Este trabalho foi apoiado pelo nacional pesquisa básica programa da China (2014CB932400), Nacional Natural Science Foundation da China (n º s 51525204 e U1607206) e projeto de pesquisa básica de Shenzhen (n. º JCYJ20150529164918735). Também, gostaríamos de agradecer a Daicel-Allnex Ltd. e co. JSR gentilmente forneceu poliuretanos e borracha de butadieno estireno, respectivamente.

1. preparação de 1 wt % 2,2,6,6-Tetramethylpiperidin-1-Oxil (ritmo)-mediada Sol (TOCN) de nanofibras de celulose oxidada
Nota: O sol é definida como uma suspensão coloidal de partículas muito pequenas de sólidos em um meio contínuo de líquido.
<ol><li>Suspenda 66,7 g de celulose Kraft branqueada de Nadelholz (NBKP, que contém 12 g de celulose) em 700 mL de água desionizada (DI) com um agitador mecânico a 300 rpm por 20 min.</li>
	<li>Adicione 20 mL de solução aquosa de ritmo (contendo 0,15 g de ritmo) e 20 mL de solução aquosa de NaBr (contendo 1,5 g de NaBr) lentamente para o acima NBKP suspensão14,15.</li>
	<li>Ajuste o pH da suspensão acima de aproximadamente 10.5 (medido com um medidor de pH) com lentamente adicionando solução de NaOH de 3,0 M.</li>
	<li>Lentamente, adicione cerca de 63,8 g de solução aquosa de NaClO (com 6-14 wt % cloro ativo) com uma pipeta para a mistura acima para iniciar a oxidação mediada por TEMPO.</li>
	<li>Enquanto a adição de NaClO, continue a adicionar a solução de NaOH para manter o pH do sistema dentro do intervalo de 10,0 para ~ 10.5. Este processo demora cerca de 2,5 h.</li>
	<li>Enxague as fibras de celulose oxidada mediada em andamento com água 3 vezes (1.200 mL de água DI cada vez) para remover o NaClO residual, NaOH e outros produtos químicos.</li>
	<li>Trate o colar com um misturador mecânico poderoso para desintegrar as fibras de celulose oxidada em nanofibras. Realizar o tratamento mecânico cuidadosamente várias vezes acompanhado com uma adição de uma quantidade igual de água. Finalmente, um 1 wt % sol (TOCN) de nanofibras de celulose oxidada mediada por TEMPO é obtido. Os TOCNs tem um diâmetro de 4 a 6 ~ nm e um comprimento de 0,5 a 2 ~ μm.</li>
	<li>Armazene o 1 sol TOCN % wt a 4 ° C (celulose nanofibras tendem a apodrecer a uma temperatura ambiente).</li>
</ol>2. preparação da borracha de TOCN estireno butadieno (SBR) misturada com Sol
<ol><li>Adicione 0,21 g de coloide SBR (48,5% em peso) em 10 g de 1 sol TOCN % a wt (etapa 11,7.) em um recipiente de vidro de 20 mL.</li>
	<li>Agite a mistura acima de 3 min com um misturador do vortex no nível de potência de 6 para alcançar um sol uniformemente dispersos loja da sol mistura acima a 4 ° C antes do uso.</li>
</ol>3. preparação de TOCN-TiO2 misturado Sol
<ol><li>Adicionar 0,1 g de TiO2 nanopartículas (com um tamanho de partícula médio de 20 nm) em 10 g de 1 wt % TOCN sol num vaso de vidro de 20 mL.</li>
	<li>Agite a mistura acima com um homogenizador para 10 min para alcançar um sol uniformemente misturado executar este 10 min-processo intermitente, desde que uma quantidade significativa de calor é gerada no processo e resulta no aumento da temperatura, que pode degradar TOCNs. Armazene o sol mistura a 4 ° C antes do uso.</li>
</ol>4. preparação da superfície-TOCN oxidado misturado Sols de fibra de carbono (SOCF)
<ol><li>Refluxo 1,7 g de fibra de carbono (malha de 300, com um diâmetro de 5.5 para ~6.0 μm e um comprimento de aproximadamente 50 μm) em 150 mL de ácido nítrico concentrado a 60 ° C, durante 6 h alcançar SOCF16. Adicione 0,01 g do SOCF acima em 10 g de 1 sol TOCN % wt dentro de um recipiente de vidro de 20 mL.</li>
	<li>Shake-Misture a mistura acima e ultraproceda à sonicação a mistura por 5 min para conseguir um sol uniformemente misturado loja o sol mistura a 4 ° C antes do uso.</li>
</ol>5. preparação do monolito de Microhoneycomb da 1 wt % TOCN Sol (denotado por MHM-TOCN)
<ol><li>Carregar um tubo (PP) polipropileno (com um diâmetro interno de 13 mm, diâmetro externo de 15 mm e um comprimento de 150 mm) com contas de vidro e encha a parte inferior de 5 cm do tubo13.</li>
