Name: observation and analysis of blinking surface-enhanced raman scattering
Uploaded: 2018-01-11T14:00:00.000+00:00
Duration: 5 min 52 s
Description: Watch this Scientific Journal Video about Observation and Analysis of Blinking Surface-enhanced Raman Scattering at JoVE.com

O autor agradece a Prof Y. Ozaki (Kwansei Gakuin University) e Dr. T. Itoh (National Institute of Advanced Industrial Science e Technology) para sua discussão proveitosa deste trabalho. Este trabalho foi financiado pelo KAKENHI (subsídio para C de investigação científica) do Ministério da educação, cultura, esportes, ciência e tecnologia (n º 16K. 05671).

1. preparação da amostra
<ol><li>
Preparação de nanopartículas de prata coloidais 20<ol>
<li>Para fabricar a nanopartículas de prata coloidais, dissolva 0,030 g de nitrato de prata e 0,030 g de citrato trissódico dihidratado em 150 mL de água num balão de fundo redondo de 200 mL.</li>
		<li>Combine o balão com um condensador de refluxo (Dimroth).</li>
		<li>Misture a solução do frasco com uma barra magnética de agitador e mexa. Em seguida, aqueça a solução agita o balão em banho de óleo a 150 ° C por 60 min. Nota: A solução vai virar cinza amarela, então leitosa.</li>
		<li>Arrefecer a suspensão em temperatura ambiente e manter a suspensão no frasco coberto com folha de alumínio em um frigorífico. Nota: O protocolo pode ser interrompido neste ponto. Use as nanopartículas coloidais, depois armazenar no frigorífico, dentro de um mês.</li>
	</ol>
</li>
	<li>
Preparação da amostra para multi-coloridas piscando de emissão 11<ol>
<li>Para preparar uma lâmina de microscópio, lave à mão uma placa de vidro com sabão e enxágue com água.</li>
		<li>Adicionar 0,1% solução aquosa de poli-L-lisina para a placa de vidro e remover a solução com um ventilador.</li>
		<li>Adicionar a suspensão coloidal de prata para a placa de vidro e remover a suspensão com um ventilador.</li>
		<li>Coloque uma área para soltar a placa de vidro com uma caneta de bloqueador líquido.</li>
		<li>Gota de água destilada na placa de vidro e cubra-o com outra placa de vidro para criar um slide de microscópio e evitar que a água evapora.</li>
	</ol>
</li>
	<li>
Preparação da amostra para monótonos coloridas piscando SERS 7 , 8 , 9 , 10<ol>
<li>Para preparar uma lâmina de microscópio, lave à mão uma placa de vidro com sabão e enxágue com água.</li>
		<li>Misturar a suspensão coloidal de prata com tintura de thiacyanine ou thiacarbocyanine (µM 25 ou 4, respectivamente) e uma solução aquosa de NaCl (10 mM) em uma relação de volume de 2:1:1.</li>
		<li>Deixar a suspensão da amostra na placa de vidro e remover a suspensão com um ventilador.</li>
		<li>Coloque uma área para soltar a placa de vidro com uma caneta de bloqueador líquido.</li>
		<li>Gota de solução aquosa de NaCl (1 M) na placa de vidro para imobilizar as nanopartículas de prata e cubra-o com outra placa de vidro para criar um prato de corrediça do microscópio e impedir a evaporação da solução.</li>
	</ol>
</li>
</ol>2. observação de nanopartículas de prata a piscar
<ol><li>
Iluminação da amostra
	<ol>
<li>Coloque a placa de vidro de amostra preparada usando protocolo 1.2 ou 1.3 no palco de um microscópio invertido.</li>
		<li>Ilumine a placa de vidro de amostra usando luz branca através de um condensador de campo escuro e foco em vários pontos coloridos (azuis, verdes, amarelos e vermelhos) na placa de vidro, usando uma lente objetiva (60 X).</li>
		<li>Ilumine a placa de vidro de amostra utilizando um feixe atenuado, entregado a um ângulo de 30° em relação à superfície da amostra, de um laser de assemelhace (cw) diodo bombeado de estado sólido (DPSS) através de um filtro de interferência.</li>
		<li>Para usar iluminação laser para observar a nanoaggregates de prata como monótonas manchas coloridas em uma envolvente da mesma cor, mover a área de iluminação do laser para o centro da vista e focalizar os pontos na placa de vidro, ajustando o estágio na direção z.</li>
	</ol>
</li>
	<li>
Observação de piscar
	<ol>
<li>Inserir um filtro de passa-tempo após a lente objetiva e iluminam a placa de vidro de amostra usando um feixe de cw-laser DPSS entregado a um ângulo de 30° em relação à superfície da amostra através de um filtro de interferência.</li>
