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Investigating the molecular mechanism underlying the aggregation process of amyloid fibers is of great importance both for its implications in several degenerative diseases and for the design of new materials based on self-assembly. In particular, micro/nanotubes of L,L-diphenylalanine have been investigated as a model of amyloid plaques in Alzheimer's disease and also for their broad range of physical properties, e.g., good thermo- and mechanical stability, semiconductivity, piezoelectricity and optical properties. It has been reported that the assembly/disassembly dynamics of L,L-diphenylalanine crystals is influenced by the solvent composition being triggered by evaporation of solvents. In fact the solvatomorphism of this peptide-based nanomaterial is complex and rich attracting great attention. Here we investigated the growing kinetics of the micro/nanotubes of L,L-diphenylalanine in samples prepared with toluene, ethanol, and acetic acid solvents by time-resolved Raman spectroscopy. Our results indicated that the self-assembly in this case competes with the water evaporation process contrary to what is reported by samples prepared with widely used solvent 1,1,1,3,3,3-hexafluoro-2-propanol. We note that exclusively tubular structures (being hollow for the toluene solvent case) were observed. Interestingly our results support the fact that for acetic acid, ethanol, and toluene the micro/nanotube formation process is autocatalytic instead of being nucleation-dominating as reported for samples prepared using solvent 1,1,1,3,3,3-hexafluoro-2-propanol.
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Nanotubos , Solventes/química , Cinética , Nanotubos/química , Dipeptídeos/química , Etanol , ToluenoRESUMO
It has been reported that 58% of individuals with chronic kidney disease (CKD) have moderate to advanced periodontitis due to alterations of pH and biochemical composition in the saliva. In fact, the composition of this important biofluid may be modulated by systemic disorders. Here we investigate the micro-reflectance Fourier-transform infrared spectroscopy (FTIR) spectra of saliva that CKD patients submitted to periodontal treatment, aiming to identify spectral biomarkers of kidney disease evolution and the effectiveness of periodontal treatment, proposing possible biomarkers of disease evolution. Saliva from 24 CKD patients-stage-5 men, 29 to 64 years old-was evaluated in (i) patients starting periodontal treatment; (ii) patients 30 days after periodontal treatment; and (iii) patients 90 days after periodontal treatment. Our findings indicated that there are statistically relevant changes among the groups after 30 and 90 days of periodontal treatment, when considering the overall spectra in the fingerprint region (800-1800cm-1). The key bands presenting good prediction power (area under the receiver operating characteristic curve >0.70) were related to poly (ADP-ribose) polymerase (PARP) conjugated to DNA at 883, 1031, and 1060cm-1 (carbohydrates at 1043 and 1049cm-1) and triglycerides (1461cm-1). Interestingly when analyzing the derivative spectra in the secondary structure region (1590-1700cm-1), we detected over-expression of the ß-sheet class of secondary structures in 90 days of periodontal treatment, possibly related to over-expression of human B-defensins. Conformational changes in ribose sugar in this region corroborate the interpretation concerning PARP detection. To our knowledge, PARP was detected for the first time in saliva samples of stage-5 CKD patients by FTIR. All observed changes were correctly interpreted in terms of intensive apoptosis and dyslipidemia due to kidney disease progression. Biomarkers due to CKD predominate in saliva, and the relative improvement in the periodontal state did not cause remarkable changes in the spectra of saliva.
