Os autores reconhecem uma concessão do National Health and Medical Research Council da Austrália (NHMRC # 1000674) para LJR Foster.

1. Preparação da Solução SurgiLux <ol><li> Prepara-se uma solução de 2% (v / v) de ácido acético utilizando água desionizada num copo de vidro limpo, utilizar uma câmara de fluxo laminar para evitar a contaminação. </li><li> Pesar 0,02% (w / v) do cromóforo, verde de indocianina, ICG, em um tubo Eppendorf estéril, assegurar o tubo é envolvido em folha de prata para evitar qualquer penetração de luz. </li><li> Usando uma pipeta descartável e limpa, transferir aproximadamente 1 ml de solução diluída de ácido acético, para o tubo para dissolver o corante, agitar e manter envolvido em folha. </li><li> Transferir o ICG solubilizado no copo e adicionar 2% (w / v) de pó de quitosano antes da adição de um agitador magnético estéril. </li><li> Cobrir a proveta com Parafilm seguida, enrole em folha de prata, antes de misturar o conteúdo a cerca de 125 rpm durante 72 horas à temperatura ambiente numa câmara de fluxo laminar. </li><li> Transferir o conteúdo em tubos de centrífuga limpo e centrifugar a 15000 xg durante 15 min a 4 ° C para remover qualquer particulate importa. </li><li> Transferir cuidadosamente a solução SurgiLux verde, num copo de vidro limpo, cobrir com Parafilm seguida, enrole em folha de prata, antes de guardar num frigorífico durante 12 h para aumentar a viscosidade da solução. </li></ol> 2. Fundição de SurgiLux Films <ol><li> Utilizando uma seringa estéril, dispensar 8 ml da solução SurgiLux frio num prato, limpo Petri de 95 mm de diâmetro, e incline suavemente a placa para assegurar uma cobertura completa da solução. Variando a razão entre o volume da solução a área de fundição permite o controlo da espessura da película, ver Figura 1. </li><li> Remover quaisquer bolhas visíveis na solução usando a ponta de uma agulha estéril. Cubra o prato em folha de prata e coloque no frigorífico para remover qualquer resíduo micro-empresas bolhas. </li><li> Após 20 min cuidadosamente remover a placa de Petri do frigorífico, em lugar de uma câmara de fluxo laminar, cobrir com folha de prata e deixar a solução a evaporar, durante 3 semanas. </li><li> Após complete evaporação, a pontuação dos bordos exteriores da película SurgiLux verde claro na placa de Petri e suavemente &quot;casca&quot; da película afastado da superfície do prato. </li><li> O filme SurgiLux deve ser flexível e facilmente manipulados sem rasgar ou quebrar. </li><li> Armazenar os filmes SurgiLux circulares na placa de Petri, embrulhados em folha de prata sob condições secas até que esteja pronto para uso. </li></ol> 3. Ativação Laser de Filmes SurgiLux adesivas <ol><li> Para demonstrar o processo de activação de laser que vai usar um pedaço de tecido de bovino como bife cortado com um tamanho de 15 mm de largura e 20 mm de comprimento. Dissecar o tecido em linha recta, utilizando um número 10 da lâmina cirúrgica, para produzir duas tiras de 15 por 10 mm. </li><li> Aproximar as duas peças de tecido, de modo que as suas extremidades se tocam, mas não se sobrepondo, e usando um cotonete de algodão ou de gaze, suavemente absorver qualquer excesso de líquido. </li><li> Em seguida, corte um pedaço de filme SurgiLux 7 x 9 mm e coloque cuidadosamente as longitudinalmente cinema em todo o p bisectedIECE de tecido, em seguida, pressione suavemente com um cotonete seco. </li><li> Filmes SurgiLux são activadas através de um diodo laser de infra-vermelhos para um nível de 120 mW. Como este é um laser de classe III-B, medidas de segurança apropriadas devem ser tomadas, incluindo o uso de óculos de segurança apropriados para todas as pessoas. </li><li> Começando no canto, irradiar a SurgiLux com um laser de infravermelhos fixado a 120 mW e um tamanho de mancha de feixe de 1 mm de diâmetro. Passar o ponto de feixe ao longo do filme verde a uma taxa de cerca de 1 mm por segundo. Repetir o processo de irradiação mais duas vezes. </li></ol> 4. Força da Reparação <ol><li> Cuidadosamente fixar as extremidades do tecido em as pinças de um instrumento de teste de tracção. Estamos usando um sistema Instron Mini55 com uma célula de carga de 50 Newton. A carga máxima, a força de tracção, e de extensão na ruptura foram calculados utilizando software de computador Bluehill (EUA). Meio de, pelo menos, 10 amostras foram determinados (n = 10). </li><li> Tome-se o &#39;folga&#39;e em seguida separar os pedaços de tecido a uma velocidade de 1 mm por segundo, até que as duas peças de tecido unidas por a tira SurgiLux separada completamente. </li></ol>

