Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 75
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Clin Pediatr Dent ; 44(6): 451-458, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33378466

RESUMO

OBJECTIVE: The surface roughness of various orthodontic materials could affect biofilm formation and friction. The purpose of this study was to examine the surface roughness and chemical composition of the slots and wings of several ceramic self-ligating brackets. STUDY DESIGN: Four types of ceramic self-ligating brackets were separated into experimental groups (DC, EC, IC, and QK) while a metal self-ligating bracket (EM) was used as the control group. Atomic force microscopy and energy-dispersive x-ray spectroscope were used to examine the surface roughness and chemical composition of each bracket slot and wing. RESULTS: The control group was made of ferrum and chrome while all the experimental groups were comprised of aluminum and oxide. There was a statistically significant difference in the roughness average (Sa) among the various self-ligating brackets (p< 0.001 in slots and p<0.01 in the wing). The slots in the EC group had the lowest Sa, followed by the DC, IC, control, and QK groups. The wings in the IC group had the lowest Sa, followed by the EC, DC, control, and QK groups. CONCLUSIONS: There is a significant difference in the surface roughness of the slots and wings among several types of ceramic self-ligating brackets.


Assuntos
Braquetes Ortodônticos , Biofilmes , Cerâmica , Ligas Dentárias , Fricção , Humanos , Teste de Materiais , Desenho de Aparelho Ortodôntico , Fios Ortodônticos , Aço Inoxidável , Propriedades de Superfície
2.
Artigo em Inglês | MEDLINE | ID: mdl-33248886

RESUMO

We investigated the effect of Raman excitation wavelengths on the surface-enhanced Raman spectroscopy (SERS)-based identification of isolated nontuberculous mycobacteria (NTM). The SERS spectra with 3 commonly used excitation wavelengths, 532, 638, and 785 nm, were compared across 6 representative NTM species that primarily cause human NTM infections in Korea and the United States; these species were identified. The statistical differences among NTM SERS spectra at each Raman excitation wavelength were verified using 1-way analysis of variance, and the 6 NTM species were identified using principal components-linear discriminant analysis with leave-one-out cross validation. The identification accuracies with aromatic amino acid biomarkers were 99.3%, 91.3%, and 90.7% for 532, 638, and 785 nm, respectively. We believe that the proposed SERS protocol with aromatic amino acid biomarkers at the 532-nm Raman excitation wavelength will enable fast and accurate identification of NTM compared to previous identification methods.

3.
ACS Appl Mater Interfaces ; 12(7): 7897-7904, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31971765

RESUMO

Surface-enhanced Raman scattering (SERS) is an ultrasensitive molecular screening technique with greatly enhanced Raman scattering signals from trace amounts of analytes near plasmonic nanostructures. However, research on the development of a sensor that balances signal enhancement, reproducibility, and uniformity has not yet been proposed for practical applications. In this study, we demonstrate the potential of the practical application for detecting or predicting asymptomatic breast cancer from human tears using a portable Raman spectrometer with an identification algorithm based on multivariate statistics. This potentiality was realized through the fabrication of a plasmonic SERS substrate equipped with a well-aligned, gold-decorated, hexagonal-close-packed polystyrene (Au/HCP-PS) nanosphere monolayer that provided femtomole-scale detection, giga-scale enhancement, and <5% relative standard deviation for reliability and reproducibility, regardless of the measuring site. Our results can provide a first step toward developing a noninvasive, real-time screening technology for detecting asymptomatic tumors and preventing tumor recurrence.

