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de Fávere VT, Hinze WL. Evaluation of the potential of chitosan hydrogels to extract polar organic species from nonpolar organic solvents: Application to the extraction of aminopyridines from hexane. J Colloid Interface Sci 2009; 330:38-44. [DOI: 10.1016/j.jcis.2008.10.035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 10/12/2008] [Accepted: 10/16/2008] [Indexed: 10/21/2022]
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52
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Weng L, Romanov A, Rooney J, Chen W. Non-cytotoxic, in situ gelable hydrogels composed of N-carboxyethyl chitosan and oxidized dextran. Biomaterials 2008; 29:3905-13. [PMID: 18639926 DOI: 10.1016/j.biomaterials.2008.06.025] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Accepted: 06/27/2008] [Indexed: 10/21/2022]
Abstract
A series of in situ gelable hydrogels were prepared from oxidized dextran (Odex) and N-carboxyethyl chitosan (CEC) without any extraneous crosslinking agent. The gelation readily took place at physiological pH and body temperature. The gelation process was monitored rheologically, and the effect of the oxidation degree of dextran on the gelation process was investigated. The higher the oxidation degree of Odex, the faster the gelation. A highly porous hydrogel structure was revealed under scanning electron microscopy (SEM). Swelling and degradation of the Odex/CEC hydrogels in PBS showed that both swelling and degradation were related to the crosslinking density of the hydrogels. In particular, the hydrogels underwent fast mass loss in the first 2 weeks, followed by a more moderate degradation. The results of long-term cell viability tests revealed that the hydrogels were non-cytotoxic. Mouse fibroblasts were encapsulated in the hydrogels and cell viability was at least 95% within 3 days following encapsulation. Furthermore, cells entrapped inside the hydrogel assumed round shape initially but they gradually adapted to the new environment and spread-out to assume more spiny shapes. Additionally, the results from applying the Odex/CEC system to mice full-thickness transcutaneous wound models suggested that it was capable of enhancing wound healing.
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Affiliation(s)
- Lihui Weng
- Department of Biomedical Engineering, State University of New York-Stony Brook, Stony Brook, NY 11794-8181, USA
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53
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Zhou HY, Chen XG, Kong M, Liu CS, Cha DS, Kennedy JF. Effect of molecular weight and degree of chitosan deacetylation on the preparation and characteristics of chitosan thermosensitive hydrogel as a delivery system. Carbohydr Polym 2008. [DOI: 10.1016/j.carbpol.2007.11.026] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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54
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Iliescu M, Hoemann CD, Shive MS, Chenite A, Buschmann MD. Ultrastructure of hybrid chitosan-glycerol phosphate blood clots by environmental scanning electron microscopy. Microsc Res Tech 2008; 71:236-47. [PMID: 18041781 DOI: 10.1002/jemt.20545] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chitosan-based polymers have been extensively studied for biomedical applications. Recently, liquid solutions of chitosan in a glycerol phosphate buffer (chitosan-GP) with physiological pH and osmolality were mixed with autologous blood to form hybrid chitosan-GP/blood implants that improved the repair of articular cartilage lesions in a large animal model. The mixture of chitosan-GP and blood forms a viscous liquid, which solidifies in minutes via normal blood coagulation as well as chitosan-mediated mechanisms. Here we have examined the ultrastructure of these chitosan-GP/blood clots as well as regular blood clots and chitosan-GP gels, the latter produced by heating. Both unfixed and fixed samples of chitosan-GP/blood clots, regular blood clots, and chitosan-GP gels were investigated by environmental scanning electron microscopy (ESEM) in conjunction with energy dispersive X-ray spectrometry (EDS), the former permitting direct observation of the ultrastructure in hydrated conditions simulating the natural state. By examination of unfixed specimens using ESEM we found that chitosan formed a network structure in both chitosan-GP gels and chitosan-GP/blood clots; however this structure was altered by aldehyde fixation to produce artifactual aggregates of chitosan microparticles. We were also able to identify chitosan in chitosan-GP/blood clots by washing samples in low concentration NaCl solutions followed by local EDS analyses to identify excess chloride versus sodium, and thus presence of cationic chitosan in analyzed features. Additional results indicated that the majority of glycerol phosphate diffuses freely from chitosan-GP gels (by EDS of phosphorus) and that hyperosmotic paraformaldehyde-based fixatives (i.e. 4% w/v) significantly disturb erythrocyte morphology in fixed whole blood clots.