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Doenças Periodontais , Insuficiência Renal Crônica , Masculino , Humanos , Adulto , Pessoa de Meia-Idade , Espectroscopia de Infravermelho com Transformada de Fourier , Inibidores de Poli(ADP-Ribose) Polimerases , Ribose , Doenças Periodontais/diagnóstico , Insuficiência Renal Crônica/complicações , BiomarcadoresRESUMO
Genomic surveillance has been applied since the beginning of the COVID-19 pandemic to track the spread of the virus, leading to the characterization of multiple SARS-CoV-2 variants, including variants of concern (VOC). Although sequencing is the standard method, a rapid molecular test for screening and surveillance of VOC is considered for detection. Furthermore, using alternative saliva as specimen collection facilitates the implementation of a less invasive, self-collected sample. In this study, we applied a combinatory strategy of saliva collection and reverse transcription polymerase chain reaction (RT-PCR) for SARS-CoV-2 VOC detection. Saliva samples from patients attending a tertiary hospital with suspected COVID-19 were collected and SARS-CoV-2 RNA was detected using SARS-CoV-2 RT-qPCR reagent kit (PerkinElmer). Positive saliva samples were screened for SARS-CoV-2 VOC with previously described RT-PCR for Alpha, Beta, and Gamma variants. Saliva samples were positive in 171 (53%) of 324 tested. A total of 108 (74%) from positive samples were also positive for VOC by RT-PCR screening. Those samples were found between January and August 2021. This approach allowed us to successfully use an alternative and complementary tool to genomic surveillance to monitor the circulation of SARS-CoV-2 VOC in the studied population.
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COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , COVID-19/epidemiologia , Humanos , Pandemias , RNA Viral/análise , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , SARS-CoV-2/genética , SalivaRESUMO
Cardiovascular diseases are the main cause of death worldwide. Recent studies have revealed the influence of histone-modifying enzymes in cardiac remodeling and heart dysfunction. The Set7 methyltransferase regulates the expression of several genes through the methylation of histones and modulates the activity of non-histone proteins. However, the role of Set7 in cardiac remodeling and heart dysfunction remains unknown. To address this question, wild-type (WT) and Set7 knockout (KO) male mice were injected with isoproterenol or saline. WT mice injected with isoproterenol displayed a decrease in Set7 activity in the heart. In addition, WT and Set7 KO mice injected with isoproterenol exhibited cardiac hypertrophy. Interestingly, Set7 deletion exacerbated cardiac hypertrophy in response to isoproterenol but attenuated myocardial fibrosis. Echocardiograms revealed that WT mice injected with isoproterenol had lowered ejection fractions and fractional shortening, and increased E'-wave deceleration time and E/A ratio compared with their controls. Conversely, Set7 KO mice did not show alteration in these parameters in response to isoproterenol. However, prolonged exposure to isoproterenol induced cardiac dysfunction both in WT and Set7 KO mice. Both isoproterenol and Set7 deletion changed the transcriptional profile of the heart. Moreover, Set7 deletion increased the expression of Pgc1α and mitochondrial DNA content in the heart, and reduced the expression of cellular senescence and inflammation markers in response to isoproterenol. Taken together, our data suggest that Set7 deletion attenuates isoproterenol-induced myocardial fibrosis and delays heart dysfunction, suggesting that Set7 plays an important role in cardiac remodeling and dysfunction in response to stress.
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Cardiomiopatias , Remodelação Ventricular , Camundongos , Masculino , Animais , Isoproterenol/efeitos adversos , Isoproterenol/metabolismo , Cardiomegalia/induzido quimicamente , Cardiomegalia/genética , Cardiomegalia/metabolismo , Camundongos Knockout , Cardiomiopatias/induzido quimicamente , Cardiomiopatias/diagnóstico por imagem , Cardiomiopatias/genética , Fibrose , Miócitos Cardíacos/metabolismo , Camundongos Endogâmicos C57BLRESUMO
The control of skin permeability to specific substances (e.g., medications, vitamins, and nutrients) through stratum corneum is a challenge. Iontophoresis is an option in spite of the lack of a detailed understanding of the underlying molecular mechanism. In the present work, the simulations concerning application of an external continuous electric field to stratum corneum, in a range of low intensity (0-24 mV nm-1), were carried out using the coarse-grained molecular dynamics approach. Using a set of random seed replicas of the starting configuration, we observed that in the range of electric field intensity of 22-23 mV nm-1, water-rich lipid vesicles were formed in 20% of cases. Pores appeared in the remaining 80%. We argue that lipids undergo fast re-orientations under electric field inducing mechanical instability, which originates the pores. We presented a simple electrostatic model to interpret the results where the mismatch between electrical permittivities of the membrane and external media and the gradient of the local electric field in the membrane surface, govern the time scales and electric fields for vesicle formation. Our results indicate that just 10% difference between electrical permittivities of the membrane and external media decreases 1/6 the minimal time required for vesicle formation. The minimal electric field required decreases 10 times. The control and tunning of formation of biologically compatible vesicles, capable of transporting substances under low-intensity electric fields, has a promising application in fields such as drug therapy and dermo-cosmetics allowing the use of hydrophilic substances in dermal applications.