		<li>Encontrar a piscar pontos conforme mostrado na Figura 1 (ver também Figura S1 no material complementar) movendo o palco na x - e y-direções.</li>
		<li>Gravar vídeo dos pontos piscando com o microscópio invertido, acoplado a uma câmera de refrigeração digital dispositivo de carga acoplada (CCD), que tem uma resolução de tempo de 61-120 ms, por 20 min.</li>
	</ol>
</li>
</ol>3. análise de piscar SERS
<ol><li>
Derivação do perfil do tempo de vídeo
	<ol>
<li>No software que controla a câmera CCD, abra o arquivo de vídeo.</li>
		<li>Para selecionar os pontos piscando e área escura, arraste áreas que cobrem separadamente as regiões com e sem manchas na imagem de vídeo.</li>
		<li>Para derivar perfis de tempo de intensidade de sinal o pontos piscando e áreas escuras no vídeo, selecione Análise Temporal em análisee clique a calcular na janela de Análise Temporal .</li>
		<li>Salve os dados como um arquivo de texto.</li>
	</ol>
</li>
	<li>
Análise do perfil do tempo
	<ol>
<li>Achate uma linha de base do perfil tempo subtraindo-se o perfil de tempo do área escura e/ou montagem com uma função polinomial, como mostrado nas figuras 2A e 2B.</li>
		<li>Avalie uma intensidade média de base que consiste em aproximadamente 2000 pontos, eubasee um desvio-padrão das intensidades de linha de base, σ, como mostrado nas figuras 2 e 2D.</li>
		<li>Distinguir eventos brilhantes de acontecimentos sinistros usando intensidades maiores do que um limiar de eubase + 3σ e registar a duração de cada evento. Na Figura 3, por exemplo, registrar o evento de 0 para 3.5476 s como o evento escuro (com uma duração de t = 3.5476 s) e registrar o evento de 3.5476 para 4.0981 s como o evento brilhante (com uma duração de t = 0.5505 s). Repita o procedimento como mostrado na tabela 1.</li>
		<li>Conte o número de eventos brilhantes e escuros para cada duração, tal como expresso nas primeiras e segunda linhas da tabela 2.</li>
		<li>Soma do número de eventos para cada duração, exceto para eventos mais curtos do que a duração t. Conforme expresso nas segunda e terceiros linhas da tabela 2, por exemplo, somar o número de eventos para cada duração (excepto os eventos para t = 0.0612 s) como 41 + 18 + 9 +...; o resultado é igual a soma de t = 0.1223 s, ou seja, 103.</li>
		<li>Divida os somatórios por cada duração e normalizá-los. Conforme expresso na tabela 2, por exemplo, dividir o somatório para duração t = 0.0612 s pela duração 0.0612 s. O resultado é 3,351.5791. Em seguida, divida o resultado pelo total dos resultados na quarta linha da tabela 2. A distribuição de probabilidade é derivada para ser 0.64494.</li>
		<li>Plotar as distribuições de probabilidade para o brilhante eventos Pem(t) contra sua duração t em um gráfico do logaritmo-logaritmo e caber Log10Pem(t) pelo Log10 (<img alt="Equation 1" src="/files/ftp_upload/56729/56729eq1.jpg">) para deduzir o poder lei expoente α para um determinado ponto a piscar. Se Pem(t) é montado por <img alt="Equation 1" src="/files/ftp_upload/56729/56729eq1.jpg"> </img>, a linha cabida se desvia as parcelas em valores pequenos de Pem(t), como mostrado pela linha pontilhada na Figura 4A.</li>
		<li>Plotar as distribuições de probabilidade para eventos escuro Pfora(t) contra sua duração t em um gráfico do logaritmo-logaritmo e apto Log10Pfora(t) por Log10( <img alt="Equation 3" src="/files/ftp_upload/56729/56729eq3.jpg"> a deduzir a energia lei expoente αfora e o truncamento de tempo τ a piscar mesmo local. Se Pfora(t) é montado por <img alt="Equation 3" src="/files/ftp_upload/56729/56729eq3.jpg"> </img>, a cabido curva desvia as parcelas em valores pequenos de Pfora(t).</li>
		<li>Repita 3.2.1 para 3.2.8 para os outros pontos piscando no vídeo.</li>
	</ol>
</li>
</ol>

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O autor não tem nada para divulgar.

Da junção da prata nanoaggregate, SERS é emitido. Assim, precisamos preparar nanoaggregates ao invés de nanopartículas coloidais, que são cobertas com ânions de citrato. Agregados de prata são formados a partir a salgar-para fora o efeito criado pela adição de poli-L-lisina, que tem -NH3+ e é a origem dos SERS, ou cátions at+ de NaCl, conforme mostrado na Figura S2 do material complementar. Além disso, para iluminar os muitos locais na área ampla, o feixe de...

