Tuesday, December 22, 2015

PCL-PEG electrospun mesh investigated for scaffold treatment of damaged periodontal ligament

PolySciTech Division of Akina, Inc. (www.polyscitech.com) provides a wide array of block copolymers including PCL-PEG copolymers. One means of processing these polymers is using electrospinning. Electrospinning is a manufacturing technique based on applying a highly charged polymer solution onto a grounded metal collector. When this is done under the right conditions the polymer forms into an open mesh similar to woven fabric but with no particular weave pattern hence it is sometimes refered to as ‘non-woven.’ All the empty spaces in the micron scale work well for cell-permeation and so this is a popular technique for generating a tissue scaffold to help with guided tissue regeneration (GTR). The drawback to this technique is that the scaffold is somewhat generic and does not typically serve for regrowth of tissue which has a particular orientation to it. For example, the periodontal ligament tissue, which connects the jaw-bone to the root surface of teeth must be formed in a particular arrangement for it to hold everything in place the way it should. Recently, researchers electrospun PCL-PEG-PCL triblock polymer into sheets and then compressed together with a chitosan based ‘glue’ to form a tissue scaffold. This scaffold worked well to regenerate this oriented tissue both in-vitro and in vivo. Read more: Jiang, Wenlu, Long Li, Ding Zhang, Shishu Huang, Zheng Jing, Yeke Wu, Zhihe Zhao, Lixing Zhao, and Shaobing Zhou. "Incorporation of aligned PCL–PEG nanofibers into porous chitosan scaffolds improved the orientation of collagen fibers in regenerated periodontium." Acta biomaterialia 25 (2015): 240-252. http://www.sciencedirect.com/science/article/pii/S1742706115300210

“Abstract: The periodontal ligament (PDL) is a group of highly aligned and organized connective tissue fibers that intervenes between the root surface and the alveolar bone. The unique architecture is essential for the specific physiological functionalities of periodontium. The regeneration of periodontium has been extensively studied by researchers, but very few of them pay attention to the alignment of PDL fibers as well as its functionalities. In this study, we fabricated a three-dimensional multilayered scaffold by embedding highly aligned biodegradable poly (ε-caprolactone)-poly(ethylene glycol) (PCE) copolymer electrospun nanofibrous mats into porous chitosan (CHI) to provide topographic cues and guide the oriented regeneration of periodontal tissue. In vitro, compared with random group and porous control, aligned nanofibers embedded scaffold could guide oriented arrangement and elongation of cells with promoted infiltration, viability and increased periodontal ligament-related genes expression. In vivo, aligned nanofibers embedded scaffold showed more organized arrangement of regenerated PDL nearly perpendicular against the root surface with more extensive formation of mature collagen fibers than random group and porous control. Moreover, higher expression level of periostin and more significant formation of tooth-supporting mineralized tissue were presented in the regenerated periodontium of aligned scaffold group. Incorporation of aligned PCE nanofibers into porous CHI proved to be applicable for oriented regeneration of periodontium, which might be further utilized in regeneration of a wide variety of human tissues with a specialized direction. Statement of Significance: The regeneration of periodontium has been extensively studied by researchers, but very few of them give attention to the alignment of periodontal ligament (PDL) fibers as well as its functionalities. The key issue is to provide guidance to the orientation of cells with aligned arrangement of collagen fibers perpendicular against the root surface. This study aimed to promote oriented regeneration of periodontium by structural mimicking of scaffolds. The in vitro and in vivo performances of the scaffolds were further evaluated to test the topographic-guiding and periodontium healing potentials. We also think our research may provide ideas in regeneration of a wide variety of human tissues with a specialized direction. Keywords: Periodontal tissue engineering; Biomimetics; Electrospun scaffold; Oriented regeneration; Periodontal ligament”

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