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Membrana Celular/metabolismo , Água/metabolismo , Transporte Biológico , Membrana Celular/química , Ceramidas/química , Colesterol/química , Epiderme/química , Ácidos Graxos/química , Iontoforese , Simulação de Dinâmica Molecular , Eletricidade Estática , Água/químicaRESUMO
Resorbable polylactic acid (PLA) ultrathin fibers have been applied as scaffolds for tissue engineering applications due to their micro- and nanoporous structure that favor cell adhesion, besides inducing cell proliferation and upregulating gene expression related to tissue regeneration. Incorporation of multiwalled carbon nanotubes into PLA fibers has been reported to increase the mechanical properties of the scaffold, making them even more suitable for tissue engineering applications. Ideally, scaffolds should be degraded simultaneously with tissue growth. Hydration and swelling are factors related to scaffold degradation. Hydration would negatively impact the mechanical properties since PLA shows hydrolytic degradation. Water absorption critically affects the catalysis and allowance of the hydrolysis reactions. Moreover, either mass transport and chemical reactions are influenced by confined water, which is an unexplored subject for PLA micro- and nanoporous fibers. Here, we probe and investigate confined water onto highly porous PLA microfibers containing few amounts of incorporated carbon nanotubes by Fourier transform infrared (FTIR) spectroscopy. A hydrostatic pressure was applied to the fibers to enhance the intermolecular interactions between water molecules and C=O groups from polyester bonds, which were evaluated over the wavenumber between 1600 and 2000 cm-1. The analysis of temperature dependence of FTIR spectra indicated the presence of confined water which is characterized by a non-Arrhenius to Arrhenius crossover at T0 = 190 K for 1716 and 1817 cm-1 carbonyl bands of PLA. These bands are sensitive to a hydrogen bond network of confined water. The relevance of our finding relies on the challenge detecting confined water in hydrophobic cavities as in the PLA one. To the best of our knowledge, we present the first report referring the presence of confined water in a hydrophobic scaffold as PLA for tissue engineering. Our findings can provide new opportunities to understand the role of confined water in tissue engineering applications. For instance, we argue that PLA degradation may be affected the most by confined water. PLA degradation involves hydrolytic and enzymatic degradation reactions, which can both be sensitive to changes in water properties.
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Discriminate the severity level of COVID-19 disease is still a challenge. Here we investigate the capability of micro-infrared absorption spectroscopy (micro-FTIR) to probe COVID-19 severity level and predict hyperinflammation, correlating the assigned vibrational data to relevant biomolecules related to the immune system. Saliva of 184 patients was analysed by ELISA assay (Hepcidin) and micro-FTIR. Vibrational bands related to IgM and IgA can discriminate healthy from Severe individuals (sensitivity ≥ 0.749, specificity ≥ 0.945) and are less effective in discriminating Mild or Moderate individuals from the Severe group (sensitivity ≥ 0.628, specificity ≥ 0.867). Analysis of the second derivative of spectra probed increased levels of IL-6 in the saliva a key additional information for the degree of severity prediction. Because the model discriminates all the groups regarding the Severe group, it predicts an intense state of inflammation based on FTIR analysis. It is a powerful tool for predicting hyperinflammation conditions related to SARS-CoV-2 infection and may be an ally in implementing drugs or therapeutic approaches to manage COVID-19 in the Severe stage in healthcare facilities.
