Article

Suture pullout strength and in vitro fibroblast and RAW 264.7 monocyte biocompatibility of genipin crosslinked nanofibrous chitosan mats for guided tissue regeneration.

Department of Biomedical Engineering, University of Memphis, Memphis, Tennessee.
Journal of Biomedical Materials Research Part A (impact factor: 2.63). 06/2012; 100(11):2890-6. DOI:10.1002/jbm.a.34224 pp.2890-6
Source: PubMed

ABSTRACT Guided tissue regeneration (GTR) is a surgical technique used to direct the formation of bone in the graft space by protecting it with a barrier membrane used to exclude soft tissues during healing. Chitosan has been advocated for GTR applications because of its biocompatibility, degradability, wound healing, and osteogenic properties. In this study, electrospun chitosan membranes, crosslinked with 5 mM or 10 mM geinipin, a natural crosslinker extracted from the gardenia plant, were evaluated for suture pullout strength, crystallinity, and cytocompatibility with normal human dermal fibroblast and TIB 71(™) RAW 264.7 monocyte cells. Ultimate suture pullout strength was significantly lower (51-67%) than that of commercially available collagen membranes. Crystallinity of the electrospun chitosan mats decreased upon crosslinking by 14-17% (p = 0.013). The molecular weight of the chitosan polymer was decreased by 75% during the electrospinning process. Uncrosslinked and genipin-crosslinked chitosan mats were cytocompatible and supported fibroblast cell proliferation for 9 days. Uncrosslinked and genipin-crosslinked membranes did not activate monocytes to produce nitric oxide (NO) in vitro in the absence of lipopolysaccharide (LPS). Finally, chitosan membranes inhibited LPS-induced NO production of RAW 264.7 cells by 59-67% as compared to tissue culture plastic and collagen membrane. Improvements are needed in the tear strength of electrospun chitosan membranes for clinical application. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:2890-2896, 2012.

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    Article: Electrospun hydroxyapatite-containing chitosan nanofibers crosslinked with genipin for bone tissue engineering.
    Michael E Frohbergh, Anna Katsman, Gregory P Botta, Phillip Lazarovici, Caroline L Schauer, Ulrike G K Wegst, Peter I Lelkes
    [show abstract] [hide abstract]
    ABSTRACT: Reconstruction of large bone defects remains problematic in orthopedic and craniofacial clinical practice. Autografts are limited in supply and are associated with donor site morbidity while other materials show poor integration with the host's own bone. This lack of integration is often due to the absence of periosteum, the outer layer of bone that contains osteoprogenitor cells and is critical for the growth and remodeling of bone tissue. In this study we developed a one-step platform to electrospin nanofibrous scaffolds from chitosan, which also contain hydroxyapatite nanoparticles and are crosslinked with genipin. We hypothesized that the resulting composite scaffolds represent a microenvironment that emulates the physical, mineralized structure and mechanical properties of non-weight bearing bone extracellular matrix while promoting osteoblast differentiation and maturation similar to the periosteum. The ultrastructure and physicochemical properties of the scaffolds were studied using scanning electron microscopy and spectroscopic techniques. The average fiber diameters of the electrospun scaffolds were 227 ± 154 nm as spun, and increased to 335 ± 119 nm after crosslinking with genipin. Analysis by X-ray diffraction, Fourier transformed infrared spectroscopy and energy dispersive spectroscopy confirmed the presence of characteristic features of hydroxyapatite in the composite chitosan fibers. The Young's modulus of the composite fibrous scaffolds was 142 ± 13 MPa, which is similar to that of the natural periosteum. Both pure chitosan scaffolds and composite hydroxyapatite-containing chitosan scaffolds supported adhesion, proliferation and osteogenic differentiation of mouse 7F2 osteoblast-like cells. Expression and enzymatic activity of alkaline phosphatase, an early osteogenic marker, were higher in cells cultured on the composite scaffolds as compared to pure chitosan scaffolds, reaching a significant, 2.4 fold, difference by day 14 (p < 0.05). Similarly, cells cultured on hydroxyapatite-containing scaffolds had the highest rate of osteonectin mRNA expression over 2 weeks, indicating enhanced osteoinductivity of the composite scaffolds. Our results suggest that crosslinking electrospun hydroxyapatite-containing chitosan with genipin yields bio-composite scaffolds, which combine non-weight-bearing bone mechanical properties with a periosteum-like environment. Such scaffolds will facilitate the proliferation, differentiation and maturation of osteoblast-like cells. We propose that these scaffolds might be useful for the repair and regeneration of maxillofacial defects and injuries.
    Biomaterials 09/2012; 33(36):9167-78. · 7.40 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

Keywords

barrier membrane
 
collagen membrane
 
commercially available collagen membranes
 
Crystallinity
 
electrospinning process
 
electrospun chitosan membranes
 
fibroblast cell proliferation
 
genipin-crosslinked membranes
 
graft space
 
GTR applications
 
Guided tissue regeneration
 
J Biomed Mater Res Part
 
molecular weight
 
nitric oxide
 
normal human dermal fibroblast
 
soft tissues
 
surgical technique
 
tissue culture plastic
 
Ultimate suture pullout strength
 
© 2012 Wiley Periodicals