Os autores agradecem o apoio financeiro do Labex-Imust.

1. Biológica Preparação de Amostras Todos os experimentos descritos neste estudo foram aprovados pelo Comitê do CECCAPP (Lyon, França) (autorização # LYONSUD_2012_004) Animal Care e Use, e os experimentos foram realizados sob a supervisão de pessoas autorizadas (L. Sancey, DDPP autorização # 38 05 32). <ol><li> Adicionar 1 ml de H 2 O para 100 umol de nanopartículas à base de gadolínio (Gd), aguardar 15 minutos e adicionar 20 ul de HEPES 50 mM, NaCl 1,325 M, CaCl2 20 mM para 100 ul de H2O e 80 ul da solução primária de nanopartículas à base de Gd para obter uma solução de 200 mL em 40 mM prontos para injetar (Cidade: Villeurbanne, em laboratório). </li><li> Injectar a solução de nanopartículas de Gd 200 mL por via intravenosa em roedores portadores de tumor anestesiados (Cidade: Lyon Sud (Oullins), a 15 km do laboratório). </li><li> 1-24 horas após a injeção, sacrificar os ratos umad colocar as amostras biológicas em isopentano resfriado por nitrogênio líquido. Conservar as amostras a - 80 ° C (Cidade: Lyon Sud (Oullins), a 15 km do laboratório). </li><li> Corte da amostra (Cidade: geralmente Grenoble, a 100 km do laboratório, vou tentar ter um acesso em Lyon Sud) em 100 slides m de espessura e colocar os slides biológicos em pratos de plástico específicos (Petri). Armazenar a -80 ° C. Nota: pratos de plástico são, basicamente, uma amostra de polímero muito puro. Eles são utilizados para evitar a interferência com os elementos contidos no tecido. </li></ol> 2. Preparação de Amostras para Calibração <ol><li> Prepare frascos com doses crescentes de nanopartículas à base de Gd em água (0 nM, 100 nM, 500 nM, 1 pM, 5 pM, 10 pM, 50 uM, 100 uM, 500 pM, 1 mM e 5 mM). </li><li> Coloque um pi-gota de cada solução espaçados regularmente por 3 mm em placas de Petri 5. </li><li> Seca à temperatura ambiente durante 20 min. </li></ol>3. LIBS Experiment <ol><li> Inicialização da Configuração LIBS <ol><li> Configurações de laser. Depois de ligar os instrumentos, esperar 10-20 min para pulso estabilização energia do laser e resfriamento da câmera ICCD até -20 ° C. Ajuste a energia de pulso com o atenuador. Nota: Os parâmetros do laser ideais para tecidos de mapeamento são 5 ns duração de pulso, 1.064 nm de comprimento de onda e energia de pulso de cerca de 4 mJ. O laser usa é um típico Nd: YAG nanossegundo. </li><li> LIBS Configurações. Definir a posição do laser de focagem (em relação à superfície da amostra) para se obter o diâmetro da cratera menor (cerca de 50 um ou inferior). Nota: Isto corresponde a um impulso de laser de focalização 100 um abaixo da superfície da amostra. </li><li> Configurações espectrômetro. Use o espectrômetro de Czerny-Turner combinado com um 1200 linhas / mm grade e uma câmera de resolução ICCD temporais alta. Controlar todos esses dispositivos por computador. Defina o valor de fenda de entrada para 40 mM. Defina a faixa espectral reGarding o elemento a ser analisado. Utilizar a faixa espectral abrangendo 325-355 nm para a detecção Gd com elevada sensibilidade, bem como Na, Ca e Cu. Defina os parâmetros ICCD com um atraso de 300 ns, um portão de 2 ms, e um ganho de 200. </li></ol></li><li> Medição Mapping <ol><li> Colocar a amostra biológica em porta-amostras de LIBS motorizados. </li><li> Ajuste a altura da amostra de acordo com a posição do foco do laser. </li><li> Tire uma foto de alta resolução da fatia da amostra. </li><li> Coloque o módulo de mapeamento do software de aquisição de LIBS para realizar um mapa com tipicamente 100 x 100 pontos de medição espaçados por uma resolução de cerca de 100 mm. </li><li> Comece a aquisição. A partir deste ponto de automatizar tudo; o movimento seqüência, bem como a gravação de espectro e poupança. 40 minutos são necessários para um mapeamento de 10.000 pontos (equivalente a 1 cm2 por resolução de 100 um). Reagrupar todos os espectros registrados em um mesmo arquivo. </li><li> Quando finished, dê uma segunda fotografia da fatia de amostra </li></ol></li><li> Medição Calibração </li></ol> Com os mesmos parâmetros experimentais, medir as amostras de calibração (para detalhes de preparação, ver secção 2). Executar um mapa ou ficha 25 espectros (obtido a partir de locais de medição na parte do centro da gota) em cada uma das gotas de calibração. 4 LIBS Análise de Espectro:. Construção de Química Images <ol><li> Grave todos os espectros LIBS a partir do mapeamento de tecidos e carregá-los na análise de software LIBS. Subtraia a linha de base para cada espectro e construir as imagens químicas com escala de intensidade relativa usando uma cor falsa. Nota: Um algoritmo recupera intensidades de linhas específicas, como D&#39;us, Cu, Na, ou Ca. </li><li> Realizar a mesma operação no espectro medido a partir da amostra de calibração para permitir o cálculo das curvas de calibração (relação entre a intensidade e a concentração) e de construção aqmapa quantitativas ou imagem para D&#39;us (ou outro elemento de interesse). </li><li> Aplicar os tratamentos adequados para as imagens de produtos químicos, tais como a interpolação ou de alisamento. Salve os mapas de intensidade ou concentração em formato de imagem (bitmap). </li></ol>

