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1.
Clin Gastroenterol Hepatol ; 22(3): 642-652.e2, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37879520

RESUMO

BACKGROUND & AIMS: We describe the experience of Lynch syndrome (LS) diagnosis in the province of Manitoba, Canada, over the past 20 years. METHODS: We performed a retrospective review of charts from the provincial Genetics Clinic from January 1, 2000, to May 31, 2023. We extracted data on individuals identified to carry a germline pathogenic or likely pathogenic LS gene variant, the mode of ascertainment, family history, and cascade genetic testing (CGT). Data were stratified and compared before and after the year of implementation (October 2013) of the provincial LS screening program (LSSP) and ascertainment by the LSSP vs clinic referrals (CRs). RESULTS: Between 2014 and 2021, 50 of 101 (49.5%) index cases were identified by the LSSP compared with 51 of 101 (50.5%) from CRs. The proportion of PMS2 variants was 34% (17 of 50) for LSSP index cases compared with 21.6% (11 of 51) for CRs from 2014 to 2021 (P < .001). Among CRs from 2014 to 2021, 24 of 51 (47.1%) families met the Amsterdam criteria, compared with 11 of 50 (22.0%) for the LSSP (P = .01). CGT occurred among 46.8% (95 of 203; average, 1.9 relatives/index) of first-degree relatives of CR index cases vs 36.5% (84 of 230; average, 1.7 relatives/index) of first-degree relatives of LSSP index cases (P = .03). Daughters were most likely to undergo CGT. CONCLUSIONS: A tumor screening program is more effective at detecting individuals with lower penetrant gene variants and families who do not meet traditional family history-based criteria. Cascade genetic testing is higher among clinic referrals compared with the screening program. These findings suggest a complementary role of these 2 ascertainment methods for Lynch syndrome.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose , Humanos , Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Neoplasias Colorretais Hereditárias sem Polipose/epidemiologia , Neoplasias Colorretais Hereditárias sem Polipose/genética , Manitoba/epidemiologia , Estudos Retrospectivos , Mutação em Linhagem Germinativa , Testes Genéticos/métodos , Reparo de Erro de Pareamento de DNA
2.
Rev Cardiovasc Med ; 23(5): 166, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-39077603

RESUMO

Background: Hypertension is one of the most prevalent diseases in the United States, affecting an estimated 3.5% of children and adolescents. It can be adversely affect most organ systems but is particularly detrimental to the heart and vascular systems. The repercussions can be gauged through well-established measures of cardiovascular function including left ventricular mass index (LVMI), left ventricular hypertrophy (LVH), carotid intima media thickness (cIMT), and aortic stiffness. Cardiovascular function is also affected by underlying etiologies of hypertension including chronic kidney disease, polycystic kidney disease, coarctation of the aorta, adrenal disorders, renal artery stenosis, obstructive sleep apnea, as well as various drugs and medications (decongestants, stimulants, Non-steroidal Anti-inflammatory Drugs (NSAIDs), and steroids). Methods: An exhaustive literature search was conducted for clinical data regarding pediatric hypertension. Sixty-seven articles were incorporated with data on 189,477 subjects total. The data was then extracted and categorized as relating to hypertension incidence, LVMI, LVH, cIMT, and/or aortic stiffness. Results: The prevalence of pediatric ( < 18 years) hypertension extracted from 47 studies from 1994 to 2018 averaged 4%. The LVMI assessed over 7 studies (n = 661) averaged 39.3 g/ m 2.7 in the hypertensive cohort and 30.1 g/ m 2.7 in the control cohort. The cIMT assessed over 7 studies (n = 580) averaged 0.55 mm in the hypertensive cohort and 0.49 mm in the control cohort. Ambulatory arterial stiffness parameters assessed over 5 studies (n = 573) in the normotensive cohort averaged 99.73 mmHg, 69.81 mmHg, 76.85 mmHg, and 46.90 mmHg, for SBP, DBP, MAP, and PP respectively. Ambulatory arterial stiffness parameters assessed over 5 studies (n = 573) in the hypertensive cohort averaged 129.56 mmHg, 73.69 mmHg, 95.08 mmHg, and 56.80 mmHg, for SBP, DBP, MAP, and PP respectively. Conclusions: The significance of pediatric hypertension is emphasized by evidence of early cardiovascular disease as demonstrated by non-invasive measures including cIMT and arterial stiffness parameters, and target organ damage and including LVH and LVMI factors. Thus, early diagnosis and treatment of high blood pressure is paramount for improving long term cardiovascular health and preventing long term morbidity and mortality.