4.
PLoS One ; 14(5): e0216425, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31083660

RESUMO

BACKGROUND: Myopia is the most common ocular disorder and is mainly caused by axial elongation of the sclera. If the stiffness of sclera increased, it can inhibit myopia progression. The aim of this study is to compare the effect of the collagen crosslinking with different types and concentrations of carbohydrates on chemical bond and ultrastructural change of rabbit sclera. METHODS: Nine New Zealand white rabbits were treated with five, sequential sub-Tenon injections of 0.15 mL solutions of ribose, sucrose, and glycogen of 0.1, 0.2 and 0.4 M concentration at the right eye over 14 days. Ten weeks after the last injection, the rabbits were sacrificed and chemical bond and ultrastructural changes were compared with those of the untreated left sclera using Raman spectroscopy, atomic force microscopy (AFM), and histology. RESULTS: Raman spectroscopy of the control and cross-linked rabbit sclera tissue revealed different types of collagen interactions. Raman shift of 919 cm-1 (C-C stretching and vibration of the proline ring in collagen) was the highest in ribose, followed by sucrose and glycogen. Total energy intensity was also highest in ribose, followed by sucrose and glycogen, and showed a tendency to increase at higher concentrations. AFM revealed interlocking arrangements of collagen fibrils. The collagen fibril diameter was 105.6 ± 21.2 nm, 109.4 ± 28.8 nm, 113.1 ± 30.8 nm and 137.6 ± 25.3 nm for control group, 0.4 M glycogen, sucrose, and ribose, respectively. Histology indicated increased density of the collagen bundle and no increase in inflammatory cell recruitment compared to control at high concentrations of ribose. CONCLUSIONS: Scleral crosslinking using glycation increased the scleral biomechanical rigidity and these results were particularly pronounced in ribose. Scleral crosslinking using glycation may be a promising method for inhibiting high myopia progression.


Assuntos
Colágeno/metabolismo , Glicogênio/metabolismo , Miopia Degenerativa , Ribose/metabolismo , Esclera , Sacarose/metabolismo , Animais , Modelos Animais de Doenças , Glicosilação , Miopia Degenerativa/metabolismo , Miopia Degenerativa/patologia , Coelhos , Esclera/metabolismo , Esclera/ultraestrutura
5.
Korean J Orthod ; 49(1): 12-20, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30603621

RESUMO

Objective: The aim of this study was to analyze the surface composition, roughness, and relative friction of metal clips from various ceramic self-ligating brackets. Methods: Six kinds of brackets were examined. The control group (mC) consisted of interactive metal self-ligating brackets while the experimental group (CC, EC, MA, QK, and WA) consisted of interactive ceramic self-ligating brackets. Atomic force microscopy-lateral force microscopy and scanning electron microscopy-energy-dispersive X-ray spectroscopy were used to analyze the surface of each bracket clip. Results: All the clips in the experimental groups were coated with rhodium except for the QK clip. The results showed that the QK clip had the lowest average roughness on the outer surface, followed by the MA, EC, WA, and CC clips. However, the CC clip had the lowest average roughness on the inner surface, followed by the QK, WA, MA, and EC clips. The QK clip also had the lowest relative friction on the outer surface, followed by the MA, EC, CC, and WA clips. Likewise, the CC clip had the lowest relative friction on the inner surface, followed by the QK, WA, MA, and EC clips. Conclusions: The surface roughness and relative friction of the rhodium-coated clips were generally higher than those of the uncoated clips.

6.
ACS Nano ; 12(7): 7100-7108, 2018 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-29920065

RESUMO

We report the development of a surface-enhanced Raman spectroscopy sensor chip by decorating gold nanoparticles (AuNPs) on ZnO nanorod (ZnO NR) arrays vertically grown on cellulose paper (C). We show that these chips can enhance the Raman signal by 1.25 × 107 with an excellent reproducibility of <6%. We show that we can measure trace amounts of human amniotic fluids of patients with subclinical intra-amniotic infection (IAI) and preterm delivery (PTD) using the chip in combination with a multivariate statistics-derived machine-learning-trained bioclassification method. We can detect the presence of prenatal diseases and identify the types of diseases from amniotic fluids with >92% clinical sensitivity and specificity. Our technology has the potential to be used for the early detection of prenatal diseases and can be adapted for point-of-care applications.