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COVID-19 , Inflamação , SARS-CoV-2 , Saliva , Índice de Gravidade de Doença , Humanos , COVID-19/diagnóstico , Saliva/química , Saliva/virologia , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Feminino , Masculino , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/imunologia , Adulto , Pessoa de Meia-Idade , Interleucina-6/análise , Idoso , Imunoglobulina A/análise , Imunoglobulina M/análise , Imunoglobulina M/imunologiaRESUMO
OBJECTIVES: Electronic nicotine delivery systems (e-cigarette, pod, and vape) are currently among the tobacco consumption of adolescents and young adults. The aim is to show oral mucosa and saliva alterations related to vape. MATERIAL AND METHODS: A vape-user patient, presenting a white plaque in the posterior region of the hard palate, underwent clinical examination, sialometry, pH evaluation, and excisional biopsy of the white lesion. Molecular changes in saliva and vape liquid were analyzed by vibrational spectroscopy. RESULTS: The histopathological analyses showed hyperparakeratosis without dysplasia. Formaldehyde, ketones, and aromatic hydrocarbon species were identified in e-cig liquid by the FTIR. CONCLUSIONS: The use of vape may be related to the development of hyperkeratotic lesions in the oral mucosa as well as significantly modify the patient's salivary patterns as the vape liquid presents carcinogenic and cytotoxic components in its composition.
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Mucosa Bucal , Saliva , Humanos , Saliva/química , Mucosa Bucal/patologia , Sistemas Eletrônicos de Liberação de Nicotina , Vaping/efeitos adversos , Masculino , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Adulto , Palato Duro/patologia , Adulto Jovem , BiópsiaRESUMO
Melaleuca alternifolia essential oil (MaEO) is a green antimicrobial agent suitable for confection eco-friendly disinfectants to substitute conventional chemical disinfectants commonly formulated with toxic substances that cause dangerous environmental impacts. In this contribution, MaEO-in-water Pickering emulsions were successfully stabilized with cellulose nanofibrils (CNFs) by a simple mixing procedure. MaEO and the emulsions presented antimicrobial activities against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Moreover, MaEO deactivated the SARS-CoV-2 virions immediately. FT-Raman and FTIR spectroscopies indicate that the CNF stabilizes the MaEO droplets in water by the dipole-induced-dipole interactions and hydrogen bonds. The factorial design of experiments (DoE) indicates that CNF content and mixing time have significant effects on preventing the MaEO droplets' coalescence during 30-day shelf life. The bacteria inhibition zone assays show that the most stable emulsions showed antimicrobial activity comparable to commercial disinfectant agents such as hypochlorite. The MaEO/water stabilized-CNF emulsion is a promissory natural disinfectant with antibacterial activity against these bacteria strains, including the capability to damage the spike proteins at the SARS-CoV-2 particle surface after 15 min of direct contact when the MaEO concentration is 30 % v/v.
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Anti-Infecciosos , COVID-19 , Desinfetantes , Melaleuca , Óleo de Melaleuca , Celulose/química , Emulsões/química , SARS-CoV-2 , Escherichia coli , Staphylococcus aureus , Anti-Infecciosos/farmacologia , Água/químicaRESUMO
BACKGROUND: The SARS-CoV-2 infections are still imposing a great public health challenge despite the recent developments in vaccines and therapy. Searching for diagnostic and prognostic methods that are fast, low-cost and accurate are essential for disease control and patient recovery. The MALDI-TOF mass spectrometry technique is rapid, low cost and accurate when compared to other MS methods, thus its use is already reported in the literature for various applications, including microorganism identification, diagnosis and prognosis of diseases. METHODS: Here we developed a prognostic method for COVID-19 using the proteomic profile of saliva samples submitted to MALDI-TOF and machine learning algorithms to train models for COVID-19 severity assessment. RESULTS: We achieved an accuracy of 88.5%, specificity of 85% and sensitivity of 91.5% for classification between mild/moderate and severe conditions. When we tested the model performance in an independent dataset, we achieved an accuracy, sensitivity and specificity of 67.18, 52.17 and 75.60% respectively. CONCLUSION: Saliva is already reported to have high inter-sample variation; however, our results demonstrates that this approach has the potential to be a prognostic method for COVID-19. Additionally, the technology used is already available in several clinics, facilitating the implementation of the method. Further investigation using a larger dataset is necessary to consolidate the technique.