3.
Blood Purif ; 51(8): 649-659, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35468595

RESUMO

BACKGROUND: Pediatric sepsis is a significant public health issue. This condition is exacerbated by rising serum creatinine and inflammatory cytokines that lead to deleterious effects upon the body. The current standard of care involves the use of continuous kidney replacement therapy to remove harmful cytokines until the body returns to homeostasis. In order to promote faster clearance and reduced stay in the ICU, high-volume hemofiltration (HVHF) has shown promise. However, there is a paucity of studies to fully elucidate its benefits. METHODS: A literature search was done using PubMed/ MEDLINE and Embase. The literature was reviewed by two independent reviewers, who independently assessed the quality of randomized controlled trials by using the Cochrane risk of bias tool for RCTs and Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomized controlled trials. Data were combined from studies with a similar design. RESULTS: The primary endpoint of all-cause mortality was found to be reduced by 40% across all of the pooled studies. For secondary endpoints, significant reductions of serum creatinine were found. Additionally, duration of ICU stays and treatment course was found to be significantly shorter in HVHF patients than the current standard of care. The rate of adverse effects was analyzed, and there was no difference in the proportion of patients developing hypokalemia, hyperkalemia, hypernatremia, or hyponatremia. The proportion of patients developing hyperglycemia was higher in patients undergoing HVHF, whereas the proportions of patients developing bleeding were significantly less in patients undergoing HVHF. One study reported a total number of adverse events between the two groups which were significantly lesser in patients undergoing HVHF. CONCLUSION: HVHF shows promise as a modality to treat pediatric patients with sepsis. In order to confirm the benefits of this modality, future studies need significantly more patients for analysis.


Assuntos
Hemofiltração , Sepse , Criança , Creatinina , Estado Terminal/terapia , Citocinas , Humanos , Sepse/terapia
4.
Analyst ; 146(20): 6288-6296, 2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34549732

RESUMO

Increased acidification of aquatic habitats due to climate change is damaging mollusks. Non-destructive methods for analysis are necessary to study these endangered species. We analyzed five Unionidae gastropods using Raman spectroscopy. Shells were primarily composed of aragonite, a polymorph of calcium carbonate found in shell microstructure. Lattice mode Raman peaks from vaterite, a thought to be rare polymorph of calcium carbonate, were identified in each mollusk. Vaterite is present in mollusks at instances of shell damage and subsequent repair. We demonstrate that Raman spectroscopy is sensitive to vaterite, and it may not be as rare as previously thought. We also collected Raman spectra across the interior of Lampsillis fasciola. This data was analyzed through multivariate analysis, combining Principal Component Analysis with Linear Discriminant Analysis (PCA-LDA). Results of PCA-LDA correlate with growth of the mollusks, demonstrating that Raman spectroscopy combined with multivariate analysis could be used to monitor shell growth.


Assuntos
Moluscos , Análise Espectral Raman , Animais , Carbonato de Cálcio , Análise Discriminante , Água Doce , Análise de Componente Principal
5.
Anal Chem ; 92(2): 2052-2057, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31874025

