Ability to use the diazo dye, C.I. Acid Black 1 as a nitrogen source by the marine cyanobacterium Oscillatoria curviceps BDU92191

Ten different strains of marine cyanobacteria were tested for their ability to decolourise and degrade a recalcitrant diazo dye, C.I. Acid Black 1. Of them, Oscillatoria curvicepsBDU92191 was able to grow up to a tested concentration of 500 mG L⁻¹. The organism degraded 84% of the dye at 100 mG L⁻¹ in 8 days in a medium free of combined nitrogen. The dye degrading ability is attributed to the activities of the enzymes: laccase, polyphenol oxidase and azoreductase. The absence of the doublet amine peak in addition to the overall reduction of absorption in the IR spectra confirmed the mineralisation of the tested azo dye. The nitrogen assimilating enzyme studies along with nitrogenase assay strongly suggested the ability of the non-heterocystous, filamentous marine cyanobacterium, O. curvicepsBDU92191 to use C.I. Acid Black 1 as a nitrogen source in an oligotrophic environment.     

Prospective of guar gum and its derivatives as controlled drug delivery systems

Guar gum is a non-ionic polysaccharide that is found abundantly in nature and has many properties desirable for drug delivery applications. However, due to its high swelling characteristics in aqueous solution, the use of guar gum as delivery carriers is limited. Guar gum can be modified by derivatization, grafting and network formation to improve its property profile for a wide spectrum of biomedical applications. This review article is aimed at focusing the recent efforts and developments on guar gum and its derivatives as colon-specific, antihypertensive, protein and transdermal drug delivery systems. Based on the literatures reviewed, it is concluded that guar gum and its derivatives in the various forms such as coatings, matrix tablets, hydrogels and nano/microparticles can be exploited as potential carriers for targeted drug delivery.     

Circulating NOD1 Activators and Hematopoietic NOD1 Contribute to Metabolic Inflammation and Insulin Resistance

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Biodegradable and biocompatible multi-arm star amphiphilic block copolymer as a carrier for hydrophobic drug delivery

Multi-arm star amphiphilic block copolymers (SABCs) with approximately 32 arms were synthesized and characterized for drug delivery applications. A hyperbranched polyester, boltorn^® H40 (H40), was used as the macroinitiator for the ring-opening polymerization of ?-caprolactone (?-CL). The resulting multi-arm H40-poly(?-caprolactone) (H40-PCL-OH) was further reacted with carboxyl terminated methoxy poly(ethylene glycol) (MPEG-COOH) to form H40-PCL-b-MPEG copolymers. The resulting SABCs were characterized by ¹H NMR spectroscopy and gel permeation chromatography (GPC). The critical aggregation concentration (CAC) of H40-PCL-b-MPEG was 3.8 mg/L as determined by fluorescence spectrophotometry. Below the CAC, stable unimolecular micelles were formed with an average diameter of 18 nm as measured by TEM. Above the CAC, unimolecular micelles exhibited agglomeration with an average diameter of 98 nm. The hydrodynamic diameter of these agglomerates was found to be 122 nm, as measured by dynamic light scattering (DLS). The drug loading efficacy of the H40-PCL-b-MPEG micelles was 26 wt%. Drug release study showed an initial burst followed by a sustained release of the entrapped hydrophobic model drug, 5-fluorouracil, over a period of 9–140 h. These results indicate that the H40-PCL-b-MPEG micelles have great potential as hydrophobic drug delivery carriers.     

Treatment of wool fibres with subtilisin and subtilisin-PEG

In this work the diffusion of serine proteases into wool fabrics and yarns was studied. The proteases used were free subtilisin and subtilisin-PEG (the same enzyme that was covalently cross linked to polyethylene glycol). It is shown that the adsorption and diffusion is facilitated by the pre-treatment performed, being the alkaline surfactant washing and bleaching the most effective in what concerns enzyme adsorption. Furthermore, this study suggests that the diffusion of proteases into wool is dependent on the size of the protease. The free enzyme penetrates into wool fibre cortex while the modified bigger enzyme is retained only at the surface, in the cuticle layer. Also, proteins without proteolytic activity do not adsorb considerably on wool due to its hydrophobic nature, therefore the diffusion is facilitated by hydrolytic action.