Assuntos
Papel , Complicações Infecciosas na Gravidez/diagnóstico , Nascimento Prematuro/diagnóstico , Diagnóstico Pré-Natal , Análise Espectral Raman/métodos , Líquido Amniótico/química , Celulose/química , Feminino , Ouro/química , Humanos , Nanopartículas Metálicas/química , Tamanho da Partícula , Gravidez , Propriedades de Superfície , Óxido de Zinco/química
7.
Biosens Bioelectron ; 111: 59-65, 2018 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-29649653

RESUMO

It is very difficult to predict some complications after subarachnoid hemorrhage (SAH), despite rapid advances in medical science. Herein, we introduce a label-free cellulose surface-enhanced Raman spectroscopy (SERS) biosensor chip with pH-functionalized, gold nanoparticle (AuNP)-enhanced localized surface plasmon resonance (LSPR) effects for identification of SAH-induced cerebral vasospasm and hydrocephalus caused by cerebrospinal fluid (CSF). The SERS biosensor chip was implemented by the synthesis reaction of the AuNPs, which were charged positively through pH level adjustment, onto a negatively-charged cellulose substrate with ξ = -30.7 mV. The zeta potential, nanostructural properties, nanocrystallinity, and computational calculation-based electric field distributions of the cellulose-originated AuNPs were optimized to maximize LSPR phenomena and then characterized. Additionally, the performance of the SERS biosensor was compared under two representative excitation laser sources in the visible region (532 nm) and near-infrared region (785 nm). The Raman activities of our SERS biosensor chip were evaluated by trace small molecules (crystal violet, 2 µL), and the biosensor achieved an enhancement factor of 3.29 × 109 for the analytic concept with an excellent reproducibility of 8.5% relative standard deviation and a detection limit of 0.74 pM. Furthermore, the experimental results revealed that the five proposed SERS-based biomarkers could provide important information for identifying and predicting SAH-induced cerebral vasospasm and hydrocephalus complications (91.1% reliability and 19.3% reproducibility). Therefore, this facile and effective principle of our SERS biosensor chip may inspire the basis and strategies for the development of sensing platforms to predict critical complications in various neurosurgical diagnoses.


Assuntos
Hidrocefalia/líquido cefalorraquidiano , Hidrocefalia/etiologia , Análise Espectral Raman/métodos , Hemorragia Subaracnóidea/complicações , Vasoespasmo Intracraniano/líquido cefalorraquidiano , Vasoespasmo Intracraniano/etiologia , Biomarcadores/líquido cefalorraquidiano , Técnicas Biossensoriais/métodos , Celulose/química , Celulose/ultraestrutura , Diagnóstico Precoce , Ouro/química , Humanos , Hidrocefalia/diagnóstico , Limite de Detecção , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Reprodutibilidade dos Testes , Propriedades de Superfície , Vasoespasmo Intracraniano/diagnóstico
8.
Microsc Res Tech ; 81(6): 544-550, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29473284

RESUMO

Although the confirmation of inflammatory changes within tissues at the onset of various diseases is critical for the early detection of disease and selection of appropriate treatment, most therapies are based on complex and time-consuming diagnostic procedures. Raman spectroscopy has the ability to provide non-invasive, real-time, chemical bonding analysis through the inelastic scattering of photons. In this study, we evaluate the feasibility of Raman spectroscopy as a new, easy, fast, and accurate diagnostic method to support diagnostic decisions. The molecular changes in carrageenan-induced acute inflammation rat tissues were assessed by Raman spectroscopy. Volumes of 0 (control), 100, 150, and 200 µL of 1% carrageenan were administered to rat hind paws to control the degree of inflammation. The prominent peaks at [1,062, 1,131] cm-1 and [2,847, 2,881] cm-1 were selected as characteristic measurements corresponding to the C-C stretching vibrational modes and the symmetric and asymmetric C-H (CH2 ) stretching vibrational modes, respectively. Principal component analysis of the inflammatory Raman spectra enabled graphical representation of the degree of inflammation through principal component loading profiles of inflammatory tissues on a two-dimensional plot. Therefore, Raman spectroscopy with multivariate statistical analysis represents a promising method for detecting biomolecular responses based on different types of inflammatory tissues.


