluated by detecting the levels of miR-21 and miR-196a-5p in urine samples from NSCLC patients and healthy subjects. The developed SERS-LFA strip has wide application prospect in biomedical research, drug development and early clinical diagnosis.


Assuntos
Técnicas Biossensoriais , Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Nanopartículas Metálicas , MicroRNAs , Carcinoma Pulmonar de Células não Pequenas/genética , Ouro , Humanos , Limite de Detecção , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/genética , MicroRNAs/genética , Análise Espectral Raman
3.
Anal Chim Acta ; 1177: 338784, 2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34482902

RESUMO

In this study, two approaches to salivary glands studies are presented: Raman imaging (RI) of tissue cross-section and surface-enhanced Raman spectroscopy (SERS) of tissue homogenates prepared according to elaborated protocol. Collected and analyzed data demonstrate the significant potential of SERS combined with multivariate analysis for distinguishing carcinoma or tumor from the normal salivary gland tissues as a rapid, label-free tool in cancer detection in oncological diagnostics. Raman imaging allows a detailed analysis of the cell wall's chemical composition; thus, the compound's distribution can be semi-quantitatively analyzed, while SERS of tissue homogenates allow for detailed analysis of all moieties forming these tissues. In this sense, SERS is more sensitive and reliable to study any changes in the area of infected tissues. Principal component analysis (PCA), as an unsupervised pattern recognition method, was used to identify the differences in the SERS salivary glands homogenates. The partial least squares-discriminant analysis (PLS-DA), the supervised pattern classification technique, was also used to strengthen further the computed model based on the latent variables in the SERS spectra. Moreover, the chemometric quantification of obtained data was analyzed using principal component regression (PCR) multivariate calibration. The presented data prove that the PCA algorithm allows for 91% in seven following components and the determination between healthy and tumor salivary gland homogenates. The PCR and PLS-DA methods predict 90% and 95% of the variance between the studied groups (in 6 components and 4 factors, respectively). Moreover, according to calculated RMSEC (RMSEP), R2C (R2P) values and correlation accuracy (based on the ROC curve), the PLS-DA model fits better for the studied data. Thus, SERS methods combined with PLS-DA analysis can be used to differentiate healthy, neoplastic, and mixed tissues as a competitive tool in relation to the commonly used method of histopathological staining of tumor tissue.


Assuntos
Carcinoma , Análise Espectral Raman , Análise Discriminante , Humanos , Análise dos Mínimos Quadrados , Análise de Componente Principal
4.
J Nanobiotechnology ; 19(1): 273, 2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34496881

RESUMO

The control of contagious or refractory diseases requires early, rapid diagnostic assays that are simple, fast, and easy-to-use. Here, easy-to-implement CRISPR/Cas12a-based diagnostic platform through Raman transducer generated by Raman enhancement effect, term as SERS-CRISPR (S-CRISPR), are described. The S-CRISPR uses high-activity noble metallic nanoscopic materials to increase the sensitivity in the detection of nucleic acids, without amplification. This amplification-free platform, which can be performed within 30-40 min of incubation time, is then used for detection of SARS-CoV-2 derived nucleic acids in RNA extracts obtained from nasopharyngeal swab specimens (n = 112). Compared with the quantitative reverse transcription polymerase chain reaction (RT-qPCR), the sensitivity and specificity of S-CRISPR reaches 87.50% and 100%, respectively. In general, the S-CRISPR can rapidly identify the RNA of SARS-CoV-2 RNA without amplification and is a potential strategy for nucleic acid point of care test (POCT).


Assuntos
Sistemas CRISPR-Cas/genética , Técnicas de Amplificação de Ácido Nucleico , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Análise Espectral Raman , COVID-19/diagnóstico , COVID-19/virologia , Regulação Fúngica da Expressão Gênica , Genes Virais , Humanos , RNA Viral/análise , Sensibilidade e Especificidade
5.
Nanoscale ; 13(34): 14469-14479, 2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34473176

RESUMO

The development of various degenerative diseases is suggested to be triggered by the uncontrolled organisation and aggregation of proteins into amyloid fibrils. For this reason, there are ongoing efforts to develop novel agents and approaches, including metal nanoparticle-based colloids, that dissolve amyloid structures and prevent pathogenic protein aggregation. In this contribution, the role of gold nanoparticles (AuNPs) in degrading amyloid fibrils of the model protein lysozyme is investigated. The amino acid composition of fibril surfaces before and after the incubation with AuNPs is determined at the single fibril level by exploiting the high spatial resolution and sensitivity provided by tip-enhanced and surface-enhanced Raman spectroscopies. This combined spectroscopic approach allows to reveal the molecular mechanisms driving the interaction between fibrils and AuNPs. Our results provide an important input for the understanding of amyloid fibrils and could have a potential translational impact on the development of strategies for the prevention and treatment of amyloid-related diseases.