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It has been reported that patients diagnosed with COVID-19 become critically ill primarily around the time of activation of the adaptive immune response. However the role of antibodies in the worsening of disease is not obvious. Higher titers of anti-spike immunoglobulin IgG1 associated with low fucosylation of the antibody Fc tail have been associated to excessive inflammatory response. In contrast it has been also reported that NP-, S-, RBD- specific IgA, IgG, and IgM are not associated with SARS-CoV-2 viral load, indicating that there is no obvious correlation between antibody response and viral antigen detection. In the present work the micro-Fourier-transform infrared reflectance spectroscopy (micro-FTIR) was employed to investigate blood serum samples of healthy and COVID-19-ill (mild or oligosymptomatic) individuals (82 healthcare workers volunteers in "Instituto de Infectologia Emilio Ribas", São Paulo, Brazil). The molecular-level-sensitive, multiplexing quantitative and qualitative FTIR data probed on 1 µL of dried biofluid was compared to signal-to-cutoff index of chemiluminescent immunoassays CLIA and ELISA (IgG antibodies against SARS-CoV-2). Our main result indicated that 1702-1785 [Formula: see text] spectral window (carbonyl C=O vibration) is a spectral marker of the degree of IgG glycosylation, allowing to probe distinctive sub-populations of COVID-19 patients, depending on their degree of severity. The specificity was 87.5 % while the detection rate of true positive was 100%. The computed area under the receiver operating curve was equivalent to CLIA, ELISA and other ATR-FTIR methods ([Formula: see text]). In summary, overall discrimination of healthy and COVID-19 individuals and severity prediction as well could be potentially implemented using micro-FTIR reflectance spectroscopy on blood serum samples. Considering the minimal and reagent-free sample preparation procedures combined to fast (few minutes) outcome of FTIR we can state that this technology is suitable for fast screening of immune response of individuals with COVID-19. It would be an important tool in prospective studies, helping investigate the physiology of the asymptomatic, oligosymptomatic, or severe individuals and measure the extension of infection dissemination in patients.
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COVID-19/metabolismo , Imunoglobulina G/metabolismo , SARS-CoV-2/imunologia , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Adulto , Anticorpos Antivirais/imunologia , COVID-19/diagnóstico por imagem , COVID-19/imunologia , Teste para COVID-19/métodos , Ensaio de Imunoadsorção Enzimática , Feminino , Glicosilação , Humanos , Medições Luminescentes , Masculino , Pessoa de Meia-Idade , Gravidade do Paciente , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectroscopia de Infravermelho com Transformada de Fourier/instrumentação , Carga ViralRESUMO
Renal injury caused by renal ischemia and reperfusion strongly influences heart morphology, electrophysiology, and redox unbalance. The so-called cardiorenal syndrome is an important class of dysfunction since heart and kidneys are responsible for hemodynamic stability and organ perfusion through a complex network. In the present work we investigate the vibrational spectral features probed by Fourier-Transform Raman (FT-Raman) spectroscopy due to physiological alterations induced by renal ischemic reperfusion aiming to detect molecular markers related to progression of acute to chronic kidney injury and mortality predictors as well. C57BL/6J mice were subjected to unilateral occlusion of the renal pedicle for 60 min and reperfusion for 5, 8, and 15 days. Biopsies of heart and kidney tissues were analyzed. Our findings indicated that cysteine/cystine, fatty acids, methyl groups of Collagen, α-form of proteins, Tyrosine, and Tryptophan were modulated during renal ischemia and reperfusion process. These changes are consistent with fibroblast growth factors and Collagen III contents changes. Interestingly, Tyrosine and Tryptophan, precursor molecules for the formation of uremic toxins such as indoxyl sulfate and p-cresyl sulfate were also modulated. They are markers of kidney injury and their increase is strongly correlated to cardiovascular mortality. Regarding this aspect, we notice that monitoring the Tyrosine and Tryptophan bands at 1558, 1616, and 1625 cm-1 is a viable and and advantageous way to predict fatality in cardiovascular diseases both "in vivo" or "in vitro", using the real-time, multiplexing, and minimally invasive advantages of FT-Raman spectroscopy.
