Polysaccharide chitosan

Further examples of enzymatically degradable drug formulation wrappings are capsule shells made of the polysaccharides chitosan [65,66] or cross-linked dextran [67]. 

Dunlap et al., 1997 Godbey et al., 1999), dendrimers (Chen et al., 2000) and cationic polysaccharide, chitosan (Erbacher et al., 1998). It was suggested that DNA condensation is induced by multivalent cations where approximately 90% of its charge is neutralized, and that divalent cations have insufficient potency to attain the charge neutralization on such a level (Wilson and Bloomfield, 1979 Bloomfield, 1991, 1996 He etal., 2000 Stevens, 2001). 

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... 

Vachoud L, Chen T, Payne GF et al (2001) Peroxidase catalyzed grafting of gallate esters onto the polysaccharide chitosan. Enzyme Microb Technol 29 380-385... 

One phase contains the polysaccharide chitosan (CS) and a diblock copolymer of ethylene oxide and the polyanion sodium tripolyphosphate (TPP). It was stated that the size (200-1000 nm) and zeta potential (between + 20 mV and + 60 mV) of nanoparticles can be conventionally modulated by varying the ratio of CS/PEO to PPO. Furthermore, using BSA as a model protein, it was shown that these new nanoparticles have a high protein loading capacity (entrapment efficiency up to 80 % of the protein) and provide a continuous release of the entrapped protein for up to 1 week [56]. 

Difficulties are encountered in carrying out controlled, partial hydrolyses of chitin because of the need to use concentrated acids to dissolve the polysaccharide. Chitosan (de-A -acetylated chitin), however, is water-soluble and amenable to controlled hydrolysis. Using ion-exchange chromatography, a chitosan hydrolyzate has been fractionated to give at least five saccharides, the first two of these having been characterized as 2-amino-2-deoxy-D-glucose hydrochloride and chitobiose hydrochloride. > Fractionation of chitosan hydrolyzates on oarbon-Celite was only successful after selective A-acetylation and then it yielded the first seven members of a series of chitin saccharides, the properties of which clearly indicate the... 

We demonstrated that a naturally derived polysaccharide, chitosan, is capable of forming composite nanoparticles with silica. For encapsulated particles, we used silicification and biosilicification to encapsulate curcumin and analyzed the physicochemical properties of curcumin nanoparticles. It proved that encapsulated curcumin nanoparticles enhanced stability toward ultraviolet (UV) irradiation, antioxidation and antitumor activity, enhanced/added function, solubility, bioactivities/ bioavailability, and control release and overcame the immunobarrier. We present an in vitro study that examined the cytotoxicity of amorphous and composite silica nanoparticles to different cell lines. These bioactives include curcumin mdAntrodia cinnamomea. It is hoped that by examining the response of multiple cell lines to silica nanoparticles more basic information regarding the cytotoxicity as well as potential functions of silica in future oncological applications could become available. 

Wu L-Q et al (2002) Voltage-dependent assembly of the polysaccharide chitosan onto an electrode surface. Langmuir 18(22) 8620-8625... 

The best decomposition conditions for the fungal mycelia was treatment with 11 M NaOH at 45°C for 13 h and then treatment with 0.35 M acetic acid at 95°C for 5 h [36]. Moreover the Termamyl treatment is obviously highly efficient at separating the chitosan from the glucan and offers possibilities for the isolation of purified chitosan [4, 36]. Based on these observations, it has been proved that these two polysaccharides, chitosan and glucan, are linked by a-(l )-glycosidic bond [4, 8, 37]. The IR spectra of alkaline-soluble and alkaline-insoluble glucan, and chitosan are shown in Fig. 8. 

Most of the early studies on chitosan system processing dealt with the purification of chitosan itself to remove impurities such as proteins, pyrogens, toxic metals, and low molecular weight polysaccharides. Chitosan purification was pursued primarily to allow its use in parenteral pharmaceutical products and/or implantable biomedical devices. Parallel to chitosan purification, a great deal of effort was directed toward chitosan processing into ... 

In another study, dendritic amidoamine side chains of different generations were covalently attached to the polysaccharide chitosan in an attempt to combine the biological activity of chitosan in gene delivery. 

Polysaccharides are among the most versatile polymers because of their vast structural diversity and nontoxicity. Among polysaccharides, chitosan, alginate, pectin, hylauronic acid, and dextran have received much attention. Protein-based polymers such as albumin, casein, and gelatin have also been investigated for oral peptide delivery. 

Boddohi, S., KUlingsworth, C.E. and Kipper, M.J. (2008) Polyelectrolyte multilayer assembly as a function of pH and ionic strength using the polysaccharides chitosan and heparin. Biomacromolecules, 9, 2021-2028. 

The treatment of a PP film surface to improve its dyeing behaviour was studied. A plasma treatment was carried out to try to create oxidising groups on this surface, so that it could be then easier to apply a specific polysaccharide chitosan which is reported to be much more reactive than PP and easy to dye. A study about the various parameters of the plasma instrument was necessary to find the optimal treatment. The possible formed oxidising groups were emphasised by FTIR and ATR analyses. Chitosan was applied after the plasma treatment and the dyeing result which was then observed was quite encouraging in certain conditions. 8 refs. 

Chitosan, a copolymer of glucosamine and A -acetylglucosamine units linked by one to four glucosidic bonds, is commerdally obtained from chitin, which is one of the most abundant natural amino polysaccharide. Chitosan could be converted by using proper reagents into a number of 0-alkyl and 0-acyl derivatives. Chitosan also behaves as a moderately basic cationic polyelectrolyte, which readily forms salts with acids. In addition, the presence of the primary amino group in chitosan offers further possibilities for modifications such as Af-acylation, Af-alkylation, and Af-alkyUdenation. Therefore, numerous varieties of chitosan derivatives can be synthesized from this nature s abundant polymer. 

The subject of this review is complexes of DNA with synthetic cationic polymers and their application in gene delivery [1 ]. Linear, graft, and comb polymers (flexible, i.e., non-conjugated polymers) are its focus. This review is not meant to be exhaustive but to give representative examples of the various types (chemical structure, architecture, etc.) of synthetic cationic polymers or polyampholytes that can be used to complex DNA. Other interesting synthetic architectures such dendrimers [5-7], dendritic structures/polymers [8, 9], and hyperbranched polymers [10-12] will not be addressed because there are numerous recent valuable reports about their complexes with DNA. Natural or partially synthetic polymers such as polysaccharides (chitosan [13], dextran [14,15], etc.) and peptides [16, 17] for DNA complexation or delivery will not be mentioned. 

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