Superfície-enhanced Raman espalhamento (SERS) é altamente sensível Espectroscopia Raman de uma superfície de metal nobre. Desde que o espectro Raman fornece informações detalhadas sobre a estrutura molecular com base nas posições do pico afiado, através dos modos vibracionais dos grupos funcionais nas moléculas, as informações de uma única molécula sobre uma superfície metálica podem ser investigadas usando SERS1,2,3. De um nanoaggregate de prata com um adsorbate no nível do único-molécula, um sinal intermitente é observado1,2,3,4,5,6, 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16e o espectro varia1,2,3,4,5,6,7,8, 9,10,11,12,13,14. Piscando pode ser induzida por uma única molécula que aleatoriamente se move dentro e fora de um campo de (EM) eletromagnético melhorado em uma junção de nanoaggregate prata nanômetros de tamanho. Portanto, piscando é considerada uma prova simples para a deteção de único-molécula, comparada com uma técnica usando uma distribuição de Poisson de intensidades SERS e um bi-analito2,3,17. No entanto, os mecanismos detalhados do espectro piscando e flutuante, que pode depender fortemente de comportamento molecular na superfície Ag, são ainda controversos.
Em estudos anteriores, piscar SERS foi analisada usando a função de autocorrelação, que pode calcular o coeficiente de difusão e concentração de moléculas entrando e um reforço EM campo12,13,14 . Além disso, uma pontuação normalizada desvio-padrão, que representa a instabilidade na intensidade total, foram obtida a partir do perfil de tempo do sinal15. No entanto, essas abordagens analíticas podem basear-se sobre o comportamento de algumas moléculas. Em contraste, em uma imagem de super-resolução de piscar SERS, comportamento único-molécula em um campo EM avançado pode ser identificados16. No entanto, essas técnicas podem obter tais parâmetros somente em um campo EM reforçada. O comportamento aleatório de uma única molécula dentro de uma grande variedade (por exemplo, no piscar SERS) pode ser representado como uma lei de potência, ao invés de uma média de4,5,6,7,8 ,9,10,11, semelhante à fluorescência pisca de um único semicondutor quantum dot (QD)18,19. Usando um poder lei análise4,5,6,7,8,9,10,11, comportamento molecular pode ser estimado no estado brilhante (no campo EM reforçada) e no estado escuro10; ou seja, o comportamento da molécula sobre toda a superfície de prata pode ser estimado.
Para esta técnica, a prata coloidais nanoaggregates são usados4,5,6,7,8,9,10,11. Estes nanoaggregates mostrar várias bandas de ressonância (LECC) de plasmon de superfície localizadas que afetam fortemente reforçada de campos eletromagnéticos quando eles estão animados em certos comprimentos de onda. Assim, prata SERS-ativo nanopartículas existem em suspensão coloidal e alguns dados pode ser obtida imediatamente. No caso de nanoestruturas simples, que têm regimes, formas e tamanhos específicos, a dependência de LECC de SERS piscando pode esconder outras dependências7; ou seja, se o bom ou mau nanostructure de LECC é usado, os parâmetros será constantes, e outras dependências, portanto, ficará oculta. Análise de lei do poder tem sido usado para descobrir várias dependências dos SERS piscando de prata coloidal nanoaggregates4,5,6,7,8, 9 , 10 , 11.