Assuntos
Inflamação/diagnóstico , Inflamação/patologia , Análise Espectral Raman/métodos , Animais , Carragenina , Diagnóstico Precoce , Inflamação/induzido quimicamente , Masculino , Análise de Componente Principal , Ratos , Ratos Sprague-Dawley
9.
Anal Chem ; 89(12): 6448-6454, 2017 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-28509533

RESUMO

We introduce a label-free biosensing cellulose strip sensor with surface-enhanced Raman spectroscopy (SERS)-encoded bimetallic core@shell nanoparticles. Bimetallic nanoparticles consisting of a synthesis of core Ag nanoparticles (AgNP) and a synthesis of shell gold nanoparticles (AuNPs) were fabricated on a cellulose substrate by two-stage successive ionic layer absorption and reaction (SILAR) techniques. The bimetallic nanoparticle-enhanced localized surface plasmon resonance (LSPR) effects were theoretically verified by computational calculations with finite element models of optimized bimetallic nanoparticles interacting with an incident laser source. Well-dispersed raspberry-like bimetallic nanoparticles with highly polycrystalline structure were confirmed through X-ray and electron analyses despite ionic reaction synthesis. The stability against silver oxidation and high sensitivity with superior SERS enhancement factor (EF) of the low-cost SERS-encoded cellulose strip, which achieved 3.98 × 108 SERS-EF, 6.1%-RSD reproducibility, and <10%-degraded sustainability, implicated the possibility of practical applications in high analytical screening methods, such as single-molecule detection. The remarkable sensitivity and selectivity of this bimetallic biosensing strip in determining aquatic toxicities for prohibited drugs, such as aniline, sodium azide, and malachite green, as well as monitoring the breast cancer progression for urine, confirmed its potential as a low-cost label-free point-of-care test chip for the early diagnosis of human diseases.


Assuntos
Técnicas Biossensoriais , Celulose/química , Ouro/química , Nanopartículas Metálicas/química , Prata/química , Íons/química , Estrutura Molecular , Tamanho da Partícula , Análise Espectral Raman , Propriedades de Superfície
10.
Artigo em Inglês | MEDLINE | ID: mdl-28437685

RESUMO

Although many methodologies have been developed to identify unknown bacteria, bacterial identification in clinical microbiology remains a complex and time-consuming procedure. To address this problem, we developed a label-free method for rapidly identifying clinically relevant multilocus sequencing typing-verified quinolone-resistant Klebsiella pneumoniae strains. We also applied the method to identify three strains from colony samples, ATCC70063 (control), ST11 and ST15; these are the prevalent quinolone-resistant K. pneumoniae strains in East Asia. The colonies were identified using a drop-coating deposition surface-enhanced Raman scattering (DCD-SERS) procedure coupled with a multivariate statistical method. Our workflow exhibited an enhancement factor of 11.3×106 to Raman intensities, high reproducibility (relative standard deviation of 7.4%), and a sensitive limit of detection (100 pM rhodamine 6G), with a correlation coefficient of 0.98. All quinolone-resistant K. pneumoniae strains showed similar spectral Raman shifts (high correlations) regardless of bacterial type, as well as different Raman vibrational modes compared to Escherichia coli strains. Our proposed DCD-SERS procedure coupled with the multivariate statistics-based identification method achieved excellent performance in discriminating similar microbes from one another and also in subtyping of K. pneumoniae strains. Therefore, our label-free DCD-SERS procedure coupled with the computational decision supporting method is a potentially useful method for the rapid identification of clinically relevant K. pneumoniae strains.


Assuntos
Farmacorresistência Bacteriana , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/química , Klebsiella pneumoniae/efeitos dos fármacos , Análise Espectral Raman/métodos , Antibacterianos/farmacologia , Humanos , Limite de Detecção , Análise Multivariada , Análise de Componente Principal , Reprodutibilidade dos Testes , Vibração
11.
ACS Appl Mater Interfaces ; 9(7): 5891-5899, 2017 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-28156092