<ol>
	<li>Smith, M. A., Harris, P. L., Sayre, L. M., Perry, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Iron+accumulation+in+Alzheimer+disease+is+a+source+of+redox-generated+free+radicals.">Iron accumulation in Alzheimer disease is a source of redox-generated free radicals.</a> Proceedings of the National Academy of Sciences of the United States of America. 94, 9866-9868 (1997).</li><li>Wang, Y., Zhu, S., Weisman, G. A., Gitlin, J. D., Petris, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conditional+knockout+of+the+Menkes+disease+copper+transporter+demonstrates+its+critical+role+in+embryogenesis.">Conditional knockout of the Menkes disease copper transporter demonstrates its critical role in embryogenesis.</a> PloS one. 7, (2012).</li><li>Reske-Nielson, E., Lou, H. O., Andersen, P., Vagn-Hansen, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brain-copper+concentration+in+Menkes'+disease.">Brain-copper concentration in Menkes' disease.</a> Lancet. 1, 613 (1973).</li><li>Hayashi, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Various+copper+and+iron+overload+patterns+in+the+livers+of+patients+with+Wilson+disease+and+idiopathic+copper+toxicosis.">Various copper and iron overload patterns in the livers of patients with Wilson disease and idiopathic copper toxicosis.</a> Medical molecular morphology. 46, (2013).</li><li>Lobinski, R., Moulin, C., Ortega, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+and+speciation+of+trace+elements+in+biological+environment.">Imaging and speciation of trace elements in biological environment.</a> Biochimie. 88, 1591-1604 (2006).</li><li>Dev&#232;s, G., Bouhacina, T., Ortega, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=STIM+mass+measurements+for+quantitative+trace+element+analysis+within+biological+samples+and+validation+using+AFM+thickness+measurements.">STIM mass measurements for quantitative trace element analysis within biological samples and validation using AFM thickness measurements.</a> Spectrochimica Acta B. 59, 1733-1738 (2004).</li><li>Twining, B. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantifying+trace+elements+in+individual+aquatic+protist+cells+with+a+synchrotron+X-ray+fluorescence+microprobe.">Quantifying trace elements in individual aquatic protist cells with a synchrotron X-ray fluorescence microprobe.</a> Analytical chemistry. 75, 3806-3816 (2003).</li><li>Guerquin-Kern, J. L., Wu, T. D., Quintana, C., Croisy, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Progress+in+analytical+imaging+of+the+cell+by+dynamic+secondary+ion+mass+spectrometry+(SIMS+microscopy).">Progress in analytical imaging of the cell by dynamic secondary ion mass spectrometry (SIMS microscopy).</a> Biochimica et biophysica acta. 1724, 228-238 (2005).</li><li>Binet, M. R., Ma, R., McLeod, C. W., Poole, R. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+and+characterization+of+zinc-+and+cadmium-binding+proteins+in+Escherichia+coli+by+gel+electrophoresis+and+laser+ablation-inductively+coupled+plasma-mass+spectrometry.">Detection and characterization of zinc- and cadmium-binding proteins in Escherichia coli by gel electrophoresis and laser ablation-inductively coupled plasma-mass spectrometry.</a> Analytical biochemistry. 318, 30-38 (2003).</li><li>Becker, J., Gorbunoff, A., Zoriy, M., Izmer, A., Kayser, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+of+near-field+laser+ablation+inductively+coupled+plasma+mass+spectrometry+(NF-LA-ICP-MS)+at+nanometre+scale+for+elemental+and+isotopic+analysis+on+gels+and+biological+samples.">Evidence of near-field laser ablation inductively coupled plasma mass spectrometry (NF-LA-ICP-MS) at nanometre scale for elemental and isotopic analysis on gels and biological samples.</a> J. Anal. Atom. Spectrom. 21, 19-25 (2006).</li><li>Seeley, E. H., Caprioli, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3D+imaging+by+mass+spectrometry:+a+new+frontier.">3D imaging by mass spectrometry: a new frontier.</a> Analytical chemistry. 84, 2105-2110 (2012).</li><li>Pornwilard, M. -. M., Weiskirchen, R., Gassler, N., Bosserhoff, A. K., Becker, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+bioimaging+techniques+of+metals+by+laser+ablation+inductively+coupled+plasma+mass+spectrometry+for+diagnosis+of+fibrotic+and+cirrhotic+liver+disorders.">Novel bioimaging techniques of metals by laser ablation inductively coupled plasma mass spectrometry for diagnosis of fibrotic and cirrhotic liver disorders.</a> PloS one. 8, (2013).</li><li>Cremers, D. A., Radziemski, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Handbook of laser-induced breakdown spectroscopy. , (2006).</li><li>Miziolek, A. W., Palleschi, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Laser-Induced Breakdown Spectroscopy: Fundamentals and Applications. , (2006).</li><li>Motto-Ros, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mapping+nanoparticles+injected+into+a+biological+tissue+using+laser-induced+breakdown+spectroscopy.">Mapping nanoparticles injected into a biological tissue using laser-induced breakdown spectroscopy.</a> Spectrochimica Acta Part B. , (2013).</li><li>Motto-Ros, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mapping+of+native+inorganic+elements+and+injected+nanoparticles+in+a+biological+organ+with+laser-induced+plasma.">Mapping of native inorganic elements and injected nanoparticles in a biological organ with laser-induced plasma.</a> Applied Physics Letters. 101, (2012).</li><li>Mignot, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+top-down+synthesis+route+to+ultrasmall+multifunctional+Gd-based+silica+nanoparticles+for+theranostic+applications.">A top-down synthesis route to ultrasmall multifunctional Gd-based silica nanoparticles for theranostic applications.</a> Chemistry. 19, 6122-6136 (2013).</li><li>Lux, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasmall+rigid+particles+as+multimodal+probes+for+medical+applications.">Ultrasmall rigid particles as multimodal probes for medical applications.</a> Angew Chem Int Ed Engl. 50, 12299-12303 (2011).</li></ol>

