Bu çalışma Ulusal Sağlık Enstitüleri (DBC için HL068915), (CAP) Thrasher Araştırma Fonundan Yeni Araştırmacı Ödülü bir araştırma bursuyla, bir Grant-in-Aid (DBC için 12GRNT11910008) Amerikan Kalp Derneği tarafından desteklenen , Çocuk Kalp Vakfı (DBC için), ve Boston Çocuk Hastanesi Kalp İletim Fonu, Ryan Aile Endowment ve David Pullman tarafından yapılan bağışlardan bir araştırma hibe.

Burada kuzu derisinden COL1 ve izolasyonu gösterecektir. Yazılmış olduğu gibi, bu protokol de başarıyla tavşan ve insan cilt Süt1 izole etmek için kullanılabilir. 1.. Dermal örnek hazırlayın <ol><li> Kullanımdan önce 4 ° C&#39;ye bütün reaktifler dengelenmesi. </li><li> Buz dH 2 O dermal örneği (25-50 g) durulayın ve tüy dökücü krem ile herhangi yün, kürk, ya da tüylerden. </li><li> Bağ dokusu ve yağ numune tozunu kazımak için bir tek kenar jilet kullanın. </li><li> Buz dH 2 O&#39;da örnek durulayın </li><li> Tek bir kenar jilet ile 1 cm x 1 cm parçalar halinde deri örneği dilimleyin. </li></ol> 2. Nonkollagenöz Çözündürülmüş Malzeme kaldır <ol><li> Numune, 50 ml konik tüp başına 5 g tartılır ve buz soğukluğundaki 0,5 M sodyum asetat, 30 ml. </li><li> Tezgah üstü homojenizatör içinde bir 50 ml tüp adaptörü ile 6 m / saniye ayarında 1 dakika boyunca tüpleri karıştırın. </li><li> Sup atın7 sodyum asetat yıkama döngüleri toplam ernatant ve tekrarlayın. </li><li> Buz soğukluğunda dH 2 O örnek yıkayın ve kalıntı sodyum asetat giderilmiş, bir kez karıştırın. </li><li> Fazla sıvının çıkması ve daha sonra yeni bir 50 mL konik tüp aktarmak için tüpün kenarına karşı örnek sıkıştırmak için bir spatula kullanın. </li></ol> 3. Kollajen Ekstraksiyon yazın <ol><li> Örnek sıkıştırma ve her bir yıkamadan sonra süpernatant atarak tezgah üstü homojenleştirici içinde 6 m / sn &#39;de 1 dakika boyunca ml / g 2 iki kez örnek yıkayın 0.075 M sodyum sitrat tampon maddesi. </li><li> Numuneye 0.075 M sodyum sitrat tamponu taze bir 2 ml / g bir kısım ekleyin. </li><li> Her çevrim arasındaki tampon çıkarmadan 6 sıralı 1 dk, ajitasyon 6 m / sn tezgah üstü homojenleştirici mix çevrimi gerçekleştirin. </li><li> Bir toplama tüpüne kalın, berrak süpernatant aktarın. </li><li> Numuneye bir ml / g 1 ek 0.075 M sodyum sitrat tamponu ilave edin ve bir final tezgah üstü homojenleştirici agita yerinetion çevrimi. </li><li> Bir toplama tüpüne bu son süpernatant ekleyin. </li><li> 4 ° C&#39;de 10 dakika boyunca 3,200 x g de santrifüj toplama tüpü </li><li> 100.000 molekül ağırlığına sahip üst bölmesine süpernatant aktarın santrifügal filtre cihazı kesti. </li><li> 4 ° C&#39;de 30 dakika boyunca 3200 x g&#39;de santrifüje </li><li> 4 ° C &#39;de bir temiz konik tüp ve saklamak için, üst bölmeden saflaştırılmış Süt1 aktarın </li></ol>