Assuntos
Ouro , Nanopartículas Metálicas , Amiloide , Muramidase , Análise Espectral Raman
6.
Talanta ; 235: 122718, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517586

RESUMO

A chairside tool for quantitative analysis of dental caries would improve clinical dental inspections. The wireless caries sensing tool with dental-explorer size has been developed comparing two sensing methods, Raman reading and pH reading for evaluating dental caries. The Raman spectra at 575 cm-1 and 960 cm-1 for in inorganic compounds, as well as 1450 cm-1 and 2940 cm-1 for organic compounds reinforced and supported the pH results. An Iridium/Iridium oxide (Ir/IrOx) pH sensing probe and wireless pH sensor (comprising an ESP8266 ESP-01 wireless module and ADS1115 analog digital converter) has been developed to quantitatively evaluate dental caries. All the operations of the wireless pH sensor were performed with a developed LabVIEW-based real-time data monitoring program. The slope and the linear fitting regression value (R2) of the wireless pH sensor using seven standards were -54.9 mV/pH and 0.999, respectively, showing high accuracy and stability for the pH measurements. The pH on the dental caries surface was measured with the wireless pH sensor, and the pH mapping results in the non-caries and caries areas were 6.9 and 5.7, respectively. The developed wireless pH sensor would be useful to understand the condition of dental caries and support dentists' inspection to remove only the caries part while keeping the non-caries structure.


Assuntos
Cárie Dentária , Análise Espectral Raman , Cárie Dentária/diagnóstico , Humanos , Concentração de Íons de Hidrogênio , Modelos Lineares , Compostos Orgânicos
7.
Talanta ; 235: 122743, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517611

RESUMO

The analysis of contaminants in migration of food contact material (FCMs) is an urgent demand for food safety. In this study, melamine and formaldehyde in melamine kitchenware were selectively analyzed by surface-enhanced Raman scattering (SERS) via aptamer/derivatization-based membrane assembly. The membrane assembly was designed by simple filtration of Ag nanoparticles-decorated "stellate" silicon dioxide (SiO2/Ag) and composites of reduced graphene oxide and Ag nanoparticles (rGO/Ag) functioned with specific reagents. High selectivity can be realized by melamine aptamer and derivatization reagent of formaldehyde, respectively. The relative standard deviations (RSDs) of melamine and formaldehyde analysis for 11 replicate measurements, 14 consecutive days and 25 batches are less than 6.0 %, which shows excellent repeatability and reproducibility. After the method was validated, the limits of detection (LOD) for melamine and formaldehyde are 0.15 mg/L and 0.21 mg/L, respectively. The developed method was applied to determine the content of melamine and formaldehyde in migration of melamine kitchenware with low relative errors (less than 5.3 %) compared to chromatographic results. The recoveries of melamine and formaldehyde for migrations of melamine kitchenware are 91.2-110.0 % and 94.0-106.0 % with RSDs in range of 1.8-8.3 % and 4.7-9.1 %, respectively. The method proposed a new concept of convenient, portable and reliable strategy for analysis of melamine and formaldehyde in migration from FCMs.


Assuntos
Nanopartículas Metálicas , Análise Espectral Raman , Formaldeído , Reprodutibilidade dos Testes , Dióxido de Silício , Prata , Triazinas
8.
Talanta ; 235: 122777, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517634