Os autores não têm nada a revelar.

Aplicado a amostra biológica, a técnica permite a imagem química, isto é, o mapeamento e quantificação, de Gd e Si a partir de nanopartículas à base de Gd injectados em diferentes órgãos. A partir das configurações principais críticos, o controlo das propriedades de laser (comprimento de onda, a energia do pulso, centradas, e de estabilidade) é crítico para uma ablação de tecido preciso e fino (ou seja, uma resolução de mapeamento), bem como para a sensibilidade. Trabalhando em alta ...

O grande desenvolvimento de nanopartículas para aplicações biológicas incitou a melhoria paralela de técnicas analíticas para a sua quantificação e formação de imagens de amostras biológicas. Normalmente, a detecção e o mapeamento das nanopartículas em órgãos são feitos por fluorescência ou microscopia confocal. Infelizmente, estes métodos requerem a rotulagem das nanopartículas por um corante do infravermelho próximo que pode alterar a biodistribuição das nanopartículas, em especial para as nanopartículas de muito pequenas, devido às suas propriedades hidrofóbicas. A detecção de nanopartículas rotulados, e especialmente as muito pequenas nanopartículas (tamanho &lt;10 nm), pode, assim, interferir com a sua biodistribuição em toda a escala do corpo, mas também a nível de tecidos e células. O desenvolvimento de novos dispositivos capazes de detectar nanopartículas sem qualquer rotulagem oferece novas possibilidades para o estudo do seu comportamento e cinética. Além disso, o papel de elementos vestigiais tais como ferro e cobre em doenças cérebro umd doenças neurodegenerativas, como Alzheimer 1, Menkes 2,3, ou Wilson 4 sugerem o interesse de estudar e localizar esses elementos em tecidos. Várias técnicas têm sido utilizadas para fornecer mapeamento elementar ou microanálise de materiais diferentes. Em seu artigo de revisão publicado em 2006, R. lobinski et al. Forneceu uma visão geral das técnicas padrão disponíveis para microanálise elementar em meio biológico, um dos ambientes mais desafiadores para as ciências analíticas 5. A microssonda de electrões, que é constituído por energia dispersiva de microanálise de raios X de um microscópio electrónico de transmissão, pode ser aplicado a numerosos estudos se a concentração do elemento é suficiente (&gt; 100-1.000 mg / g). Para alcançar limites de detecção mais baixos, foram utilizadas as seguintes técnicas: <ul><li> microssonda feixe de íons através das partículas induzida emissão de raios X μ-PIXE (1-10 mg / g) 6 </li><li> synchrotron microanálise radiação μ-SXRF (0,1-1 mg / g) 7 </li><li> espectrometria de massa de iões secundários SIMS (0,1 ug / g) 8 </li><li> ablação a laser em espectrometria de massas LA-ICP-MS (até 0,01 mg / g) 9,10 </li></ul> As técnicas acima mencionadas proporcionam resolução micrométrica, como mostrado na Tabela 1 extraiu-se a partir de lobinski et al. Reconstrução 3D de investigações 2D de série também pode ser proposto para a reconstrução de tecidos mais profundos 11. No entanto, todos os dispositivos e sistemas exigem profissionais qualificados, ambos moderados para equipamentos de alto custo e experimentos de longa duração (normalmente mais de 4 h para um mM 100 x 100 mm para μ-SXRF de 10 mm x 10 mm para LA-ICP-MS ) 12. Em conjunto, esses requisitos tornam microanálise elementar muito restritivo e incompatível com sistemas de imagem óptica convencional,A microscopia de fluorescência ou microscopia não linear. Um outro ponto que se pode mencionar aqui é que a capacidade de medição quantitativa ainda é bastante limitada e depende da disponibilidade dos padrões laboratoriais de correspondência de matriz. Quanto mais generalização do uso de microanálise elementar em processos da indústria, geologia, biologia e outros domínios de aplicações irá gerar avanços conceituais e tecnológicos significativos. O objectivo da presente manuscrito é propor soluções para mapeamento elementar quantitativa (ou microanálise elementar) em tecidos biológicos com uma instrumentação mesa compatível com microscopia óptica convencional. A nossa abordagem é baseada na espectroscopia de decomposição induzida por laser (tecnologia LIBS). Em LIBS, um pulso de laser é focado na amostra de interesse para criar a composição e centelha do material. A radiação emitida atómica no plasma é subsequentemente analisados ​​por um espectrómetro e os elemenTal concentração pode ser recuperada com medidas de calibração realizados previamente 13,14. As vantagens de LIBS incluem sensibilidade (mg / g para quase todos os elementos), compacidade, preparação muito básico amostra, ausência de contato com a amostra, a resposta instantânea e precisamente localizada (micro) análise de superfície. No entanto, a aplicação da imagem química de tecido permanece um desafio uma vez que a ablação a laser dos tecidos devem ser finamente controlado para realizar mapas com uma elevada resolução espacial, juntamente com o intervalo de sensibilidade em ug / g 15,16. Com esta solução, a adjunção de marcadores ou agentes de rotulagem não é necessário, o que permite a detecção de elementos inorgânicos directamente no seu ambiente nativo em tecidos biológicos. O instrumento LIBS desenvolvido em nosso laboratório oferece uma resolução atual inferior a 100 mm, com uma sensibilidade estimada para Gd abaixo de 35 mg / g, o equivalente a 0,1 mM 16, que permite queo mapeamento de grandes amostras (&gt; 1 cm 2) dentro de 30 min. Além disso, o software caseiro facilita a aquisição e exploração dos dados. Este instrumento é usado para detectar, mapear e quantificar a distribuição de tecido de gadolínio de nanopartículas à base de (Gd), 17 - 18, em rins e amostras de tumor de animais de pequeno porte, de 1 a 24 horas após a injecção intravenosa das partículas (tamanho &lt;5 nm) . Elementos inorgânicos, que são intrinsecamente contidos em um tecido biológico, tais como Fe, Ca, Na e P, foram também detectadas e gravadas.