These results have important practical implications for the establishment of enzymatic wool finishing processes, since they allow for control of the enzyme hydrolysis, which was the major drawback of this environmental friendly option to the conventional chlorine treatments.     

Novel chitin and chitosan nanofibers in biomedical applications

Chitin and its deacetylated derivative, chitosan, are non-toxic, antibacterial, biodegradable and biocompatible biopolymers. Due to these properties, they are widely used for biomedical applications such as tissue engineering scaffolds, drug delivery, wound dressings, separation membranes and antibacterial coatings, stent coatings, and sensors. In the recent years, electrospinning has been found to be a novel technique to produce chitin and chitosan nanofibers. These nanofibers find novel applications in biomedical fields due to their high surface area and porosity. This article reviews the recent reports on the preparation, properties and biomedical applications of chitin and chitosan based nanofibers in detail.     

Chitosan-graft-β-cyclodextrin scaffolds with controlled drug release capability for tissue engineering applications

Biodegradable scaffolds composed of chitosan-g-β-cyclodextrin (chit-g-β-CD) were prepared by freeze-drying method as synthetic extracellular matrices to fill the gap during the healing process. Due to the presence of β-CD, these scaffolds can be used as a matrix for drug loading and controlled release. The morphology, swelling and drug release properties of the scaffolds were found to be dependent on the extent of cross-linking density in the scaffolds. The drug dissolution profile showed that chit-g-β-CD scaffolds provided a slower release of the entrapped ketoprofen than chitosan scaffold. The MTT assay showed that there is no obvious cytotoxicity of chit-g-β-CD scaffolds cross-linked with 0.01 M of glutaraldehyde against the fibroblasts (L929) cells. These results suggest that chit-g-β-CD scaffolds may become a potential biodegradable active filling material with controlled drug release capability, which provide a healthy environment and enhance the surrounding tissue regeneration.     

Biomaterials based on chitin and chitosan in wound dressing applications

Wound dressing is one of the most promising medical applications for chitin and chitosan. The adhesive nature of chitin and chitosan, together with their antifungal and bactericidal character, and their permeability to oxygen, is a very important property associated with the treatment of wounds and burns. Different derivatives of chitin and chitosan have been prepared for this purpose in the form of hydrogels, fibers, membranes, scaffolds and sponges. The purpose of this review is to take a closer look on the wound dressing applications of biomaterials based on chitin, chitosan and their derivatives in various forms in detail.     

PI 3-kinase p110beta: a new target for antithrombotic therapy

Platelet activation at sites of vascular injury is essential for the arrest of bleeding; however, excessive platelet accumulation at regions of atherosclerotic plaque rupture can result in the development of arterial thrombi, precipitating diseases such as acute myocardial infarction and ischemic stroke. Rheological disturbances (high shear stress) have an important role in promoting arterial thrombosis by enhancing the adhesive and signaling function of platelet integrin alpha(IIb)beta(3) (GPIIb-IIIa). In this study we have defined a key role for the Type Ia phosphoinositide 3-kinase (PI3K) p110beta isoform in regulating the formation and stability of integrin alpha(IIb)beta(3) adhesion bonds, necessary for shear activation of platelets. Isoform-selective PI3K p110beta inhibitors have been developed which prevent formation of stable integrin alpha(IIb)beta(3) adhesion contacts, leading to defective platelet thrombus formation. In vivo, these inhibitors eliminate occlusive thrombus formation but do not prolong bleeding time. These studies define PI3K p110beta as an important new target for antithrombotic therapy.