Les auteurs reconnaissent une subvention de la Santé nationale et du Conseil de recherches médicales de l&#39;Australie (NHMRC # 1000674) à LJR Foster.

1. Préparation de la solution SurgiLux <ol><li> Préparer un 2% (v / v) d&#39;acide acétique avec de l&#39;eau désionisée dans un récipient en verre propre, utiliser une hotte à flux laminaire pour éviter toute contamination. </li><li> Peser 0,02% (p / v) du chromophore, le vert d&#39;indocyanine, ICG, dans un tube Eppendorf stérile, en sorte que le tube est enroulé dans une feuille d&#39;argent à empêcher toute pénétration de la lumière. </li><li> Avec un chiffon propre, pipette jetable, transférer environ 1 ml de la solution d&#39;acide acétique dilué dans le tube pour dissoudre le colorant, agiter doucement et garder enveloppé dans du papier. </li><li> Transférer le GIC solubilisés dans le bol et ajouter 2% (p / v) de poudre de chitosane avant l&#39;ajout d&#39;un agitateur magnétique stérile. </li><li> Couvrir le bécher avec du Parafilm, puis les envelopper dans du papier d&#39;argent, avant de mélanger le contenu à environ 125 tours par minute pendant 72 heures à température ambiante dans une hotte à flux laminaire. </li><li> Transférer le contenu dans des tubes à centrifuger et centrifuger propres à 15.000 xg pendant 15 min à 4 ° C pour éliminer toute particulate question. </li><li> Transférer délicatement la solution SurgiLux verte dans un récipient en verre propre, couvrir avec du Parafilm, puis les envelopper dans du papier d&#39;argent, avant de les ranger au réfrigérateur pendant 12 heures pour augmenter la viscosité de la solution. </li></ol> 2. Fonderie de SurgiLux Films <ol><li> Utiliser une seringue stérile, passer 8 ml de la solution SurgiLux froid dans un endroit propre, boîte de Pétri de 95 mm de diamètre, et inclinez légèrement la plaque pour assurer une couverture complète de la solution. Faire varier le rapport du volume de solution de zone de coulée permet un contrôle de l&#39;épaisseur du film, voir figure 1. </li><li> Retirer les bulles visibles dans la solution à l&#39;aide de la pointe d&#39;une aiguille stérile. Couvrir le plat de papier d&#39;aluminium et placer au réfrigérateur pour enlever les résidus de taille micronique bulles. </li><li> Après 20 minutes, retirer délicatement la boîte de Pétri du réfrigérateur, placer dans une hotte à flux laminaire, couvrir de papier d&#39;argent et de laisser la solution s&#39;évaporer pendant 3 semaines. </li><li> Après avoir complete évaporation, le score des bords extérieurs du film SurgiLux vert clair dans la boîte de Pétri et doucement «peaux» le film de la surface de plat. </li><li> Le film SurgiLux doit être souple et facile à manipuler sans se déchirer ou se rompre. </li><li> Stocker les films SurgiLux circulaires dans la boîte de Pétri enveloppées dans du papier d&#39;argent dans des conditions sèches avant d&#39;être prêt à l&#39;emploi. </li></ol> 3. L&#39;activation laser de films adhésifs SurgiLux <ol><li> Pour démontrer le processus d&#39;activation au laser, nous allons utiliser un morceau de tissu bovin comme le steak coupé à une taille de 15 mm de large et 20 mm de longueur. Disséquer le tissu, en ligne droite à l&#39;aide d&#39;une lame chirurgicale Numéro 10, pour produire des morceaux de 2 15 par 10 mm. </li><li> Rapprochant les deux pièces de tissu de telle sorte que leurs bords se touchent mais ne se chevauchent pas, et en utilisant un tampon de coton ou de gaze, doucement absorber tout liquide en excès. </li><li> Ensuite, découpez un morceau de film SurgiLux 7 x 9 mm et placer soigneusement les sens de la longueur du film à travers le coupé en deux pIECE de tissu, puis appuyez doucement avec un coton-tige sec. </li><li> Films SurgiLux sont activés à l&#39;aide d&#39;une diode laser infrarouge à un réglage de 120 mW. Comme il s&#39;agit d&#39;un laser de classe IIIB, les mesures de sécurité appropriées doivent être prises, y compris l&#39;utilisation de lunettes de sécurité appropriées pour l&#39;ensemble du personnel. </li><li> Commençant dans le coin, irradier la SurgiLux avec un laser infra-rouge fixé à 120 mW et une taille de spot de faisceau de 1 mm de diamètre. Passez le spot du faisceau sur le film vert à un taux d&#39;environ 1 mm par seconde. Répétez le processus d&#39;irradiation deux fois plus. </li></ol> 4. Force de la réparation <ol><li> Soigneusement fixer les extrémités du tissu dans les mâchoires d&#39;un appareil d&#39;essai de traction. Nous utilisons un système Instron Mini55 avec une cellule de charge de 50 Newton. La charge maximale, résistance à la traction et allongement à la rupture ont été calculées à l&#39;aide du logiciel Bluehill ordinateur (États-Unis). Moyen d&#39;au moins 10 échantillons ont été déterminés (n = 10). </li><li> Relevez le «flottement»et ensuite séparer les morceaux de tissu à une vitesse de 1 mm par seconde, jusqu&#39;à ce que les deux morceaux de tissu maintenus ensemble par la bande SurgiLux séparé complètement. </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>