<table border="0" cellpadding="0" cellspacing="0" width="747">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Laser nanosecond Nd:YAG</td>
			<td style="width:129px;">Quantel</td>
			<td style="width:119px;">Brillant</td>
			<td style="width:283px;">5ns pulse witdh, wavelength 1064 nm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Spectrometer</td>
			<td>Andor Technology</td>
			<td>Shamrock 303</td>
			<td>with 1200 l/mm blazed at 300 nm grating</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Detector ICCD</td>
			<td>Andor Technology</td>
			<td style="width:119px;">Istar</td>
			<td>2 ns temporal resolution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">LIBS Unit</td>
			<td style="width:129px;">ILM</td>
			<td style="width:119px;"></td>
			<td>Homemade Instrumentation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:129px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Gd-based nanoparticles</td>
			<td style="width:129px;">Nano-H</td>
			<td style="width:119px;"></td>
			<td>particles</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">HEPES</td>
			<td style="width:129px;">Sigma-Aldrich</td>
			<td style="width:119px;">H4034</td>
			<td>for particle&#39;s dilution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">CaCl2</td>
			<td style="width:129px;">Sigma-Aldrich</td>
			<td style="width:119px;">21108</td>
			<td>for particle&#39;s dilution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">NaCl</td>
			<td style="width:129px;">Sigma-Aldrich</td>
			<td style="width:119px;">S5886</td>
			<td>for particle&#39;s dilution</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">mice</td>
			<td style="width:129px;">Charles River</td>
			<td style="width:119px;">depending of animal breeding</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">isoflurane</td>
			<td style="width:129px;">Coveto / Virbac</td>
			<td style="width:119px;"></td>
			<td>for anaesthesia - Isofluranum</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">isopentane</td>
			<td style="width:129px;">Sigma-Aldrich</td>
			<td style="width:119px;">59060</td>
			<td>to froze the sample&#160; slowly</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">liquide nitrogen</td>
			<td style="width:129px;">Air Liquide</td>
			<td style="width:119px;"></td>
			<td>to cool down the isopentane</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">cryostat</td>
			<td style="width:129px;">Leica</td>
			<td style="width:119px;">CM-3050S</td>
			<td>to slide the samples</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">petri dishes</td>
			<td style="width:129px;">Dutscher</td>
			<td style="width:119px;">353004</td>
			<td>to stick the sample</td>
		</tr>
	</tbody>
</table>

laser-induced breakdown spectroscopy: a new approach for nanoparticle's mapping and quantification in organ tissue

A espectroscopia de emissão de plasma induzido por laser foi aplicado para a análise elementar de amostras biológicas. Espectroscopia de desagregação induzida por laser (LIBS) realizada em secções finas de tecido de roedor: rins e do tumor, permite a detecção de elementos inorgânicos, tais como (i) de Na, Ca, Cu, Mg, P, e Fe, presente naturalmente no corpo e (ii) Si e D&#39;us, detectada após a injeção de nanopartículas à base de gadolínio. Os animais foram sacrificados 1 a 24 horas após a injecção intravenosa de partículas. Um varrimento bidimensional da amostra, realizada por meio de um micrométrica 3D-platina motorizada, permitiu que o feixe de laser de infravermelho a explorar a superfície com uma resolução lateral inferior a 100 μ m. Imagens química quantitativa de elemento Gd dentro do órgão foram obtidos com sensibilidade sub-mM. LIBS oferece um método simples e robusto para estudar a distribuição de materiais inorgânicos sem qualquer labeli específicong. Além disso, a compatibilidade da instalação com microscopia óptica padrão enfatiza seu potencial para fornecer várias imagens do mesmo tecido biológico com diferentes tipos de resposta: elementares, moleculares ou celulares.

