Hyaluronan (HA)-inspired glycopolymers as molecular tools for studying HA functions.

Hyaluronic acid (HA), the only non-sulphated glycosaminoglycan, serves numerous structural and biological functions in the human body, from providing viscoelasticity in tissues to creating hydrated environments for cell migration and proliferation. HA is also involved in the regulation of morphogenesis, inflammation and tumorigenesis through interactions with specific HA-binding proteins. Whilst the physicochemical and biological properties of HA have been widely studied for decades, the exact mechanisms by which HA exerts its multiple functions are not completely understood.

Nano-to-meso structure of cellulose nanocrystal phases in ethylene-glycol-water mixtures.

The self-assembly and phase behavior of cellulose nanocrystals (CNCs) in binary liquid mixtures of ethylene-glycol (EG):water was investigated. Our findings indicate that a small fraction of water delays the onset of colloidal jammed states previously reported in water-free organic solvents. Here the full phase diagram of CNCs evolves, including the chiral nematic phase (N*), characterized by long-range orientational order and non-isotropic macroscopic properties.

Effect of the C-terminal amino acid of the peptide on the structure and mechanical properties of alginate-peptide hydrogels across length-scales.

Alginate is a natural anionic polysaccharide that exhibits excellent biocompatibility and biodegradability. Alginate hydrogels have many different applications in the field of regenerative medicine especially when peptides are conjugated to the alginate backbone. Here, we systematically investigate the effect of six arginine-glycine-aspartic acid (RGD)-containing peptides, G6KRGDY/S, A6KRGDY/S and V6KRGDY/S, on the macroscopic and microscopic physical properties and spatial organization of alginate-peptides hydrogels.

Short and Soft: Multidomain Organization, Tunable Dynamics, and Jamming in Suspensions of Grafted Colloidal Cylinders with a Small Aspect Ratio.

The yet virtually unexplored class of soft colloidal rods with a small aspect ratio is investigated and shown to exhibit a very rich phase and dynamic behavior, spanning from liquid to nearly melt state. Instead of the nematic order, these short and soft nanocylinders alter their organization with increasing concentration from isotropic liquid with random orientation to small domains with preferred local orientation and eventually a multidomain arrangement with a local orientational order. The latter gives rise to a kinetically suppressed state akin to structural glass with detectable terminal relaxation, which, on further increasing concentration, reveals features of hexagonally packed order as in ordered block copolymers.

Physico-chemical characteristics of the sulfated polysaccharides of the red microalgae Dixoniella grisea and Porphyridium aerugineum.

The sulfated polysaccharides of red microalgae have attracted increasing attention in recent years due to their unique rheological and bioactivities. Todate, most studies are devoted to the polysaccharide of the marine species Porphyridium sp., with limited information about that of the brackish water- Dixoniella grisea and the freshwater- Porphyridium aerugineum.

Tuning the mechanical properties of alginate-peptide hydrogels.

Alginate, a polysaccharide that gels in the presence of divalent ions, has been used in the field of regenerative medicine to facilitate cell growth in impaired tissues by providing an artificial bio-surrounding similar to the natural extra cellular matrix (ECM). Here, we present a systematic investigation of the effect of three arginine-glycine-aspartic acid (RGD)-containing peptides, G6KRGDY, A6KRGDY and V6KRGDY, on the physical properties of alginate-peptide hydrogels. Rheology measurements showed that the storage modulus of the alginate-A6KRGDY and alginate-V6KRGDY gels is an order of magnitude higher than that of the alginate-G6KRGDY gel.

RGD-presenting peptides in amphiphilic and anionic β-sheet hydrogels for improved interactions with cells.

The interest in developing functional biomaterials based on designed peptides has been increasing in recent years. The amphiphilic and anionic β-sheet peptide Pro-Asp-(Phe-Asp)-Pro, denoted FD, was previously shown to assemble into a hydrogel that induces adsorption of calcium and phosphate ions and formation of the bone mineral hydroxyapatite. In this study the integrin binding peptide, Arg-Gly-Asp (RGD), was incorporated into the hydrogel to assess its influence on an osteoblast culture.

Enzymatic activation of cell-penetrating peptides in self-assembled nanostructures triggers fibre-to-micelle morphological transition.

We report here a proof-of-concept design of a multi-domain cell-penetrating peptide amphiphile (CPPA) which can self-assemble into fibrous nanostructures and transform into spherical micelles upon enzymatic degradation by matrix metalloproteinase-2 (MMP-2) up-regulated in the tumour environment. Concomitant with this morphological transition, the cell-penetrating peptide (CPP), which was previously buried inside the CPPA fibers, could be presented on the surface of the CPPA micelles, enhancing their cell-penetrating ability. These multifunctional and enzyme-responsive CPP nanostructures hold potential as nanocarriers for tumour-targeted intracellular delivery of therapeutic and diagnostic agents.

The sulfated polysaccharide from a marine red microalga as a platform for the incorporation of zinc ions.

The cell-wall sulfated polysaccharide of the marine red microalga Porphyridium sp. is a high molecular weight biopolymer that has potential for use as a platform for metal complexation for various applications. This paper describes the structural and rheological characterization and antibacterial activity of the polysaccharide in combination with Zn(2+) (Zn-PS).

The effect of covalently linked RGD peptide on the conformation of polysaccharides in aqueous solutions.

Covalently modified polysaccharides are routinely used in tissue engineering due to their tailored biofunctionality. Understanding the effect of single-chain level modification on the solution conformation of the single chain, and more importantly on the self-assembly and aggregation of the ensemble of chains is expected to improve our ability to control network topology and the properties of the resulting gels. Attaching an RGD peptide to a polysaccharide backbone is a common procedure used to promote cell adhesion in hydrogel scaffolds.