<table><tbody><tr><td>Silver nitrate, 99.8%</td><td>Wako</td><td>194-00832</td><td></td></tr><tr><td>Trisodium citrate dihydrate, 99. %</td><td>Wako</td><td>191-01785</td><td></td></tr><tr><td>Poly-L-lysine aqueous solution, 0.1%</td><td>Sigma-Aldrich</td><td>P8920</td><td></td></tr><tr><td>3,3&#039;-disulfopropylthiacyanine triethylamine</td><td>Hayashibara Biochemical Laboratories</td><td>NK-2703</td><td>a kind of thiacyanine dyes</td></tr><tr><td>3,3&#039;-diethyl-5,5&#039;-dichloro-9-methylthiacarbocyanine iodine salt</td><td>Hayashibara Biochemical Laboratories</td><td>SMP-9</td><td>a kind of thiacarobocyanine dyes</td></tr><tr><td>Sodium chloride, 99.5%</td><td>Wako</td><td>191-01665</td><td></td></tr><tr><td>Dimroth condenser</td><td>Iwaki</td><td>61-9722-22</td><td>perchased from AS ONE</td></tr><tr><td>Magnetic stirrer</td><td>Corning</td><td>DC-420D</td><td></td></tr><tr><td>Oil bath</td><td>Advantech</td><td>OS-220</td><td></td></tr><tr><td>Glass plate</td><td>Matsunami</td><td>S-1112</td><td>Microscope slide</td></tr><tr><td>Blower</td><td>Hozan</td><td>Z-288</td><td>Air duster</td></tr><tr><td>Liquid blocker pen</td><td>Daido Sangyo</td><td></td><td>LIQUID BLOCKER (Super Pap Pen). Ready-to-use hydrophobic barrier pen designed for immunohistochemistry applications</td></tr><tr><td>Inverted microscope</td><td>Olympus</td><td>IX-70</td><td></td></tr><tr><td>Objective lens</td><td>Olympus</td><td>LCPlanFl 60&amp;times;</td><td>NA 0.7</td></tr><tr><td>Dark field condenser</td><td>Olympus</td><td>U-DCD</td><td>NA 0.8&amp;ndash;0.92</td></tr><tr><td>Cooled digital CCD camera</td><td>Hamamatsu</td><td>ORCA-AG</td><td>controlled by software Aqua Cosmos</td></tr><tr><td>Software for the cooled digital CCD camera</td><td>Hamamatsu</td><td>AquaCosmos</td><td>used for also derivation of the time-profiles from the blinking spots in the video&amp;nbsp;</td></tr><tr><td>Color CCD camera</td><td>ELMO</td><td>TNC-C920</td><td>not used for analysis</td></tr><tr><td>DPSS laser</td><td>RGB laser system</td><td>NovaPro532-75</td><td>&amp;lambda; = 532 nm;&lt;br/&gt; 60 mW (corresponds to a power density of 600 W/cm2)</td></tr><tr><td>Interference filter</td><td>Semrock</td><td>LL01-532-12.5</td><td></td></tr><tr><td>Long pass filter</td><td>Semrock</td><td>BLP01-532R-25</td><td></td></tr><tr><td>Software for the distinguishment and counting of the bright/dark events</td><td>home-maid</td><td></td><td>programmed by C++</td></tr><tr><td>Software for the fitting by a power law</td><td>LightStone</td><td>Origin6.1</td><td></td></tr></tbody></table>

observation and analysis of blinking surface-enhanced raman scattering

De uma única molécula em uma junção de prata nanoaggregate, piscar superfície-enhanced Raman espalhamento (SERS) é observada. Aqui, um protocolo é apresentado em como preparar o SERS-ativo nanoaggregate de prata, gravar um vídeo de determinados pontos piscando em imagem microscópica e analisar as estatísticas pisca. Nesta análise, uma lei de potência reproduz as distribuições de probabilidade para eventos brilhantes em relação a sua duração. As distribuições de probabilidade para eventos escuros são montadas por uma lei de potência com uma função exponencial. Os parâmetros da lei poder representam o comportamento molecular nos Estados brilhantes e escuros. O modelo de passeio aleatório e a velocidade da molécula através de toda a superfície de prata podem ser estimados. É difícil de estimar, mesmo quando usando as médias, funções de autocorrelação e imagem latente de super-resolução SERS. No futuro, análises de lei de poder devem ser combinadas com imagem espectral, porque as origens de piscar não podem ser confirmadas por este método de análise sozinho.

Do nanoaggregates prata com poli-L-lisina, preparado pelo Protocolo 1.2, multicoloridos pontos piscando de SERS e fluorescência avançada superfície são observados, como mostrado na Figura 111. Em contraste, monótonos pontos piscando coloridos de SERS foram observados para a nanoaggregates de prata com as moléculas de corante preparadas pelo Protocolo 1.37,8,<su...

Watch this Scientific Journal Video about Observation and Analysis of Blinking Surface-enhanced Raman Scattering at JoVE.com

Observation and Analysis of Blinking Surface-enhanced Raman Scattering

Este protocolo descreve a análise de superfície-enhanced Raman a piscar espalhamento devido o passeio aleatório de uma única molécula em uma superfície de prata usando as leis do poder.

Observação e Análise da Espalhamento Raman Aprimorado por Superfície do Piscar de Olhos.

From a single molecule at a silver nanoaggregate junction, blinking surface-enhanced Raman scattering (SERS) is observed. Here, a protocol is presented on ...

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7.4K visualizações.  Kwansei Gakuin University. Este protocolo descreve a análise de superfície-enhanced Raman a piscar espalhamento devido o passeio aleatório de uma única molécula em uma superfície de prata usando as leis do poder.

