ABSTRACT
The development of a novel, three-dimensional, macroporous artificial extracellular matrix (AECM) based on chondroitin sulfate (ChS)-chitosan (Chito) combination is reported. The composite AECM composed of ChS-Chito conjugated network was prepared by a homogenizing interpolyelectrolyte complex/covalent conjugation technique through co-crosslinked with N,N-(3-dimethylaminopropyl)-N'-ethyl carbodiimide (EDC) and N-hydroxysuccinimide (NHS). In contrast to EDC/NHS, two different reagents, calcium ion and glutaraldehyde, were used to react with ChS or Chito for the preparation of ChS-Chito composites containing crosslinked ChS or Chito network in the matrix. The stability and in vitro enzymatic degradability of the glutaraldehyde-, EDC/NHS-, and Ca2+ -crosslinked ChS-Chito composite AECMs were all investigated in this study. The results showed that crosslinking improved the stability of prepared ChS-Chito AECMs in physiological buffer solution (PBS) and provided superior protective effect against the enzymatic hydrolysis of ChS, compared with their non-crosslinked counterpart. Because ChS was a heparin-like glycosaminoglycan (GAG), the ChS-Chito composite AECMs appeared to promote binding efficiency for basic fibroblast growth factor (bFGF). The bFGF releasing from the ChS-Chito composite AECMs retained its biological activity as examined by the in vitro proliferation of human fibroblast, depending on the crosslinking mode for the preparation of these composite AECMs. Histological assay showed that the EDC/NHS-crosslinked ChS-Chito composite AECM, after incorporated with bFGF, was biodegradable and could result in a significantly enhanced vascularization effect and tissue penetration. These results suggest that the ChS-Chito composite AECMs fabricated in this study may be a promising approach for tissue-engineering application.
Subject(s)
Biocompatible Materials/isolation & purification , Chitosan/isolation & purification , Chondroitin Sulfates/isolation & purification , Extracellular Matrix , Fibroblast Growth Factor 2/administration & dosage , Animals , Biocompatible Materials/chemistry , Biodegradation, Environmental , Cell Proliferation/drug effects , Cells, Cultured , Chitosan/chemistry , Chondroitin Sulfates/chemistry , Cross-Linking Reagents , Drug Stability , Extracellular Matrix/chemistry , Fibroblasts/cytology , Fibroblasts/drug effects , Humans , Materials Testing , Microscopy, Electron, Scanning , Rats , Rats, Wistar , Tissue Engineering , X-Ray DiffractionABSTRACT
Novel chitin/PLGAs and chitin/PLA based microspheres were developed for the delivery of protein. These biodegradable microspheres were prepared by polymers blending and wet phase-inversion methods. The parameters such as selected non-solvents, temperature of water and ratio of polylactide to polyglycolide were adjusted to improve thermodynamic compatibility of individual polymer (chitin and PLGAs or chitin/PLA), which affects the hydration and degradation properties of the blend microspheres. Triphasic pattern of drug release model is observed from the release of protein from the chitin/PLGAs and chitin/PLA microspheres: the initially fast release (the first phase), the following slow release (the second phase) and the second burst release (the third phase). Formulations of the blends, which are based on the balance among the hydration rate of the chitin phase and degradation of chitin/PLA and PLGA phase, can lead to a controllable release of bovine serum albumin (BSA). In conclusion, such a chitin/PLGA 50/50 microsphere is novel and interesting, and may be used as a protein delivery system.
Subject(s)
Chitin/chemistry , Coated Materials, Biocompatible/chemistry , Delayed-Action Preparations/chemistry , Lactic Acid/chemistry , Microspheres , Pharmaceutical Vehicles/chemistry , Polyglycolic Acid/chemistry , Polymers/chemistry , Serum Albumin, Bovine/administration & dosage , Serum Albumin, Bovine/chemistry , Absorbable Implants , Adsorption , Coated Materials, Biocompatible/chemical synthesis , Coated Materials, Biocompatible/isolation & purification , Delayed-Action Preparations/chemical synthesis , Delayed-Action Preparations/isolation & purification , Drug Delivery Systems/instrumentation , Drug Delivery Systems/methods , Materials Testing , Molecular Conformation , Motion , Pharmaceutical Vehicles/chemical synthesis , Pharmaceutical Vehicles/isolation & purification , Polylactic Acid-Polyglycolic Acid Copolymer , Proteins/administration & dosage , Proteins/chemistry , Surface PropertiesABSTRACT
A novel chitin-based microsphere was developed for anti-cancer drug-delivery purpose in the present study. These biodegradable microspheres were prepared by directly blending chitin with different contents of poly(D,L-lactide-co-glycolide 50:50) (PLGA 50/50) in dimethylacetamide-lithium chloride solution, and following it by coagulating in water via wet phase inversion. Scanning electron microscopy (SEM) micrography of the blend microsphere showed that there are numerous PLGA particulates homogeneously dispersed in chitin matrix, suggesting the occurrence of obvious phase separation from the blended chitin and PLGA 50/50 phase due to their thermodynamic incompatibility. Degradation of the chitin/PLGA 50/50 blend microsphere depends on the surface erosion of chitin phase and bulk hydrolysis of PLGA phase, according to the examinations of SEM and differential scanning calorimetry studies. Weight loss of the chitin/PLGA 50/50 blend microsphere increases with the increase of chitin content in the microsphere. A two-phase drug-release model is observed from the release of chlorambucil from chitin/PLGA 50/50 blend microspheres. The initial stage of drug-release rate increases with the increased chitin content due to the hydration and surface erosion of hydrophilic chitin phase; however, the following stage of slow release is sustained for several days, mainly contributed by the bulk hydrolysis of hydrophobic PLGA phase. In conclusion, such a chitin/PLGA 50/50 blend microsphere is novel and interesting, and may be used as a special drug-delivery system.
Subject(s)
Biocompatible Materials , Chitin , Lactic Acid , Polyglycolic Acid , Polymers , Biodegradation, Environmental , Chlorambucil/administration & dosage , Drug Delivery Systems , In Vitro Techniques , Materials Testing , Microscopy, Electron, Scanning , Microspheres , Polylactic Acid-Polyglycolic Acid Copolymer , WaterABSTRACT
A novel bilayer chitosan membrane was prepared by a combined wet/dry phase inversion method and evaluated as a wound dressing. This new type of bilayer chitosan wound dressing, consisting of a dense upper layer (skin layer) and a sponge-like lower layer (sublayer), is very suitable for use as a topical delivery of silver sulfadiazine (AgSD) for the control of wound infections. Physical characterization of the bilayer wound dressing showed that it has excellent oxygen permeability, that it controls the water vapor transmission rate, and that it promotes water uptake capability. AgSD dissolved from bilayer chitosan dressings to release silver and sulfadiazine. The release of sulfadiazine from the bilayer chitosan dressing displayed a burst release on the first day and then tapered off to a much slower release. However, the release of silver from the bilayer chitosan dressing displayed a slow release profile with a sustained increase of silver concentration. The cultures of Pseudomonas aeruginosa and Staphylococcus aureus in agar plates showed effective antimicrobial activity for 1 week. In vivo antibacterial tests confirmed that this wound dressing is effective for long-term inhibition of the growth of Pseudomonas aeruginosa and Staphylococcus aureus at an infected wound site. The results in this study indicate that the AgSD-incorporated bilayer chitosan wound dressing may be a material with potential antibacterial capability for the treatment of infected wounds.
