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Regeneration of meniscus tissue using adipose mesenchymal stem cells-chondrocytes co-culture on a hybrid scaffold: In vivo study

Biomaterials - 3 hours 27 min ago
Publication date: May 2017
Source:Biomaterials, Volume 126

Author(s): Lida Moradi, Mohammad Vasei, Mohammad M. Dehghan, Mohammad Majidi, Saeed Farzad Mohajeri, Shahin Bonakdar

The meniscus has poor intrinsic regenerative capacity and its damage inevitably leads to articular cartilage degeneration. We focused on evaluating the effects of Polyvinyl alcohol/Chitosan (PVA/Ch) scaffold seeded by adipose-derived mesenchymal stem cell (ASC) and articular chondrocytes (AC) in meniscus regeneration. The PVA/Ch scaffolds with different molar contents of Ch (Ch1, Ch2, Ch4 and Ch8) were cross-linked by pre-polyurethane chains. By increasing amount of Ch tensile modulus was increased from 83.51 MPa for Ch1 to 110 MPa for Ch8 while toughness showed decrease from 0.33 mJ/mm3 in Ch1 to 0.11 mJ/mm3 in Ch8 constructs. Moreover, swelling ratio and degradation rate increased with an increase in Ch amount. Scanning electron microscopy imaging was performed for pore size measurement and cell attachment. At day 21, Ch4 construct seeded by AC showed the highest expression with 24.3 and 22.64 folds increase in collagen II and aggrecan (p ≤ 0.05), respectively. Since, the mechanical properties, water uptake and degradation rate of Ch4 and Ch8 compositions had no statistically significant differences, Ch4 was selected for in vivo study. New Zealand rabbits were underwent unilateral total medial meniscectomy and AC/scaffold, ASC/scaffold, AC-ASC (co-culture)/scaffold and cell-free scaffold were engrafted. At 7 months post-implantation, macroscopic, histologic, and immunofluorescent studies for regenerated meniscus revealed better results in AC/scaffold group followed by AC-ASC/scaffold and ASC/scaffold groups. In the cell-free scaffold group, there was no obvious meniscus regeneration. Articular cartilages were best preserved in AC/scaffold group. The best histological score was observed in AC/scaffold group. Our results support that Ch4 scaffold seeded by AC alone can successfully regenerate meniscus in tearing injury and ASC has no significant contribution in the healing process.
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Antimicrobial and Immunomodulatory Surface-Functionalized Electrospun Membranes for Bone Regeneration

Advanced Healthcare Materials - 3 hours 39 min ago

Guided bone regeneration (GBR) is a surgical procedure utilizing occlusive membranes for providing space maintenance and enabling selective repopulation of the damaged area. While this technique is effective in regenerating bone, bacterial infiltration occurs frequently and can compromise the regenerative outcome. In this study, the authors describe the development and characterization of a GBR membrane made of medical grade polycaprolactone (mPCL) electrospun fibers with antibacterial and immunomodulatory properties. This is achieved by the immobilization of the antibiotic azithromycin into the membrane via a solvent evaporation technique leading to a sustained release of the drug over 14 d. In vitro testing shows that this controlled release of azithromycin is proficient at inhibiting the growth of Staphylococcus aureus for 14 d. Implantation of azithromycin loaded mPCL membrane in a rodent calvarial defect induces macrophage polarization toward the M2 phenotype after one week and results in significantly more bone regeneration eight weeks post-surgery. The results suggest that this antibacterial membrane should be effective at preventing infection and also impacts on the macrophage polarization enhancing bone regeneration. The drug loading technique developed in this study is simple, effective with a strong potential for clinical translation and can be applied to different types of scaffolds and implants for applications in craniofacial and orthopedics applications.

A calcium phosphate coated polycaprolactone (mPCL-CaP) electrospun membrane loaded with azithromycin is developed for improving the clinical outcomes of bone regeneration. The sustained local delivery of azithromycin using mPCL-CaP membrane inhibits bacterial growth, and enhances bone regeneration by promoting transition of pro-inflammatory M1 macrophages to a reparative M2 phenotype.

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One-Step Hierarchical Assembly of Spheres-in-Lamellae Nanostructures from Solvent-Annealed Thin Films of Binary Diblock Copolymer Micelles

Advanced Functional Materials - 4 hours 11 min ago

Hierarchical assemblies of dissimilar block copolymers (BCPs) can reveal interesting perspectives on material properties and device performance by providing multiple functionalities. Up to now, hierarchical assemblies of BCPs have been mostly prepared by stepwise assembling methods, in which the first type of BCP nanodomains is used as predefined patterns to guide the second-level assembly of another BCP. On the other hand, single-step blending methods suffer from a dilemma in the creation of hierarchical patterns because blending dissimilar BCPs typically induces either macrophase separation of component BCPs or chain-level hybridization into a single morphology. The present study is designed to overcome this apparent dilemma in polymer blends by exploiting a solvent annealing method. In particular, hierarchically assembled spheres-in-lamellae structures from a solvent-annealed blended film of binary polystyrene-block-poly(2-vinylpyrdine) and polystyrene-block-poly(4-vinyl pyridine) micelles are prepared. The focus of the current study is to understand the different effects of solvent vapor on the component BCPs and the molecular mechanism for the one-step assembling process. By addressing this issue, the parallelism in the phase behavior of BCP micelles and inorganic nanoparticles is highlighted, the underlying physical processes of which could be suggested as a one-step assembly principle for hierarchical superstructures beyond the previously reported multistep methods.