Le chitosane peut être obtenue dans une variété de poids moléculaires et avec différents degrés de deactylation (PDD). Les variations de la pureté chitosane peut conduire à la présence de particules dans la solution SurgiLux; centrifugation est utilisée pour éliminer ceux-ci et devrait aboutir à une solution transparente verte. Cependant, la filtration peut également être utilisé comme étape de fabrication supplémentaire ou de remplacement. Comme pour tout traitement de matériaux, variations, tels que ...

<table border="1"><tbody><tr><td> Nom du réactif / équipement </td><td> Entreprise </td><td> Numéro de catalogue </td><td> Commentaires (optionnel) </td></tr><tr><td> Chitosan </td><td> Sigma-Aldrich </td><td> 448877 </td><td></td></tr><tr><td> Vert d&#39;indocyanine </td><td> Sigma-Aldrich </td><td> I2633 </td><td> Aussi connu sous Cardiogreen </td></tr><tr><td> L&#39;acide acétique </td><td> Sigma-Aldrich </td><td> 320099 </td><td></td></tr><tr><td> Diode laser infra-rouge avec la livraison de la fibre. (808 nm, 120 mW, le noyau du faisceau 200 um) </td><td> CNI Lasers </td><td> Fc-808 </td><td> Système variable jusqu&#39;à 5 W </td></tr><tr><td> Lunettes laser de sécurité </td><td> CNI Lasers </td><td> LS-G </td><td></td></tr><tr><td> Appareil d&#39;essai de traction </td><td> Instron Pty Ltd </td><td> 5542 </td><td> 50 N cellule de charge </td></tr></tbody></table>