	<li>Carregar uma certa quantidade (a quantidade não é controlada pela cada vez, mas é normalmente maior que 2,7 mL para assegurar o processo de corte posterior) da 1 sol wt % TOCN, no tubo PP acima contendo esferas de vidro. Nota: Sol TOCN foi preenchido diretamente no tubo PP sem derramar em esferas de vidro para o estudo do efeito de distância que tem estado envolvido no processo de congelação unidirecional. Neste caso, a quantidade de sol TOCN foi 11 mL.</li>
	<li>Retire cuidadosamente as bolhas que podem ter sido geradas durante o carregamento de sol. Mantenha o tubo PP, contendo o sol TOCN a 4 ° C durante a noite antes do uso.</li>
	<li>Fixe o tubo PP acima, contendo o sol TOCN à máquina de imersão que é usada para congelamento unidirecional. Defina os parâmetros relevantes e começar mergulhando o tubo PP um jarro de thermo contendo nitrogênio líquido (196 ° C) a uma velocidade constante de 50 cm h-1 (Figura 1).</li>
	<li>Corte a parte do tubo PP com uma serra e quebrar a parte de sol TOCN congelada em várias seções. Congelar-seco estas seções com uma máquina de liofilização a-10 ° C, durante 1 dia e, em seguida, a-5 ° C durante 1 dia e finalmente a 0 ° C, durante 1 dia. A MHM-TOCN obteve-se como monolitos de cor branca (Figura 1).</li>
</ol>6. preparação do monolito de Microhoneycomb do TOCN-SBR misturado Sol (denotado por MHM-TOCN/SBR) e TOCN-TiO2 misturado Sol (denotado por MHM-TOCN/TiO2 )
<ol><li>Carregar tubos de polipropileno (PP) (com um diâmetro interno de 13 mm, diâmetro externo de 15 mm e um comprimento de 150 mm) com contas de vidro, parte inferior de 5 cm do tubo de enchimento. Nota: Os grânulos de vidro são usados para cobrir a área onde ocorre crescimento de cristais de gelo instável, para conseguir o uniforme morfologia da amostra resultante. O tamanho e a propriedade de superfície dos grânulos de vidro não afetam a morfologia da amostra resultante.</li>
	<li>Carregar certa quantidade (a quantidade não é controlada pela cada vez, mas é normalmente maior que 2,7 mL para assegurar o processo de corte posterior) do TOCN-SBR misturado sol ou TOCN-TiO2 sol misturado em PP tubos contendo grânulos de vidro.</li>
	<li>Retire cuidadosamente as bolhas que podem ter sido geradas durante o carregamento de sol. Manter os tubos PP contendo acima misturado sol a 4 ° C durante a noite antes do uso.</li>
	<li>Anexe os tubos PP contendo acima misturado sols para a máquina de imersão que é usado para congelamento unidirecional. Defina os parâmetros relevantes e começar a mergulhar o tubo PP em um tanque contendo nitrogênio líquido (196 ° C) a uma velocidade constante de 20 cm h-1.</li>
	<li>Corte a parte do tubo PP com uma serra e rachar o congelado TOCN-SBR misturado parte do sol em várias seções.</li>
	<li>Congelar-seco estas seções com uma máquina de liofilização a-10 ° C, durante 1 dia e, em seguida, a-5 ° C durante 1 dia e finalmente a 0 ° C, durante 1 dia. A MHM-TOCN/SBR e MHM-TOCN/TiO2 foram obtidos como monolitos de brancos.</li>
</ol>7. preparação do monolito de Microhoneycomb do TOCN-SOCF misturado Sol (denotado por MHM-TOCN/SOCF)
<ol><li>Carrega um tubo de polipropileno (PP) com (um diâmetro interno de 13 mm) e um diâmetro externo de 15 mm e um comprimento de 150 mm com contas de vidro, parte inferior de 5 cm do tubo de enchimento.</li>
	<li>Carregar certa quantidade (a quantidade não é controlada pela cada vez, mas é normalmente maior que 2,7 mL para assegurar o processo de corte posterior) do TOCN-SOCF misturado sol no tubo PP acima contendo esferas de vidro.</li>
	<li>Retire cuidadosamente as bolhas que podem ter sido geradas durante o carregamento de sol. Mantenha o tubo PP contendo acima misturado sol a 4 ° C durante a noite antes do uso.</li>
	<li>Anexe o tubo PP contendo acima misturado sol à máquina de imersão que é usada para congelamento unidirecional. Defina os parâmetros relevantes e começar a mergulhar o tubo PP em um tanque contendo nitrogênio líquido (196 ° C) a uma velocidade constante de 20 cm h-1.</li>
	<li>Corte a parte do tubo PP com uma serra e crack a parte de sol TOCN-SOCF congelada em várias seções. Congelar-seco estas seções com uma máquina de liofilização a-10 ° C, durante 1 dia e, em seguida, a-5 ° C durante 1 dia e finalmente a 0 ° C, durante 1 dia. A MHM-TOCN/SOCF obteve-se como um monólito branco-cinza.</li>
</ol>