Como mostrado na Figura 1, o feixe de um laser Nd: YAG do comprimento de onda fundamental de 1,064 nm foi focado verticalmente para baixo sobre a fatia de tecido através de uma lente de quartzo de 50 mm de distância focal. A energia de pulso foi de 4 mJ e taxa de repetição de 10 Hz. A fim de evitar a geração de plasma no ar, o feixe de laser foi centrada em torno de 100 mm abaixo da superfície da amostra. No plasma do ar foi observada nesta condição. Durante as experiências, a amostra foi movi...

Watch this Scientific Journal Video about Laser-induced Breakdown Spectroscopy: A New Approach for Nanoparticle's Mapping and Quantification in Organ Tissue at JoVE.com

Laser-induced Breakdown Spectroscopy: A New Approach for Nanoparticle&#039;s Mapping and Quantification in Organ Tissue

Espectroscopia de decomposição induzida por laser realizada em órgão fina e tecido do tumor detectado com sucesso elementos naturais e gadolínio injetado artificialmente (Gd), emitidos a partir de nanopartículas à base de Gd. Imagens de elementos químicos atingiu uma resolução de 100 um e sensibilidade quantitativa sub-mM. A compatibilidade da instalação com microscopia óptica padrão enfatiza seu potencial para fornecer várias imagens de um mesmo tecido biológico.

Induzida por laser Breakdown Spectroscopy: Uma Nova Abordagem para Mapeamento e Quantificação de nanopartículas em Organ Tissue

Emission spectroscopy of laser-induced plasma was applied to elemental analysis of biological samples. Laser-induced breakdown spectroscopy (LIBS) ...

laser-induced-breakdown-spectroscopy-new-approach-for-nanoparticle-s

Research

JoVE Journal

Engineering

Laser-induced Breakdown Spectroscopy: A New Approach for Nanoparticle's Mapping and Quantification in Organ Tissue

13.6K visualizações.  CNRS - Université Lyon 1.  Espectroscopia de decomposição induzida por laser realizada em órgão fina e tecido do tumor detectado com sucesso elementos naturais e gadolínio injetado artificialmente (Gd), emitidos a partir de nanopartículas à base de Gd. Imagens de elementos químicos atingiu uma resolução de 100 um e sensibilidade quantitativa sub-mM. A compatibilidade da instalação com microscopia óptica padrão enfatiza seu potencial para fornecer várias imagens de um mesmo tecido bi...

Vídeo: Laser-induced Breakdown Spectroscopy: A New Approach for Nanoparticle's Mapping and Quantification in Organ Tissue

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

The physical properties of a material are defined by its electronic structure. Electrons in solids are characterized by energy (&omega;) and momentum (k) and the probability to find them in a particular state with given &omega; and k is described by the spectral function A(k, &omega;). This function can be directly measured in an experiment based on the well-known photoelectric effect, for the explanation of which Albert Einstein received the Nobel Prize back in 1921. In the photoelectric effect the light shone on a surface ejects electrons from the material. According to Einstein, energy conservation allows one to determine the energy of an electron inside the sample, provided the energy of the light photon and kinetic energy of the outgoing photoelectron are known. Momentum conservation makes it also possible to estimate k relating it to the momentum of the photoelectron by measuring the angle at which the photoelectron left the surface. The modern version of this technique is called Angle-Resolved Photoemission Spectroscopy (ARPES) and exploits both conservation laws in order to determine the electronic structure, i.e. energy and momentum of electrons inside the solid. In order to resolve the details crucial for understanding the topical problems of condensed matter physics, three quantities need to be minimized: uncertainty* in photon energy, uncertainty in kinetic energy of photoelectrons and temperature of the sample.
In our approach we combine three recent achievements in the field of synchrotron radiation, surface science and cryogenics. We use synchrotron radiation with tunable photon energy contributing an uncertainty of the order of 1 meV, an electron energy analyzer which detects the kinetic energies with a precision of the order of 1 meV and a He3 cryostat which allows us to keep the temperature of the sample below 1 K. We discuss the exemplary results obtained on single crystals of Sr2RuO4 and some other materials. The electronic structure of this material can be determined with an unprecedented clarity.

The overall goal of this method is to determine the low-energy electronic structure of solids at ultra-low temperatures using Angle-Resolved Photoemission Spectroscopy with synchrotron radiation.

Ângulo resolvido espectroscopia de fotoelétrons em ultra-baixas temperaturas

The physical properties of a material are defined by its  electronic structure. Electrons in solids are characterized by energy (&omega;)  and momentum ...