<ol>
	<li>Nageotte, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coagulation+fibrillaire+in+vitro+du+collag&#232;ne+dissous+dans+un+acide+dilu&#233;.">Coagulation fibrillaire in vitro du collag&#232;ne dissous dans un acide dilu&#233;.</a> CR hebd. s&#233;ances Acad. Sei. 184, 115 (1927).</li><li>Schmitt, F. O., Hall, C. E., Jakus, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electron+microscope+investigation+of+the+structure+of+collagen.">Electron microscope investigation of the structure of collagen.</a> J. Cell Comp. Physiol. 20, 11-33 (1942).</li><li>Choi, Y. 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=Cardiac+conduction+through+engineered+tissue.">Cardiac conduction through engineered tissue.</a> Am. J. Pathol. 169, 72-85 (2006).</li><li>Pacak, C. A., Cowan, D. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+of+myogenic+engineered+tissue+constructs.">Fabrication of myogenic engineered tissue constructs.</a> J. Vis. Exp. (27), (2009).</li><li>Cliche, S., Amiot, J., Avezard, C., Gariepy, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extraction+and+characterization+of+collagen+with+or+without+telopeptides+from+chicken+skin.">Extraction and characterization of collagen with or without telopeptides from chicken skin.</a> Poultry Sci. 82, 503-509 (2003).</li><li>Rajan, N., Habermehl, J., Cote, M. F., Doillon, C. J., Mantovani, D. <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+ready-to-use,+storable+and+reconstituted+type+I+collagen+from+rat+tail+tendon+for+tissue+engineering+applications.">Preparation of ready-to-use, storable and reconstituted type I collagen from rat tail tendon for tissue engineering applications.</a> Nat. Protoc. 1, 2753-2758 (2006).</li><li>Seifter, S., Gallop, P., Colowick, S., Kaplan, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+properties+of+soluble+collagens.">Preparation and properties of soluble collagens.</a> Methods in Enzymology. , (1963).</li><li>Pacak, C. A., Powers, J. M., Cowan, D. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrarapid+purification+of+collagen+type+I+for+tissue+engineering+applications.">Ultrarapid purification of collagen type I for tissue engineering applications.</a> Tissue Eng. Part C Methods. 17, 879-885 (2011).</li><li>Ohan, M. P., Dunn, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glucose+stabilizes+collagen+sterilized+with+gamma+irradiation.">Glucose stabilizes collagen sterilized with gamma irradiation.</a> J. Biomed. Mater. Res. A. 67, 1188-1195 (2003).</li><li>Tyan, Y. C., Liao, J. D., Lin, S. P., Chen, C. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+study+of+the+sterilization+effect+of+gamma+ray+irradiation+of+immobilized+collagen+polypropylene+nonwoven+fabric+surfaces.">The study of the sterilization effect of gamma ray irradiation of immobilized collagen polypropylene nonwoven fabric surfaces.</a> J. Biomed. Mater. Res. A. 67, 1033-1043 (2003).</li><li>Ber, S., Torun Kose, G., Hasirci, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bone+tissue+engineering+on+patterned+collagen+films:+an+in+vitro+study.">Bone tissue engineering on patterned collagen films: an in vitro study.</a> Biomaterials. 26, 1977-1986 (2005).</li><li>Liu, Y., Sun, S., Singha, S., Cho, M. R., Gordon, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3-D+femtosecond+laser+patterning+of+collagen+for+directed+cell+attachment.">3-D femtosecond laser patterning of collagen for directed cell attachment.</a> Biomaterials. 26, 4597-4605 (2005).</li><li>Thakar, R. G., Ho, F., Huang, N. F., Liepmann, D., Li, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+vascular+smooth+muscle+cells+by+micropatterning.">Regulation of vascular smooth muscle cells by micropatterning.</a> Biochem. Biophys. Res. Comm. 307, 883-890 (2003).</li><li>Leighton, J., Justh, G., Esper, M., Kronenthal, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collagen-coated+cellulose+sponge:+three+dimensional+matrix+for+tissue+culture+of+Walker+tumor+256.">Collagen-coated cellulose sponge: three dimensional matrix for tissue culture of Walker tumor 256.</a> Science. 155, 1259-1261 (1967).</li></ol>

Yazarlar ifşa etmek hiçbir rakip mali çıkarları var.

Bu yöntemin önemli bir öğesi, fazla sıvının çıkması için dermal numunenin tekrar etkili sıkıştırma. Bu örnek sıkıştırılmasıyla aşamasında 2,5 mümkün olduğu kadar, sodyum asetatın ayrılması için çok önemlidir. Bu tüpün yanına karşı cildi sıkıştırmak için bir ıspatula ile birlikte, bir tülbent de kullanılabilir, bu tüpten numune çıkarılmasını gerektirir ve bu adımları gerçekleştirmek için gereken süreyi uzatır olsa da. Benzer şekilde, sodyum sitrat hacmi daha son...