RESUMO

Gold-decorated, vertically grown ZnO nanorods (NRs) on a flexible graphite sheet (Au/ZnONRs/G) were developed for surface-enhanced Raman scattering (SERS)-based biosensing to identify trace amounts of human aqueous humors. This Au/ZnONRs/G SERS-functionalized sensor was fabricated via two steps: hydrothermal synthesis-induced growth of ZnO NRs on graphite sheets for nanostructure fabrication, followed by e-beam evaporator-induced gold metallization on ZnONRs/G for SERS functionalization. The thickness of the Au layer and the height of the ZnO NRs for enhancing SERS performance were adjusted to maximize Raman intensity, and the optimized Au/ZnONRs/G nanostructures were verified by the electric finite element computational models to maximize the electric fields. The proposed Au/ZnONRs/G SERS sensor showed an enhancement factor of 2.3 × 106 via rhodamine 6G Raman probe and excellent reproducibility (relative standard deviation of <10%) via Raman mapping of a SERS active area with a square of 100 × 100 µm2. To evaluate the actual bioapplicability of point-of-care-testing (POCT) analysis in clinics, SERS data acquisition was performed with an integration time of 1 s from a 1 µL analytic droplet of the sample. The performance of this Au/ZnONRs/G sensor was evaluated using human aqueous humors with cataract and two oxidative stress-induced eye diseases, age-related macular degeneration, and diabetic macular edema. These three eye diseases could be identified without any labeling or modification using the Au/ZnONRs/G SERS sensor and the computational algorithm incorporating a support vector machine and multivariate statistical prediction. Therefore, these findings indicate that our label-free, highly reproducible and flexible Au/ZnONRs/G SERS-functionalized sensor supported by a multivariate statistics-derived bioclassification method has great potential in POCT applications for identifying eye diseases.


Assuntos
Nanotubos , Humor Aquoso , Grafite , Humanos , Reprodutibilidade dos Testes , Análise Espectral Raman , Óxido de Zinco
12.
Microsc Res Tech ; 80(2): 177-182, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27696639

RESUMO

We introduce a label-free spectroscopic method to classify subtypes of quinolone-nonsusceptible Escherichia coli (E. coli) isolates obtained from human blood cultures. Raman spectroscopy with a 30-nm gold-deposited, surface-enhanced Raman scattering (SERS) substrate was used to evaluate three multilocus sequencing typing (MLST)-predefined groups including E. coli ATCC25922, E. coli ST131:O75, and E. coli ST1193:O25b. Although there was a coffee-ring effect, the ring zone was selected at the ideal position to screen E. coli isolates. Strong Raman peaks were present at 1001-1004 cm-1 (CC aromatic ring breathing stretching vibrational mode of phenylalanine), 1447-1448 cm-1 (CH2 scissoring deformation vibrational mode), and 1667 cm-1 (amide I α-helix). Although the three MLST-predefined E. coli isolates had similar Raman spectral patterns, a support vector machine (SVM) learning algorithm-assisted principal component analysis (PCA) analysis had superior performance in detecting the presence of quinolone-nonsusceptible E. coli isolates as well as classifying similar microbes, such as quinolone-nonsusceptible E. coli ST131:O75 and E. coli ST1193:O25b isolates. Therefore, this label-free and nondestructive technique is likely to be useful for clinically diagnosing quinolone-nonsusceptible E. coli isolates with the MLST method.


Assuntos
Farmacorresistência Bacteriana Múltipla , Escherichia coli/classificação , Escherichia coli/isolamento & purificação , Análise Espectral Raman/métodos , Algoritmos , Escherichia coli/química , Escherichia coli/efeitos dos fármacos , Infecções por Escherichia coli/sangue , Infecções por Escherichia coli/diagnóstico , Infecções por Escherichia coli/microbiologia , Humanos , Tipagem de Sequências Multilocus , Projetos Piloto , Análise de Componente Principal , Quinolonas/farmacologia , Máquina de Vetores de Suporte
13.
Artigo em Inglês | MEDLINE | ID: mdl-27865935

RESUMO

This study investigates why a silver nanoparticle (SNP)-induced surface-enhanced Raman scattering (SERS) paper chip fabricated at low successive ionic layer absorption and reaction (SILAR) cycles leads to a high SERS enhancement factor (7×108) with an inferior nanostructure and without generating a hot spot effect. The multi-layered structure of SNPs on cellulose fibers, verified by magnified scanning electron microscopy (SEM) and analyzed by a computational simulation method, was hypothesized as the reason. The pattern of simulated local electric field distribution with respect to the number of SILAR cycles showed good agreement with the experimental Raman intensity, regardless of the wavelength of the excitation laser sources. The simulated enhancement factor at the 785-nm excitation laser source (2.8×109) was 2.5 times greater than the experimental enhancement factor (1.1×109). A 532-nm excitation laser source exhibited the highest maximum local electric field intensity (1.9×1011), particularly at the interparticle gap called a hot spot. The short wavelength led to a strong electric field intensity caused by strong electromagnetic coupling arising from the SNP-induced local surface plasmon resonance (LSPR) effects through high excitation energy. These findings suggest that our paper-based SILAR-fabricated SNP-induced LSPR model is valid for understanding SNP-induced LSPR effects.