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Affiliation(s)
- M Iliescu
- Department of Chemical Engineering, Institute of Biomedical Engineering, Ecole Polytechnique, Montreal, Quebec, Canada H3C 3A7
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55
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Cho J, Heuzey MC. Dynamic scaling for gelation of a thermosensitive chitosan-β-glycerophosphate hydrogel. Colloid Polym Sci 2007. [DOI: 10.1007/s00396-007-1789-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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56
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Meister A, Bastrop M, Koschoreck S, Garamus VM, Sinemus T, Hempel G, Drescher S, Dobner B, Richtering W, Huber K, Blume A. Structure-property relationship in stimulus-responsive bolaamphiphile hydrogels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:7715-23. [PMID: 17547425 DOI: 10.1021/la7003479] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The formation of temperature-, concentration-, and pH-responsive hydrogels composed of the symmetric long-chain bolaamphiphile dotriacontane-1,1'-diyl bis[[2-(dimethylammonio)ethyl]phosphate] (Me(2)PE-C32-Me(2)PE) was investigated by rheological, scattering, and spectroscopic techniques. At pH 5, this bolaamphiphile is known to form a dense network of helically structured nanofibers (Köhler et al. Soft Matter 2006, 2, 77-86). Rheological measurements and dynamic light scattering were used to describe the macroscopic behavior of the hydrogels. Small-angle neutron scattering (SANS) and time-resolved static light scattering were applied to get information about the morphology of the self-assembled aggregates. Finally, solid-state 31P NMR spectroscopy was used to gain insight into the mobility of the bolaamphiphile molecules within the fiber aggregates. In comparison with the previously examined trimethylammonio analogue PC-C32-PC, which forms temperature-dependent hydrogels, Me(2)PE-C32-Me(2)PE exhibits additional concentration- and pH-dependent gelling properties. The significantly higher stability of the Me(2)PE-C32-Me(2)PE hydrogel is supported by the SANS data, which indicate the presence of fiber aggregates up to 50 degrees C.
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Affiliation(s)
- Annette Meister
- Institute of Chemistry, MLU Halle-Wittenberg, Mühlpforte 1, 06108 Halle, Germany.
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57
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Tago K, Naito Y, Nagata T, Morimura T, Furuya M, Seki T, Kato H, Ohara N. A ninety-day feeding, subchronic toxicity study of oligo-N-acetylglucosamine in Fischer 344 rats. Food Chem Toxicol 2007; 45:1186-93. [PMID: 17303300 DOI: 10.1016/j.fct.2006.12.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Revised: 11/21/2006] [Accepted: 12/22/2006] [Indexed: 11/28/2022]
Abstract
Oligo-N-acetylglucosamine (OAG) is a hydrolyzed derivative of chitin that has been used as a sweetener in foods. Since, no information has been published about the safety of OAG, a 90-day feeding study was conducted, using F344 Fischer rats of both sexes, to characterize and evaluate the toxicity of OAG, and the results of the study are presented here. Dietary levels of 0% (control), 0.2%, 1%, and 5% OAG did not change any measurements in ophthalmological examinations, clinical signs, body weights, food consumption, hematology, blood biochemistry, urinalysis, necropsies, organ weights or histological examinations. The sole finding, which could not be clarified to be attributed to OAG or not, was a decrease in the relative weight of the submaxillary gland to body weight in the male animals given the 5% OAG diet. Although no lesions were found in either gross or histological examination in the present study, further studies using OAG levels higher than 5% might provide a clue to the mechanisms underlying the decreased organ weight observed here. Taken together, under the conditions in the present study, the No Observed Adverse Effect Level (NOAEL) for males was found to be 1% (0.641 g/kg/day); and that for females, 5% (3.64 /kg/day) or more, based on the lack of toxicological effects.
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Affiliation(s)
- Kazumi Tago
- Hatano Research Institute, Food and Drug Safety Center, Ochiai 729-5, Hadano, Kanagawa 257-8523, Japan
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58
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Ganji F, Abdekhodaie MJ, Ramazani S.A. A. Gelation time and degradation rate of chitosan-based injectable hydrogel. JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY 2007; 42:47-53. [DOI: 10.1007/s10971-006-9007-1] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
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59
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Crompton KE, Goud JD, Bellamkonda RV, Gengenbach TR, Finkelstein DI, Horne MK, Forsythe JS. Polylysine-functionalised thermoresponsive chitosan hydrogel for neural tissue engineering. Biomaterials 2007; 28:441-9. [PMID: 16978692 DOI: 10.1016/j.biomaterials.2006.08.044] [Citation(s) in RCA: 213] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2006] [Accepted: 08/25/2006] [Indexed: 11/21/2022]
Abstract
Foetal mouse cortical cells were cultured on 2D films and within 3D thermally responsive chitosan/glycerophosphate salt (GP) hydrogels. The biocompatibility of chitosan/GP 2D films was assessed in terms of cell number and neurites per cell. Osmolarity of the hydrogel was a critical factor in promoting cell survival with isotonic GP concentrations providing optimal conditions. To improve cell adhesion and neurite outgrowth, poly-D-lysine (PDL) was immobilised onto chitosan via azidoaniline photocoupling. Increase in PDL concentrations did not alter cell survival in 2D cultures but neurite outgrowth was significantly inhibited. Neurons exhibited a star-like morphology typical of 2D culture systems. The effects of PDL attachment on cell number, cell morphology and neurite outgrowth were more distinct in 3D culture conditions. Neurones exhibited larger cell bodies and sent out single neurites within the macroporous gel. Immobilised PDL improved cell survival up to an optimum concentration of 0.1%, however, further increases resulted in drops in cell number and neurite outgrowth. This was attributed to a higher cell interaction with PDL within a 3D hydrogel compared to the corresponding 2D surface. The results show that thermally responsive chitosan/GP hydrogels provide a suitable 3D scaffolding environment for neural tissue engineering.