On yıllardır, araştırmacılar ve ticari satıcılar kullanılabilir düzenlenmiş col1 fibrillerin bir matrisin yeniden süspansiyon haline getirilmesi ile sonuçlanan nötralizasyonu ardından basit bir asit ekstraksiyon protokolü, bir varyasyonunu kullanılarak deri ve tendon dokusu da dahil olmak üzere bir çeşit kaynaklardan gelen çözündürülmüş Süt1 izole var biyomedikal uygulamalarda 1-4 çok sayıda için. COL1 için klinik uygulamalar birçok örnek olsa da, bu proteinin hazırlık 5-7 gerçekleştirmek için gün veya hafta alarak uzun ekstraksiyonlanm gerektirdiğinden, bu birkaç otolog kaynaklı col1 kullanır. Sonuç olarak, araştırmacılar, araştırma ve hekimler, genellikle, örneğin, sıçan, sığır, domuz veya insan olmayan altderinin gibi dokuları kullanılarak veya kadavra derisi kullanılarak kaldırılır veya sünnet izleyerek hazırlanır COL1 pahalı, ticari preparatları kullanın. Rejeneratif uygulamalar için, yetenekleri ile ilgili olarak bu ürünler, sergi değişkenlik çok katı oluşturulması içinmatrisler veya hücre eki ve büyümeyi destekleme yeteneğine doku yapıları. Sonuç olarak, hızlı erişilebilir ve bol otolog doku kaynaklarından Süt1 ayıklamak için tasarlanmış yeni bir standart yöntem için ayrı bir ihtiyaç vardır. Bu tür bir yöntem col1 ilgi hayvan modeli çıkarılır ve kollajen bazlı iskeleler üzerine monte tasarlanmış dokuların klinik öncesi test edilmesi için kullanılabilecek bir araştırma ortamında zaman ve paradan tasarruf sağlayacaktır. Aynı zamanda, klinikte bir hızla izole, otolog kaynaklı Süt1 kullanma seçeneğine sahip aksi allojenik veya ksenogeneik hazırlıkları alacak hastalar için genel güvenliği artıracak. Bir autogeneic hazırlık alan hastalar için, bu akıcı yöntem büyük ölçüde biyopsi toplama ve kolajen uygulama arasındaki süreyi azaltacaktır. Bu nedenlerden dolayı, yüksek hızlı ag kullanarak köklü bir col1 izolasyon ve saflaştırma yöntemi geliştirmek için arananrehabilitasyonu amaçlayan ve boyut dışlama santrifüj. Bu yöntem birçok laboratuvarlarda bulunan standart tamponlar ve ekipman kullanarak gerçekleştirmek için basit. Yüksek hızda çalkalama kullanılarak, protokolümüz az 3 saat 8 için yaklaşık 10 gün arasında çözülebilir, dermal Süt1 izole etmek için gerekli olan zamanı azaltır. Önemli olarak, bu metod prosedürleri tek bir kümesi esnasında hastalar için otolog türetilmiş Süt1 hazırlamak için klinik ortamda gerçekleştirilebilir.

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an improved method for the preparation of type i collagen from skin

