Preparation of water-soluble/insoluble derivatives of hyaluronic acid by cross-linking with epichlorohydrin in aqueous NaOH/NH4OH solution

Polysaccharide nanoparticles: from fabrication to applications

The present review highlights the developments in polysaccharide nanoparticles with a particular focus on applications in biomedicine, cosmetics and food.

The tribology of cartilage: Mechanisms, experimental techniques, and relevance to translational tissue engineering

Diarthrodial joints, found at the ends of long bones, function to dissipate load and allow for effortless articulation. Essential to these functions are cartilages, soft hydrated tissues such as hyaline articular cartilage and the knee meniscus, as well as lubricating synovial fluid. Maintaining adequate lubrication protects cartilages from wear, but a decrease in this function leads to tissue degeneration and pathologies such as osteoarthritis. To study cartilage physiology, articular cartilage researchers have employed tribology, the study of lubrication and wear between two opposing surfaces, to characterize both native and engineered tissues. The biochemical components of synovial fluid allow it to function as an effective lubricant that exhibits shear-thinning behavior. Although tribological properties are recognized to be essential to native tissue function and a critical characteristic for translational tissue engineering, tribology is vastly understudied when compared to other mechanical properties such as compressive moduli. Further, tribometer configurations and testing modalities vary greatly across laboratories. This review aims to define commonly examined tribological characteristics and discuss the structure-function relationships of biochemical constituents known to contribute to tribological properties in native tissue, address the variations in experimental set-ups by suggesting a move toward standard testing practices, and describe how tissue-engineered cartilages may be augmented to improve their tribological properties.

Synergistic active targeting of dually integrin αvβ3/CD44-targeted nanoparticles to B16F10 tumors located at different sites of mouse bodies

Conventional enhanced permeation and retention (EPR) mediates the effects of many drugs, including the accumulation of nanocarriers at tumor sites, but its efficiency remains low. In this study, this limitation was overcome by developing a dual-targeting delivery system based on hyaluronan (HA, a major ligand of CD44) and tetraiodothyroacetic acid (tetrac, a specific ligand of αvβ3), which was exploited to carry docetaxel (DTX) for the synergistic active targeting to tumors. First, a tetrac-HA (TeHA) conjugate was synthesized and grafted onto the surfaces of solid lipid nanoparticles (SLNs) (TeHA-SLNs/DTX), with a high encapsulation efficiency of >91.6%. The resulting SLNs exhibited an approximately toroid morphology revealed using TEM. The cellular uptake and cytotoxicity of various formulations on CD44/αvβ3-enriched B16F10 cells were then assessed, and both results confirmed the selective uptake and high cytotoxicity of the TeHA-SLNs/DTX in a TeHA-dependent manner. In vivo imaging and vessel distribution tests revealed the efficiency of synergistic active targeting was higher than that of EPR-mediated passive targeting by the TeHA-SLNs to αvβ3-expressing tumor blood vessels and CD44-expressing tumor cells via selective targeting. Finally, in both xenograft tumor mice and in situ lung metastasis tumor mice, tumor growth was significantly inhibited by TeHA-SLNs/DTX. Therefore, TeHA-SLNs are an efficient system for the dual-targeted delivery of drugs to treat cancer in vivo.

Catch bond interaction allows cells to attach to strongly hydrated interfaces

Hyaluronans are a class of glycosaminoglycans that are widespread in the mammalian body and serve a variety of functions. Their most striking characteristic is their pronounced hydrophilicity and their capability to inhibit unspecific adhesion when present at interfaces. Catch-bond interactions are used by the CD44 receptor to interact with this inert material and to roll on the surfaces coated with hyaluronans. In this minireview, the authors discuss the general properties of hyaluronans and the occurrence and relevance of the CD44 catch-bond interaction in the context of hematopoiesis, cancer development, and leukemia.

Cellulose Derivative−Hyaluronic Acid-Based Microporous Hydrogels Cross-Linked through Divinyl Sulfone (DVS) To Modulate Equilibrium Sorption Capacity and Network Stability

The aim of this work is to obtain a chemically cross-linked hydrogel from hyaluronic acid and cellulose derivatives that exhibits sensitivity to variation of the composition of the external absorbing medium and an equilibrium sorption capacity higher than a common hyaluronic acid-based hydrogel, in view of its potential use in prevention of postsurgical soft tissue adhesion. This has been achieved by chemical stabilization of hyaluronic acid (HA) and cellulose derivatives, hydroxyethylcellulose (HEC) and carboxymethylcellulose (CMCNa) through the difunctional cross-linker divinyl sulfone. Significant increase in sorption capacity, both in water and in water solutions at different ionic strength, has been observed for these samples in comparison with hydrogels obtained through chemical stabilization of hyaluronic acid. Moreover, different dehydration procedures adopted for the xerogel synthesis have been used, which resulted in a modulation of the equilibrium sorption capacity. Hyaluronic acid stability has been confirmed by means of NMR analysis.

Molecular characterization of two host-guest associating hyaluronan derivatives

Molecular characteristics were determined of two high-molecular-weight water-soluble hyaluronan derivatives, namely beta-cyclodextrin (HA-beta-CD) and N-acylurea (EDC-HA). The weight-average molecular weight (M(w)) of HA-beta-CD and of EDC-HA, determined with a multi-angle light scattering detector connected on-line to a size exclusion chromatographic system, was respectively 185.3 and 86.8 kDa. However the M(w) value determined for the equimolar mixture of the two HA derivatives equaled 556.0 kDa. Similarly, the gyration radius of the above equimolar mixture, Rg = 80.6 nm, was significantly greater than the values found for the single HA derivative, i.e. 40.2 nm for HA-beta-CD and 23.8 nm for EDC-HA. These data indicate that the two kinds of substituents, bound to the polymeric chains, form host-guest/inclusion complexes resulting in polymacromolecular associates/aggregates.