RESUMO

DNA G-quadruplexes (G4s) formed by guanine(G)-rich sequences show diversity of structural topologies. The detection of structural details is of great significance for understanding of their functions and for the target drug design, but is very challenging. Herein, we demonstrate that the surface-enhanced Raman spectroscopy (SERS) via Ag IANPs as substrates is able to identify the numbers of Adenine (A) located on the G-quartet of the G4s. Eight G4s are selected for SERS studies. Besides the detection of series of characteristic bands indicating the formation of G4s, the intensity of the band represented A base ring breath (νA, ~733 cm-1) is observed particularly enhanced when there are A bases coplanar with G-quartet, and which is higher than the intensity of the band corresponding to G base ring breath (νG, ~655 cm-1). Furthermore, the band intensity ratio of νA to νG versus the ratio of the numbers of A on the plane to the sum of numbers of A and G shows very good linear relationship. Thus, based on the band intensities of νA to νG and their ratio in the SERS spectrum, the G-quadruplexes with or without a coplanar A base and numbers of A bases on the plane of G-quartet can be facilely identified. The method is simple, fast, low cost and sensitive to provide particular details of the structure in aqueous solution, therefore, implies widespread applications.


Assuntos
Quadruplex G , Análise Espectral Raman , Adenina , Guanina
9.
Nanoscale ; 13(32): 13906, 2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34477665

RESUMO

Correction for 'Surface-enhanced Raman spectroscopy for bioanalysis and diagnosis' by Muhammad Ali Tahir et al., Nanoscale, 2021, 13, 11593-11634, DOI: .


Assuntos
Análise Espectral Raman
10.
Nanoscale ; 13(31): 13344-13352, 2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34477740

RESUMO

The construction and clinical application of a surface-enhanced Raman scattering (SERS) platform for the early diagnosis of lung cancer could improve the survival rate of patients and would be of great significance. Nevertheless, a sensitive and reusable method for the detection of aldehydes, as biomarkers of lung cancer, in exhaled breath is still an enormous challenge. Aldehydes generally have a low cross section in Raman scattering and have a weak specific affinity to plasmonic nanoparticle surfaces, meaning that sensing them at low concentrations is incredibly difficult. Herein, an ultrasensitive SERS strategy, that can be recycled for further use, for the detection of lung cancer biomarkers in the form of aldehydes was realized by fabrication of a multifunctional Ag NPs@ZIF-67/g-C3N4 solid phase extraction (SPE) membrane. Based on the change in the vibrational fingerprints of 4-ATP before and after reaction with the aldehydes, the SPE membrane was successfully used for the ultrasensitive detection of aldehydes with a detection limit of 1.35 nM. The excellent SERS performance was attributed to the synergistic effect of the densely and closely distributed Ag NPs (providing SERS "hot spots"), ZIF-67 (concentrating the analyte molecules) and g-C3N4 (forming a membrane to prolong the contact time between the aldehydes and the substrate). In addition, recycling of the SPE membrane was achieved by utilizing the self-cleaning ability of the Ag NPs@ZIF-67/g-C3N4 membrane originating from the photocatalytic properties of g-C3N4. The proposed SERS membrane was easy to operate, rapid and portable, thus providing a potential tool for a point-of-care test in clinical and diagnostic practice.


Assuntos
Neoplasias Pulmonares , Nanopartículas Metálicas , Biomarcadores Tumorais , Humanos , Neoplasias Pulmonares/diagnóstico , Prata , Extração em Fase Sólida , Análise Espectral Raman
11.
Analyst ; 146(18): 5740-5746, 2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34515704

RESUMO

Ampicillin and nitrofurantoin, as broad-spectrum antibiotics, are widely used in the prevention of animal diseases and to ensure livestock growth. Large amounts of antibiotic residues exist in animal-derived foods, affecting food quality and safety, causing adverse side effects, such as allergic and toxic reactions, and increasing bacterial resistance. A sensitive surface enhanced Raman scattering (SERS) sensor is provided to detect low-concentration antibiotics (ampicillin and nitrofurantoin). The sensor is based on an Au nanoparticles/graphene oxide hybrid nanocomposite prepared by an in situ reduction method. The detection limits of ampicillin and nitrofurantoin are as low as 0.01 ng mL-1 and 5 ng mL-1, respectively. The relative spectral intensity of the nitrofurantoin characteristic peak has a good linear relationship with the concentration of nitrofurantoin in the range of 500 ng mL-1 and 5 ng mL-1 (R2 = 0.99235). The structure also allows multi-sample measurement for a variety of antibiotics at the same time. The SERS sensor is easy to prepare, with high uniformity and reproducibility, and the sample does not require complex pretreatment and preparation. Sensitive and quantitative detection of antibiotics by the SERS sensor is of great interest in the fields of health care, food preparation, and environmental sampling.