Engenharia

Probing and Mapping Electrode Surfaces in Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen 1-7. The performance of SOFCs and the rates of many chemical and energy transformation processes in energy storage and conversion devices in general are limited primarily by charge and mass transfer along electrode surfaces and across interfaces. Unfortunately, the mechanistic understanding of these processes is still lacking, due largely to the difficulty of characterizing these processes under in situ conditions. This knowledge gap is a chief obstacle to SOFC commercialization. The development of tools for probing and mapping surface chemistries relevant to electrode reactions is vital to unraveling the mechanisms of surface processes and to achieving rational design of new electrode materials for more efficient energy storage and conversion2. Among the relatively few in situ surface analysis methods, Raman spectroscopy can be performed even with high temperatures and harsh atmospheres, making it ideal for characterizing chemical processes relevant to SOFC anode performance and degradation8-12. It can also be used alongside electrochemical measurements, potentially allowing direct correlation of electrochemistry to surface chemistry in an operating cell. Proper in situ Raman mapping measurements would be useful for pin-pointing important anode reaction mechanisms because of its sensitivity to the relevant species, including anode performance degradation through carbon deposition8, 10, 13, 14 ("coking") and sulfur poisoning11, 15 and the manner in which surface modifications stave off this degradation16. The current work demonstrates significant progress towards this capability. In addition, the family of scanning probe microscopy (SPM) techniques provides a special approach to interrogate the electrode surface with nanoscale resolution. Besides the surface topography that is routinely collected by AFM and STM, other properties such as local electronic states, ion diffusion coefficient and surface potential can also be investigated17-22. In this work, electrochemical measurements, Raman spectroscopy, and SPM were used in conjunction with a novel test electrode platform that consists of a Ni mesh electrode embedded in an yttria-stabilized zirconia (YSZ) electrolyte. Cell performance testing and impedance spectroscopy under fuel containing H2S was characterized, and Raman mapping was used to further elucidate the nature of sulfur poisoning. In situ Raman monitoring was used to investigate coking behavior. Finally, atomic force microscopy (AFM) and electrostatic force microscopy (EFM) were used to further visualize carbon deposition on the nanoscale. From this research, we desire to produce a more complete picture of the SOFC anode.

We present a unique platform for characterizing electrode surfaces in solid oxide fuel cells (SOFCs) that allows simultaneous performance of multiple characterization techniques (e.g. in situ Raman spectroscopy and scanning probe microscopy alongside electrochemical measurements). Complementary information from these analyses may help to advance toward a more profound understanding of electrode reaction and degradation mechanisms, providing insights into rational design of better materials for SOFCs.

Sondagem e Mapeamento superfície do eletrodo em células a combustível de óxido sólido

Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen ...

Scanning-probe Single-electron Capacitance Spectroscopy

The integration of low-temperature scanning-probe techniques and single-electron capacitance spectroscopy represents a powerful tool to study the electronic quantum structure of small systems - including individual atomic dopants in semiconductors. Here we present a capacitance-based method, known as Subsurface Charge Accumulation (SCA) imaging, which is capable of resolving single-electron charging while achieving sufficient spatial resolution to image individual atomic dopants. The use of a capacitance technique enables observation of subsurface features, such as dopants buried many nanometers beneath the surface of a semiconductor material1,2,3. In principle, this technique can be applied to any system to resolve electron motion below an insulating surface.
As in other electric-field-sensitive scanned-probe techniques4, the lateral spatial resolution of the measurement depends in part on the radius of curvature of the probe tip. Using tips with a small radius of curvature can enable spatial resolution of a few tens of nanometers. This fine spatial resolution allows investigations of small numbers (down to one) of subsurface dopants1,2. The charge resolution depends greatly on the sensitivity of the charge detection circuitry; using high electron mobility transistors (HEMT) in such circuits at cryogenic temperatures enables a sensitivity of approximately 0.01 electrons/Hz&frac12; at 0.3 K 5.

Scanning-probe single-electron capacitance spectroscopy facilitates the study of single-electron motion in localized subsurface regions. A sensitive charge-detection circuit is incorporated into a cryogenic scanning probe microscope to investigate small systems of dopant atoms beneath the surface of semiconductor samples.

-Sonda de varredura único elétron Espectroscopia de capacitância

The integration of low-temperature scanning-probe techniques and single-electron capacitance spectroscopy represents a powerful tool to study the ...

Measurement and Analysis of Atomic Hydrogen and Diatomic Molecular AlO, C2, CN, and TiO Spectra Following Laser-induced Optical Breakdown

In this work, we present time-resolved measurements of atomic and diatomic spectra following laser-induced optical breakdown. A typical LIBS arrangement is used. Here we operate a Nd:YAG laser at a frequency of 10 Hz at the fundamental wavelength of 1,064 nm. The 14 nsec pulses with anenergy of 190 mJ/pulse are focused to a 50 &#181;m spot size to generate a plasma from optical breakdown or laser ablation in air. The microplasma is imaged onto the entrance slit of a 0.6 m spectrometer, and spectra are recorded using an 1,800 grooves/mm grating an intensified linear diode array and optical multichannel analyzer (OMA) or an ICCD. Of interest are Stark-broadened atomic lines of the hydrogen Balmer series to infer electron density. We also elaborate on temperature measurements from diatomic emission spectra of aluminum monoxide (AlO), carbon (C2), cyanogen (CN), and titanium monoxide (TiO).
The experimental procedures include wavelength and sensitivity calibrations. Analysis of the recorded molecular spectra is accomplished by the fitting of data with tabulated line strengths. Furthermore, Monte-Carlo type simulations are performed to estimate the error margins. Time-resolved measurements are essential for the transient plasma commonly encountered in LIBS.