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Biomarcadores , Nefropatias/etiologia , Nefropatias/metabolismo , Triptofano/metabolismo , Tirosina/metabolismo , Animais , Síndrome Cardiorrenal/diagnóstico , Síndrome Cardiorrenal/etiologia , Síndrome Cardiorrenal/metabolismo , Gerenciamento Clínico , Suscetibilidade a Doenças , Nefropatias/diagnóstico , Masculino , Camundongos , Especificidade de Órgãos , Traumatismo por Reperfusão/complicações , Análise Espectral/métodos , Triptofano/análise , Tirosina/análiseRESUMO
Many questions concerning the biophysical and physiological properties of skin are still open. Skin aging, permeability, dermal absorption, hydration, and drug transdermal delivery, are few examples of processes with unveiled underlying mechanisms. In this work, it is presented a comparison between Fourier transform infrared absorption (FTIR) of dry stratum corneum and stratum corneum under lipase action supported by first-principles density functional vibrational calculations. The molecular structure of stratum corneum was modeled by an archetype of its hygroscopic proteic portion inside the corneocytes, the natural moisturizing factor, coupled to glycerol molecules which represent the lipid fraction of stratum corneum. Vibrational spectra were calculated and compared to experimental data obtained on the animal model of stratum corneum. The experimental results indicated prominent spectral differences between dry and lipase-treated stratum corneum. Principal components analysis and hyerarchical clustering indicated that 1200, 1650, and 1695 cm-1 bands are the most influential on the discrimination. It is noticed that bands in the fingerprint region (800-1800 cm-1) were correctly assigned. Moreover, the calculations revealed the existence of two coupled vibration between the hydroxyl group of lipid and methylene (1120 and 1160 cm-1), which are of special interest since they probe the lipid-amino acid coupling. The model was also able to predict the shear modulus of dry stratum corneum in excellent agreement with the reported values from the literature. Other physical/chemical properties could be calculated exploring the chemical accuracy and molecular resolution of this model. Research in dermatology, cosmetology, and biomedical engineering in the specific topics of drug delivery and/or mechanical properties of skin are examples of fields that would potentially take advantage of this approach.
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Pele , Vibração , Animais , Análise de Fourier , Lipídeos , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Oral squamous cell carcinoma (OSCC) represents 90% of oral malignant neoplasms. The search for specific biomarkers for OSCC is a very active field of research contributing to establishing early diagnostic methods and unraveling underlying pathogenic mechanisms. In this work we investigated the salivary metabolites and the metabolic pathways of OSCC aiming find possible biomarkers. Salivary metabolites samples from 27 OSCC patients and 41 control individuals were compared through a gas chromatography coupled to a mass spectrometer (GC-MS) technique. Our results allowed identification of pathways of the malate-aspartate shuttle, the beta-alanine metabolism, and the Warburg effect. The possible salivary biomarkers were identified using the area under receiver-operating curve (AUC) criterion. Twenty-four metabolites were identified with AUC > 0.8. Using the threshold of AUC = 0.9 we find malic acid, maltose, protocatechuic acid, lactose, 2-ketoadipic, and catechol metabolites expressed. We notice that this is the first report of salivary metabolome in South American oral cancer patients, to the best of our knowledge. Our findings regarding these metabolic changes are important in discovering salivary biomarkers of OSCC patients. However, additional work needs to be performed considering larger populations to validate our results.