RESUMO

Cortisol is an important steroid hormone in human physiology. Variations or abnormalities in the physiological cortisol levels control acute and chronic stress response, as well as contribute to diseases and syndromes including Addison's disease and Cushing syndrome. The ability to monitor cortisol levels in the physiological range is key in diagnosis and monitoring of these conditions, where current methodology for determination of cortisol levels relies on instrumentation that requires extensive sample preparation, long run times, and is destructive to the sample. Raman spectroscopy provides rapid sample analysis with relatively simple instrumentation; however, Raman spectroscopy is an inherently weak technique. To provide an enhanced Raman signal, we use surface enhanced Raman spectroscopy (SERS) which utilizes oscillating electric fields of metal nanoparticles, enhancing the overall electric field and therefore resulting in an enhanced signal. We demonstrate SERS-based detection of cortisol in the physiologically relevant range using colloidal silver nanoparticles in ethanolic solutions and bovine serum albumin. The SERS spectra obtained in an ethanol matrix demonstrate a sigmoidal concentration response over the physiologically relevant concentration range, with a limit of detection established at 177 nM. Analysis of cortisol solutions in a complex matrix (bovine serum albumin in phosphate buffered saline) is also demonstrated through the use of principal components analysis, a multivariate technique, which shows the separation of cortisol in a linear fashion with respect to cortisol concentration.


Assuntos
Hidrocortisona/análise , Animais , Bovinos , Teoria da Densidade Funcional , Hidroxilamina/química , Nanopartículas Metálicas/química , Conformação Molecular , Soroalbumina Bovina/química , Prata/química , Análise Espectral Raman , Propriedades de Superfície
6.
Analyst ; 145(5): 1885-1893, 2020 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-31971169

RESUMO

Detection techniques for neurotransmitters that are rapid, label-free, and non-invasive are needed to move towards earlier diagnosis of neurological disease. Surface-enhanced Raman spectroscopy (SERS) allows for sensitive and selective detection of target analytes. The combination of SERS with spatially offset Raman spectroscopy (SORS) in a technique termed surface enhanced spatially offset Raman spectroscopy (SESORS) permits a sensitive and selective detection of neurotransmitters through the skull. Here, we present the SESORS detection of individual neurotransmitters and mixtures of neurotransmitters at physiologically relevant concentrations, while also establishing limits of detection.


Assuntos
Encéfalo/metabolismo , Neurotransmissores/análise , Crânio , Animais , Ouro/química , Limite de Detecção , Masculino , Nanopartículas Metálicas/química , Camundongos Endogâmicos BALB C , Ratos , Análise Espectral Raman/métodos
7.
Analyst ; 145(10): 3461-3480, 2020 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-32301450

RESUMO

Neuroscience would directly benefit from more effective detection techniques, leading to earlier diagnosis of disease. The specificity of Raman spectroscopy is unparalleled, given that a molecular fingerprint is attained for each species. It also allows for label-free detection with relatively inexpensive instrumentation, minimal sample preparation, and rapid sample analysis. This review summarizes Raman spectroscopy-based techniques that have been used to advance the field of neuroscience in recent years.


Assuntos
Diagnóstico por Imagem/métodos , Neurociências/métodos , Análise Espectral Raman/métodos , Humanos
8.
Anal Chem ; 89(11): 5688-5692, 2017 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-28493674

RESUMO

The ability to noninvasively detect neurotransmitters through the skull would aid in understanding brain function and the development of neurological diseases. Surface enhanced spatially offset Raman spectroscopy (SESORS) is a powerful technique that combines the sensitivity of surface-enhanced Raman spectroscopy (SERS) with the ability of spatially offset Raman spectroscopy (SORS) to probe subsurface layers. Here we present SERS measurements of neurotransmitters (melatonin, serotonin, and epinephrine) at various concentrations followed by the SESORS measurements of the neurotransmitters to a concentration as low as 100 µM in a brain tissue mimic through a cat skull. Principal components analysis was performed to distinguish between the surface bone layer and the subsurface layer, comprised of a brain tissue mimic modified with neurotransmitters, and to determine if each individual neurotransmitter could be accurately identified.