Measurement and Analysis of Atomic Hydrogen and Diatomic Molecular AlO, C2, CN, and TiO Spectra Following Laser-induced Optical Breakdown

Time-resolved atomic and diatomic molecular species are measured using LIBS. The spectra are collected at various time delays following the generation of optical breakdown plasma with Nd:YAG laser radiation&#160;and are analyzed to infer electron density and temperature.

Medição e Análise de hidrogênio atômico e Diatomic AlO Molecular, C<sub&gt; 2</sub&gt;, CN, e TiO Spectra Following induzida por laser Breakdown Optical

In this work, we present time-resolved measurements of atomic and diatomic spectra following laser-induced optical breakdown. A typical LIBS arrangement ...

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Monitoring the dynamics of protonation and protein backbone conformation changes during the function of a protein is an essential step towards understanding its mechanism. Protonation and conformational changes affect the vibration pattern of amino acid side chains and of the peptide bond, respectively, both of which can be probed by infrared (IR) difference spectroscopy. For proteins whose function can be repetitively and reproducibly triggered by light, it is possible to obtain infrared difference spectra with (sub)microsecond resolution over a broad spectral range using the step-scan Fourier transform infrared technique. With ~102-103 repetitions of the photoreaction, the minimum number to complete a scan at reasonable spectral resolution and bandwidth, the noise level in the absorption difference spectra can be as low as ~10-4, sufficient to follow the kinetics of protonation changes from a single amino acid. Lower noise levels can be accomplished by more data averaging and/or mathematical processing. The amount of protein required for optimal results is between 5-100 &#181;g, depending on the sampling technique used. Regarding additional requirements, the protein needs to be first concentrated in a low ionic strength buffer and then dried to form a film. The protein film is hydrated prior to the experiment, either with little droplets of water or under controlled atmospheric humidity. The attained hydration level (g of water / g of protein) is gauged from an IR absorption spectrum. To showcase the technique, we studied the photocycle of the light-driven proton-pump bacteriorhodopsin in its native purple membrane environment, and of the light-gated ion channel channelrhodopsin-2 solubilized in detergent.

Key steps of protein function, in particular backbone conformational changes and proton transfer reactions, often take place in the microsecond to millisecond time scale. These dynamical processes can be studied by time-resolved step-scan Fourier-transform infrared spectroscopy, in particular for proteins whose function is triggered by light.

Transferência de prótons e Proteína Conformação Dynamics em fotossensíveis Proteínas por Time-resolvido Passo-scan-Fourier Transform Infrared Spectroscopy

Monitoring the dynamics of protonation and protein backbone conformation changes during the function of a protein is an essential step towards ...

In Situ Time-dependent Dielectric Breakdown in the Transmission Electron Microscope: A Possibility to Understand the Failure Mechanism in Microelectronic Devices

The time-dependent dielectric breakdown (TDDB) in on-chip interconnect stacks is one of the most critical failure mechanisms for microelectronic devices. The aggressive scaling of feature sizes, both on devices and interconnects, leads to serious challenges to ensure the required product reliability. Standard reliability tests and post-mortem failure analysis provide only limited information about the physics of failure mechanisms and degradation kinetics. Therefore it is necessary to develop new experimental approaches and procedures to study the TDDB failure mechanisms and degradation kinetics in particular. In this paper, an in situ experimental methodology in the transmission electron microscope (TEM) is demonstrated to investigate the TDDB degradation and failure mechanisms in Cu/ULK interconnect stacks. High quality imaging and chemical analysis are used to study the kinetic process. The in situ electrical test is integrated into the TEM to provide an elevated electrical field to the dielectrics. Electron tomography is utilized to characterize the directed Cu diffusion in the insulating dielectrics. This experimental procedure opens a possibility to study the failure mechanism in interconnect stacks of microelectronic products, and it could also be extended to other structures in active devices.

In Situ Time-dependent Dielectric Breakdown in the Transmission Electron Microscope: A Possibility to Understand the Failure Mechanism in Microelectronic Devices

The time-dependent dielectric breakdown (TDDB) in on-chip interconnect stacks is one of the most critical failure mechanisms for microelectronic devices. This paper demonstrates the procedure of an in situ TDDB experiment in the transmission electron microscope, which opens a possibility to study the failure mechanism in microelectronic products.

Em ruptura dielétrica Situ dependentes do tempo no Microscópio Eletrônico de Transmissão: A possibilidade de compreender o mecanismo de falha em dispositivos microeletrônicos

The time-dependent dielectric breakdown (TDDB) in on-chip interconnect stacks is one of the most critical failure mechanisms for microelectronic devices. ...

Laser-induced Forward Transfer for Flip-chip Packaging of Single Dies

Flip-chip (FC) packaging is a key technology for realizing high performance, ultra-miniaturized and high-density circuits in the micro-electronics industry. In this technique the chip and/or the substrate is bumped and the two are bonded via these conductive bumps. Many bumping techniques have been developed and intensively investigated since the introduction of the FC technology in 19601 such as stencil printing, stud bumping, evaporation and electroless/electroplating2. Despite the progress that these methods have made they all suffer from one or more than one drawbacks that need to be addressed such as cost, complex processing steps, high processing temperatures, manufacturing time and most importantly the lack of flexibility. In this paper, we demonstrate a simple and cost-effective laser-based bump forming technique known as Laser-induced Forward Transfer (LIFT)3. Using the LIFT technique a wide range of bump materials can be printed in a single-step with great flexibility, high speed and accuracy at RT. In addition, LIFT enables the bumping and bonding down to chip-scale, which is critical for fabricating ultra-miniature circuitry.