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Affiliation(s)
- K E Crompton
- School of Physics, Department of Materials Engineering, Monash University, Wellington Rd., Clayton, VIC 3800, Australia
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60
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Hawkins DM, Trache A, Ellis EA, Stevenson D, Holzenburg A, Meininger GA, Reddy SM. Quantification and Confocal Imaging of Protein Specific Molecularly Imprinted Polymers. Biomacromolecules 2006; 7:2560-4. [PMID: 16961318 DOI: 10.1021/bm060494d] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have employed FITC--albumin as the protein template molecule in an aqueous phase molecular imprinted polymer (HydroMIP) strategy. For the first time, the use of a fluorescently labeled template is reported, with subsequent characterization of the smart material to show that the HydroMIP possesses a significant molecular memory in comparison to that of the nonimprinted control polymer (HydroNIP). The imaging of the FITC--albumin imprinted HydroMIP using confocal microscopy is described, with the in situ removal of the imprinted protein displayed in terms of observed changes in the fluorescence of the imprinted polymer, both before and after template elution (using a 10% SDS/10% AcOH (w/v) solution). We also report the imaging of a bovine hemoglobin (BHb) imprinted HydroMIP using two-photon confocal microscopy and describe the effects of template elution upon protein autofluorescence. The findings further contribute to the understanding of aqueous phase molecular imprinting protocols and document the use of fluorescence as a useful tool in template labeling/detection and novel imaging strategies.
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Affiliation(s)
- Daniel M Hawkins
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom
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61
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Crompton KE, Tomas D, Finkelstein DI, Marr M, Forsythe JS, Horne MK. Inflammatory response on injection of chitosan/GP to the brain. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2006; 17:633-9. [PMID: 16770548 DOI: 10.1007/s10856-006-9226-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Accepted: 08/23/2005] [Indexed: 05/10/2023]
Abstract
Chitosan is a well-known biomaterial that, with the addition of glycerophosphate salt (GP), gels at physiological temperatures and therefore is useful for tissue engineering purposes. This study examines the procedure of injecting chitosan/ GP to the brain in order to form a gel track. The gel system and surgical technique were successful in this endeavour; however, on examining the inflammatory response to the material it was found that the chitosan/GP was wholly engulfed by macrophages within 7 days. This was determined by staining for both the gel and the macrophages, an important technique for localising injected material. The chitosan/GP-containing macrophages formed a neat tract at the lesion site, but after 45 days no chitosan/GP was found. It was concluded that, although chitosan/GP is present after implantation, it is not available for direct scaffolding in the brain.
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Affiliation(s)
- K E Crompton
- Department of Materials Engineering, Monash University, Wellington Road, Clayton, 3168, Australia
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62
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Nisbet DR, Crompton KE, Hamilton SD, Shirakawa S, Prankerd RJ, Finkelstein DI, Horne MK, Forsythe JS. Morphology and gelation of thermosensitive xyloglucan hydrogels. Biophys Chem 2006; 121:14-20. [PMID: 16406645 DOI: 10.1016/j.bpc.2005.12.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Revised: 12/08/2005] [Accepted: 12/09/2005] [Indexed: 10/25/2022]
Abstract
Galactose modified xyloglucan is a thermally reversible hydrogel that is increasingly used in the biomedical field due to the ease of altering the gelation time and temperature by modifying the galactose removal ratio. However there is little information concerning the morphology and rheological properties of the hydrogel under physiological conditions. Differential scanning microcalorimetry (DSmicroC) showed the thermal gelation process to occur over a broad temperature range (5-50 degrees C). The rheological properties of the hydrogels were investigated as a function of concentration, temperature and ionic strength. The final elastic moduli of the hydrogels increased with increases in concentration. Isothermal rheology suggests that the gelation occurred in two distinct stages, which was influenced by the solution media. Scanning electron microscopy (SEM) was used to characterize the morphology of the xyloglucan which were thermally gelled at 37 degrees C. The resultant morphology was strongly dependent on the concentration of the hydrogel. Strong hydrogels were only obtained at 3 wt.% at 37 degrees C, and the morphology characterized by an open 3-dimensional network, comprised of thin membranes. It is proposed that the first stage of the isothermal gelation is the formation and growth of the thin membranes, followed by the formation of a three dimensional network.
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Affiliation(s)
- D R Nisbet
- Department of Materials Engineering, Monash University, Wellington Rd, Clayton, VIC 3800, Australia
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