Assuntos
Química Encefálica , Imagem Molecular/métodos , Neurotransmissores/análise , Análise Espectral Raman/métodos , Animais , Biomimética , Epinefrina/análise , Melatonina/análise , Análise de Componente Principal , Serotonina/análise
9.
Nano Lett ; 16(12): 7968-7973, 2016 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-27960451

RESUMO

We report here the first fabrication of aluminum film-over nanosphere (AlFON) substrates for UV surface-enhanced resonance Raman scattering (UVSERRS) at the deepest UV wavelength used to date (λex = 229 nm). We characterize the AlFONs fabricated with two different support microsphere sizes using localized surface plasmon resonance spectroscopy, electron microscopy, SERRS of adenine, tris(bipyridine)ruthenium(II), and trans-1,2-bis(4-pyridyl)-ethylene, SERS of 6-mercapto-1-hexanol (as a nonresonant molecule), and dielectric function analysis. We find that AlFONs fabricated with the 210 nm microspheres generate an enhancement factor of approximately 104-5, which combined with resonance enhancement of the adsorbates provides enhancement factors greater than 106. These experimental results are supported by theoretical analysis of the dielectric function. Hence our results demonstrate the advantages of using AlFON substrates for deep UVSERRS enhancement and contribute to broadening the SERS application range with tunable and affordable substrates.

10.
J Am Chem Soc ; 138(42): 13952-13959, 2016 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-27668444

RESUMO

This paper demonstrates the direct sensing of glucose at physiologically relevant concentrations with surface-enhanced Raman spectroscopy (SERS) on gold film-over-nanosphere (AuFON) substrates functionalized with bisboronic acid receptors. The combination of selectivity in the bisboronic acid receptor and spectral resolution in the SERS data allow the sensors to resolve glucose in high backgrounds of fructose and, in combination with multivariate statistical analysis, detect glucose accurately in the 1-10 mM range. Computational modeling supports assignments of the normal modes and vibrational frequencies for the monoboronic acid base of our bisboronic acids, glucose and fructose. These results are promising for the use of bisboronic acids as receptors in SERS-based in vivo glucose monitoring sensors.

11.
Anal Chem ; 88(13): 6638-47, 2016 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-27268724

RESUMO

This perspective presents recent developments in the application of surface-enhanced Raman spectroscopy (SERS) to biosensing, with a focus on in vivo diagnostics. We describe the concepts and methodologies developed to date and the target analytes that can be detected. We also discuss how SERS has evolved from a "point-and-shoot" stand-alone technique in an analytical chemistry laboratory to an integrated quantitative analytical tool for multimodal imaging diagnostics. Finally, we offer a guide to the future of SERS in the context of clinical diagnostics.


Assuntos
Técnicas Biossensoriais , Neoplasias/diagnóstico , Análise Espectral Raman , Animais , Anticorpos/química , Anticorpos/metabolismo , Antineoplásicos/química , Antineoplásicos/uso terapêutico , Biomarcadores/análise , Doxorrubicina/química , Doxorrubicina/uso terapêutico , Corantes Fluorescentes/química , Humanos , Camundongos , Camundongos Nus , Microscopia Confocal , Imagem Multimodal , Nanopartículas/química , Neoplasias/tratamento farmacológico
12.
Chem Soc Rev ; 43(4): 1230-47, 2014 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-23982428

RESUMO

Surface- and tip-enhanced Raman and LSPR spectroscopies have developed over the past 15 years as unique tools for uncovering the properties of single particles and single molecules that are unobservable in ensemble measurements. Measurements of individual events provide insight into the distribution of molecular properties that are averaged over in ensemble experiments. Raman and LSPR spectroscopy can provide detailed information on the identity of molecular species and changes in the local environment, respectively. In this review a detailed discussion is presented on single-molecule and single-particle Raman and LSPR spectroscopy focusing on the major developments in the fields and applications of the techniques.