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Morphological, spectroscopic and scattering studies of the self-assembly and aggregation process of hybrids containing gold nanoparticles (AuNPs) and the amyloid peptides [RF]4 and P[RF]4 (where R = arginine; F = phenylalanine; P = proline) in aqueous solution were performed. Two methodologies were tested for the AuNP nucleation, using sodium borohydride (NaBH4) or epigallocatechin gallate (EGCG) as a reducing agent. This led to remarkable distinct modes of assembly, AuNP decorated fibrils with NaBH4 reduction or isolated AuNPs with EGCG reduction. For both methodologies, the presence of spherical AuNPs was observed by plasmonic resonance bands in absorption spectra at â¼520 nm. Zeta potential measurements confirmed stable systems, with a similar aggregation state. Circular dichroism spectra revealed an antiparallel ß-sheet conformation of the peptides. The transmission electron microscopy (TEM) images showed the coexistence of nanometer fibers and globular nanoparticles with 20 nm size. The small-angle X-ray scattering (SAXS) results show that the NaBH4 systems presented large cylindrical structures, while with increasing P[RF]4 content, a decrease in radius was observed. However, the EGCG-AuNPs were characterized by spherical particles, with a radius of 10-20 nm. Also, the colorimetric efficiency of the hybrids in the capture of Cu2+ ions in solution was monitored. Raman spectroscopy data confirmed the conformation/structure of self-assembled samples. Moreover, there are indications for a surface-enhanced Raman spectroscopy (SERS) effect for Cu2+ sites. The set of results indicates that these systems could act as a promising sensitive metal concentration probes.
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Colorimetria/métodos , Cobre/análise , Cobre/química , Ouro/química , Interações Hidrofóbicas e Hidrofílicas , Nanopartículas Metálicas/químicaRESUMO
Confined and interstitial water has a key role in several chemical, physical and biological processes. It is remarkable that many aspects of water behavior in this regime (e.g., chemical reactivity) remain obscure and unaddressed. In particular for gold surfaces, results from simulations indicated that the first wetting layer would present hydrophilic behavior in contrast to the overall hydrophobic character of the bulk water on this surface. In the present work we investigate the properties of confined water on Au ã111ã nanochannels. Our findings, based on a large set of morphological, structural and spectroscopic experimental data and ab initio computer simulations, strongly support the hypothesis of hydrophilicity of the first wetting layer of the Au ã111ã surface. A unique oxidation process was also observed in the nanochannels driven by confined water. Our findings indicated that the oxidation product is Au(OH)3. Therefore, the Au surface reactivity against confined water needs to be considered for nanoscopic applications such as, e.g., catalysis in fine chemicals, pharmaceuticals, and the food industry green processes.
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The diagnosis of thyroid pathologies is usually made by cytologic analysis of the fine needle aspiration (FNA) material. However, this procedure has a low sensitivity at times, presenting a variation of 2-37%. The application of optical spectroscopy in the characterization of alterations could result in the development of a minimally invasive and non-destructive method for the diagnosis of thyroid diseases. Thus, the objective of this work was to study the biochemical alterations of tissues and hormones (T3 and T4) of the thyroid gland by means of molecular vibrations probed by FT-Raman spectroscopy. Through the discriminative linear analysis of the Raman spectra of the tissue, it was possible to establish (in percentages) the correct classification index among the groups: goitre adjacent tissue, goitre nodular region, follicular adenoma, follicular carcinoma and papillary carcinoma. As a result of the comparison between the groups goitre adjacent tissue versus goitre nodular region, an index of 58.3% of correct classification was obtained; this percentage was considered low, and it was not possible to distinguish the Raman spectra of these groups. Between goitre (nodular region and adjacent tissue) versus papillary carcinoma, the index of correct classification was 64.9%, which was considered good. A relevant result was obtained in the analysis of the benign tissues (goitre and follicular adenoma) versus malignant tissues (papillary and follicular carcinomas), for which the index was 72.5% and considered good. It was also possible, by means of visual observation, to find similar vibrational modes in the hormones and pathologic tissues. In conclusion, some biochemical alterations, represented by the FT-Raman spectra, were identified that could possibly be used to classify histologic groups of the thyroid. However, more studies are necessary due to the difficulty in setting a standard for pathologic groups.