14.
Microsc Res Tech ; 79(12): 1193-1199, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27862630

RESUMO

Various labial and lingual orthodontic appliances with aesthetic materials have been developed due to an increased demand in aesthetic orthodontic treatment. However, there are few reports regarding the morphology of lingual orthodontic appliances. Therefore, this study evaluates the roughness of slot surfaces of various orthodontic lingual brackets using field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). Three types of stainless steel lingual brackets (Stealth® , 7th Generation® , and Clippy L® ) and one gold lingual bracket (Incognito™) with a slot size of 0.018 inches × 0.025 inches (0.457 × 0.635 mm2 ) were selected as representative lingual materials. Both FE-SEM and AFM examinations showed that the Stealth® and Clippy L® brackets had the lowest surface roughness, while the 7th Generation® bracket had the highest surface roughness. There was a significant difference in surface morphology between the types of lingual brackets, even when composed of the same material. The surface roughness of the bracket slot was dependent on the manufacturing process or surface polishing process rather than the fundamental properties of the bracket materials. There was no significant difference in the mean surface roughness of the slot floor between gold and stainless steel lingual brackets. These findings suggest that, although the gold lingual bracket is very expensive, it has great potential for use in patients with nickel allergy.


Assuntos
Teste de Materiais/métodos , Microscopia de Força Atômica/métodos , Microscopia Eletrônica de Varredura/métodos , Braquetes Ortodônticos , Propriedades de Superfície
15.
Microsc Res Tech ; 79(11): 1050-1055, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27507597

RESUMO

In this study, we investigate the biochemical characteristics of oxidative stress in age-related macular degeneration (AMD) and diabetic retinopathy (DR) by analyzing aqueous humors. Nondiabetic cataract aqueous humor was used as the control. The level of oxidative damage was evaluated based on changes in Raman spectral intensity. Seven prominent peaks were detected at 1002, 1043, 1062, 1352, 1419, 1454, and 1656 cm-1 . We proposed four multimodal biomarkers to distinguish these peaks based on the ratios of Raman intensities in two wavelengths, including CHO (C-O stretching or C-O-H bending modes), AG (adenine and guanine), PRO-AG (protein and AG), and PHEα (phenylalanine symmetric ring breath and amide I α-helix) markers. The presence of oxidative damage was detected by CHO and AG markers associated with C-O stretching, C-O-H bending modes in carbohydrates (1043 cm-1 ), and the nucleic acids adenine and guanine (1352 cm-1 ), respectively. DR-related oxidative damage was identified by PRO-AG and PHEα markers associated with adenine, guanine, and protein components (1419 and 1454 cm-1 ) and amide I α-helix protein structure (1656 cm-1 ), respectively. AMD-related oxidative damage was identified by four biomarkers. Four multimodal biomarkers with simple linear threshold values achieved high sensitivity of 100% and high specificity of 100% for classifying oxidative stress-induced AMD and DR diseases. Therefore, Raman-based label-free optical detection is effective for detecting the presence of age-related or diabetic oxidative damage in aqueous humor.


Assuntos
Humor Aquoso/diagnóstico por imagem , Catarata/diagnóstico por imagem , Retinopatia Diabética/diagnóstico por imagem , Degeneração Macular/diagnóstico por imagem , Imagem Óptica/métodos , Idoso , Biomarcadores , Humanos , Pessoa de Meia-Idade , Estresse Oxidativo , Análise Espectral Raman
16.
Microsc Res Tech ; 79(10): 966-972, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27435509