<ol>
	<li>Nishihara, H., Mukai, S. R., Yamashita, D., Tamon, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ordered+macroporous+silica+by+ice+templating.">Ordered macroporous silica by ice templating.</a> Chem. Mater. 17, 683-689 (2005).</li><li>Mukai, S. R., Nishihara, H., Yoshida, T., Taniguchi, K., Tamon, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphology+of+resorcinol-formaldehyde+gels+obtained+through+ice-templating.">Morphology of resorcinol-formaldehyde gels obtained through ice-templating.</a> Carbon. 43 (7), 1563-1565 (2005).</li><li>Mukai, S. R., Nishihara, H., Tamon, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Porous+microfibers+and+microhoneycombs+synthesized+by+ice+templating.">Porous microfibers and microhoneycombs synthesized by ice templating.</a> Catal. Surv. Asia. 10 (3-4), 161-171 (2006).</li><li>Nishihara, 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=Preparation+of+monolithic+SiO2-Al2O3+cryogels+with+inter-connected+macropores+through+ice+templating.">Preparation of monolithic SiO2-Al2O3 cryogels with inter-connected macropores through ice templating.</a> J. Mater. Chem. 16 (31), 3231-3236 (2006).</li><li>Mukai, S. R., Mitani, K., Murata, S., Nishihara, H., Tamon, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assembling+of+nanoparticles+using+ice+crystals.">Assembling of nanoparticles using ice crystals.</a> Mater. Chem. Phys. 123 (2), 347-350 (2010).</li><li>Cui, K., 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=Self-assembled+microhoneycomb+network+of+single-walled+carbon+nanotubes+for+solar+cells.">Self-assembled microhoneycomb network of single-walled carbon nanotubes for solar cells.</a> J. Phy. Chem. Lett. 4 (15), 2571-2576 (2013).</li><li>Xu, T., Wang, C. -. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+two-step+sintering+on+micro-honeycomb+BaTiO3+ceramics+prepared+by+freeze-casting+process.">Effect of two-step sintering on micro-honeycomb BaTiO3 ceramics prepared by freeze-casting process.</a> J. Eur. Ceram. Soc. 36 (10), 2647-2652 (2016).</li><li>Yoshida, 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=CO2+Separation+in+a+flow+system+by+silica+microhoneycombs+loaded+with+an+ionic+liquid+prepared+by+the+ice-templating+method.">CO2 Separation in a flow system by silica microhoneycombs loaded with an ionic liquid prepared by the ice-templating method.</a> Ind. Eng. Chem. Res. 56 (10), 2834-2839 (2017).</li><li>Mukai, S. R., Nishihara, H., Tamon, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formation+of+monolithic+silica+gel+microhoneycombs+(SMHs)+using+pseudosteady+state+growth+of+microstructural+ice+crystals.">Formation of monolithic silica gel microhoneycombs (SMHs) using pseudosteady state growth of microstructural ice crystals.</a> Chem. Commun. (7), 874-875 (2004).</li><li>Gutie&#180;rrez, M. C., 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=Macroporous+3D+Architectures+of+Self-Assembled+MWCNT+Surface+Decorated+with+Pt+Nanoparticles+as+Anodes+for+a+Direct+Methanol+Fuel+Cell.">Macroporous 3D Architectures of Self-Assembled MWCNT Surface Decorated with Pt Nanoparticles as Anodes for a Direct Methanol Fuel Cell.</a> J. Phys. Chem. C. 111, 5557-5560 (2007).</li><li>Mukai, S. R., Nishihara, H., Tamon, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphology+maps+of+ice-templated+silica+gels+derived+from+silica+hydrogels+and+hydrosols.">Morphology maps of ice-templated silica gels derived from silica hydrogels and hydrosols.</a> Micropor. Mesopor. Mat. 116 (1-3), 166-170 (2008).</li><li>Okaji, R., Taki, K., Nagamine, S., Ohshima, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+of+porous+honeycomb+monolith+from+UV-curable+monomer/dioxane+solution+via+unidirectional+freezing+and+UV+irradiation.">Preparation of porous honeycomb monolith from UV-curable monomer/dioxane solution via unidirectional freezing and UV irradiation.</a> J. Appl. Polym. Sci. 125 (4), 2874-2881 (2012).</li><li>Pan, Z. -. Z., 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=Cellulose+nanofiber+as+a+distinct+structure-directing+agent+for+xylem-like+microhoneycomb+monoliths+by+unidirectional+freeze-drying.">Cellulose nanofiber as a distinct structure-directing agent for xylem-like microhoneycomb monoliths by unidirectional freeze-drying.</a> ACS Nano. 10 (12), 10689-10697 (2016).</li><li>Saito, T., Nishiyama, Y., Putaux, J. -. L., Vigon, M., Isogai, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Homogeneous+Suspensions+of+Individualized+Microfibrils+from+TEMPO-Catalyzed+Oxidation+of+Native+Cellulose.">Homogeneous Suspensions of Individualized Microfibrils from TEMPO-Catalyzed Oxidation of Native Cellulose.</a> Biomacromolecules. 7 (6), 1687-1691 (2006).</li><li>Saito, T., Kimura, S., Nishiyama, Y., Isogai, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellulose+Nanofibers+Prepared+by+TEMPO-Mediated+Oxidation+of+Native+Cellulose.">Cellulose Nanofibers Prepared by TEMPO-Mediated Oxidation of Native Cellulose.</a> Biomacromolecules. 8, 2485-2491 (2007).</li><li>Bekyarova, E., 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=Multiscale+carbon+nanotube&#8722;+carbon+fiber+reinforcement+for+advanced+epoxy+composites.">Multiscale carbon nanotube&#8722; carbon fiber reinforcement for advanced epoxy composites.</a> Langmuir. 23, 3970-3974 (2007).</li><li>Nishihara, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Study on the simultaneous control of the nanostructure and morphology of the porous materials prepared via the ice-templating method [D]. , (2005).</li><li>Zhang, R., 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=Three-dimensional+porous+graphene+sponges+assembled+with+the+combination+of+surfactant+and+freeze-drying.">Three-dimensional porous graphene sponges assembled with the combination of surfactant and freeze-drying.</a> Nano Research. 7 (10), 1477-1487 (2014).</li><li>Tao, Y., 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=Towards+ultrahigh+volumetric+capacitance:+graphene+derived+highly+dense+but+porous+carbons+for+supercapacitors.">Towards ultrahigh volumetric capacitance: graphene derived highly dense but porous carbons for supercapacitors.</a> Sci. Rep. 3, 2975 (2013).</li></ol>