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

Les sutures sont une technologie vieille 4.000 années qui restent le «gold standard» pour la fermeture des plaies, en vertu de leur force réparation (~ 100 kPa). Cependant, les sutures peuvent agir comme un foyer d&#39;infection et dans de nombreuses procédures sont pas en mesure d&#39;effectuer la réparation des blessures ou interférer avec la régénération des tissus fonctionnels. 1 colles et adhésifs chirurgicaux, tels que ceux à base de fibrine et de cyanoacrylates, ont été développées comme alternatives aux sutures pour la réparation de telles plaies. Cependant, le courant adhésifs commerciaux ont aussi des inconvénients importants, allant de transfert viral et de prion et un manque de force réparation comme avec les colles de fibrine, à la toxicité tissulaire et un manque de biocompatibilité pour les adhésifs à base de cyanoacrylate. De plus, actuellement disponibles adhésifs chirurgicaux ont tendance à être à base de gel et peuvent avoir des temps de durcissement prolongé qui limitent leur application. 2 De même, l&#39;utilisation de lasers UV pour faciliter réticulation mécanismes à base de protéines ou d&#39;albumine «solDER »peut conduire à endommager l&#39;ADN pendant le soudage des tissus laser (LTW) prédispose dommages thermiques aux tissus. 3 Malgré leurs inconvénients, les adhésifs et les LTW ont capturé environ 30% du marché fermeture de la plaie rapporté à plus de 5 milliards de dollars par an, un témoignage significatif de la nécessité de la technologie sans suture 4. Dans la poursuite de la technologie sans suture, nous avons utilisé le chitosane comme biomatériau pour le développement d&#39;un film souple et mince, laser activé adhésif chirurgical appelé «SurgiLux». Ce roman bioadhésif utilise une combinaison unique de biomatériaux et de la photonique qui sont approuvés par la FDA et utilisé avec succès dans une variété d&#39;applications biomédicales et des produits. SurgiLux surmonte tous les inconvénients associés aux sutures et adhésifs chirurgicaux actuels (voir le tableau 1). Dans cette présentation, nous présentons le protocole relativement simple pour la fabrication de SurgiLux et de démontrerson activation laser et de la force de soudure de tissu. SurgiLux films adhérer au tissu collagénique sans modification chimique tel que la réticulation par irradiation et à l&#39;aide d&#39;une relativement faible puissance (120 mW) laser infrarouge au lieu d&#39;une lumière UV. Films de chitosane ont une attirance naturelle mais faible adhésif au collagène (~ 3 kPa), l&#39;activation du laser à base de chitosan films SurgiLux souligne la force de cette adhésion par des interactions de la chaîne polymère comme une conséquence de la dilatation thermique transitoire. 5 Sans cette &quot;activation&quot; processus de , les films SurgiLux sont facilement éliminés. 6-9 SurgiLux a été testé à la fois in vitro et in vivo sur une variété de tissus y compris le nerf, l&#39;intestin, la dure-mère et de la cornée. Dans tous les cas, il a démontré une bonne biocompatibilité et négligeable des dommages thermiques à la suite de l&#39;irradiation. 6-10

Centrifugation conduit à une solution transparente verte, ce qui augmente la viscosité après stockage à 4-6 ° C. Après un repos de 3 semaines, la solution verte est transformée en un film SurgiLux vert transparent d&#39;environ 20 microns d&#39;épaisseur et, comme démontré dans la vidéo, est facilement flexible. Lors de l&#39;irradiation avec le laser, les liaisons de film SurgiLux au tissu. Cela peut être observé sur les bords du film, où le tissu semble se contracter que le f...

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

La fabrication d&#39;un roman, adhésif flexible à couche mince chirurgicale à partir d&#39;ingrédients approuvés par la FDA, le chitosane et le vert d&#39;indocyanine est décrite. Collage de cette colle à tissu collagène à travers un processus d&#39;activation simple avec une faible puissance laser infrarouge est démontrée.

Un Based Chitosan, Laser adhésif activé Thin Film chirurgicaux, «SurgiLux &#39;: Préparation et démonstration

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 ...

a-chitosan-based-laser-activated-thin-film-surgical-adhesive-surgilux

Research

JoVE Journal

Bioengineering

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

13.1K vues.  University of New South Wales. La fabrication d'un roman, adhésif flexible à couche mince chirurgicale à partir d'ingrédients approuvés par la FDA, le chitosane et le vert d'indocyanine est décrite. Collage de cette colle à tissu collagène à travers un processus d'activation simple avec une faible puissance laser infrarouge est démontrée.

Vidéo: 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.

Construction d&#39;un hydrogel de collagène pour la prestation de souches microsphères Cell-chargé Chitosan

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 ...

Recherche

Bio-ingénierie

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.

Fabrication et application de Rose Bengale-chitosane Films à la réparation des tissus au 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.

Création de dégradés et adhésifs solubles pour la migration des cellules d&#39;imagerie par microscopie à fluorescence

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.

Insertion de flexible Neural sondes utilisant renforts rigides attachés avec Biodissolvable adhésif

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.

Le développement de l&#39;Amelogenin-chitosane Hydrogel pour<em&gt; In Vitro</em&gt; Émail repousse avec une interface dense

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.

Spécialement conçu à base de laser appareils de chauffage à libération déclenchée de cisplatine de thermosensible liposomes avec guidage par l&#39;image par résonance magnétique

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.

Formation automatisée Lipid bicouche Membrane Utilisation d&#39;un Thin Film Polydiméthylsiloxane

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.

, Fabrication de réseaux microfluidiques vasculaire dérivés à base de laser guidée par l&#39;image

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.

Feuil sec axée sur la résine photosensible de biocapteurs microfluidiques électrochimiques plate-forme : Fabrication de dispositifs, préparation de dosage sur puce et fonctionnement du système

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.