Polysaccharide scaffold

CHITOSAN AS POLYSACCHARIDE SCAFFOLD TOWARD HYPERBRANCHED SIALOSIDES... 

Kumbar, S.G., et al., 2011. Novel mechanically competent polysaccharide scaffolds for bone tissue engineering. Biomedical Materials 6, 065005. 

Abstract Synthetic polymers and biopolymers are extensively used within the field of tissue engineering. Some common examples of these materials include polylactic acid, polyglycolic acid, collagen, elastin, and various forms of polysaccharides. In terms of application, these materials are primarily used in the construction of scaffolds that aid in the local delivery of cells and growth factors, and in many cases fulfill a mechanical role in supporting physiologic loads that would otherwise be supported by a healthy tissue. In this review we will examine the development of scaffolds derived from biopolymers and their use with various cell types in the context of tissue engineering the nucleus pulposus of the intervertebral disc. 

Abstract Carbohydrates have been investigated and developed as delivery vehicles for shuttling nucleic acids into cells. In this review, we present the state of the art in carbohydrate-based polymeric vehicles for nucleic acid delivery, with the focus on the recent successes in preclinical models, both in vitro and in vivo. Polymeric scaffolds based on the natural polysaccharides chitosan, hyaluronan, pullulan, dextran, and schizophyllan each have unique properties and potential for modification, and these results are discussed with the focus on facile synthetic routes and favorable performance in biological systems. Many of these carbohydrates have been used to develop alternative types of biomaterials for nucleic acid delivery to typical polyplexes, and these novel materials are discussed. Also presented are polymeric vehicles that incorporate copolymerized carbohydrates into polymer backbones based on polyethylenimine and polylysine and their effect on transfection and biocompatibility. Unique scaffolds, such as clusters and polymers based on cyclodextrin (CD), are also discussed, with the focus on recent successes in vivo and in the clinic. These results are presented with the emphasis on the role of carbohydrate and charge on transfection. Use of carbohydrates as molecular recognition ligands for cell-type specific dehvery is also briefly... 

Natural Polysaccharides as Nucleic Acid Delivery Scaffolds.134... 

Scaffolds can be made from natural or synthetic materials. Such materials fall under the category of biomaterials. A biomaterial can be considered a single element or compound, which is a composite or mixture of elements, and is synthesized or derived to be used in the body to preserve, restore, or augment the structure or function of the body. Examples of natural materials for scaffold construction are extracellular matrix, collagen, fibrin, and polysaccharides (e.g., chitosan or glycosaminoglycans). Natural materials, unless they are obtained from the patient who receives the neo-organ implant, will cause an immunogenic response. This is not always the case with synthetic materials. 

There is increasing interest in the development of foldamers or polymeric structures that can adopt organised secondary structures like those of proteins, nucleic acids and some polysaccharides [42]. Sugar amino acid-based foldamer research has so far been primarily concerned with synthesis of polymers with secondary sfructural features. Such foldamers may find application as scaffolds for peptidomimetic development if they adopt turn, helical and strand sfructures observed for peptides or if derivatives can act as ligands for peptide receptors ... 

For the construction of artificial metalloproteins, protein scaffolds should be stable, both over a wide range of pH and organic solvents, and at high temperature. In addition, crystal structures of protein scaffolds are crucial for their rational design. The proteins reported so far for the conjugation of metal complexes are listed in Fig. 1. Lysozyme (Ly) is a small enzyme that catalyzes hydrolysis of polysaccharides and is well known as a protein easily crystallized (Fig. la). Thus, lysozyme has been used as a model protein for studying interactions between metal compounds and proteins [13,14,42,43]. For example, [Ru(p-cymene)] L [Mn(CO)3l, and cisplatin are regiospecificaUy coordinated to the N = atom of His 15 in hen egg white lysozyme [14, 42, 43]. Serum albumin (SA) is one of the most abundant blood proteins, and exhibits an ability to accommodate a variety of hydrophobic compounds such as fatty acids, bilirubin, and hemin (Fig. lb). Thus, SA has been used to bind several metal complexes such as Rh(acac)(CO)2, Fe- and Mn-corroles, and Cu-phthalocyanine and the composites applied to asymmetric catalytic reactions [20, 28-30]. 

---