Os autores não têm nada para divulgar.

O passo mais crítico para alcançar os MHMs é a etapa de congelamento unidirecional, durante que a água se solidifica para formar cristais de gelo colunar e aperte a dispersoid lado para formar o quadro. O processo de congelação unidirecional basicamente envolve transferência térmica entre o sol do precursor e o líquido de arrefecimento. Em nossa configuração, uma máquina de imersão foi usada para inserir um tubo PP, contendo um sol de precursor para o refrigerante (nitrogênio líquido), com uma velocidade c...

Como um material novinho em folha, microhoneycomb monólito (denotado por MHM) recentemente atraiu tremenda atenção multidisciplinar campos1,2,3,4,5, 6 , 7 , 8. the MHM primeiro foi preparado por Mukai S. et al . através de uma abordagem unidirecional de liofilização (UDF) modificado como um monolito com uma matriz de microcanais reta com seções transversais de favo de mel9. MHM possui as vantagens gerais de estruturas de favo de mel, ou seja, mosaico eficiente, alta relação resistência-peso e queda de pressão baixa. Além disso, comparado com o monolito de favo de mel com um tamanho maior do canal, a MHM tem uma muito maior área de superfície específica. O método UDF envolve o crescimento unidirecional de cristais de gelo e separação de fases simultâneas sobre congelamento. Após a remoção dos cristais de gelo, é obtido um componente sólido moldado pelo cristal de gelo. A morfologia formada após a separação de fase depende da natureza intrínseca do precursor (sol ou gel) e na maioria dos casos, lamela10, fibra11e fishbone12 estruturas são susceptíveis de formar em vez dos MHMs. Como resultado, a formação de MHMs tem sido relatada apenas em precursores limitadas, e isto significativamente tem dificultado a diversidade das suas propriedades químicas. Recentemente descobrimos que nanofibras de celulose têm uma função forte estrutura-direcionando para formar a estrutura MHM através do processo UDF13. Simplesmente pela mistura de nanofibras de celulose com outros componentes dispersáveis em água, é possível preparar uma variedade de MHMs com propriedades químicas diferentes. Além disso, suas formas exteriores e tamanhos de canal são13de forma flexível e facilmente controlada. Assim, MHMs são esperados para ser usado como filtros, catalisador suporta, eletrodos tipo de fluxo, sensores e andaimes para biomateriais.
Neste trabalho, nós primeiro explicar a técnica de preparação básica de MHMs de dispersão aquosa de nanofibras de celulose através do processo UDF em detalhe. Além disso, demonstramos a preparação de vários tipos diferentes de compostos MHMs.

<table border="0" cellpadding="0" cellspacing="0" width="572">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Nadelholz Bleached Kraft Pulp</td>
			<td style="width:100px;">Seioko PMC company</td>
			<td style="width:89px;">CSF=600</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">TEMPO</td>
			<td style="width:100px;">Macklin Inc.</td>
			<td style="width:89px;">T819129</td>
			<td style="width:167px;">98%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">NaBr</td>
			<td style="width:100px;">Macklin Inc.</td>
			<td style="width:89px;">S818075</td>
			<td style="width:167px;">AR, 99%</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">NaClO</td>
			<td style="width:100px;">Aladin Inc.</td>
			<td style="width:89px;">S101636</td>
			<td style="width:167px;">6-14 wt% active chlorine basis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">SBR colloid</td>
			<td style="width:100px;">JSR corp.</td>
			<td style="width:89px;">TRD102A</td>
			<td style="width:167px;">48.5 wt%</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">TiO2</td>
			<td style="width:100px;">Sinopharm Chemical Reagent Co., Ltd.</td>
			<td style="width:89px;">A63725402</td>
			<td style="width:167px;">crystalline anatase phase</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">carbon fiber</td>
			<td style="width:100px;">Shenzhen Xian&#8217;gu Ltd.</td>
			<td style="width:89px;">XGCP-300</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Nitric acid</td>
			<td style="width:100px;">Huada Reagent Ltd.</td>
			<td style="width:89px;">7697-37-2</td>
			<td style="width:167px;">65-68 wt%</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Mixer</td>
			<td style="width:100px;">Scientific Industries, Inc</td>
			<td style="width:89px;">G-560</td>
			<td style="width:167px;">the mixer&#160;</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Mechanical blender</td>
			<td style="width:100px;">Waring Lab Ltd.</td>
			<td style="width:89px;">MX1000XTX</td>
			<td style="width:167px;">For disintegrating cellulose bundles into nanofibers.</td>
		</tr>
		<tr height="46">
			<td height="46" style="height:46px;width:216px;">Homogenizer</td>
			<td style="width:100px;">Scientz Ltd.</td>
			<td style="width:89px;">HXF-DY</td>
			<td style="width:167px;">For dispersing TiO2 nanoparticles</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">pH meter&#160;</td>
			<td style="width:100px;">Horiba Ltd.</td>
			<td style="width:89px;">F-74BW</td>
			<td></td>
		</tr>
	</tbody>
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microhoneycomb monoliths prepared by the unidirectional freeze-drying of cellulose nanofiber based sols: method and extensions