Vídeo: Observation and Analysis of Blinking Surface-enhanced Raman Scattering

Rejection of Fluorescence Background in Resonance and Spontaneous Raman Microspectroscopy

Raman spectroscopy is often plagued by a strong fluorescent background, particularly for biological samples. If a sample is excited with a train of ultrafast pulses, a system that can temporally separate spectrally overlapping signals on a picosecond timescale can isolate promptly arriving Raman scattered light from late-arriving fluorescence light. Here we discuss the construction and operation of a complex nonlinear optical system that uses all-optical switching in the form of a low-power optical Kerr gate to isolate Raman and fluorescence signals. A single 808 nm laser with 2.4 W of average power and 80 MHz repetition rate is split, with approximately 200 mW of 808 nm light being converted to &lt; 5 mW of 404 nm light sent to the sample to excite Raman scattering. The remaining unconverted 808 nm light is then sent to a nonlinear medium where it acts as the pump for the all-optical shutter. The shutter opens and closes in 800 fs with a peak efficiency of approximately 5%. Using this system we are able to successfully separate Raman and fluorescence signals at an 80 MHz repetition rate using pulse energies and average powers that remain biologically safe. Because the system has no spare capacity in terms of optical power, we detail several design and alignment considerations that aid in maximizing the throughput of the system. We also discuss our protocol for obtaining the spatial and temporal overlap of the signal and pump beams within the Kerr medium, as well as a detailed protocol for spectral acquisition. Finally, we report a few representative results of Raman spectra obtained in the presence of strong fluorescence using our time-gating system.

We discuss the construction and operation of a complex nonlinear optical
system that uses ultrafast all-optical switching to isolate Raman from fluorescence
signals. Using this system we are able to successfully separate Raman and fluorescence
signals utilizing pulse energies and average powers that remain biologically safe.

Rejeição de fundo de fluorescência em Ressonância e microspectroscopy Raman espontâneo

Raman spectroscopy is often plagued by a strong fluorescent background, particularly for biological samples. If a sample is excited with a train of ...

Bioengenharia

Surface Enhanced Raman Spectroscopy Detection of Biomolecules Using EBL Fabricated Nanostructured Substrates

Fabrication and characterization of conjugate nano-biological systems interfacing metallic nanostructures on solid supports with immobilized biomolecules is reported. The entire sequence of relevant experimental steps is described, involving the fabrication of nanostructured substrates using electron beam lithography, immobilization of biomolecules on the substrates, and their characterization utilizing surface-enhanced Raman spectroscopy (SERS). Three different designs of nano-biological systems are employed, including protein A, glucose binding protein, and a dopamine binding DNA aptamer. In the latter two cases, the binding of respective ligands, D-glucose and dopamine, is also included. The three kinds of biomolecules are immobilized on nanostructured substrates by different methods, and the results of SERS imaging are reported. The capabilities of SERS to detect vibrational modes from surface-immobilized proteins, as well as to capture the protein-ligand and aptamer-ligand binding are demonstrated. The results also illustrate the influence of the surface nanostructure geometry, biomolecules immobilization strategy, Raman activity of the molecules and presence or absence of the ligand binding on the SERS spectra acquired.

We describe the fabrication and characterization of nano-biological systems interfacing nanostructured substrates with immobilized proteins and aptamers. The relevant experimental steps involving lithographic fabrication of nanostructured substrates, bio-functionalization, and surface-enhanced Raman spectroscopy (SERS) characterization, are reported. SERS detection of surface-immobilized proteins, and probing of protein-ligand and aptamer-ligand binding is demonstrated.

Superfície reforçada Raman Detection Espectroscopia de Biomoléculas Usando EBL Fabricadas Nanoestruturados Substratos

Fabrication and characterization of conjugate nano-biological systems interfacing metallic nanostructures on solid supports with immobilized biomolecules ...

Engenharia

Non-contact, Label-free Monitoring of Cells and Extracellular Matrix using Raman Spectroscopy

Non-destructive, non-contact and label-free technologies to monitor cell and tissue cultures are needed in the field of biomedical research.1-5 However, currently available routine methods require processing steps and alter sample integrity. Raman spectroscopy is a fast method that enables the measurement of biological samples without the need for further processing steps. This laser-based technology detects the inelastic scattering of monochromatic light.6 As every chemical vibration is assigned to a specific Raman band (wavenumber in cm-1), each biological sample features a typical spectral pattern due to their inherent biochemical composition.7-9 Within Raman spectra, the peak intensities correlate with the amount of the present molecular bonds.1 Similarities and differences of the spectral data sets can be detected by employing a multivariate analysis (e.g. principal component analysis (PCA)).10
Here, we perform Raman spectroscopy of living cells and native tissues. Cells are either seeded on glass bottom dishes or kept in suspension under normal cell culture conditions (37 &deg;C, 5% CO2) before measurement. Native tissues are dissected and stored in phosphate buffered saline (PBS) at 4 &deg;C prior measurements. Depending on our experimental set up, we then either focused on the cell nucleus or extracellular matrix (ECM) proteins such as elastin and collagen. For all studies, a minimum of 30 cells or 30 random points of interest within the ECM are measured. Data processing steps included background subtraction and normalization.