RESUMO

The Pap smear is the primary screening tool for invasive cervical cancer resulting from a persistent infection with oncogenic human papillomavirus (HPV); however, there are the problems such as the inability to distinguish between HPV infection and cervical dysplasia and a low sensitivity remain. We present preliminary findings of a label-free method to detect and classify HPV infection and cervical dysplasia using human cervical fluids. Three experimental groups, defined as normal, HPV-positive, and cervical dysplasia, were evaluated through their Raman spectral patterns for noise-independence, high reproducibility, and uniformity. Clinical diagnosis was performed through liquid-based cervical cytology, HPV test, and cervical histologic examination. Healthy cervical fluids showed a strong Raman intensity at 877 cm-1 (symmetric C-C stretching), and at 963 cm-1 (phosphate), compared to a reference Raman peak at 1003 cm-1 (phenylalanine symmetric ring breath). The HPV-positive cervical fluids showed a strong intensity of a Raman peak at 1448 cm-1 corresponding to C-H deformation vibration mode and the highest similarity between the central and ring zones among the three groups. The cervical dysplasia fluids showed the presence of strong peaks compared to the control and HPV-positive groups. In addition, different Raman spectra were acquired according to HPV type. Therefore, all ranges of cervical fluid-induced Raman spectra could be used to detect the presence of cervical pre-cancer. Raman peak-gated assessment provides a label-free and nondestructive tool for the clinical diagnosis of HPV infection and cervical precancerous changes.


Assuntos
Líquidos Corporais , Colo do Útero/virologia , Papillomaviridae , Infecções por Papillomavirus/virologia , Displasia do Colo do Útero/virologia , Líquidos Corporais/química , Líquidos Corporais/virologia , Feminino , Humanos , Papillomaviridae/química , Papillomaviridae/ultraestrutura , Análise Espectral Raman
17.
Sci Rep ; 6: 28588, 2016 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-27333815

RESUMO

We present the fabrication of an ultra-low cost, disposable, solvent-free air cathode all-paper microbial fuel cell (MFC) that does not utilize any chemical treatments. The anode and cathode were fabricated by depositing graphite particles by drawing them on paper with a pencil (four strokes). Hydrophobic parchment paper was used as a proton exchange membrane (PEM) to allow only H(+) to pass. Air cathode MFC technology, where O2 was used as an electron acceptor, was implemented on the paper platform. The bioelectric current was generated by an electrochemical process involving the redox couple of microbial-activated extracellular electron transferred electrons, PEM-passed H(+), and O2 in the cathode. A fully micro-integrated pencil-traced MFC showed a fast start-time, producing current within 10 s after injection of bacterial cells. A single miniaturized all-paper air cathode MFC generated a maximum potential of 300 mV and a maximum current of 11 µA during 100 min after a single injection of Shewanella oneidensis. The micro-fabricated solvent-free air cathode all-paper MFC generated a power of 2,270 nW (5.68 mW/m(2)). The proposed solvent-free air cathode paper-based MFC device could be used for environmentally-friendly energy storage as well as in single-use medical power supplies that use organic matter.

18.
Anal Chem ; 88(10): 5531-7, 2016 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-27127842

RESUMO

We introduce a surface-enhanced Raman scattering (SERS)-functionalized, gold nanoparticle (GNP)-deposited paper strip capable of label-free biofluid sensing for the early detection of infectious eye diseases. The GNP biosensing paper strip was fabricated by the direct synthesis and deposition of GNPs on wax-divided hydrophilic areas of a permeable porous substrate through a facile, power-free synthesizable, and highly reproducible successive ionic layer absorption and reaction (SILAR) technique. To maximize localized surface plasmon resonance-generated SERS activity, the concentration of the reactive solution and number of SILAR cycles were optimized by controlling the size and gap distance of GNPs and verified by computational modeling with geometrical hypotheses of Gaussian-estimated metallic nanoparticles. The responses of our SERS-functionalized GNP paper strip to Raman intensities exhibited an enhancement factor of 7.8 × 10(8), high reproducibility (relative standard deviation of 7.5%), and 1 pM 2-naphthalenethiol highly sensitive detection limit with a correlation coefficient of 0.99, achieved by optimized SILAR conditions including a 10/10 mM/mM HAuCl4/NaBH4 concentration and six SILAR cycles. The SERS-functionalized GNP paper is supported by a multivariate statistics-preprocessed machine learning-judged bioclassification system to provide excellent label-free chemical structure sensitivity for identifying infectious keratoconjunctivitis. The power-free synthesizable fabrication, label-free, rapid analysis, and high sensitivity feature of the SILAR-fabricated SERS-functionalized GNP biosensing paper strip makes it an excellent alternative in point-of-care applications for the early detection of various infectious diseases.