Estruturas monolíticas do favo de mel tem sido atraentes para campos multidisciplinares devido a sua alta proporção de força-à-peso. Particularmente, microhoneycomb monólitos (MHMs) com canais de micrômetro-escala são esperados como plataformas eficientes para reações e separações por causa de suas grandes áreas de superfície. Até agora, MHMs foram preparadas por um método de liofilização (UDF) unidirecional apenas a partir de precursores muito limitados. Neste documento, nós relatamos um protocolo a partir do qual uma série de MHMs consistindo de diferentes componentes pode ser obtida. Recentemente, encontramos essa função de nanofibras de celulose como agente de estrutura-direcionando distinto no sentido da formação de MHMs através do processo UDF. Misturando as nanofibras de celulose com substâncias solúveis de água que não rendem MHMs, uma variedade de MHMs compostos pode ser preparada. Isto enriquece significativamente a constituição química dos MHMs para aplicações versáteis.

As morfologias para diferentes posições da MHM-TOCN na direção do congelamento unidirecional são investigadas e mostradas na Figura 2. Com a posição de ser mais longe da parte inferior da MHM-TOCN, revelou-se uma mudança gradual de morfologia (Figura 2, discussão). Através da introdução de um segundo componente para o sol TOCN para formar um sol de mistura homogênea, é possível preparar vários tip...

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Microhoneycomb Monoliths Prepared by the Unidirectional Freeze-drying of Cellulose Nanofiber Based Sols: Method and Extensions

Aqui, apresentamos um protocolo geral para preparar uma variedade de monólitos de microhoneycomb (MHMs) no qual o fluido pode passar com uma queda de pressão extremamente baixa. MHMs obtidos são esperados para ser usados como filtros, catalisador suporta, eletrodos tipo de fluxo, sensores e andaimes para biomateriais.

Monólitos de Microhoneycomb preparados pela liofilização unidirecional de nanofibras de celulose com base Sols: método e extensões

Monolithic honeycomb structures have been attractive to multidisciplinary fields due to their high strength-to-weight ratio. Particularly, microhoneycomb ...

microhoneycomb-monoliths-prepared-unidirectional-freeze-drying

Research

JoVE Journal

Bioengineering

8.8K visualizações.  Tsinghua University. Aqui, apresentamos um protocolo geral para preparar uma variedade de monólitos de microhoneycomb (MHMs) no qual o fluido pode passar com uma queda de pressão extremamente baixa. MHMs obtidos são esperados para ser usados como filtros, catalisador suporta, eletrodos tipo de fluxo, sensores e andaimes para biomateriais.

Vídeo: Microhoneycomb Monoliths Prepared by the Unidirectional Freeze-drying of Cellulose Nanofiber Based Sols: Method and Extensions

Improved Method for the Preparation of a Human Cell-based, Contact Model of the Blood-Brain Barrier

The blood-brain barrier (BBB) comprises impermeable but adaptable brain capillaries which tightly control the brain environment. Failure of the BBB has been implied in the etiology of many brain pathologies, creating a need for development of human in vitro BBB models to assist in clinically-relevant research. Among the numerous BBB models thus far described, a static (without flow), contact BBB model, where astrocytes and brain endothelial cells (BECs) are cocultured on the opposite sides of a porous membrane, emerged as a simplified yet authentic system to simulate the BBB with high throughput screening capacity. Nevertheless the generation of such model presents few technical challenges. Here, we describe a protocol for preparation of a contact human BBB model utilizing a novel combination of primary human BECs and immortalized human astrocytes. Specifically, we detail an innovative method for cell-seeding on inverted inserts as well as specify insert staining techniques and exemplify how we use our model for BBB-related research.

Establishment of human models of the blood-brain barrier (BBB) can benefit research into brain conditions associated with BBB failure. We describe here an improved technique for preparation of a contact BBB model, which permits coculturing of human astrocytes and brain endothelial cells on the opposite sides of a porous membrane.

Melhoria da Metodologia para a Elaboração de um baseado em celular, Contact Modelo Humano da barreira hemato-encefálica

The blood-brain barrier (BBB) comprises impermeable but adaptable brain capillaries which tightly control the brain environment. Failure of the BBB has ...

Bioengenharia

Manufacturing Of Robust Natural Fiber Preforms Utilizing Bacterial Cellulose as Binder

A novel method of manufacturing rigid and robust natural fiber preforms is presented here. This method is based on a papermaking process, whereby loose and short sisal fibers are dispersed into a water suspension containing bacterial cellulose. The fiber and nanocellulose suspension is then filtered (using vacuum or gravity) and the wet filter cake pressed to squeeze out any excess water, followed by a drying step. This will result in the hornification of the bacterial cellulose network, holding the loose natural fibers together.
Our method is specially suited for the manufacturing of rigid and robust preforms of hydrophilic fibers. The porous and hydrophilic nature of such fibers results in significant water uptake, drawing in the bacterial cellulose dispersed in the suspension. The bacterial cellulose will then be filtered against the surface of these fibers, forming a bacterial cellulose coating. When the loose fiber-bacterial cellulose suspension is filtered and dried, the adjacent bacterial cellulose forms a network and hornified to hold the otherwise loose fibers together.
The introduction of bacterial cellulose into the preform resulted in a significant increase of the mechanical properties of the fiber preforms. This can be attributed to the high stiffness and strength of the bacterial cellulose network. With this preform, renewable high performance hierarchical composites can also be manufactured by using conventional composite production methods, such as resin film infusion (RFI) or resin transfer molding (RTM). Here, we also describe the manufacturing of renewable hierarchical composites using double bag vacuum assisted resin infusion.

