ABSTRACT
A one-pot synthesis was used to produce chitosan derivatives with polyphenolic side chains via a regioselective phenolic coupling reaction. Under Mannich reaction conditions, treatment of chitosan with formaldehyde and methyl 2,4-dihydroxybenzoate gave N-(2,6-dihydroxy-3-methoxycarbonylphenyl)methylated chitosan in good yield (87%). Formation of a CC bond occurred regioselectively at the C(3) position of methyl 2,4-dihydroxybenzoate. Chitosan derivatives having various phenolic compounds as a side chain were easily synthesized in a similar manner. The chitosan derivatives showed good biodegradability and improved their solubility in methanol (9.8mg mL(-1)) and 2-methoxyethanol (> 10mg mL(-1)). The UV protection provided by the derivatives with phenolic benzophenone side chain was evaluated using UV spectra of polyethylene terephthalate and poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) films coated with the derivatives and the derivatives absorbed effectively in the UV-A region (<60%). Self-aggregation of the chitosan derivatives with the phenolic side chain was observed by using a fluorescent probe in aqueous solution.
Subject(s)
Chitosan/chemistry , Chitosan/chemical synthesis , Hydroxybenzoates/chemistry , Spectrophotometry, UltravioletABSTRACT
Chitosan is a biodegradable and biocompatible polymer and is useful as a non-viral vector for gene delivery. In order to deliver pDNA/chitosan complex into macrophages expressing a mannose receptor, mannose-modified chitosan (man-chitosan) was employed. The cellular uptake of pDNA/man-chitosan complexes through mannose recognition was then observed. The pDNA/man-chitosan complexes showed no significant cytotoxicity in mouse peritoneal macrophages, while pDNA/man-PEI complexes showed strong cytotoxicity. The pDNA/man-chitosan complexes showed much higher transfection efficiency than pDNA/chitosan complexes in mouse peritoneal macrophages. Observation with a confocal laser microscope suggested differences in the cellular uptake mechanism between pDNA/chitosan complexes and pDNA/man-chitosan complexes. Mannose receptor-mediated gene transfer thus enhances the transfection efficiency of pDNA/chitosan complexes.
Subject(s)
Chitosan/pharmacokinetics , Gene Transfer Techniques , Macrophages, Peritoneal , Plasmids/genetics , Transfection/methods , Animals , Cells, Cultured , Chitosan/chemistry , DNA , Genetic Vectors/chemical synthesis , Lectins, C-Type/metabolism , Lectins, C-Type/physiology , Mannose , Mannose Receptor , Mannose-Binding Lectins/metabolism , Mannose-Binding Lectins/physiology , Mice , Microscopy, Confocal , Receptors, Cell Surface/metabolism , Receptors, Cell Surface/physiologyABSTRACT
Chitosan is a useful nonviral vector for gene delivery. To make a pDNA/chitosan complex specific to hepatocytes, lactose-modified chitosan (lac-chitosan) was synthesized. When the percentage of lactose residues substituted was 8%, lac-chitosan showed excellent DNA-binding ability, good protection of DNA from nuclease, and the suppression of self-aggregation and serum-induced aggregation. Although the cellular uptake efficiency of the pDNA/lac-chitosan complex was almost the same as that of the pDNA/chitosan complex, the cell transfection efficiency of the former was greater for HepG2 cells having asialoglycoprotein receptors. Inhibitor of endocytosis such as bafilomycin A1 and nocodazole significantly reduced the transfection efficiency of the pDNA/lac-chitosan complex. Observations with a confocal laser scanning microscope indicated that the pDNA/lac-chitosan complexes traversed endocytic compartments more rapidly than the pDNA/chitosan complex. Furthermore, the pDNA/lac-chitosan complexes were delivered to the late endosome and have the advantage of delivering DNA to the perinuclear region.
Subject(s)
Biocompatible Materials , Chitosan , DNA/metabolism , Hepatocytes/metabolism , Lactose/chemistry , Animals , Biocompatible Materials/chemistry , Biocompatible Materials/metabolism , Biological Transport , Carbohydrate Conformation , Carbohydrate Sequence , Cell Line , Chitosan/chemistry , Chitosan/metabolism , Deoxyribonuclease I/metabolism , Humans , Lactose/metabolism , Macromolecular Substances , Molecular Sequence Data , Molecular Structure , TransfectionABSTRACT
UV-curable chitosans (UVCC-7-10) were synthesized using less-toxic agents. The UVCC-7 was completely cured by UV spot irradiation for 4 s. The UVCC-7 was implanted into murine subcutaneous tissues, and the response to the implantation was observed by histological examination at 7 days after implantation. In the histological findings, the implant was surrounded by thin fibrous granulating tissue with no inflammatory cellular infiltration. Fibroblasts infiltrate between the cured implant. The novel synthesized UVCC-7 showed good biocompatibility.
Subject(s)
Biocompatible Materials/chemistry , Chitosan/chemistry , Implants, Experimental , Ultraviolet Rays , Aldehydes/chemistry , Animals , Carbohydrate Sequence , Cyanoacrylates/chemistry , Cyanoacrylates/pharmacology , Epidermis/metabolism , Female , Fibroblasts/metabolism , Inflammation , Light , Magnetic Resonance Spectroscopy , Materials Testing , Mice , Models, Chemical , Molecular Sequence Data , Neutrophils/metabolism , Random Allocation , Skin/drug effects , Skin/radiation effects , Spectroscopy, Fourier Transform Infrared , Time FactorsABSTRACT
Collagen synthesis was evaluated by measuring prolyl hydroxylase (PHL) activity induced within rat granulation tissue by a polyester non-woven fabric (NWF, 1 x 1 cm, 0.6 mm in thickness) impregnated with a chitin or chitosan suspension ranging in concentration from 0.1 to 10 mg/ml. In addition, PHL activity induced in rat granulation tissue by a NWF impregnated with a phosphate buffer solution was examined as a control. The PHL activity in each group remained low until 4 days post-implantation (Day 4). However, in the 10 mg chitin group, the PHL activity increased rapidly without scatter of the data at Day 7 and remained at a plateau until Day 14. In other groups, PHL activity increased linearly until Day 14. The data varied widely at Day 7. Compared to chitosan, chitin at the higher concentration was found to induce stable collagen synthesis in the early wound healing process.
Subject(s)
Chitin/pharmacology , Chitosan/pharmacology , Collagen/biosynthesis , Wound Healing/drug effects , Animals , Cells, Cultured , Granulation Tissue/metabolism , Histological Techniques , Polyesters , Procollagen-Proline Dioxygenase/metabolism , Rats , Time FactorsABSTRACT
Effects of chitin/chitosan and their oligomers/monomers on migrations of fibroblasts (3T6) and vascular endothelial cells (human umbilical vascular endothelial cell: HUVEC) were evaluated in vitro. In direct migratory assay using the blind well chamber method, migratory activity of 3T6 was seen to be reduced by chitin, chitosan and the chitosan monomer (GlcN). Migratory activity of HUVECs was enhanced by chitin, chitosan and the chitin monomer (GlcNAc), and was reduced by chitosan oligomers and GlcN. Supernatant of 3T6 preincubated with chitin or chitosan reduced migratory activity of 3T6 cells. Supernatant of HUVECs preincubated with chitosan also reduced migratory activity of HUVECs, but supernatant preincubated with chitin had no effect on them. In a proliferation (MTT reduction) assay, none of the samples affected proliferation of either type of cell.