Assuntos
Nanopartículas Metálicas , Nanocompostos , Animais , Antibacterianos , Atenção à Saúde , Ouro , Grafite , Reprodutibilidade dos Testes , Análise Espectral Raman
12.
Anal Chem ; 93(36): 12360-12366, 2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34472338

RESUMO

Facing the complex environment of on-site detection, the development of active substrates with wide-spectrum surface-enhanced Raman scattering (SERS) activity is essential. Herein, we report on the low temperature and reproducible synthesis of plasmonic δ-MoN yolk microspheres by in situ-nitriding amorphous MoO2 microspheres at 500 °C and 1 atm. The yolk-structured δ-MoN exhibits strong and wide-spectrum surface plasmon resonance and SERS effects and can perform highly selective detection for probes with different absorption wavelengths under excitation of 532, 633, and 785 nm lasers, with a limitation of 10-11 M and an enhanced factor of 3.6 × 107. Moreover, the plasmonic δ-MoN yolk microspheres have high environmental durability, which can maintain high sensitivity in strong acid and alkaline solutions.


Assuntos
Análise Espectral Raman , Ressonância de Plasmônio de Superfície , Microesferas
13.
Nanoscale ; 13(35): 14760-14776, 2021 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34473170

RESUMO

Given the emerging diagnostic utility of extracellular vesicles (EVs), it is important to account for non-EV contaminants. Lipoprotein present in EV-enriched isolates may inflate particle counts and decrease sensitivity to biomarkers of interest, skewing chemical analyses and perpetuating downstream issues in labeling or functional analysis. Using label free surface enhanced Raman scattering (SERS), we confirm that three common EV isolation methods (differential ultracentrifugation, density gradient ultracentrifugation, and size exclusion chromatography) yield variable lipoprotein content. We demonstrate that a dual-isolation method is necessary to isolate EVs from the major classes of lipoprotein. However, combining SERS analysis with machine learning assisted classification, we show that the disease state is the main driver of distinction between EV samples, and largely unaffected by choice of isolation. Ultimately, this study describes a convenient SERS assay to retain accurate diagnostic information from clinical samples by overcoming differences in lipoprotein contamination according to isolation method.


Assuntos
Vesículas Extracelulares , Neoplasias , Cromatografia em Gel , Humanos , Lipoproteínas , Neoplasias/diagnóstico , Análise Espectral Raman , Ultracentrifugação
14.
J Hazard Mater ; 416: 126251, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492994

RESUMO

Due to the nonbiodegradability and accumulation of mercury ion, even in extremely small amount, it will cause varying degrees of harm to environment and human health. Although researchers have developed many strategies to detect and monitor trace Hg2+, only a few provide sensitivities of less than 1.0 pM. Surface Enhanced Raman Spectroscopy (SERS) is a common method to detect mercury ion due to its high sensitivity, rapid detection and easy operation. In this work, we report a new SERS aptasensor based on dual recycling amplification for the detection of trace mercury ion, which combines SERS with nucleic acid signal amplification through functional aptamer and elaborately designed hairpin DNA. Under the optimal experimental conditions, this SERS aptasensor exhibits excellent selectivity and high sensitivity. A linear range (0.2-125 fM) and a low detection limit (0.11 fM) are obtained. By using specific aptamers, the strategy will provide a new idea for the trace detection of toxic contaminants in water environment.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Mercúrio , DNA , Ouro , Humanos , Limite de Detecção , Análise Espectral Raman , Água
15.
Molecules ; 26(16)2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34443382