<ol>
	<li>Kjaergard, H. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Suture+support:+is+it+advantageous.">Suture support: is it advantageous.</a> Am. J. Surg. 182, 15S-20S (2001).</li><li>Lauto, A., Mawad, D., Foster, L. J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adhesive+biomaterials+for+tissue+reconstruction.">Adhesive biomaterials for tissue reconstruction.</a> J. Chem. Tech. Biotech. 83, 464-472 (2008).</li><li>Fung, L. C., Mingin, G. C., Massicotte, M., Felsen, D., Poppas, D. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+temperature+on+tissue+thermal+injury+and+wound+strength+after+photochemical+wound+closure.">Effects of temperature on tissue thermal injury and wound strength after photochemical wound closure.</a> Lasers Surg. Med. 25, 285-290 (1999).</li><li>Piribo, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Glues &amp; Sealants: Industry Background Report. , (2005).</li><li>Lauto, A., Hook, J., Doran, M., Camacho, F., Poole-Warren, L. A., Avolio, A., Foster, L. J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chitosan+adhesive+for+laser+tissue-welding:+in+vitro+characterisation.">Chitosan adhesive for laser tissue-welding: in vitro characterisation.</a> Lasers Surg. Med. 36, 193-201 (2005).</li><li>Lauto, A., Stoodley, M., Marcel, H., Avolio, A., Sarris, M., McKenzie, G., Sampson, D. D., Foster, L. J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+and+in+vivo+tissue+repair+with+laser-activated+chitosan+adhesive.">In vitro and in vivo tissue repair with laser-activated chitosan adhesive.</a> Lasers Surg. Med. 39, 19-27 (2007).</li><li>Lauto, A., Foster, L. J. R., Avolio, A., Sampson, D., Raston, C., Sarris, M., McKenzie, G., Stoodley, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sutureless+Nerve+Repair+with+Laser-Activated+Chitosan+Adhesive:+A+Pilot+in+vivo+Study.">Sutureless Nerve Repair with Laser-Activated Chitosan Adhesive: A Pilot in vivo Study.</a> J. Photomed. Laser. Surg. 26 (3), 227-234 (2008).</li><li>Mar&#231;al, H., Badylak, S. F., Sellaro, T. L., Lauto, A., Foster, L. J. R., Mahler, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+coalescence+of+decellularized+tissue+scaffolds,+laser-activated+chitosan+bioadhesive+and+olfactory+ensheathing+cells+for+tissue+repair+and+regeneration+of+the+spinal+cord.">The coalescence of decellularized tissue scaffolds, laser-activated chitosan bioadhesive and olfactory ensheathing cells for tissue repair and regeneration of the spinal cord.</a> Lasers Med. Sci. 23 (1), 96 (2008).</li><li>Foster, L. J. R., Thomson, K., Marcal, H., Butt, J., Watson, S., Wakefield, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+chitosan-vancomycin+composite+biomaterial+as+a+laser+activated+surgical+adhesive+with+regional+antimicrobial+activity.">A chitosan-vancomycin composite biomaterial as a laser activated surgical adhesive with regional antimicrobial activity.</a> Biomacromolecules. 11 (12), 3563-3570 (2010).</li><li>Shahbazi, J., Marcal, H., Watson, S., Wakefield, D., Sarris, M., Foster, L. J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sutureless+sealing+of+penetrating+corneal+wounds+using+a+laser-activated+thin+film+adhesive.">Sutureless sealing of penetrating corneal wounds using a laser-activated thin film adhesive.</a> Lasers Surg. Med. , .</li><li>Meyers, M. A., Chen, P. -. Y., Lin, A. Y. -. M., Seki, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biological+materials:+Structure+and+mechanical+properties.">Biological materials: Structure and mechanical properties.</a> Prog. Mater. Sci. 53 (1), 1-206 (2008).</li></ol>