We present a novel method of manufacturing rigid and robust short natural fiber preforms using a papermaking process. Bacterial cellulose acts simultaneously as the binder for the loose fibers and provides rigidity to the fiber preforms. These preforms can be infused with a resin to produce truly green hierarchical composites.

Fabricação de fibras naturais robustos Preformas Utilizando bacteriana Celulose como Binder

A novel method of manufacturing rigid and robust natural fiber preforms is presented here. This method is based on a papermaking process, whereby loose ...

Quantification of Global Diastolic Function by Kinematic Modeling-based Analysis of Transmitral Flow via the Parametrized Diastolic Filling Formalism

Quantitative cardiac function assessment remains a challenge for physiologists and clinicians.&#160;Although historically invasive methods have comprised the only means available, the development of noninvasive imaging modalities (echocardiography, MRI, CT) having high temporal and spatial resolution provide a new window for quantitative diastolic function assessment. Echocardiography is the agreed upon standard for diastolic function assessment, but indexes in current clinical use merely utilize selected features of chamber dimension (M-mode) or blood/tissue motion (Doppler) waveforms without incorporating the physiologic causal determinants of the motion itself.&#160;The recognition that all left ventricles (LV) initiate filling by serving as mechanical suction pumps allows global diastolic function to be assessed based on laws of motion that apply to all chambers. What differentiates one heart from another are the parameters of the equation of motion that governs filling. Accordingly, development of the Parametrized Diastolic Filling (PDF) formalism&#160;has shown that the entire range of clinically observed early transmitral flow (Doppler E-wave) patterns are extremely well fit by the laws of damped oscillatory motion.&#160;This permits analysis of individual E-waves in accordance with a causal mechanism (recoil-initiated suction) that yields three (numerically) unique lumped parameters whose physiologic analogues are chamber stiffness (k), viscoelasticity/relaxation (c), and load (xo).&#160;The recording of transmitral flow (Doppler E-waves) is standard practice in clinical cardiology and, therefore, the echocardiographic recording method is only briefly reviewed. Our focus is on determination of the PDF parameters from routinely recorded E-wave data.&#160;As the highlighted results indicate, once the PDF parameters have been obtained from a suitable number of load varying E-waves, the investigator is free to use the parameters or construct indexes from the parameters (such as stored energy 1/2kxo2, maximum A-V pressure gradient kxo, load independent index of diastolic function, etc.) and select the aspect of physiology or pathophysiology to be quantified.

Accurate, causality-based quantification of global diastolic function has been achieved by kinematic modeling-based analysis of transmitral flow via the Parametrized Diastolic Filling (PDF) formalism. PDF generates unique stiffness, relaxation,&#160;and load parameters and elucidates &#39;new&#39; physiology while providing sensitive and specific indexes of dysfunction.

Quantificação da função global diastólica por análise baseada em Modelagem cinemática de transmitral fluxo através do formalismo de enchimento parametrizada diastólica

Quantitative cardiac function assessment remains a challenge for physiologists and clinicians.&#160;Although historically invasive methods have comprised ...

Formation of Biomembrane Microarrays with a Squeegee-based Assembly Method

Lipid bilayer membranes form the plasma membranes of cells and define the boundaries of subcellular organelles. In nature, these membranes are heterogeneous mixtures of many types of lipids, contain membrane-bound proteins and are decorated with carbohydrates. In some experiments, it is desirable to decouple the biophysical or biochemical properties of the lipid bilayer from those of the natural membrane. Such cases call for the use of model systems such as giant vesicles, liposomes or supported lipid bilayers (SLBs). Arrays of SLBs are particularly attractive for sensing applications and mimicking cell-cell interactions. Here we describe a new method for forming SLB arrays. Submicron-diameter SiO2 beads are first coated with lipid bilayers to form spherical SLBs (SSLBs). The beads are then deposited into an array of micro-fabricated submicron-diameter microwells. The preparation technique uses a "squeegee" to clean the substrate surface, while leaving behind SSLBs that have settled into microwells. This method requires no chemical modification of the microwell substrate, nor any particular targeting ligands on the SSLB. Microwells are occupied by single beads because the well diameter is tuned to be just larger than the bead diameter. Typically, more 75% of the wells are occupied, while the rest remain empty. In buffer SSLB arrays display long-term stability of greater than one week. Multiple types of SSLBs can be placed in a single array by serial deposition, and the arrays can be used for sensing, which we demonstrate by characterizing the interaction of cholera toxin with ganglioside GM1. We also show that phospholipid vesicles without the bead supports and biomembranes from cellular sources can be arrayed with the same method and cell-specific membrane lipids can be identified.