We demonstrate the use of the Laser-induced Forward Transfer (LIFT) technique for flip-chip assembly of optoelectronic components. This approach provides a simple, cost-effective, low-temperature, fast and flexible solution for fine-pitch bumping and bonding on chip-scale for achieving high-density circuits for optoelectronic applications.

Transferência para a frente induzida por laser para Flip-chip Embalagem de matrizes de solteiro

Flip-chip (FC) packaging is a key technology for realizing high performance, ultra-miniaturized and high-density circuits in the micro-electronics ...

Energy Dispersive X-ray Tomography for 3D Elemental Mapping of Individual Nanoparticles

Energy dispersive X-ray spectroscopy within the scanning transmission electron microscope (STEM) provides accurate elemental analysis with high spatial resolution, and is even capable of providing atomically resolved elemental maps. In this technique, a highly focused electron beam is incident upon a thin sample and the energy of emitted X-rays is measured in order to determine the atomic species of material within the beam path. This elementally sensitive spectroscopy technique can be extended to three dimensional tomographic imaging by acquiring multiple spectrum images with the sample tilted along an axis perpendicular to the electron beam direction.
Elemental distributions within single nanoparticles are often important for determining their optical, catalytic and magnetic properties. Techniques such as X-ray tomography and slice and view energy dispersive X-ray mapping in the scanning electron microscope provide elementally sensitive three dimensional imaging but are typically limited to spatial resolutions of &gt; 20 nm. Atom probe tomography provides near atomic resolution but preparing nanoparticle samples for atom probe analysis is often challenging. Thus, elementally sensitive techniques applied within the scanning transmission electron microscope are uniquely placed to study elemental distributions within nanoparticles of dimensions 10-100 nm.
Here, energy dispersive X-ray (EDX) spectroscopy within the STEM is applied to investigate the distribution of elements in single AgAu nanoparticles. The surface segregation of both Ag and Au, at different nanoparticle compositions, has been observed.

The use of energy dispersive X-ray tomography in the scanning transmission electron microscope to characterize elemental distributions within single nanoparticles in three dimensions is described.

Tomografia de raios-X de energia dispersiva para 3D Elemental Mapeamento de nanopartículas individuais

Energy dispersive X-ray spectroscopy within the scanning transmission electron microscope (STEM) provides accurate elemental analysis with high spatial ...

Detection and Recovery of Palladium, Gold and Cobalt Metals from the Urban Mine Using Novel Sensors/Adsorbents Designated with Nanoscale Wagon-wheel-shaped Pores

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in industrialized countries. Here, the development of optical mesosensors/adsorbents (MSAs) for efficient recognition and selective recovery of Pd(II), Au(III), and Co(II) from urban mine was achieved. A simple, general method for preparing MSAs based on using high-order mesoporous monolithic scaffolds was described. Hierarchical cubic Ia3d wagon-wheel-shaped MSAs were fabricated by anchoring chelating agents (colorants) into three-dimensional pores and micrometric particle surfaces of the mesoporous monolithic scaffolds. Findings show, for the first time, evidence of controlled optical recognition of Pd(II), Au(III), and Co(II) ions and a highly selective system for recovery of Pd(II) ions (up to ~95%) in ores and industrial wastes. Furthermore, the controlled assessment processes described herein involve evaluation of intrinsic properties (e.g., visual signal change, long-term stability, adsorption efficiency, extraordinary sensitivity, selectivity, and reusability); thus, expensive, sophisticated instruments are not required. Results show evidence that MSAs will attract worldwide attention as a promising technological means of recovering and recycling palladium, gold and cobalt metals.

Because of the importance and extensive use of palladium, gold and cobalt metals in high-technology equipment, their recovery and recycling constitute an important industrial challenge. The metal recovery system described herein is a simple, low-cost means for the effective detection, removal, and recovery of these metals from the urban mine.

Detecção e recuperação de paládio, do ouro e cobalto Metais da Mina Urbana Usando novos sensores / adsorventes Designados com poros em nanoescala em forma de roda de carroça

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in ...

Blast Quantification Using Hopkinson Pressure Bars

Near-field blast load measurement presents an issue to many sensor types as they must endure very aggressive environments and be able to measure pressures up to many hundreds of megapascals. In this respect the simplicity of the Hopkinson pressure bar has a major advantage in that while the measurement end of the Hopkinson bar can endure and be exposed to harsh conditions, the strain gauge mounted to the bar can be affixed some distance away. This allows protective housings to be utilized which protect the strain gauge but do not interfere with the measurement acquisition. The use of an array of pressure bars allows the pressure-time histories at discrete known points to be measured. This article also describes the interpolation routine used to derive pressure-time histories at un-instrumented locations on the plane of interest. Currently the technique has been used to measure loading from high explosives in free air and buried shallowly in various soils.

This protocol details the use of Hopkinson pressure bars to measure reflected blast loading from near-field explosive events. It is capable of interpolating a pressure-time history at any point on a reflective boundary and as such can be used to fully characterize the spatial and temporal variations in loading produced.

Explosão Quantificação Usando barras de pressão Hopkinson

Near-field blast load measurement presents an issue to many sensor types as they must endure very aggressive environments and be able to measure pressures ...