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A quitosana pode ser obtido de uma variedade de pesos moleculares e com vários graus de deactylation (ADD). As variações na pureza quitosana pode conduzir à presença de partículas na solução SurgiLux; centrifugação é usada para eliminar estes e deve resultar em uma solução transparente verde. No entanto, a filtragem pode também ser utilizado como um passo de fabricação adicional ou alternativo. Como com qualquer material de processamento, as variações, tais como quitosana DDA e peso molecular, tem impl...

<table border="1"><tbody><tr><td> Nome do reagente / equipamento </td><td> Companhia </td><td> Número de catálogo </td><td> Comentários (opcional) </td></tr><tr><td> Quitosana </td><td> Sigma-Aldrich </td><td> 448877 </td><td></td></tr><tr><td> Indocianina verde </td><td> Sigma-Aldrich </td><td> I2633 </td><td> Também conhecido como Cardiogreen </td></tr><tr><td> Ácido acético </td><td> Sigma-Aldrich </td><td> 320099 </td><td></td></tr><tr><td> Infra-vermelho laser de diodo com entrega de fibra. (808 nm, 120 mW, feixe de núcleo de 200 um) </td><td> CNI Lasers </td><td> Fc-808 </td><td> Sistema variável até 5 W de potência </td></tr><tr><td> Laser óculos de segurança </td><td> CNI Lasers </td><td> LS-G </td><td></td></tr><tr><td> Aparelho de ensaio de tracção </td><td> Instron Pty Ltd </td><td> 5542 </td><td> Célula de carga de 50 N </td></tr></tbody></table>

a chitosan based, laser activated thin film surgical adhesive, 'surgilux': preparation and demonstration

Suturas são uma tecnologia 4.000 anos de idade que continuam a &quot;padrão-ouro&quot; para o fechamento da ferida, em virtude de sua força de reparação (~ 100 kPa). No entanto, as suturas podem agir como um nidus para a infecção e, em muitos procedimentos não são capazes de efectuar a reparação de feridas, ou interferir com a regeneração do tecido funcional. Uma colas e adesivos cirúrgicos, tais como as baseadas em fibrina e cianoacrilatos, têm sido desenvolvidos como alternativas à sutura para a reparação de feridas. No entanto, os actuais adesivos comerciais também têm desvantagens significativas, que vão de transferência viral e priónica e uma falta de força de reparação como com as colas de fibrina, a toxicidade dos tecidos e falta de biocompatibilidade para os adesivos de cianoacrilato à base. Além disso, actualmente disponíveis adesivos cirúrgicos tendem a ser à base de gel e pode ter estendido tempos de cura que limitam a sua aplicação. 2 Da mesma forma, o uso de lasers UV para facilitar a reticulação de proteínas em mecanismos baseados ou albumina &#39;solders &quot;pode ​​levar a danos no DNA durante a soldagem a laser de tecido (LTW) predispõe danos térmicos aos tecidos. 3 Apesar de suas desvantagens, adesivos e LTW ter capturado cerca de 30% do mercado de fechamento da ferida relatado para ser em excesso de EUA $ 5 bilhões por ano, uma prova significativa para a necessidade de uma tecnologia sem sutura 4. Na busca de tecnologia sem sutura nós utilizamos quitosana como um biomaterial para o desenvolvimento de uma película flexível fina, laser activado adesivo cirúrgico denominado «SurgiLux &#39;. Este bioadesivo novel utiliza uma combinação única de biomateriais e fotônica que são aprovados pela FDA e utilizado com sucesso numa variedade de aplicações biomédicas e produtos. SurgiLux supera todas as desvantagens associadas com suturas e correntes adesivos cirúrgicos (ver Tabela 1). Nesta apresentação, relatamos o protocolo relativamente simples para a fabricação de SurgiLux e demonstrara sua activação laser e resistência da solda de tecidos. Filmes SurgiLux aderência do tecido colagenoso, sem modificação química, tais como a ligação cruzada e através de irradiação com um relativamente baixo consumo de energia laser (120 mW) de infravermelhos em vez de luz UV. Filmes de quitosana tem uma atração natural, mas fraco adesivo para colágeno (~ KPa 3), laser ativação da base de quitosana SurgiLux filmes enfatiza a força dessa adesão por meio de interações da cadeia de polímeros, como consequência da expansão térmica transiente. 5 Sem essa &#39;ativação&#39; processo , filmes SurgiLux são facilmente removidos. 6-9 SurgiLux foi testado tanto in vitro como in vivo numa variedade de tecidos, tais como nervos, intestino dura-máter, e córnea. Em todos os casos, demonstraram boa biocompatibilidade e lesão térmica desprezável em consequência da irradiação. 6-10