13.
Elife ; 122024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-39008352

RESUMO

The basolateral amygdala (BLA), a brain center of emotional expression, contributes to acoustic communication by first interpreting the meaning of social sounds in the context of the listener's internal state, then organizing the appropriate behavioral responses. We propose that modulatory neurochemicals such as acetylcholine (ACh) and dopamine (DA) provide internal-state signals to the BLA while an animal listens to social vocalizations. We tested this in a vocal playback experiment utilizing highly affective vocal sequences associated with either mating or restraint, then sampled and analyzed fluids within the BLA for a broad range of neurochemicals and observed behavioral responses of adult male and female mice. In male mice, playback of restraint vocalizations increased ACh release and usually decreased DA release, while playback of mating sequences evoked the opposite neurochemical release patterns. In non-estrus female mice, patterns of ACh and DA release with mating playback were similar to males. Estrus females, however, showed increased ACh, associated with vigilance, as well as increased DA, associated with reward-seeking. Experimental groups that showed increased ACh release also showed the largest increases in an aversive behavior. These neurochemical release patterns and several behavioral responses depended on a single prior experience with the mating and restraint behaviors. Our results support a model in which ACh and DA provide contextual information to sound analyzing BLA neurons that modulate their output to downstream brain regions controlling behavioral responses to social vocalizations.


Assuntos
Dopamina , Emoções , Vocalização Animal , Animais , Masculino , Feminino , Vocalização Animal/fisiologia , Camundongos , Dopamina/metabolismo , Emoções/fisiologia , Acetilcolina/metabolismo , Tonsila do Cerebelo/metabolismo , Tonsila do Cerebelo/fisiologia , Comportamento Animal/fisiologia , Comportamento Sexual Animal/fisiologia , Camundongos Endogâmicos C57BL
14.
Appl Spectrosc ; 78(5): 456-476, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38439705

RESUMO

Here, Raman spectroscopy is used to develop a univariate partial least squares (PLS) calibration capable of quantifying geochemistry in synthetic and natural silicate glass samples. The calibration yields eight oxide-specific models that allow predictions of silicon dioxide (SiO2), sodium oxide (Na2O), potassium oxide (K2O), calcium oxide (CaO), titanium dioxide (TiO2), aluminum oxide (Al2O3), ferrous oxide (FeOT), and magnesium oxide (MgO) (wt%) in glasses spanning a wide range of compositions, while also providing correlation-coefficient matrices that highlight the importance of specific Raman channels in the regression of a particular oxide. The PLS suite is trained on 48 of the 69 total glasses, and tested against 21 validation samples (i.e., held out of training). Trends in root mean square error of calibration (RMSEC), root mean square error of cross-validation (RMSECV), and root mean square error of prediction (RMSEP) model accuracy metrics are investigated to uncover the efficacy of utilizing multivariate analysis for such Raman data and are contextualized against recently produced strategies. The technique yields an average root mean of calibration (∼2.4 wt%), cross-validation (∼ 2.9 wt%), prediction (∼ 2.6 wt%), and normalized variance (∼ 28%). Raman band positional shifts are also mapped against underlying chemical variations; with major influences arising primarily as a function of overall oxidation state and silica concentration: via ferric cation (Fe3+)/ferrous cation (Fe2+) ratios and SiO2 (wt%). The algorithm is further validated preliminarily against a separate external set of 11 natural basaltic glasses to unravel the limitations of the synthetic models on natural samples, and to determine the suitability of "universal" Raman-model applications in scenarios where prior chemical contextualization of the target sample is possible. This study represents the first time Raman spectra of amorphous silicates have been paired with PLS, offering a foundation for future improvements utilizing these systems.