RESUMO

The E-hook of ß-tubulin plays instrumental roles in cytoskeletal regulation and function. The last six C-terminal residues of the ßII isotype, a peptide of amino acid sequence EGEDEA, extend from the microtubule surface and have eluded characterization with classic X-ray crystallographic techniques. The band position of the characteristic amide I vibration of small peptide fragments is heavily dependent on the length of the peptide chain, the extent of intramolecular hydrogen bonding, and the overall polarity of the fragment. The dependence of the E residue's amide I ν(C=O) and the αCOO- terminal ν(C=O) bands on the neighboring side chain, the length of the peptide fragment, and the extent of intramolecular hydrogen bonding in the structure are investigated here via the EGEDEA peptide. The hexapeptide is broken down into fragments increasing in size from dipeptides to hexapeptides, including EG, ED, EA, EGE, EDE, DEA, EGED, EDEA, EGEDE, GEDEA, and, finally, EGEDEA, which are investigated with experimental Raman spectroscopy and density functional theory (DFT) computations to model the zwitterionic crystalline solids (in vacuo). The molecular geometries and Boltzmann sum of the simulated Raman spectra for a set of energetic minima corresponding to each peptide fragment are computed with full geometry optimizations and corresponding harmonic vibrational frequency computations at the B3LYP/6-311++G(2df,2pd) level of theory. In absence of the crystal structure, geometry sampling is performed to approximate solid phase behavior. Natural bond order (NBO) analyses are performed on each energetic minimum to quantify the magnitude of the intramolecular hydrogen bonds. The extent of the intramolecular charge transfer is dependent on the overall polarity of the fragment considered, with larger and more polar fragments exhibiting the greatest extent of intramolecular charge transfer. A steady blue shift arises when considering the amide I band position moving linearly from ED to EDE to EDEA to GEDEA and, finally, to EGEDEA. However, little variation is observed in the αCOO- ν(C=O) band position in this family of fragments.


Assuntos
Amidas/química , Teoria da Densidade Funcional , Ácido Glutâmico/química , Fragmentos de Peptídeos/química , Análise Espectral Raman , Simulação por Computador , Conformação Molecular , Estrutura Secundária de Proteína , Termodinâmica , Vibração
16.
Molecules ; 26(16)2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-34443690

RESUMO

In this work, different pretreatment methods for algae proved to be very effective in improving cell wall dissociation for biogas production. In this study, the Ulva intestinalis Linnaeus (U. intestinalis) has been exposed to individual pretreatments of (ultrasonic, ozone, microwave, and green synthesized Fe3O4) and in a combination of the first three mentioned pretreatments methods with magnetite (Fe3O4) NPs, (ultrasonic-Fe3O4, ozone-Fe3O4 and microwave-Fe3O4) in different treatment times. Moreover, the green synthesized Fe3O4 NPs has been confirmed by FTIR, TEM, XRD, SEM, EDEX, PSA and BET. The maximum biogas production of 179 and 206 mL/g VS have been attained when U. intestinalis has been treated with ultrasonic only and when combined microwave with Fe3O4 respectively, where sediment were used as inoculum in all pretreatments. From the obtained results, green Fe3O4 NPs enhanced the microwave (MW) treatment to produce a higher biogas yield (206 mL/g VS) when compared with individual MW (84 mL/g VS). The modified Gompertz model (R2 = 0.996 was appropriate model to match the calculated biogas production and could be used more practically to distinguish the kinetics of the anaerobic digestion (AD) period. The assessment of XRD, SEM and FTIR discovered the influence of different treatment techniques on the cell wall structure of U. intestinalis.


Assuntos
Biocombustíveis/análise , Compostos Férricos/química , Nanopartículas/química , Alga Marinha/química , Ulva/química , Anaerobiose , Cinética , Nanopartículas/ultraestrutura , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Termogravimetria , Difração de Raios X
17.
Int J Mol Sci ; 22(15)2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34361025

RESUMO

In this work, synthesis and optical properties of a new composite based on poly(o-phenylenediamine) (POPD) fiber like structures, poly(vinylidene fluoride) (PVDF) spheres and double-walled carbon nanotubes (DWNTs) are reported. As increasing the PVDF weight in the mixture of the chemical polymerization reaction of o-phenylenediamine, the presence of the PVDF spheres onto the POPD fibers surface is highlighted by scanning electron microscopy (SEM). The down-shift of the Raman line from 1421 cm-1 to 1415 cm-1 proves the covalent functionalization of DWNTs with the POPD-PVDF blends. The changes in the absorbance of the IR bands peaked around 840, 881, 1240 and 1402 cm-1 indicate hindrance steric effects induced of DWNTs to the POPD fiber like structures and the PVDF spheres, as a consequence of the functionalization process of carbon nanotubes with macromolecular compounds. The presence of the PVDF spheres onto the POPD fiber like structures surface induces a POPD photoluminescence (PL) quenching process. An additional PL quenching process of the POPD-PVDF blends is reported to be induced in the presence of DWNTs. The studies of anisotropic PL highlight a change of the angle of the binding of the PVDF spheres onto the POPD fiber like structures surface from 50.2° to 38° when the carbon nanotubes concentration increases in the POPD-PVDF/DWNTs composites mass up to 2 wt.%.