Centrifugação leva a uma solução verde transparente, o que aumenta a viscosidade após armazenamento a 4-6 ° C. Após repouso durante 3 semanas, a solução verde é convertido em um filme transparente verde SurgiLux cerca de 20 microns de espessura e, tal como demonstrado no vídeo, é facilmente flexível. Após a irradiação com o laser, as ligações de película SurgiLux ao tecido. Isto pode ser observado nos bordos do filme, onde o tecido é exibida a contrair medida que o feixe ...

Watch this Scientific Journal Video about A Chitosan Based, Laser Activated Thin Film Surgical Adhesive, 'SurgiLux': Preparation and Demonstration at JoVE.com

A Chitosan Based, Laser Activated Thin Film Surgical Adhesive, &#039;SurgiLux&#039;: Preparation and Demonstration

A fabricação de uma novela, filme flexível fino adesivo cirúrgico a partir de ingredientes aprovados pela FDA, a quitosana e indocianina verde é descrito. Bonding deste adesivo para tecido colagenoso através de um processo de activação com um simples de baixa potência de laser infra-vermelho é demonstrada.

A base de quitosana, Laser Activated adesiva Thin Film cirúrgica &quot;, SurgiLux &#39;: Preparação e demonstração

Sutures are a 4,000 year old technology that remain the 'gold-standard' for wound closure by virtue of their repair strength (~100 KPa). However, sutures ...

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Research

JoVE Journal

Bioengineering

A Chitosan Based, Laser Activated Thin Film Surgical Adhesive, 'SurgiLux': Preparation and Demonstration

13.1K visualizações.  University of New South Wales. A fabricação de uma novela, filme flexível fino adesivo cirúrgico a partir de ingredientes aprovados pela FDA, a quitosana e indocianina verde é descrito. Bonding deste adesivo para tecido colagenoso através de um processo de activação com um simples de baixa potência de laser infra-vermelho é demonstrada.

Vídeo: A Chitosan Based, Laser Activated Thin Film Surgical Adhesive, 'SurgiLux': Preparation and Demonstration

Constructing a Collagen Hydrogel for the Delivery of Stem Cell-loaded Chitosan Microspheres

Multipotent stem cells have been shown to be extremely useful in the field of regenerative medicine1-3. However, in order to use these cells effectively for tissue regeneration, a number of variables must be taken into account. These variables include: the total volume and surface area of the implantation site, the mechanical properties of the tissue and the tissue microenvironment, which includes the amount of vascularization and the components of the extracellular matrix. Therefore, the materials being used to deliver these cells must be biocompatible with a defined chemical composition while maintaining a mechanical strength that mimics the host tissue. These materials must also be permeable to oxygen and nutrients to provide a favorable microenvironment for cells to attach and proliferate. Chitosan, a cationic polysaccharide with excellent biocompatibility, can be easily chemically modified and has a high affinity to bind with in vivo macromolecules4-5. Chitosan mimics the glycosaminoglycan portion of the extracellular matrix, enabling it to function as a substrate for cell adhesion, migration and proliferation. In this study we utilize chitosan in the form of microspheres to deliver adipose-derived stem cells (ASC) into a collagen based three-dimensional scaffold6. An ideal cell-to-microsphere ratio was determined with respect to incubation time and cell density to achieve maximum number of cells that could be loaded. Once ASC are seeded onto the chitosan microspheres (CSM), they are embedded in a collagen scaffold and can be maintained in culture for extended periods. In summary, this study provides a method to precisely deliver stem cells within a three dimensional biomaterial scaffold.

A major hurdle in current stem cell therapies is determining the most effective method to deliver these cells to host tissues. Here, we describe a chitosan-based delivery method that is efficient and simple in approach, while allowing adipose-derived stem cells to maintain their multipotency.