Raman spectroscopy is a suitable technique for the non-contact, label-free analysis of living cells, tissue-engineered constructs and native tissues. Source-specific spectral fingerprints can be generated and analyzed using multivariate analysis.

Sem contato, Monitoramento Label livre de células e matriz extracelular utilizando Espectroscopia Raman

Non-destructive, non-contact and label-free technologies to monitor cell and tissue cultures are needed in the field of biomedical research.1-5 However, ...

High-speed Continuous-wave Stimulated Brillouin Scattering Spectrometer for Material Analysis

Recent years have witnessed a significant increase in the use of spontaneous Brillouin spectrometers for non-contact analysis of soft matter, such as aqueous solutions and biomaterials, with fast acquisition times. Here, we discuss the assembly and operation of a Brillouin spectrometer that uses stimulated Brillouin scattering (SBS) to measure stimulated Brillouin gain (SBG) spectra of water and lipid emulsion-based tissue-like samples in transmission mode with &lt;10 MHz spectral-resolution and &lt;35 MHz Brillouin-shift measurement precision at &lt;100 ms. The spectrometer consists of two nearly counter-propagating continuous-wave (CW) narrow-linewidth lasers at 780 nm whose frequency detuning is scanned through the material Brillouin shift. By using an ultra-narrowband hot rubidium-85 vapor notch filter and a phase-sensitive detector, the signal-to-noise-ratio of the SBG signal is significantly enhanced compared to that obtained with existing CW-SBS spectrometers. This improvement enables measurement of SBG spectra with up to 100-fold faster acquisition times, thereby facilitating high spectral-resolution and high-precision Brillouin analysis of soft materials at high speed.

We describe the construction of a rapid continuous-wave-stimulated-Brillouin-scattering (CW-SBS) spectrometer. The spectrometer employs single-frequency diode-lasers and an atomic vapor notch-filter to acquire transmission spectra of turbid/non-turbid samples with high spectral-resolution at speeds up to 100-fold faster than those of existing CW-SBS spectrometers. This improvement enables high-speed Brillouin material analysis.

Espectrômetro de espalhamento Brillouin estimulado assemelhace de alta velocidade para análise de Material

Recent years have witnessed a significant increase in the use of spontaneous Brillouin spectrometers for non-contact analysis of soft matter, such as ...

Implementation of a Nonlinear Microscope Based on Stimulated Raman Scattering

Stimulated Raman scattering (SRS) microscopy uses near-infrared excitation light; therefore, it shares many multi-photon microscopic imaging properties. SRS imaging modality can be obtained using commercial laser-scanning microscopes by equipping with a non-descanned forward detector with proper bandpass filters and lock-in amplifier (LIA) detection scheme. A schematic layout of a typical SRS microscope includes the following: two pulsed laser beams, (i.e., the pump and probe directed in a scanning microscope), which must be overlapped in both space and time at the image plane, then focused by a microscope objective into the sample through two scanning mirrors (SMs), which raster the focal spot across an x-y plane. After interaction with the sample, transmitted output pulses are collected by an upper objective and measured by a forward detection system inserted in an inverted microscope. Pump pulses are removed by a stack of optical filters, whereas the probe pulses that are the result of the SRS process occurring in the focal volume of the specimen are measured by a photodiode (PD). The readout of the PD is demodulated by the LIA to extract the modulation depth. A two-dimensional (2D) image is obtained by synchronizing the forward detection unit with the microscope scanning unit. In this paper, the implementation of an SRS microscope is described and successfully demonstrated, as well as the reporting of label-free images of polystyrene beads with diameters of 3 &#181;m. It is worth noting that SRS microscopes are not commercially available, so in order to take advantage of these characteristics, the homemade construction is the only option. Since SRS microscopy is becoming popular in many fields, it is believed that this careful description of the SRS microscope implementation can be very useful for the scientific community.

In this manuscript, the implementation of a stimulated Raman scattering (SRS) microscope, obtained by the integration of an SRS experimental set-up with a laser scanning microscope, is described. The SRS microscope is based on two femtosecond (fs) laser sources, a Ti-Sapphire (Ti:Sa) and synchronized optical parametric oscillator (OPO).

Implementação de um microscópio não-linear baseado em espalhamento Raman estimulado

Stimulated Raman scattering (SRS) microscopy uses near-infrared excitation light; therefore, it shares many multi-photon microscopic imaging properties. ...