15.
NeuroImmune Pharm Ther ; 3(1): 7-15, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38532784

RESUMO

Objectives: Cerebrovascular complications are prevalent in COVID-19 infection and post-COVID conditions; therefore, interactions of SARS-CoV-2 with cerebral microvascular cells became an emerging concern. Methods: We examined the inflammatory responses of human brain microvascular endothelial cells (HBMEC), the main structural element of the blood-brain barrier (BBB), following exposure to the S1 subunit of the spike protein of different SARS-CoV-2 variants. Specifically, we used the S1 subunit derived from the D614 variant of SARS-CoV-2, which started widely circulating in March of 2020, and from the Delta variant, which started widely circulating in early 2021. We then further examined the impact of the HBMEC secretome, produced in response to the S1 exposure, on microglial proinflammatory responses. Results: Treatment with S1 derived from the D614 variant and from the Delta variant resulted in differential alterations of the IL-6 signaling pathway. Moreover, the HBMEC secretome obtained after exposure to the S1 subunit of the D614 variant activated STAT3 in microglial cells, indicating that proinflammatory signals from endothelial cells can propagate to other cells of the neurovascular unit. Overall, these results indicate the potential for different SARS-CoV-2 variants to induce unique cellular signatures and warrant individualized treatment strategies. The findings from this study also bring further awareness to proinflammatory responses involving brain microvasculature in COVID-19 and demonstrate how the surrounding microglia react to each unique variant derived response.

16.
Oral Oncol ; 157: 106957, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39018695

RESUMO

BACKGROUND: Advancements in immunotherapy for recurrent head and neck cancer have necessitated a better understanding of salvage surgical outcomes. This study aimed to determine patterns of failure following salvage head and neck surgery. METHODS: A retrospective cohort study was conducted of 280 patients who underwent salvage surgery for recurrent mucosal squamous cell carcinoma from 1997 to 2018. Cumulative incidence was calculated using the nonparametric Aalen-Johansen estimator. Time to recurrence (TTR) and overall survival (OS) were estimated using the Kaplan-Meier method and multivariable Cox proportional hazard models were used to evaluate associated factors. RESULTS: The 2 and 5-year cumulative incidence rates of second recurrence were 48.3 % (95 % CI 42.4-54.3) and 54.9 % (95 % CI 48.9-60.8), respectively. At 5 years, second locoregional recurrence was twice as common as distant recurrence (41.5 % [95 % CI 35.6-47.4] vs. 21.7 % [95 % CI 16.8-26.6]). The median TTR was 21.1 months (95 % CI 4.4-34.8), which varied by site (38.2 larynx/hypopharynx, 13.9 oral cavity, 8.3 sinonasal, and 7.8 oropharynx, P=.0001). The median OS was 32.1 months (95 % CI 24.1-47.6) and was worse for patients who were Black (hazard ratio [HR] 2.15, 95 % CI 1.19-3.9), current smokers (HR 2.73, 95 % CI 1.53-4.88), former smokers (HR 2.00, 95 % CI 1.19-3.35), ≥ 60 years of age (HR 1.41, 95 % CI 1.01-1.97), or received multimodal primary therapy (HR 1.98, 95 % CI 1.26-3.13). CONCLUSION: Rates of recurrence and mortality after salvage surgery were poor but worse for patients who were Black, older, smoked, had initial multimodal therapy, or had sinonasal or oropharyngeal cancers.


Assuntos
Neoplasias de Cabeça e Pescoço , Recidiva Local de Neoplasia , Terapia de Salvação , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Estudos Retrospectivos , Idoso , Neoplasias de Cabeça e Pescoço/cirurgia , Neoplasias de Cabeça e Pescoço/mortalidade , Carcinoma de Células Escamosas de Cabeça e Pescoço/cirurgia , Carcinoma de Células Escamosas de Cabeça e Pescoço/mortalidade , Adulto , Falha de Tratamento , Idoso de 80 Anos ou mais
17.
Curr Probl Cardiol ; 49(1 Pt C): 102179, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37923029

RESUMO

Gut microbiota, which comprises a broad range of bacteria inhabiting the human intestines, plays a crucial role in establishing a mutually beneficial relationship with the host body. Dysbiosis refers to the perturbations in the composition or functioning of the microbial community, which can result in a shift from a balanced microbiota to an impaired state. This alteration has the potential to contribute to the development of chronic systemic inflammation. Heart failure (HF) is a largely prevalent clinical condition that has been demonstrated to have variations in the gut microbiome, indicating a potential active involvement in the pathogenesis and advancement of the disease. The exploration of the complex interplay between the gut microbiome and HF presents a potential avenue for the discovery of innovative biomarkers, preventive measures, and therapeutic targets. This review aims to investigate the impact of gut bacteria on HF.