Supported lipid bilayers and natural membrane particles are convenient systems that can approximate the properties of cell membranes and be incorporated in a variety of analytical strategies. Here we demonstrate a method for preparing microarrays composed of supported lipid bilayer-coated SiO2 beads, phospholipid vesicles or natural membrane particles.

Formação de biomembrana Microarrays com um método de montagem baseada em Rodo

Lipid bilayer membranes form the plasma membranes of cells and define the boundaries of subcellular organelles. In nature, these membranes are ...

Electrospun Nanofiber Scaffolds with Gradations in Fiber Organization

The goal of this protocol is to report a simple method for generating nanofiber scaffolds with gradations in fiber organization and test their possible applications in controlling cell morphology/orientation. Nanofiber organization is controlled with a new fabrication apparatus that enables the gradual decrease of fiber organization in a scaffold. Changing the alignment of fibers is achieved through decreasing deposition time of random electrospun fibers on a uniaxially aligned fiber mat. By covering the collector with a moving barrier/mask, along the same axis as fiber deposition, the organizational structure is easily controlled. For tissue engineering purposes, adipose-derived stem cells can be seeded to these scaffolds. Stem cells undergo morphological changes as a result of their position on the varied organizational structure, and can potentially differentiate into different cell types depending on their locations. Additionally, the graded organization of fibers enhances the biomimicry of nanofiber scaffolds so they more closely resemble the natural orientations of collagen nanofibers at tendon-to-bone insertion site compared to traditional scaffolds. Through nanoencapsulation, the gradated fibers also afford the possibility to construct chemical gradients in fiber scaffolds, and thereby further strengthen their potential applications in fast screening of cell-materials interaction and interfacial tissue regeneration. This technique enables the production of continuous gradient scaffolds, but it also can potentially produce fibers in discrete steps by controlling the movement of the moving barrier/mask in a discrete fashion.

Here, we present a protocol to fabricate electrospun nanofiber scaffolds with gradated organization of fibers and explore their applications in regulating cell morphology/orientation. Gradients with regard to physical and chemical properties of the nanofiber scaffolds offer a wide variety of applications in the biomedical field.

Electrospun nanofibras Andaimes com gradações de Organização Fiber

The goal of this protocol is to report a simple method for generating nanofiber scaffolds with gradations in fiber organization and test their possible ...

Biomembrane Fabrication by the Solvent-assisted Lipid Bilayer (SALB) Method

In order to mimic cell membranes, the supported lipid bilayer (SLB) is an attractive platform which enables in vitro investigation of membrane-related processes while conferring biocompatibility and biofunctionality to solid substrates. The spontaneous adsorption and rupture of phospholipid vesicles is the most commonly used method to form SLBs. However, under physiological conditions, vesicle fusion (VF) is limited to only a subset of lipid compositions and solid supports. Here, we describe a one-step general procedure called the solvent-assisted lipid bilayer (SALB) formation method in order to form SLBs which does not require vesicles. The SALB method involves the deposition of lipid molecules onto a solid surface in the presence of water-miscible organic solvents (e.g., isopropanol) and subsequent solvent-exchange with aqueous buffer solution in order to trigger SLB formation. The continuous solvent exchange step enables application of the method in a flow-through configuration suitable for monitoring bilayer formation and subsequent alterations using a wide range of surface-sensitive biosensors. The SALB method can be used to fabricate SLBs on a wide range of hydrophilic solid surfaces, including those which are intractable to vesicle fusion. In addition, it enables fabrication of SLBs composed of lipid compositions which cannot be prepared using the vesicle fusion method. Herein, we compare results obtained with the SALB and conventional vesicle fusion methods on two illustrative hydrophilic surfaces, silicon dioxide and gold. To optimize the experimental conditions for preparation of high quality bilayers prepared via the SALB method, the effect of various parameters, including the type of organic solvent in the deposition step, the rate of solvent exchange, and the lipid concentration is discussed along with troubleshooting tips. Formation of supported membranes containing high fractions of cholesterol is also demonstrated with the SALB method, highlighting the technical capabilities of the SALB technique for a wide range of membrane configurations.

Biomembrane Fabrication by the Solvent-assisted Lipid Bilayer SALB Method

We present an experimental protocol to form a supported lipid bilayer on solid substrates without using lipid vesicles. We demonstrate a one-step method to form a lipid bilayer on silicon dioxide and gold as well as supported membranes with cholesterol-enriched domain for various biological applications.

Biomembrane Fabrication pelo Solvent-assistida Lipid bicamada (SALB) Método

In order to mimic cell membranes, the supported lipid bilayer (SLB) is an attractive platform which enables in vitro investigation of membrane-related ...

Synthesis of Keratin-based Nanofiber for Biomedical Engineering

Electrospinning, due to its versatility and potential for applications in various fields, is being frequently used to fabricate nanofibers. Production of these porous nanofibers is of great interest due to their unique physiochemical properties. Here we elaborate on the fabrication of keratin containing poly (&#949;-caprolactone) (PCL) nanofibers (i.e., PCL/keratin composite fiber). Water soluble keratin was first extracted from human hair and mixed with PCL in different ratios. The blended solution of PCL/keratin was transformed into nanofibrous membranes using a laboratory designed electrospinning set up. Fiber morphology and mechanical properties of the obtained nanofiber were observed and measured using scanning electron microscopy and tensile tester. Furthermore, degradability and chemical properties of the nanofiber were studied by FTIR. SEM images showed uniform surface morphology for PCL/keratin fibers of different compositions. These PCL/keratin fibers also showed excellent mechanical properties such as Young&#39;s modulus and failure point. Fibroblast cells were able to attach and proliferate thus proving good cell viability. Based on the characteristics discussed above, we can strongly argue that the blended nanofibers of natural and synthetic polymers can represent an excellent development of composite materials that can be used for different biomedical applications.