Multiplex Chemical Imaging Based on Broadband Stimulated Raman Scattering Microscopy

Stimulated Raman scattering (SRS) microscopy is a nonlinear optical technique for label-free chemical imaging. This analytical tool delivers chemical maps at high speed, and high spatial resolution of thin samples by directly interrogating their molecular vibrations. In its standard implementation, SRS microscopy is narrowband and forms images with only a single vibrational frequency at a time. However, this approach not only hinders the chemical specificity of SRS but also neglects the wealth of information encoded within vibrational spectra. 
These limitations can be overcome by broadband SRS, an implementation capable of extracting a vibrational spectrum per pixel of the image in parallel. This delivers hyperspectral data that, when coupled with chemometric analysis, maximizes the amount of information retrieved from the specimen. Thus, broadband SRS improves the chemical specificity of the system, allowing the quantitative determination of the concentration of the different constituents of a sample. Here, we report a protocol for chemical imaging with broadband SRS microscopy, based on a home-built SRS microscope operating with a custom differential multichannel-lock-in amplifier detection. It discusses the sample preparation, alignment of the SRS apparatus, and chemometric analysis. By acquiring vibrational Raman spectra, the protocol illustrates how to identify different chemical species within a mixture, determining their relative concentrations.

We present a protocol to acquire chemical images with broadband stimulated Raman scattering (SRS) microscopy. Based on an SRS microscope that operates with differential multichannel-lock-in detection, the protocol describes the sample preparation, adjustment of the SRS apparatus, and chemometrics to disentangle different constituents of chemically heterogeneous samples.

Multiplex Imagem química baseada em banda larga estimulada raman dispersão microscopia

Stimulated Raman scattering (SRS) microscopy is a nonlinear optical technique for label-free chemical imaging. This analytical tool delivers chemical maps ...

Direct Comparison of Hyperspectral Stimulated Raman Scattering and Coherent Anti-Stokes Raman Scattering Microscopy for Chemical Imaging

Stimulated Raman scattering (SRS) and coherent anti-Stokes Raman scattering (CARS) microscopy are the most widely used coherent Raman scattering imaging technologies. Hyperspectral SRS and CARS imaging offer Raman spectral information at every pixel, which enables better separation of different chemical compositions. Although both techniques require two excitation lasers, their signal detection schemes and spectral properties are quite different. The goal of this protocol is to perform both hyperspectral SRS and CARS imaging on a single platform and compare the two microscopy techniques for imaging different biological samples. The spectral focusing method is employed to acquire spectral information using femtosecond lasers. By using standard chemical samples, the sensitivity, spatial resolution, and spectral resolution of SRS and CARS in the same excitation conditions (i.e., power at the sample, pixel dwell time, objective lens, pulse energy) are compared. The imaging contrasts of CARS and SRS for biological samples are juxtaposed and compared. The direct comparison of CARS and SRS performances would allow for optimal selection of the modality for chemical imaging.

This paper directly compares the resolution, sensitivity, and imaging contrasts of stimulated Raman scattering (SRS) and coherent anti-Stokes Raman scattering (CARS) integrated into the same microscope platform. The results show that CARS has a better spatial resolution, SRS gives better contrasts and spectral resolution, and both methods have similar sensitivity.

Comparação direta da dispersão de Raman estimulada hiperespectral e microscopia de dispersão de Raman coerente para imagem química

Stimulated Raman scattering (SRS) and coherent anti-Stokes Raman scattering (CARS) microscopy are the most widely used coherent Raman scattering imaging ...

Química

In vivo Imaging of Biological Tissues with Combined Two-Photon Fluorescence and Stimulated Raman Scattering Microscopy

Stimulated Raman scattering (SRS) microscopy enables label-free imaging of the biological tissues in its natural microenvironment based on intrinsic molecular vibration, thus providing a perfect tool for in vivo study of biological processes at subcellular resolution. By integrating two-photon excited fluorescence (TPEF) imaging into the SRS microscope, the dual-modal in vivo imaging of tissues can acquire critical biochemical and biophysical information from multiple perspectives which helps understand the dynamic processes involved in cellular metabolism, immune response and tissue remodeling, etc. In this video protocol, the setup of a TPEF-SRS microscope system as well as the in vivo imaging method of the animal spinal cord is introduced. The spinal cord, as part of the central nervous system, plays a critical role in the communication between the brain and peripheral nervous system. Myelin sheath, abundant in phospholipids, surrounds and insulates the axon to permit saltatory conduction of action potentials. In vivo imaging of myelin sheaths in the spinal cord is important to study the progression of neurodegenerative diseases and spinal cord injury. The protocol also describes animal preparation and in vivo TPEF-SRS imaging methods to acquire high-resolution biological images.