Çözülebilir kolajen tip 1 (col1) hücre kültürleri için bir yapışkan tabaka olarak ve rejeneratif uygulamalar için hücresel bir yapı iskelesi olarak yaygın bir biçimde kullanılmaktadır. Klinik olarak, bu proteinin yaygın kozmetik cerrahi, dermal enjeksiyonlar, kemik grefti ve rekonstrüktif cerrahi için kullanılır. Bu işlemler için COL1 ve kaynakları inflamasyon ve ret potansiyeli yanı sıra ksenobiyotiksiz hastalık bulaşmasını arttırır, genellikle insan kaynaklı değildir. Bu görüş, verimli ve hızlı bir otolog-türevi dokuların sınırlı miktarlarda ikinci Süt1 saflaştırılması için bir yöntem olup, bu sorunların çoğu aşmak olur, ancak, standart ayırma protokoller uzun ve genellikle kollajen dokularının büyük miktarlarda gerektirir. Burada, en az 3 saat ila yaklaşık 10 gün arasında bu proteinin izole edilmesi ve saflaştırılması için gerekli olan zamanı azaltır etkili bir col1 çıkarma yöntemi göstermektedir. Biz birçok cerrahi işlemler sırasında, çünkü onun durumu bizim doku kaynağı olarak dermis seçti. Tonun yöntemi altderinin, az miktarda yüksek ölçüde saf, çözünebilir Süt1 elde etmek için güçlü çalkalama ve santrifüj filtre ile birlikte geleneksel ekstre etme tamponları kullanır. Kısaca, dermal biyopsiler yağ, bağ dokusu ve saç çıkardıktan sonra buz gibi soğuk dH 2 O iyice yıkanır. Deri örnekleri, 0.5 M sodyum asetat ve yüksek hızlı bir tezgah üstü homojenizörü kullanılarak nonkollagenöz protein ve polisakaritlerin kaldırılır. Artık katı maddelerden kollajen, daha sonra homojenleştirici kullanılarak bir 0.075 M sodyum sitrat tampon maddesi ile ekstre edilir. Bu ekstreler karşılaştırılabilir ya da üstün ticari ürünler için kalite ya da geleneksel prosedürler kullanılarak elde edilmiş olan col1 preparatları elde 100,000 MW kesme santrifüj filtresi kullanılarak saflaştırılır. Bu yöntem, araştırma ve klinik uygulamalarda çok sayıda için otolog kaynaklı COL1 kullanımını kolaylaştıracak tahmin.

Bu col1 izolasyon protokol tamamlanması için yaklaşık 2 saat 15 dakika gerektirir. Şekil 1, bu prosedürdeki önemli adımlar şematik bir diyagramını göstermektedir. Örnek hazırlama ve yüksek hızlı ajitasyon 7 döngülerini gerçekleştirmek ve sodyum asetat ile durulama ürünleri, yaklaşık 35 dakika (Şekil 1A-C) alır. Bir ajitasyon Sahne ve dH 2 O ile durulama yaklaşık 5 dk (Şekil 1D ve 1E) alır. Sodyum sitrat eklemek ve bir çalkalama...

Watch this Scientific Journal Video about An Improved Method for the Preparation of Type I Collagen From Skin at JoVE.com

An Improved Method for the Preparation of Type I Collagen From Skin

Çözünebilen bir tip 1 kollajen (col1) izolasyonu için geleneksel işlemleri de, uzun inkubasyon tampon ve fibrillerin zahmetli resuspensions of baştan sona yaklaşık 10 gün gerektirmektedir. Burada, biz az 3 saat küçük dermal biyopsilerden Süt1 arındırmak için bir araç açıklar.

Cilt Tip I Kolajen hazırlanması için geliştirilmiş bir yöntem

Soluble type 1 collagen (COL1) is used extensively as an adhesive substrate for cell cultures and as a cellular scaffold for regenerative applications. ...

an-improved-method-for-the-preparation-of-type-i-collagen-from-skin

Research

JoVE Journal

Bioengineering

22.7K Görüntüleme.  Boston Children's Hospital.  Çözünebilen bir tip 1 kollajen (col1) izolasyonu için geleneksel işlemleri de, uzun inkubasyon tampon ve fibrillerin zahmetli resuspensions of baştan sona yaklaşık 10 gün gerektirmektedir. Burada, biz az 3 saat küçük dermal biyopsilerden Süt1 arındırmak için bir araç açıklar. 

Video: An Improved Method for the Preparation of Type I Collagen From Skin

The Three-Dimensional Human Skin Reconstruct Model: a Tool to Study Normal  Skin and Melanoma Progression