Assuntos
Dimetilformamida/química , Nanotubos de Carbono/química , Polivinil/química , Anisotropia , Nanocompostos/química , Análise Espectral Raman
18.
Stomatologiia (Mosk) ; 100(4): 137-142, 2021.
Artigo em Russo | MEDLINE | ID: mdl-34357743

RESUMO

The aim of the review is to learn about the areas of application of the Raman spectroscopy in medicine, particularly in dentistry. The method is widely used in biology, medicine, pharmacy, forensic science, gemology, food industry and other industries. The main advantages of Raman spectroscopy are no need for sample preparation and small amounts of the object of study, as well as the ability to contactlessly obtain unique information about the conformation and microenvironment of living cell molecules. The disadvantages are high costs of the equipment that are compensated with the long-term use by having no costs for additional reagents. The combinatorial scattering is used in dermatology, as it is a high-accuracy automated method of visualization and diagnostics of both benign growths as pigmented nevus, seborrheic keratosis, and malignant neoplasms as melanoma and basal cell carcinoma. This method is an analytical tool for diagnosing various diseases, making the direct measurements in hard and liquid media easier, does not require special treatment of samples and is not sensitive to absorption bands. The Raman spectroscopy use in dentistry allows diagnosing and comparative analysis of the changes of hard tissues of teeth and mucous membrane of the mouth, which improves security and rationalization of treatment and further prevention of complications before and after making different operations.


Assuntos
Melanoma , Neoplasias Cutâneas , Humanos , Análise Espectral Raman , Microambiente Tumoral
19.
Talanta ; 234: 122585, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364414

RESUMO

The detection of multiple pesticides in food and environment is of great importance for human health and safety. In this study, the DNA backbone structure and Ag@Au nanoparticles (NPs) to construct a nano-tetrahedron with the help of the surface-enhanced Raman scattering (SERS) effect by controlling the formation of SERS hotspots and subsequently realized the simultaneous detection of multiple pesticides. The DNA aptamers corresponding to the three pesticides of profenofos, acetamiprid and carbendazim were embedded into the three edges of the DNA tetrahedral skeleton, and the tetrahedral corners were connected to modify the Ag@Au NPs with different Raman signaling molecules. When aptamers recognize the related pesticides, the DNA backbone is deformed. Then Ag@Au NPs approach to each other with SERS hotspots formed and the intensity of the Raman signal increased, realizing the detection of the pesticide content. The biosensor constructed from the SERS substrate with higher sensitivity and lower detection limit (profenofos: 0.0021 ng mL-1; acetamiprid: 0.0046 ng mL-1; carbendazim: 0.0061 ng mL-1). The practicability of this proposed method was verified by adding the recovery rate detection and the accuracy of the method was examined by the analysis of the HPLC-MS method. The proposed SERS biosensor could distinguish and detect three pesticides in food and environmental samples with high sensitivity and low detection limit that can be used in practical applications.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Praguicidas , Ouro , Humanos , Praguicidas/análise , Prata , Análise Espectral Raman
20.
Talanta ; 234: 122651, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364460

RESUMO

Wide uses of azo dyes produce a great risk of high residuals of carcinogenic aromatic amines, and hence it is important to rapidly analyze these carcinogenic compounds in the textile products to guarantee product safety. In the present work, a surface enhanced Raman spectroscopic (SERS) method was developed for rapid detection of carcinogenic aromatic amines in textiles. In this method, target aromatic amines are extracted from textiles, and then gold nanoparticles are added to the organic extractant, which assemble into closely packed Au array at liquid interface in situ. Finally, fingerprint SERS signals of the target aromatic amines are detected on the generated Au array on the basis of strong chemical interaction between the aromatic amines and the Au surface. The proposed method provided good reproducibility with a relative standard deviation of 3.5% for ten parallel tests of benzidine. It was applied to analyze 70 textile products. To strengthen the spectroscopic data processing, a cluster analysis model was established with 50 samples to automatically identify the spectra based on the good signal reproducibility. The other 20 samples were used as test sets to validate this model. It was found that all the positive samples were successfully identified with false positive rate of 20%. With the addition of the Artificial Intelligence step, the reliability of the discriminant results can be ensured.


Assuntos
Ouro , Nanopartículas Metálicas , Aminas , Inteligência Artificial , Compostos Azo , Reprodutibilidade dos Testes , Análise Espectral Raman , Têxteis
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