Chitin and Chitosan World News in May 2009

Besides the event in the first half of the year 2009 - the European Conference on Chitin and Chitosan in Venice - many different articles in chitin and chitosan research were published in scientific journals. Here your can find an overview of some them...

In May 105 chitin and chitosan articles were published.

In the adjoinng table you can see the main areas of interest of the publications.

In the issues 13, 14 and 15 of the Biomaterials Journal six articles about chitosan were published. Four articles are about tissue engineering and chitosan, two other talk about the application of chitosan as carrier.

Tan et al discusses about: Injectable in situ forming biodegradable chitosan–hyaluronic acid based hydrogels for cartilage tissue engineering: Injectable, biodegradable scaffolds are important biomaterials for tissue engineering and drug delivery. Here, we report a new class of biocompatible and biodegradable composite hydrogels derived from water-soluble chitosan and oxidized hyaluronic acid upon mixing, without the addition of a chemical crosslinking agent. ... The results demonstrated that the composite hydrogel supported cell survival and the cells retained chondrocytic morphology. These characteristics provide a potential opportunity to use the injectable, composite hydrogels in tissue engineering applications.

Jin et al. wrote about: Injectable chitosan-based hydrogels for cartilage tissue engineering. Water-soluble chitosan derivatives, chitosan-graft-glycolic acid (GA) and phloretic acid (PA) (CH-GA/PA), were designed to obtain biodegradable injectable chitosan hydrogels through enzymatic crosslinking with horseradish peroxidase (HRP) and H2O2. CH-GA/PA polymers were synthesized by first conjugating glycolic acid (GA) to native chitosan to render the polymer soluble at pH 7.4, and subsequent modification with phloretic acid (PA). Short gelation times, as recorded by the vial tilting method, were observed for the CH-GA43/PA10 hydrogels using HRP and H2O2. It was shown that these hydrogels can be readily degraded by lysozyme. In vitro culturing of chondrocytes in CH-GA43/PA10 hydrogels revealed that after 2 weeks the cells were viable and retained their round shape. These features indicate that CH-GA/PA hydrogels are promising as an artificial extracellular matrix for cartilage tissue engineering.

Duceppe et al. wrote about: Factors influencing the transfection efficiency of ultra low molecular weight chitosan/hyaluronic acid nanoparticles. They describe nanoparticles made of ultra low molecular weight chitosan (ULMWCh)/hyaluronic acid (HA) as novel potential carriers for gene delivery. ULMWCh (<10 kDa) presents more advantageous characteristics over the higher molecular weight chitosan for clinical applications, namely increased solubility at physiological pH and improved DNA release. ... The high transfection efficiency of non-viral gene delivery system could be attributed to the synergic effect of ULMWCh and low charge density of the HA chain for easy release of DNA which makes the system suitable for targeted gene delivery.
Jennifer L.Moreau is investigation if chitosan can be used to enforce calcium-phospahte cements in her article Mesenchymal stem cell proliferation and differentiation on an injectable calcium phosphate – Chitosan composite scaffold.

Zhang-Qi Feng is referring about the effect of nanofibrous galactosylated chitosan scaffolds on the formation of rat primary hepatocyte aggregates and the maintenance of liver function: Liver tissue engineering requires a perfect extracellular matrix (ECM) for primary hepatocytes culture to maintain high level of liver-specific functions and desirable mechanical stability. The aim of this study was to develop a novel natural nanofibrous scaffold with surface-galactose ligands to enhance the bioactivity and mechanical stability of primary hepatocytes in culture. The nanofibrous scaffold was fabricated by electrospinning a natural material, galactosylated chitosan (GC). ... such GC-based nanofibrous scaffolds could be useful for various applications such as bioartificial liver-assist devices and tissue engineering for liver regeneration as primary hepatocytes culture substrates.

So Jin Lee et al. show the possibility to use chitosan as a carrier for photosensitizers that might be useful in cancer therapies. If you want to learn more about the positive results, you can read the article: Tumor specificity and therapeutic efficacy of photosensitizer-encapsulated glycol chitosan-based nanoparticles in tumor-bearing mice.

Jing Zhang et al are focussing their research in ophtalmology. In the International Journal of Pharmeceutics they published Topical use of Coenzyme Q10-loaded liposomes coated with trimethyl chitosan: Tolerance, precorneal retention and anti-cataract effect. They show that trimethylchitosan can be applied topical to the ocluar.

The controlled release by using chitosan is focus of research of the british researchers Learoyd et al. Here you can read about the project: Sustained delivery by leucine-modified chitosan spray-dried respirable powders.

Christiane Heinemann from the Max Bergmann Centre in Dresden, Germany posted her article In Vitro Evaluation of Textile Chitosan Scaffolds for Tissue Engineering using Human Bone Marrow Stromal Cells in Biomarcomolecules.

Source: http://www.sciencedirect.com/