Most in vitro studies in experimental skin biology have been done in 2-dimensional (2D) monocultures, while accumulating evidence suggests that cells behave differently when they are grown within a 3D extra-cellular matrix and also interact with other cells (1-5). Mouse models have been broadly utilized to study tissue morphogenesis in vivo. However mouse and human skin have significant differences in cellular architecture and physiology, which makes it difficult to extrapolate mouse studies to humans. Since melanocytes in mouse skin are mostly localized in hair follicles, they have distinct biological properties from those of humans, which locate primarily at the basal layer of the epidermis. The recent development of 3D human skin reconstruct models has enabled the field to investigate cell-matrix and cell-cell interactions between different cell types. The reconstructs consist of a "dermis" with fibroblasts embedded in a collagen I matrix, an "epidermis", which is comprised of stratified, differentiated keratinocytes and a functional basement membrane, which separates epidermis from dermis. Collagen provides scaffolding, nutrient delivery, and potential for cell-to-cell interaction. The 3D skin models incorporating melanocytic cells recapitulate natural features of melanocyte homeostasis and melanoma progression in human skin. As in vivo, melanocytes in reconstructed skin are localized at the basement membrane interspersed with basal layer keratinocytes. Melanoma cells exhibit the same characteristics reflecting the original tumor stage (RGP, VGP and metastatic melanoma cells) in vivo. Recently, dermal stem cells have been identified in the human dermis (6). These multi-potent stem cells can migrate to the epidermis and differentiate to melanocytes.

In this report, we describe the three-dimensional skin reconstruct model which mimics human skin in architecture and composition. Melanocyte physiology, melanoma progression and the fate of dermal stem cells have been investigated using the skin reconstruct model. The model is also useful as a preclinical tool for drug assessment.

Üç Boyutlu İnsan Cilt Model Yeniden İnşa: Aracı Normal Cilt ve Melanom İlerleme Eğitim

Most in vitro studies in experimental skin biology have been done in 2-dimensional (2D) monocultures, while accumulating evidence suggests that cells ...

Biyomühendislik

Organotypic Collagen I Assay: A Malleable Platform to Assess Cell Behaviour in a 3-Dimensional Context

Cell migration is fundamental to many aspects of biology, including development, wound healing, the cellular responses of the immune system, and metastasis of tumor cells. Migration has been studied on glass coverslips in order to make cellular dynamics amenable to investigation by light microscopy. However, it has become clear that many aspects of cell migration depend on features of the local environment including its elasticity, protein composition, and pore size, which are not faithfully represented by rigid two dimensional substrates such as glass and plastic 1. Furthermore, interaction with other cell types, including stromal fibroblasts 2 and immune cells 3, has been shown to play a critical role in promoting the invasion of cancer cells. Investigation at the molecular level has increasingly shown that molecular dynamics, including response to drug treatment, of identical cells are significantly different when compared in vitro and in vivo 4. 
Ideally, it would be best to study cell migration in its naturally occurring context in living organisms, however this is not always possible. Intermediate tissue culture systems, such as cell derived matrix, matrigel, organotypic culture (described here) tissue explants, organoids, and xenografts, are therefore important experimental intermediates. These systems approximate certain aspects of an in vivo environment but are more amenable to experimental manipulation such as use of stably transfected cell lines, drug treatment regimes, long term and high-resolution imaging. Such intermediate systems are especially useful as proving grounds to validate probes and establish parameters required to image the dynamic response of cells and fluorescent reporters prior to undertaking imaging in vivo 5. As such, they can serve an important role in reducing the need for experiments on living animals.

A method is described for the preparation of a 3-dimensional matrix consisting of collagen type I and primary human fibroblasts. This organotypic gel serves as a useful substrate to assess invasive cell migration because it mimics basic features of tissue stroma and is amenable to many forms of microscopy.

Organotipik Kollajen Ben Assay: 3-Boyutlu Bağlamında Hücre Davranışı değerlendirin A Dövülebilir Platformu

Cell migration is fundamental to many aspects of biology, including development, wound healing, the cellular responses of the immune system, and ...

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.

Kök Hücre yüklü Chitosan Mikrokürelerin teslimi için bir Kollajen Hidrojel oluşturma

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 ...

Constant Pressure-controlled Extrusion Method for the Preparation of Nano-sized Lipid Vesicles