Construindo um hidrogel de colágeno para a entrega de células-tronco carregado microesferas

Multipotent stem cells have been shown to be extremely useful in the field of regenerative medicine1-3. However, in order to use these cells effectively ...

Bioengenharia

Fabrication and Application of Rose Bengal-chitosan Films in Laser Tissue Repair

Photochemical tissue bonding (PTB) is a sutureless technique for tissue repair, which is achieved by applying a solution of rose bengal (RB) between two tissue edges1,2. These are then irradiated by a laser that is selectively absorbed by the RB. The resulting photochemical reactions supposedly crosslink the collagen fibers in the tissue with minimal heat production3. In this report, RB has been incorporated in thin chitosan films to fabricate a novel tissue adhesive that is laser-activated. Adhesive films, based on chitosan and containing ~0.1 wt% RB, are fabricated and bonded to calf intestine and rat tibial nerves by a solid state laser (&lambda;=532 nm, Fluence~110 J/cm2, spot size~0.5 cm). A single-column tensiometer, interfaced with a personal computer, is used to test the bonding strength. The RB-chitosan adhesive bonds firmly to the intestine with a strength of 15 &plusmn; 6 kPa, (n=30). The adhesion strength drops to 2 &plusmn; 2 kPa (n=30) when the laser is not applied to the adhesive. The anastomosis of tibial nerves can be also completed without the use of sutures. A novel chitosan adhesive has been fabricated that bonds photochemically to tissue and does not require sutures.

Sutures are usually needed to repair tissue during surgical procedures. However, their application can be problematic as they are invasive and may damage tissue. The fabrication and application methods of a novel tissue adhesive are here reported. This adhesive film is laser-activated and does not require the use of sutures.

Fabricação e Aplicação de Rosa Bengala-quitosana Films em Reparo de Tecidos Laser

Photochemical tissue bonding (PTB) is a sutureless technique for tissue repair, which is achieved by applying a solution of rose bengal (RB) between two ...

Creating Adhesive and Soluble Gradients for Imaging Cell Migration with Fluorescence Microscopy

Cells can sense and migrate towards higher concentrations of adhesive cues such as the glycoproteins of the extracellular matrix and soluble cues such as growth factors. Here, we outline a method to create opposing gradients of adhesive and soluble cues in a microfluidic chamber, which is compatible with live cell imaging. A copolymer of poly-L-lysine and polyethylene glycol (PLL-PEG) is employed to passivate glass coverslips and prevent non-specific adsorption of biomolecules and cells. Next, microcontact printing or dip pen lithography are used to create tracks of streptavidin on the passivated surfaces to serve as anchoring points for the biotinylated peptide arginine-glycine-aspartic acid (RGD) as the adhesive cue. A microfluidic device is placed onto the modified surface and used to create the gradient of adhesive cues (100% RGD to 0% RGD) on the streptavidin tracks. Finally, the same microfluidic device is used to create a gradient of a chemoattractant such as fetal bovine serum (FBS), as the soluble cue in the opposite direction of the gradient of adhesive cues.

A method for the assembly of adhesive and soluble gradients in a microscopy chamber for live cell migration studies is described. The engineered environment combines antifouling surfaces and adhesive tracks with solution gradients and therefore allows one to determine the relative importance of guidance cues.

Criando Gradientes adesivas e solúvel para a migração celular Imaging com Microscopia de Fluorescência

Cells can sense and migrate towards higher concentrations of adhesive cues such as the glycoproteins of the extracellular matrix and soluble cues such as ...

Insertion of Flexible Neural Probes Using Rigid Stiffeners Attached with Biodissolvable Adhesive

Microelectrode arrays for neural interface devices that are made of biocompatible thin-film polymer are expected to have extended functional lifetime because the flexible material may minimize adverse tissue response caused by micromotion. However, their flexibility prevents them from being accurately inserted into neural tissue. This article demonstrates a method to temporarily attach a flexible microelectrode probe to a rigid stiffener using biodissolvable polyethylene glycol (PEG) to facilitate precise, surgical insertion of the probe. A unique stiffener design allows for uniform distribution of the PEG adhesive along the length of the probe. Flip-chip bonding, a common tool used in microelectronics packaging, enables accurate and repeatable alignment and attachment of the probe to the stiffener. The probe and stiffener are surgically implanted together, then the PEG is allowed to dissolve so that the stiffener can be extracted leaving the probe in place. Finally, an in vitro test method is used to evaluate stiffener extraction in an agarose gel model of brain tissue. This approach to implantation has proven particularly advantageous for longer flexible probes (&gt;3 mm). It also provides a feasible method to implant dual-sided flexible probes. To date, the technique has been used to obtain various in vivo recording data from the rat cortex.