Assuntos
Técnicas Biossensoriais , Ceratoconjuntivite/diagnóstico , Naftalenos/análise , Análise Espectral Raman , Compostos de Sulfidrila/análise , Lágrimas/química , Ouro/química , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , Papel , Sistemas Automatizados de Assistência Junto ao Leito , Porosidade , Análise de Componente Principal
19.
Scanning ; 38(5): 421-426, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26814613

RESUMO

We evaluated nano-structural and chemical changes in human scleral collagen caused by non-enzymatic glycation using AFM, Raman spectroscopy, and microfluidics. Twenty 8 × 2 mm2 scleral strips (n = 5, each) were divided into four groups of pure sclera tissues (control group) and sclera tissues with incubation (1 hr in BSS and ribose) and preservation (23 hr in 90% ethanol) for 7 days (BSS + DR7 group) and 30 days (BSS + DR30 group) at room temperature, and 7 days in a microfluidic chip (BSS + DR + µF7 group). The BSS + DR7 and BSS + DR30 groups were incubated in a mixture of balanced salt solution (BSS) and 0.2 M D-ribose in PBS, pH 7.4 containing 0.1% sodium azide, while the BSS + DR + µF7 group was incubated in the same solutions supplied by two inlet reservoirs from a microfluidic chip. The scleral tissues incubated in the microfluidic environment showed a clear irregular parallel arrangement of collagen fibrils with tangled fibrils. A Raman shift was observed at 919 cm-1 in the glycation groups. Non-enzymatic glycation led to an increased in the density of scleral stromal collagen. Our method using non-enzymatic glycation in a microfluidic environment successfully induced collagen cross-linking. These in vitro results suggested that glycation can be used to strengthen connective tissues. SCANNING 38:421-426, 2016. © 2016 Wiley Periodicals, Inc.


Assuntos
Colágeno/química , Dispositivos Lab-On-A-Chip , Esclera/química , Adulto , Glicosilação , Humanos , Masculino , Microscopia de Força Atômica , Análise Espectral Raman
20.
ACS Appl Mater Interfaces ; 7(50): 27910-7, 2015 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-26619139

RESUMO

We introduce a novel, facile, rapid, low-cost, highly reproducible, and power-free synthesizable fabrication method of paper-based silver nanoparticle (AgNP) immersed surface-enhanced Raman scattering (SERS) platform, known as the successive ionic layer absorption and reaction (SILAR) method. The rough and porous properties of the paper led to direct synthesis of AgNPs on the surface as well as in the paper due to capillary effects, resulting in improved plasmon coupling with interparticles and interlayers. The proposed SERS platform showed an enhancement factor of 1.1 × 10(9), high reproducibility (relative standard deviation of 4.2%), and 10(-12) M rhodamine B highly sensitive detection limit by optimizing the SILAR conditions including the concentration of the reactive solution (20/20 mM/mM AgNO3/NaBH4) and the number of SILAR cycles (six). The applicability of the SERS platform was evaluated using two samples including human cervical fluid for clinical diagnosis of human papillomavirus (HPV) infection, associated with cervical cancer, and a malachite green (MG) solution for fungicide and parasiticide in aquaculture, associated with human carcinogenesis. The AgNP-immersed SERS-functionalized platform using the SILAR technique allowed for high chemical structure sensitivity without additional tagging or chemical modification, making it a good alternative for early clinical diagnosis of HPV infection and detection of MG-activated human carcinogenesis.


Assuntos
Bioensaio/métodos , Técnicas Biossensoriais/métodos , Íons/química , Nanopartículas Metálicas/química , Humanos , Limite de Detecção , Papel , Infecções por Papillomavirus/diagnóstico , Porosidade , Prata/química , Análise Espectral Raman
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...