Genis Ehf

Reykjavík, Iceland

Genis Ehf

Reykjavík, Iceland
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Lieder R.,Reykjavik University | Lieder R.,Innovation Center Iceland | Darai M.,Reykjavik University | Darai M.,Innovation Center Iceland | And 10 more authors.
Journal of Biomedical Materials Research - Part A | Year: 2012

Clinical treatment of orthopaedic tissue injuries often involves the use of titanium and titanium alloys with considerable research focusing on the surface modification of these materials. Chitosan, the partly deacetylated form of chitin, is one of the materials under investigation as surface coating for orthopaedic implants in order to improve osteointegration and cellular attachment. In this study, we determined the effects of the degree of deacetylation (DD) of chitosan membranes on attachment, proliferation and osteogenic differentiation of MC3T3-E1 mouse preosteoblasts. Chitosan membranes were coated with fibronectin to promote biocompatibility and cellular attachment. Membranes were characterized in terms of wettability and surface topography using water contact angle measurements and atomic force microscopy. The results in this study indicate that the surface roughness and fibronectin adsorption increase with increased DD. A higher DD also facilitates attachment and proliferation of cells, but no induction of spontaneous osteogenic differentiation was observed. Lower DD chitosan membranes were successfully prepared to sustain attachment and were modified by crosslinking with glutaraldehyde to promote long-term studies. The chitosan membranes used in this study are suitable as a potential coating for titanium implants. © 2012 Wiley Periodicals, Inc.

Lieder R.,Reykjavik University | Thormodsson F.,University of Iceland | Ng C.-H.,Genis Ehf | Einarsson J.M.,Genis Ehf | And 4 more authors.
International Journal of Biological Macromolecules | Year: 2012

Chitooligosaccharides are of interest as potential drugs due to their bioactivity and water solubility. We compared the effect of acetylated and deacetylated chitooligomers (Hexamers) on short-term expansion (7 days) and osteogenic differentiation of bone-marrow derived, human mesenchymal stem cells in terms of gene expression, cytokine secretion and quality of osteogenic differentiation. We show that chitooligomers affect hMSC gene expression and cytokine secretion, but not mineralization. The effect of chitooligomers was shown to be dependent on the acetylation degree, with significantly stronger effects when cells are stimulated with chitin-derived Hexamers (N-Acetyl Chitohexaose) than with Chitosan Hexamers (Chitohexaose). © 2012 Elsevier B.V.

Lieder R.,Reykjavik University | Gaware V.S.,University of Iceland | Thormodsson F.,University of Iceland | Einarsson J.M.,Genis Ehf | And 6 more authors.
Acta Biomaterialia | Year: 2013

Biomaterials research has been expanding over the last decade, in part to provide improved medical devices for the treatment of orthopedic tissue injuries. In the quest to provide the best performance combined with low cost for medical implants, an increasing number of non-chemists have entered the field of biomaterials research without the profound knowledge of chemistry needed to understand the complex interaction mechanisms and characteristics of natural substances. Likewise, non-biologists often lack understanding when it comes to the presence of the contaminating biota frequently found in natural substances. This lack of knowledge by researchers in the field, combined with sensitive in vitro cell-based assays, can lead to inaccurate evaluation of biomaterials. Hence, there should be both an active effort to assemble multi-disciplinary teams and a genuine concern for the possible effects of contamination on in vitro assays. Here, we show that the presence of bacterial endotoxins in chitosan derivatives can result in false-positive results, profoundly altering product performance in in vitro assays. False-positive results through uncritical use of natural substances in vitro can be avoided by proper endotoxin testing and careful evaluation of cytokine secretion patterns. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Einarsson J.M.,Genis hf | Bahrke S.,University of Potsdam | Sigurdsson B.T.,University of Iceland | Ng C.-H.,Genis hf | And 7 more authors.
Biochemical and Biophysical Research Communications | Year: 2013

Recent evidences indicating that cellular kinase signaling cascades are triggered by oligomers of N-acetylglucosamine (ChOS) and that condrocytes of human osteoarthritic cartilage secrete the inflammation associated chitolectin YKL-40, prompted us to study the binding affinity of partially acetylated ChOS to YKL-40 and their effect on primary chondrocytes in culture. Extensive chitinase digestion and filtration of partially deacetylated chitin yielded a mixture of ChOS (Oligomin™) and further ultrafiltration produced T-ChOS™, with substantially smaller fraction of the smallest sugars. YKL-40 binding affinity was determined for the different sized homologues, revealing micromolar affinities of the larger homologues to YKL-40. The response of osteoarthritic chondrocytes to Oligomin™ and T-ChOS™ was determined, revealing 2- to 3-fold increases in cell number. About 500. μg/ml was needed for Oligomin™ and around five times lower concentration for T-ChOS™, higher concentrations abolished this effect for both products. Addition of chitotriose inhibited cellular responses mediated by larger oligosaccharides. These results, and the fact that the partially acetylated T-ChOS™ homologues should resist hydrolysis, point towards a new therapeutic concept for treating inflammatory joint diseases. © 2013 Elsevier Inc.

Genis Hf. | Date: 2015-06-11

The present invention relates to compositions comprising biologically active chitinous oligomers and their endotoxin purified and partially deacetylated chitin polymer precursors, and their use in pharmaceutical compositions, biomaterial compositions, medical devices, and processes to produce the said oligomers. More specifically the present invention relates to novel compositions and processes to produce such compositions. The compositions include therapeutic hetero polymer and hetero oligomer compositions compricing specific sequences of N-acetyl glucosamine and glucosamine, developed to optimize chemical and structural features which are important for the therapeutic activity of these compositions. In addition, the present invention provides methods to use degree of deacetylation of a partially deacetylated chitin polymer in order to modulate physical and biological parameters in a calcium phosphate composite for bone implant applications.

A composition kit for bone healing medical treatment, comprising partially deacetylated chitin (PDC) with a degree of deacetylation in the range of 40-75%. The composition is provided as a kit with a solids fraction and a liquid fraction, provided in separate vials and to be mixed just prior to use. The weight:weight ratio of the solids to liquid fraction is in the range from 1:1.2 to 1:6, and preferably from 1:1.5 to 1:4. The solids fraction comprises the PDC material and calcium phosphate and the liquid fraction comprises water and an acid.

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