Liposomes are artificially prepared vesicles consisting of natural and synthetic phospholipids that are widely used as a cell membrane mimicking platform to study protein-protein and protein-lipid interactions3, monitor drug delivery4,5, and encapsulation4. Phospholipids naturally create curved lipid bilayers, distinguishing itself from a micelle.6 Liposomes are traditionally classified by size and number of bilayers, i.e. large unilamellar vesicles (LUVs), small unilamellar vesicles (SUVs) and multilamellar vesicles (MLVs)7. In particular, the preparation of homogeneous liposomes of various sizes is important for studying membrane curvature that plays a vital role in cell signaling, endo- and exocytosis, membrane fusion, and protein trafficking8. Several groups analyze how proteins are used to modulate processes that involve membrane curvature and thus prepare liposomes of diameters &lt;100 - 400 nm to study their behavior on cell functions3. Others focus on liposome-drug encapsulation, studying liposomes as vehicles to carry and deliver a drug of interest9. Drug encapsulation can be achieved as reported during liposome formation9. Our extrusion step should not affect the encapsulated drug for two reasons, i.e. (1) drug encapsulation should be achieved prior to this step and (2) liposomes should retain their natural biophysical stability, securely carrying the drug in the aqueous core. These research goals further suggest the need for an optimized method to design stable sub-micron lipid vesicles.
Nonetheless, the current liposome preparation technologies (sonication10, freeze-and-thaw10, sedimentation) do not allow preparation of liposomes with highly curved surface (i.e. diameter &lt;100 nm) with high consistency and efficiency10,5, which limits the biophysical studies of an emerging field of membrane curvature sensing. Herein, we present a robust preparation method for a variety of biologically relevant liposomes.
Manual extrusion using gas-tight syringes and polycarbonate membranes10,5 is a common practice but heterogeneity is often observed when using pore sizes &lt;100 nm due to due to variability of manual pressure applied. We employed a constant pressure-controlled extrusion apparatus to prepare synthetic liposomes whose diameters range between 30 and 400 nm. Dynamic light scattering (DLS)10, electron microscopy11 and nanoparticle tracking analysis (NTA)12 were used to quantify the liposome sizes as described in our protocol, with commercial polystyrene (PS) beads used as a calibration standard. A near linear correlation was observed between the employed pore sizes and the experimentally determined liposomes, indicating high fidelity of our pressure-controlled liposome preparation method. Further, we have shown that this lipid vesicle preparation method is generally applicable, independent of various liposome sizes. Lastly, we have also demonstrated in a time course study that these prepared liposomes were stable for up to 16 hours. A representative nano-sized liposome preparation protocol is demonstrated below.

This protocol describes an extrusion method for preparing lipid vesicles of sub-micron sizes with a high degree of homogeneity. This method uses a pressure-controlled system with controlled nitrogen flow rates for liposome preparation. The lipid preparation1,2, liposome extrusion, and size characterization will be presented herein.

Nano ölçekli Lipid Vesiküller Hazırlanması için Sabit Basınç kontrollü Ekstrüzyon Yöntemi

Liposomes are artificially prepared vesicles consisting of natural and synthetic phospholipids that are widely used as a cell membrane mimicking platform ...

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.

Yöntem kan-beyin bariyerini bir insan hücre tabanlı bir İletişim Modelinin Hazırlanması için Geliştirilmiş

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

Imaging Denatured Collagen Strands In vivo and Ex vivo via Photo-triggered Hybridization of Caged Collagen Mimetic Peptides

Collagen is a major structural component of the extracellular matrix that supports tissue formation and maintenance. Although collagen remodeling is an integral part of normal tissue renewal, excessive amount of remodeling activity is involved in tumors, arthritis, and many other pathological conditions. During collagen remodeling, the triple helical structure of collagen molecules is disrupted by proteases in the extracellular environment. In addition, collagens present in many histological tissue samples are partially denatured by the fixation and preservation processes. Therefore, these denatured collagen strands can serve as effective targets for biological imaging. We previously developed a caged collagen mimetic peptide (CMP) that can be photo-triggered to hybridize with denatured collagen strands by forming triple helical structure, which is unique to collagens. The overall goals of this procedure are i)&#160;to image denatured collagen strands resulting from normal remodeling activities in vivo, and ii) to visualize collagens in ex vivo tissue sections using the photo-triggered caged CMPs. To achieve effective hybridization and successful in vivo and ex vivo imaging, fluorescently labeled caged CMPs are either photo-activated immediately before intravenous injection, or are directly activated on tissue sections. Normal skeletal collagen remolding in nude mice and collagens in prefixed mouse cornea tissue sections are imaged in this procedure. The imaging method based on the CMP-collagen hybridization technology presented here could lead to deeper understanding of the tissue remodeling process, as well as allow development of new diagnostics for diseases associated with high collagen remodeling activity.