Insertion of flexible neural microelectrode probes is enabled by attaching probes to rigid stiffeners with polyethylene glycol (PEG). A unique assembly process ensures uniform and repeatable attachment. After insertion into tissue, the PEG dissolves and the stiffener is extracted. An in vitro test method evaluates the technique in agarose gel.

Inserção de Flexible Neural Sondas Usando Reforços rígidos anexados com Biodissolvable Adhesive

Microelectrode  arrays for neural interface devices that are made of biocompatible thin-film  polymer are expected to have extended functional lifetime ...

Development of Amelogenin-chitosan Hydrogel for In Vitro Enamel Regrowth with a Dense Interface

Biomimetic enamel reconstruction is a significant topic in material science and dentistry as a novel approach for the treatment of dental caries or erosion. Amelogenin has been proven to be a critical protein for controlling the organized growth of apatite crystals. In this paper, we present a detailed protocol for superficial enamel reconstruction by using a novel amelogenin-chitosan hydrogel. Compared to other conventional treatments, such as topical fluoride and mouthwash, this method not only has the potential to prevent the development of dental caries but also promotes significant and durable enamel restoration. The organized enamel-like microstructure regulated by amelogenin assemblies can significantly improve the mechanical properties of etched enamel, while the dense enamel-restoration interface formed by an in situ regrowth of apatite crystals can improve the effectiveness and durability of restorations. Furthermore, chitosan hydrogel is easy to use and can suppress bacterial infection, which is the major risk factor for the occurrence of dental caries. Therefore, this biocompatible and biodegradable amelogenin-chitosan hydrogel shows promise as a biomaterial for the prevention, restoration, and treatment of defective enamel.

Development of Amelogenin-chitosan Hydrogel for In Vitro Enamel Regrowth with a Dense Interface

In this article, we describe a protocol for fabricating an amelogenin-chitosan hydrogel for superficial enamel reconstruction. Organized in situ growth of apatite crystals in the hydrogel formed a dense enamel-restoration interface, which will improve the effectiveness and durability of restorations.

Desenvolvimento de Amelogenina-quitosana Hidrogel para<em&gt; In Vitro</em&gt; Esmalte Regrowth Com uma interface Densa

Biomimetic enamel reconstruction is a significant topic in material science and dentistry as a novel approach for the treatment of dental caries or ...

Custom-designed Laser-based Heating Apparatus for Triggered Release of Cisplatin from Thermosensitive Liposomes with Magnetic Resonance Image Guidance

Liposomes have been employed as drug delivery systems to target solid tumors through exploitation of the enhanced permeability and retention (EPR) effect resulting in significant reductions in systemic toxicity. Nonetheless, insufficient release of encapsulated drug from liposomes has limited their clinical efficacy. Temperature-sensitive liposomes have been engineered to provide site-specific release of drug in order to overcome the problem of limited tumor drug bioavailability. Our lab has designed and developed a heat-activated thermosensitive liposome formulation of cisplatin (CDDP), known as HTLC, to provide triggered release of CDDP at solid tumors. Heat-activated delivery in vivo was achieved in murine models using a custom-built laser-based heating apparatus that provides a conformal heating pattern at the tumor site as confirmed by MR thermometry (MRT). A fiber optic temperature monitoring device was used to measure the temperature in real-time during the entire heating period with online adjustment of heat delivery by alternating the laser power. Drug delivery was optimized under magnetic resonance (MR) image guidance by co-encapsulation of an MR contrast agent (i.e.,&#160;gadoteridol) along with CDDP into the thermosensitive liposomes as a means to validate the heating protocol and to assess tumor accumulation. The heating protocol consisted of a preheating period of 5 min prior to administration of HTLC and 20 min heating post-injection. This heating protocol resulted in effective release of the encapsulated agents with the highest MR signal change observed in the heated tumor in comparison to the unheated tumor and muscle. This study demonstrated the successful application of the laser-based heating apparatus for preclinical thermosensitive liposome development and the importance of MR-guided validation of the heating protocol for optimization of drug delivery.