In vivo Imaging of Biological Tissues with Combined Two-Photon Fluorescence and Stimulated Raman Scattering Microscopy

Stimulated Raman scattering (SRS) microscopy allows label-free imaging of biomolecules based on their intrinsic vibration of specific chemical bonds. In this protocol, the instrumental setup of an integrated SRS and two-photon fluorescence microscope is described to visualize cellular structures in the spinal cord of live mice.

In vivo Imagem de tecidos biológicos com fluorescência combinada de dois fótons e microscopia de dispersão de Raman estimulada

Stimulated Raman scattering (SRS) microscopy enables label-free imaging of the biological tissues in its natural microenvironment based on intrinsic ...

Real-Time, Two-Color Stimulated Raman Scattering Imaging of Mouse Brain for Tissue Diagnosis

Stimulated Raman scattering (SRS) microscopy has emerged as a powerful optical imaging technique for tissue diagnosis. In recent years, two-color SRS has been shown to be able to provide hematoxylin and eosin (H&amp;E)-equivalent images that allow fast and reliable diagnosis of brain cancer. Such capability has enabled exciting intraoperative cancer diagnosis applications. Two-color SRS imaging of tissue can be done with either a picosecond or femtosecond laser source. Femtosecond lasers have the advantage of enabling flexible imaging modes, including fast hyperspectral imaging and real-time, two-color SRS imaging. A spectral-focusing approach with chirped laser pulses is typically used with femtosecond lasers to achieve high spectral resolution. 
Two-color SRS acquisition can be realized with orthogonal modulation and lock-in detection. The complexity of pulse chirping, modulation, and characterization is a bottleneck for the widespread adoption of this method. This article provides a detailed protocol to demonstrate the implementation and optimization of spectral-focusing SRS and real-time, two-color imaging of mouse brain tissue in the epi-mode. This protocol can be used for a broad range of SRS imaging applications that leverage the high speed and spectroscopic imaging capability of SRS.

Stimulated Raman scattering (SRS) microscopy is a powerful, nondestructive, and label-free imaging technique. One emerging application is stimulated Raman histology, where two-color SRS imaging at the protein and lipid Raman transitions are used to generate pseudo-hematoxylin and eosin images. Here, we demonstrate a protocol for real-time, two-color SRS imaging for tissue diagnosis.

Raman estimulado em tempo real, duas cores, espalhando imagens do cérebro do rato para diagnóstico de tecido

Stimulated Raman scattering (SRS) microscopy has emerged as a powerful optical imaging technique for tissue diagnosis. In recent years, two-color SRS has ...

Label-Free Imaging of Lipid Storage Dynamics in Caenorhabditis elegans using Stimulated Raman Scattering Microscopy

Lipid metabolism is a fundamental physiological process necessary for cellular and organism health. Dysregulation of lipid metabolism often elicits obesity and many associated diseases including cardiovascular disorders, type II diabetes, and cancer. To advance the current understanding of lipid metabolic regulation, quantitative methods to precisely measure in vivo lipid storage levels in time and space have become increasingly important and useful. Traditional approaches to analyze lipid storage are semi-quantitative for microscopic assessment or lacking spatio-temporal information for biochemical measurement. Stimulated Raman scattering (SRS) microscopy is a label-free chemical imaging technology that enables rapid and quantitative detection of lipids in live cells with a subcellular resolution. As the contrast is exploited from intrinsic molecular vibrations, SRS microscopy also permits four-dimensional tracking of lipids in live animals. In the last decade, SRS microscopy has been widely used for small molecule imaging in biomedical research and overcome the major limitations of conventional fluorescent staining and lipid extraction methods. In the laboratory, we have combined SRS microscopy with the genetic and biochemical tools available to the powerful model organism, Caenorhabditis elegans, to investigate the distribution and heterogeneity of lipid droplets across different cells and tissues and ultimately to discover novel conserved signaling pathways that modulate lipid metabolism. Here, we present the working principles and the detailed setup of the SRS microscope and provide methods for its use in quantifying lipid storage at distinct developmental timepoints of wild-type and insulin signaling deficient mutant C. elegans.

Label-Free Imaging of Lipid Storage Dynamics in Caenorhabditis elegans using Stimulated Raman Scattering Microscopy

Stimulated Raman scattering (SRS) microscopy allows selective, label-free imaging of specific chemical moieties and it has been effectively employed to image lipid molecules in vivo. Here, we provide a brief introduction to the principle of SRS microscopy and describe methods for its use in imaging lipid storage in Caenorhabditis elegans.

Imagem livre de rótulos da Dinâmica de Armazenamento Lipídido em Elegans caenorhabditis usando microscopia de dispersão raman estimulada

Lipid metabolism is a fundamental physiological process necessary for cellular and organism health. Dysregulation of lipid metabolism often elicits ...