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Análise Espectral Raman , Glândula Tireoide/metabolismo , Glândula Tireoide/patologia , Análise por Conglomerados , Análise Discriminante , Humanos , Análise de Componente Principal , Doenças da Glândula Tireoide/diagnóstico , Doenças da Glândula Tireoide/metabolismo , Doenças da Glândula Tireoide/patologia , Tiroxina/metabolismo , Tri-Iodotironina/metabolismo , VibraçãoRESUMO
The Fourier transform (FT)-Raman spectroscopy technique is used to assess the biochemical alterations that occur in the degenerative process of the rotator cuff supraspinatus tendon. The main alterations observed occur in the glycine, proline, hydroxyproline, cysteine, cistine, phenylalanine, tyrosine, collagen I and III, nucleic acid, lipids, glycosaminoglycans, and metalloproteinases bands. An increasing intensity for these bands is found in degenerated tendons, a finding well correlated with hyaline state and cellular activity. Statistical analysis (principal components analysis and clustering) shows a clear separation of the spectra into nonhyalinized and hyalinized clusters, which enables the construction of a binary diagnosis model based on logistic regression. Best diagnosis provided a sensitivity of 66.0% and a specificity of 74.7% with 79.6% concordant pairs. The discriminating power of the diagnostic test is assessed by computing the area under the receiving-operator characteristic curve (AUC), which indicates good accuracy (AUC=0.81). In principle, these results indicate that Raman spectroscopy can be used as an auxiliary aid to improve shoulder tendon surgery quality by guiding anchoring onto more healthy (nonhyaline) pieces of tendons. This should contribute to a decrease in the current high rerupture rate (13 to 68%) for this procedure.
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Algoritmos , Diagnóstico por Computador/métodos , Manguito Rotador/patologia , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Análise Espectral Raman/métodos , Tendinopatia/diagnóstico , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
The Raman-based optical diagnosis of normal cervix, inflammative cervix (cervicitis), and cervical intraepithelial neoplasia was investigated on samples of 63 patients. The main alterations were found in the 857 cm(-1) (CCH deformation aromatic); 925 cm(-1) (C-C stretching); approximately 1247 cm(-1) (CN stretch, NH bending of Amide III); 1370 cm(-1) (CH2 bending); and 1525 cm(-1) (C=CC=N stretching) vibrational bands in accordance with previously reported in the literature comparing normal and malignant cervical tissue. The statistical analysis (principal components analysis, clustering, and logistic regression models) applied to the spectral data indicated that the full discrimination among normal and neoplastic tissues of cervix by Raman optical biopsy is seriously affected by the presence of inflammatory infiltrates, which increases the false-positive rate. This fact is specially relevant once cervicitis is a very common state (noncancerous) of the cervix of sexually active woman. The results suggest that, for the correct Raman-based diagnosis of normal cervix from cervical intraepithelial neoplasia, it is necessary to use an auxiliary way to discriminate the contribution from the inflammatory infiltrates.
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Algoritmos , Interpretação de Imagem Assistida por Computador/métodos , Análise Espectral Raman/métodos , Displasia do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/diagnóstico , Diagnóstico Diferencial , Feminino , Humanos , Aumento da Imagem/métodos , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Study of genetic material allows the comprehension the origin of the many biochemical changes that follow diseases, like cancer, promoting the development of early preventive inquiry and more efficient individual treatments. Raman spectroscopy can be an important tool in DNA study, since it allows probe molecular vibrations of genetic material in a fast way. The present work established a systematic way for extract DNA in suitable concentrations and structural integrity allowing studies by Raman spectroscopy or other spectroscopic technique, including bio-analytical sensors for probing genetic alterations.