AN MRI-compatible&#160;custom-designed laser-based heating apparatus has been developed to provide local heating of subcutaneous tumors in order to activate release of agents from thermosensitive liposomes specifically at the tumor region.

Customizado aparelho de aquecimento à base de laser para lançamento acionado de cisplatina de termossensível lipossomas com Ressonância Magnética Orientação Imagem

Liposomes have been employed as drug delivery systems to target solid tumors through exploitation of the enhanced permeability and retention (EPR) effect ...

Automated Lipid Bilayer Membrane Formation Using a Polydimethylsiloxane Thin Film

An artificial lipid bilayer, or black lipid membrane (BLM), is a powerful tool for studying ion channels and protein interactions, as well as for biosensor applications. However, conventional BLM formation techniques have several drawbacks and they often require specific expertise and laborious processes. In particular, conventional BLMs suffer from low formation success rates and inconsistent membrane formation time. Here, we demonstrate a storable and transportable BLM formation system with controlled thinning-out time and enhanced BLM formation rate by replacing conventionally used films (polytetrafluoroethylene, polyoxymethylene, polystyrene) to polydimethylsiloxane (PDMS). In this experiment, a porous-structured polymer such as PDMS thin film is used. In addition, as opposed to conventionally used solvents with low viscosity, the use of squalene permitted a controlled thinning-out time via slow solvent absorption by PDMS, prolonging membrane lifetime. In addition, by using a mixture of squalene and hexadecane, the freezing point of the lipid solution was increased (~16 &#176;C), in addition, membrane precursors were produced that can be indefinitely stored and readily transported. These membrane precursors have reduced BLM formation time of &#60; 1 hr and achieved a BLM formation rate of ~80%. Moreover, ion channel experiments with gramicidin A demonstrated the feasibility of the membrane system.

We demonstrate a storable, transportable lipid bilayer formation system. A lipid bilayer membrane can be formed within 1 hr with over 80% success rate when a frozen membrane precursor is brought to ambient temperature. This system will reduce laborious processes and expertise associated with ion channels.

Formação Automated Lipid bicamada da membrana Usando um polidimetilsiloxano Thin Film

An artificial lipid bilayer, or black lipid membrane (BLM), is a powerful tool for studying ion channels and protein interactions, as well as for ...

Image-guided, Laser-based Fabrication of Vascular-derived Microfluidic Networks

This detailed protocol outlines the implementation of image-guided, laser-based hydrogel degradation for the fabrication of vascular-derived microfluidic networks embedded in PEGDA hydrogels. Here, we describe the creation of virtual masks that allow for image-guided laser control; the photopolymerization of a micromolded PEGDA hydrogel, suitable for microfluidic network fabrication and pressure head-driven flow; the setup and use of a commercially available laser scanning confocal microscope paired with a femtosecond pulsed Ti:S laser to induce hydrogel degradation; and the imaging of fabricated microfluidic networks using fluorescent species and confocal microscopy. Much of the protocol is focused on the proper setup and implementation of the microscope software and microscope macro, as these are crucial steps in using a commercial microscope for microfluidic fabrication purposes that contain a number of intricacies. The image-guided component of this technique allows for the implementation of 3D image stacks or user-generated 3D models, thereby allowing for creative microfluidic design and for the fabrication of complex microfluidic systems of virtually any configuration. With an expected impact in tissue engineering, the methods outlined in this protocol could aid in the fabrication of advanced biomimetic microtissue constructs for organ- and human-on-a-chip devices. By mimicking the complex architecture, tortuosity, size, and density of in vivo vasculature, essential biological transport processes can be replicated in these constructs, leading to more accurate in vitro modeling of drug pharmacokinetics and disease.

This protocol outlines the implementation of image-guided, laser-based hydrogel degradation to fabricate vascular-derived, biomimetic microfluidic networks embedded in poly(ethylene glycol) diacrylate (PEGDA) hydrogels. These biomimetic microfluidic systems may be useful for tissue engineering applications, generation of in vitro disease models, and fabrication of advanced "on-a-chip" devices.

guiado por imagem, fabricação à base de laser de Redes microfluídicos Vascular derivadas

This detailed protocol outlines the implementation of image-guided, laser-based hydrogel degradation for the fabrication of vascular-derived microfluidic ...