Assuntos
Microbioma Gastrointestinal , Insuficiência Cardíaca , Microbiota , Humanos , Insuficiência Cardíaca/terapia , Inflamação , Disbiose/complicações , Disbiose/microbiologia
18.
J Am Chem Soc ; 135(46): 17290-3, 2013 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-24199792

RESUMO

Surface-enhanced spatially offset Raman spectroscopy (SESORS) is a label-free vibrational spectroscopy that has the potential for in vivo imaging. Previous SESORS experiments have been limited to acquiring spectra using SERS substrates implanted under the skin or from nanoparticles embedded in tissue. Here we present SESORS measurements of SERS active nanoparticles coated with a Raman reporter molecule (nanotags) acquired, for the first time, through bone. We demonstrate the ability of SESORS to measure spectra through various thicknesses (3-8 mm) of bone. We also show that diluted nanotag samples (~2 × 10(12) particles) can be detected through the bone. We apply a least-squares support vector machine analysis to demonstrate quantitative detection. It is anticipated that these through-bone SESORS measurements will enable real-time, non-invasive spectroscopic measurement of neurochemicals through the skull, as well as other biomedical applications.


Assuntos
Osso e Ossos/química , Animais , Nanopartículas Metálicas/química , Ovinos , Análise Espectral Raman , Propriedades de Superfície
19.
J Am Chem Soc ; 135(1): 301-8, 2013 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-23214430

RESUMO

Determining the existence of any direct spectral relationship between the far-field scattering properties and the near-field Raman-enhancing properties of surface-enhanced Raman spectroscopy (SERS) substrates has been a challenging task with only a few significant results to date. Here, we prove that hot spot dominated systems show little dependence on the far-field scattering properties because of differences between near- and far-field localized surface plasmon resonance (LSPR) effects as well as excitation of new plasmon modes via a localized emitter. We directly probe the relationship between the near- and far-field light interactions using a correlated LSPR-transmission electron microscopy (TEM) surface-enhanced Raman excitation spectroscopy (SERES) technique. Fourteen individual SERS nanoantennas, Au nanoparticle aggregates ranging from dimers to undecamers, coated in a reporter molecule and encased in a protective silica shell, were excited using eight laser wavelengths. We observed no correlation between the spectral position of the LSPR maxima and the maximum enhancement factor (EF). The single nanoantenna data reveal EFs ranging from (2.5 ± 0.6) × 10(4) to (4.5 ± 0.6) × 10(8) with maximum enhancement for excitation wavelengths of 785 nm and lower energy. The magnitude of maximum EF was not correlated to the number of cores in the nanoantenna or the spectral position of the LSPR, suggesting a separation between near-field SERS enhancement and far-field Rayleigh scattering. Computational electrodynamics confirms the decoupling of maximum SERS enhancement from the peak of the scattering spectrum. It also points to the importance of a localized emitter for radiating Raman photons to the far-field which, in nonsymmetric systems, allows for the excitation of radiative plasmon modes that are difficult to excite with plane waves. Once these effects are considered, we are able to fully explain the hot spot dominated SERS response of the nanoantennas.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Estrutura Molecular , Tamanho da Partícula , Análise Espectral Raman , Propriedades de Superfície
20.
Phys Chem Chem Phys ; 15(12): 4110-29, 2013 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-23420338

RESUMO

Interest in nanotechnology is driven by the unique and novel properties of nanoscale materials such as the strong interaction of metal particles with light, caused by localized surface plasmon resonances (LSPRs). In this perspective article we review and discuss prominent advantages and advances in single particle studies of plasmonic nanostructures. Common techniques and recent improvements in spatial and spectral resolution will first be outlined, covering both far-field and near-field phenomena. Then, new insight and information uniquely obtained from single particle approaches will be overviewed, including several fundamental studies of plasmonic behaviour, as well as applications using single particle tracking and chemical reaction monitoring. Finally, highly interdisciplinary future directions and experiments are discussed.

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