Hierarchically assembled spheres-in-lamellae structures have been prepared from a solvent-annealed blended film of binary polystyrene-block-poly(2-vinylpyrdine) and polystyrene-block-poly(4-vinyl pyridine) micelles. In addressing the assembling mechanism, an interesting parallelism in the phase behavior of polymer micelles and inorganic nanoparticles is discovered, the underlying physical processes of which could be suggested as a one-step assembly principle for hierarchical superstructures.

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Engineering Photocrosslinkable Bicomponent Hydrogel Constructs for Creating 3D Vascularized Bone

Advanced Healthcare Materials - 6 hours 40 min ago

Engineering bone tissue requires the generation of a highly organized vasculature. Cellular behavior is affected by the respective niche. Directing cellular behavior and differentiation for creating mineralized regions surrounded by vasculature can be achieved by controlling the pattern of osteogenic and angiogenic niches. This manuscript reports on engineering vascularized bone tissues by incorporating osteogenic and angiogenic cell-laden niches in a photocrosslinkable hydrogel construct. Two-step photolithography process is used to control the stiffness of the hydrogel and distribution of cells in the patterned hydrogel. In addittion, osteoinductive nanoparticles are utilized to induce osteogenesis. The size of microfabricated constructs has a pronounced effect on cellular organization and function. It is shown that the simultaneous presence of both osteogenic and angiogenic niches in one construct results in formation of mineralized regions surrounded by organized vasculature. In addition, the presence of angiogenic niche improves bone formation. This approach can be used for engineered constructs that can be used for treatment of bone defects.

Photocrosslinkable bicomponent hydrogel is an engineered 3D vascularized bone-like construct. Two-step photolithography process allows controlling the stiffness and distribution of cells in the patterned hydrogel. Incorporating nanoparticles can induce formation of mineralized regions surrounded by organized vasculature. This approach can be used to fabricate customized engineered constructs for treatment of bone defects.

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Colloidal alloys with preassembled clusters and spheres

Nature Materials - 10 hours 6 min ago

Nature Materials. doi:10.1038/nmat4869

Authors: Étienne Ducrot, Mingxin He, Gi-Ra Yi & David J. Pine

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Antifogging abilities of model nanotextures

Nature Materials - 10 hours 6 min ago

Nature Materials. doi:10.1038/nmat4868

Authors: Timothée Mouterde, Gaëlle Lehoucq, Stéphane Xavier, Antonio Checco, Charles T. Black, Atikur Rahman, Thierry Midavaine, Christophe Clanet & David Quéré

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Evidence for anionic redox activity in a tridimensional-ordered Li-rich positive electrode β-Li2IrO3

Nature Materials - 10 hours 6 min ago

Nature Materials. doi:10.1038/nmat4864

Authors: Paul E. Pearce, Arnaud J. Perez, Gwenaelle Rousse, Mathieu Saubanère, Dmitry Batuk, Dominique Foix, Eric McCalla, Artem M. Abakumov, Gustaaf Van Tendeloo, Marie-Liesse Doublet & Jean-Marie Tarascon

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The microstructure and micromechanics of the tendon–bone insertion

Nature Materials - 10 hours 6 min ago

Nature Materials. doi:10.1038/nmat4863

Authors: L. Rossetti, L. A. Kuntz, E. Kunold, J. Schock, K. W. Müller, H. Grabmayr, J. Stolberg-Stolberg, F. Pfeiffer, S. A. Sieber, R. Burgkart & A. R. Bausch

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Unique Proton Dynamics in an Efficient MOF-Based Proton Conductor

Journal of the American Chemical SocietyDOI: 10.1021/jacs.6b12847
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Arylazoindazole Photoswitches: Facile Synthesis and Functionalization via SNAr Substitution

Journal of the American Chemical SocietyDOI: 10.1021/jacs.6b12585
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Efficient Enantioselective Syntheses of (+)-Dalesconol A and B

Journal of the American Chemical SocietyDOI: 10.1021/jacs.7b00783
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Reinforced Hydrogels via Carbon Nitride Initiated Polymerization

Macromolecules - Fri, 2017-02-24 12:34

MacromoleculesDOI: 10.1021/acs.macromol.6b02691
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Vanillin-Derived High-Performance Flame Retardant Epoxy Resins: Facile Synthesis and Properties

Macromolecules - Fri, 2017-02-24 11:22

MacromoleculesDOI: 10.1021/acs.macromol.7b00097
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