Dry Film Photoresist-based Electrochemical Microfluidic Biosensor Platform: Device Fabrication, On-chip Assay Preparation, and System Operation

In recent years, biomarker diagnostics became an indispensable tool for the diagnosis of human disease, especially for the point-of-care diagnostics. An easy-to-use and low-cost sensor platform is highly desired to measure various types of analytes (e.g., biomarkers, hormones, and drugs) quantitatively and specifically. For this reason, dry film photoresist technology - enabling cheap, facile, and high-throughput fabrication - was used to manufacture the microfluidic biosensor presented here. Depending on the bioassay used afterwards, the versatile platform is capable of detecting various types of biomolecules. For the fabrication of the device, platinum electrodes are structured on a flexible polyimide (PI) foil in the only clean-room process step. The PI foil serves as a substrate for the electrodes, which are insulated with an epoxy-based photoresist. The microfluidic channel is subsequently generated by the development and lamination of dry film photoresist (DFR) foils onto the PI wafer. By using a hydrophobic stopping barrier in the channel, the channel is separated into two specific areas: an immobilization section for the enzyme-linked assay and an electrochemical measurement cell for the amperometric signal readout.
The on-chip bioassay immobilization is performed by the adsorption of the biomolecules to the channel surface. The glucose oxidase enzyme is used as a transducer for electrochemical signal generation. In the presence of the substrate, glucose, hydrogen peroxide is produced, which is detected at the platinum working electrode. The stop-flow technique is applied to obtain signal amplification along with rapid detection. Different biomolecules can quantitatively be measured by means of the introduced microfluidic system, giving an indication of different types of diseases, or, in regard to therapeutic drug monitoring, facilitating a personalized therapy.

A microfluidic biosensor platform was designed and fabricated using low-cost dry film photoresist technology for the rapid and sensitive quantification of various analytes. This single-use system allows for the electrochemical readout of on-chip-immobilized enzyme-linked assays by means of the stop-flow technique.

Película seca baseada em fotorresiste eletroquímica Microfluidic Biosensor plataforma: Fabricação de dispositivo, ensaio em-microplaqueta preparação e operação de sistema

In recent years, biomarker diagnostics became an indispensable tool for the diagnosis of human disease, especially for the point-of-care diagnostics. An ...

Rat Model of Adhesive Capsulitis of the Shoulder

This proposal aims to create an in vivo rat model of adhesive capsulitis for researching potential treatment options for this condition and other etiologies of comparable arthrofibrosis. The model includes extra-articular fixation of the shoulder in rats via scapular to humeral suturing, resulting in a secondary contracture without invading the intra-articular space and resulting in decreased rotational ROM and increased joint stiffness.
We used 10 Sprague-Dawley rats for the purpose of this study. Baseline ROM measurements were taken before glenohumeral immobilization. The rats were subjected to 8 weeks of immobilization before the fixation sutures were removed and changes in ROM and joint stiffness were evaluated. To evaluate whether immobilization resulted in a significant reduction in ROM, changes in kinematics were calculated. ROM was measured at each time point in the follow-up period and was compared to the baseline internal and external ROM measurements. In order to evaluate the stiffness, joint kinetics were calculated by determining the differences in torque (text and tint ) needed to reach the initial external rotation of 60&#176; and initial internal rotation of 80&#176;.
After the removal of the extra-articular suture fixation on follow-up day 0, we found a 63% decrease in total ROM compared to baseline. We observed continuous improvement until week 5 of follow-up, with the progress slowing down around a 19% restriction. On week 8 of follow-up, there was still an 18% restriction of ROM. Additionally, on follow-up day 0, we found the torque increased by 13.3 Nmm when compared to baseline. On week 8, the total torque was measured to be 1.4 &#177; 0.2 Nmm higher than initial measurements. This work introduces a rat model of shoulder adhesive capsulitis with lasting reduced ROM and increased stiffness.

This protocol presents an in vivo rat model of adhesive capsulitis. The model includes an internal fixation of the glenohumeral joint with extra-articular suture fixation for an extended time, resulting in a decreased rotational range of motion (ROM) and increased joint stiffness.