Electrospun nanofibers have a high surface area to weight ratio, excellent mechanical integrity, and support cell growth and proliferation. These nanofibers have a wide range of biomedical applications. Here we fabricate keratin/ PCL nanofibers, using the electrospinning technique, and characterize the fibers for possible applications in tissue engineering.

Síntese de nanofibras baseado em queratina de Engenharia Biomédica

Electrospinning, due to its versatility and potential for applications in various fields, is being frequently used to fabricate nanofibers. Production of ...

Dendrimer-based Uneven Nanopatterns to Locally Control Surface Adhesiveness: A Method to Direct Chondrogenic Differentiation

Cellular adhesion and differentiation is conditioned by the nanoscale disposition of the extracellular matrix (ECM) components, with local concentrations having a major effect. Here we present a method to obtain large-scale uneven nanopatterns of arginine-glycine-aspartic acid (RGD)-functionalized dendrimers that permit the nanoscale control of local RGD surface density. Nanopatterns are formed by surface adsorption of dendrimers from solutions at different initial concentrations and are characterized by water contact angle (CA), X-ray photoelectron spectroscopy (XPS), and scanning probe microscopy techniques such as scanning tunneling microscopy (STM) and atomic force microscopy (AFM). The local surface density of RGD is measured using AFM images by means of probability contour maps of minimum interparticle distances and then correlated with cell adhesion response and differentiation. The nanopatterning method presented here is a simple procedure that can be scaled up in a straightforward manner to large surface areas. It is thus fully compatible with cell culture protocols and can be applied to other ligands that exert concentration-dependent effects on cells.

A method to obtain dendrimer-based uneven nanopatterns that permit the nanoscale control of local arginine-glycine-aspartic acid (RGD) surface density is described and applied for the study of cell adhesion and chondrogenic differentiation.

Baseado em dendrímeros Nanopatterns desigual de adesividade de superfície de controle localmente: um método para direcionar Chondrogenic diferenciação

Cellular adhesion and differentiation is conditioned by the nanoscale disposition of the extracellular matrix (ECM) components, with local concentrations ...

A Net Mold-based Method of Scaffold-free Three-Dimensional Cardiac Tissue Creation

This protocol describes a novel and easy net mold-based method to create three-dimensional (3-D) cardiac tissues without additional scaffold material. Human-induced pluripotent stem-cell-derived cardiomyocytes (iPSC-CMs), human cardiac fibroblasts (HCFs), and human umbilical vein endothelial cells (HUVECs) are isolated and used to generate a cell suspension with 70% iPSC-CMs, 15% HCFs, and 15% HUVECs. They are co-cultured in an ultra-low attachment "hanging drop" system, which contains micropores for condensing hundreds of spheroids at one time. The cells aggregate and spontaneously form beating spheroids after 3 days of co-culture. The spheroids are harvested, seeded into a novel mold cavity, and cultured on a shaker in the incubator. The spheroids become a mature functional tissue approximately 7 days after seeding. The resultant multilayered tissues consist of fused spheroids with satisfactory structural integrity and synchronous beating behavior. This new method has promising potential as a reproducible and cost-effective method to create engineered tissues for the treatment of heart failure in the future.

This protocol describes a net mold-based method to create three-dimensional scaffold-free cardiac tissues with satisfactory structural integrity and synchronous beating behavior.

Um método baseado em molde líquido de criação livre de andaime tridimensional de tecido cardíaco

This protocol describes a novel and easy net mold-based method to create three-dimensional (3-D) cardiac tissues without additional scaffold material. ...

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate (LAL) Assays

When present in pharmaceutical products, a Gram-negative bacterial cell wall component endotoxin (often also called lipopolysaccharide) can cause inflammation, fever, hypo- or hypertension, and, in extreme cases, can lead to tissue and organ damage that may become fatal. The amounts of endotoxin in pharmaceutical products, therefore, are strictly regulated. Among the methods available for endotoxin detection and quantification, the Limulus Amoebocyte Lysate (LAL) assay is commonly used worldwide. While any pharmaceutical product can interfere with the LAL assay, nano-formulations represent a particular challenge due to their complexity. The purpose of this paper is to provide a practical guide to researchers inexperienced in estimating endotoxins in engineered nanomaterials and nanoparticle-formulated drugs. Herein, practical recommendations for performing three LAL formats including turbidity, chromogenic and gel-clot assays are discussed. These assays can be used to determine endotoxin contamination in nanotechnology-based drug products, vaccines, and adjuvants.

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate LAL Assays

Detection of endotoxins in engineered nanomaterials represents one of the grand challenges in the field of nanomedicine. Here, we present a case study that describes the framework composed of three different LAL formats to estimate potential endotoxin contamination in nanoparticles.

Monólitos de Microhoneycomb preparados pela liofilização unidirecional de nanofibras de celulose com base Sols: método e extensões

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