Imaging Denatured Collagen Strands In vivo and Ex vivo via Photo-triggered Hybridization of Caged Collagen Mimetic Peptides

This procedure demonstrates in vivo near IR fluorescence imaging of collagen remodeling activities in mice as well as ex vivo staining of collagens in tissue sections using caged collagen mimetic peptides that can be photo-triggered to hybridize with denatured collagen strands.

Doğallığı Kollajen Tellerinin Görüntüleme<em&gt; In vivo</em&gt; Ve<em&gt; Ex vivo</em&gt; Kafesli Kollajen Mimetik Peptidlerinin Fotoğraf-tetiklenen Hybridization yoluyla

Collagen is a major structural component of the extracellular matrix that supports tissue formation and maintenance. Although collagen remodeling is an ...

An Improved Mechanical Testing Method to Assess Bone-implant Anchorage

Recent advances in material science have led to a substantial increase in the topographical complexity of implant surfaces, both on a micro- and a nano-scale. As such, traditional methods of describing implant surfaces -&#160;namely numerical determinants of surface roughness -&#160;are inadequate for predicting in vivo performance. Biomechanical testing provides an accurate and comparative platform to analyze the performance of biomaterial surfaces. An improved mechanical testing method to test the anchorage of bone to candidate implant surfaces is presented. The method is applicable to both early and later stages of healing and can be employed for any range of chemically or mechanically modified surfaces -&#160;but not smooth surfaces. Custom rectangular implants are placed bilaterally in the distal femora of male Wistar rats and collected with the surrounding bone. Test specimens are prepared and potted using a novel breakaway mold and the disruption test is conducted using a mechanical testing machine. This method allows for alignment of the disruption force exactly perpendicular, or parallel, to the plane of the implant surface, and provides an accurate and reproducible means for isolating an exact peri-implant region for testing.

An improved method to mechanically test bone anchorage to candidate implant surfaces is presented. This method allows for alignment of the disruption force exactly perpendicular, or parallel, to the plane of the implant surface, and provides an accurate means to direct the disruption forces to an exact peri-implant region.

Kemik-implant Anchorage değerlendirmek için bir Geliştirilmiş Mekanik Test Metodu

Recent advances in material science have led to a substantial increase in the topographical complexity of implant surfaces, both on a micro- and a ...

Engineering 3D Cellularized Collagen Gels for Vascular Tissue Regeneration

Synthetic materials are known to initiate clinical complications such as inflammation, stenosis, and infections when implanted as vascular substitutes. Collagen has been extensively used for a wide range of biomedical applications and is considered a valid alternative to synthetic materials due to its inherent biocompatibility (i.e., low antigenicity, inflammation, and cytotoxic responses). However, the limited mechanical properties and the related low hand-ability of collagen gels have hampered their use as scaffold materials for vascular tissue engineering. Therefore, the rationale behind this work was first to engineer cellularized collagen gels into a tubular-shaped geometry and second to enhance smooth muscle cells driven reorganization of collagen matrix to obtain tissues stiff enough to be handled.
The strategy described here is based on the direct assembling of collagen and smooth muscle cells (construct) in a 3D cylindrical geometry with the use of a molding technique. This process requires a maturation period, during which the constructs are cultured in a bioreactor under static conditions (without applied external dynamic mechanical constraints) for 1 or 2 weeks. The &#8220;static bioreactor&#8221; provides a monitored and controlled sterile environment (pH, temperature, gas exchange, nutrient supply and waste removal) to the constructs. During culture period, thickness measurements were performed to evaluate the cells-driven remodeling of the collagen matrix, and glucose consumption and lactate production rates were measured to monitor the cells metabolic activity. Finally, mechanical and viscoelastic properties were assessed for the resulting tubular constructs. To this end, specific protocols and a focused know-how (manipulation, gripping, working in hydrated environment, and so on) were developed to characterize the engineered tissues.

In this work, we present a technique for the rapid fabrication of living vascular tissues by direct culturing of collagen, smooth muscle cells and endothelial cells. In addition, a new protocol for the mechanical characterization of engineered vascular tissues is described.

Vasküler Doku Rejenerasyon için Mühendislik 3D cellularized Kollajen jeller

Synthetic materials are known to initiate clinical complications such as inflammation, stenosis, and infections when implanted as vascular substitutes. ...

Minced Tissue in Compressed Collagen: A Cell-containing Biotransplant for Single-staged Reconstructive Repair

Conventional techniques for cell expansion and transplantation of autologous cells for tissue engineering purposes can take place in specially equipped human cell culture facilities. These methods include isolation of cells in single cell suspension and several laborious and time-consuming events before transplantation back to the patient. Previous studies suggest that the body itself could be used as a bioreactor for cell expansion and regeneration of tissue in order to minimize ex vivo manipulations of tissues and cells before transplanting to the patient. The aim of this study was to demonstrate a method for tissue harvesting, isolation of continuous epithelium, mincing of the epithelium into small pieces and incorporating them into a three-layered biomaterial. The three-layered biomaterial then served as a delivery vehicle, to allow surgical handling, exchange of nutrition across the transplant, and a controlled degradation. The biomaterial consisted of two outer layers of collagen and a core of a mechanically stable and slowly degradable polymer. The minced epithelium was incorporated into one of the collagen layers before transplantation. By mincing the epithelial tissue into small pieces, the pieces could be spread and thereby the propagation of cells was stimulated. After the initial take of the transplants, cell expansion and reorganization would take place and extracellular matrix mature to allow ingrowth of capillaries and nerves and further maturation of the extracellular matrix. The technique minimizes ex vivo manipulations and allow cell harvesting, preparation of autograft, and transplantation to the patient as a simple one-stage intervention. In the future, tissue expansion could be initiated around a 3D mold inside the body itself, according to the specific needs of the patient. Additionally, the technique could be performed in an ordinary surgical setting without the need for sophisticated cell culturing facilities.

Tissue engineering often includes in vitro expansion in order to create autografts for tissue regeneration. In this study a method for tissue expansion, regeneration, and reconstruction in vivo was developed in order to minimize the processing of cells and biological materials outside the body.

Sıkıştırılmış Kolajen kıyılmış Doku: Tek aşamalı Rekonstrüktif Onarım için Cep içeren Biotransplant

Conventional techniques for cell expansion and transplantation of autologous cells for tissue engineering purposes can take place in specially equipped ...

Preparation of 3D Collagen Gels and Microchannels for the Study of 3D Interactions In Vivo

Historically, most cellular processes have been studied in only 2 dimensions. While these studies have been informative about general cell signaling mechanisms, they neglect important cellular cues received from the structural and mechanical properties of the local microenvironment and extracellular matrix (ECM). To understand how cells interact within a physiological ECM, it is important to study them in the context of 3 dimensional assays. Cell migration, cell differentiation, and cell proliferation are only a few processes that have been shown to be impacted by local changes in the mechanical properties of a 3-dimensional ECM. Collagen I, a core fibrillar component of the ECM, is more than a simple structural element of a tissue. Under normal conditions, mechanical cues from the collagen network direct morphogenesis and maintain cellular structures. In diseased microenvironments, such as the tumor microenvironment, the collagen network is often dramatically remodeled, demonstrating altered composition, enhanced deposition and altered fiber organization. In breast cancer, the degree of fiber alignment is important, as an increase in aligned fibers perpendicular to the tumor boundary has been correlated to poorer patient prognosis1. Aligned collagen matrices result in increased dissemination of tumor cells via persistent migration2,3. The following is a simple protocol for embedding cells within a 3-dimensional, fibrillar collagen hydrogel. This protocol is readily adaptable to many platforms, and can reproducibly generate both aligned and random collagen matrices for investigation of cell migration, cell division, and other cellular processes in a tunable, 3-dimensional, physiological microenvironment.

Preparation of 3D Collagen Gels and Microchannels for the Study of 3D Interactions In Vivo

Collagen is a core component of the ECM, and provides essential cues for several cellular processes ranging from migration to differentiation and proliferation. Provided here is a protocol for embedding cells within 3D collagen hydrogels, and a more advanced technique for generating randomized or aligned collagen matrices using PDMS microchannels.

3D Etkileşimleri Çalışmaları 3D Kollajen jeller ve Mikrokanallarda Hazırlanması<em&gt; İn Vivo</em

Historically, most cellular processes have been studied in only 2 dimensions.  While these studies have been informative about general cell signaling ...