Thermal–mechanical behaviour of chitosan–cellulose derivative thermoreversible hydrogel films

Barros, Sandra Cerqueira; Silva, Ana Alves da; Costa, Diana Barbosa; Costa, Carlos M.; Lanceros‐Méndez, S.; Maciavello, M. N. Tamaño; Ribelles, J. L. Gomez; Sentanin, F.; Pawlicka, Agnieszka; Silva, Maria Manuela

doi:10.1007/s10570-015-0603-5

Cited by 58 publications

(30 citation statements)

References 52 publications

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“…According to the literature, it is difficult to measure absolute values for T g of polysaccharides and their derivatives. Barros et al reviewed the literature of T g measurements of chitosan and hydroxypropylmethylcellulose (HPMC) and found T g for the latter being in the range of 55–167 °C. Values below 100 °C were measured for HPMC stored at defined humidity, but also nonprocessed HPMC showed a glass transition at 84.9 °C.…”

Section: Resultsmentioning

confidence: 99%

Influence of Stereochemistry on Relative Reactivities of Glucosyl and Mannosyl Residues in Konjac Glucomannan (KGM)

Zhang

Mischnick

2017

Macromol. Chem. Phys.

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Methylation in water with NaOH/MeI is applied to study the influence of the stereochemistry on relative reactivities of d‐mannosyl (M) compared to d‐glucosyl (G) units in konjac glucomannan (KGM). The pH is kept constant at 13.6 over the course of the reaction and aliquots are removed after various time intervals. Methyl distribution in G and M residues is determined after perethylation, hydrolysis, and conversion to O‐ethyl‐O‐methyl‐alditol acetates. The order of relative rate constants determined for the O‐methyl Konjac glucomannans (M‐KGMs) in degree of substitution (DS) range 0.3–0.8 is G‐k6 > M‐k6 > G‐k2 ≈ M‐k2 > M‐k3 > G‐k3. Oligosaccharides obtained by partial hydrolysis after full protection of M‐KGM with MeI‐d3 are labeled with m‐amino‐benzoic acid and measured by liquid chromatography–electrospray ionization–mass spectrometry. DS/DP profiles are in full agreement with random distribution of methyl groups. Thermal properties of M‐KGMs are analyzed by differential scanning calorimetry and thermogravimetric analysis. Decomposition temperature increases with DS, while the temperature of an endothermic change decreases.

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Section: Resultsmentioning

confidence: 99%

Influence of Stereochemistry on Relative Reactivities of Glucosyl and Mannosyl Residues in Konjac Glucomannan (KGM)

Zhang

Mischnick

2017

Macromol. Chem. Phys.

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“…Eye drops account for ~90% of ophthalmic drug delivery systems available (1). Traditional eye drops are usually lost from the ocular surface by tear washing or nasolacrimal drainage immediately after administration, with poor ocular bioavailability and numerous adverse reactions (2).…”

Section: Introductionmentioning

confidence: 99%

Chitosan temperature‑sensitive gel loaded with drug microspheres has excellent effectiveness, biocompatibility and safety as an ophthalmic drug delivery system

Kong

Zhang

et al. 2017

Exp Ther Med

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In the present study, a temperature-sensitive gel composed of chitosan, carboxymethyl chitosan and glycerophosphate was prepared and loaded with chitosan microspheres encapsulating levofloxacin. The bioavailability of levofloxacin and the safety of this novel opthalmic drug delivery formulation were evaluated. Levofloxacin chitosan microspheres were prepared using the ionic gelation method, and the particle size and entrapment rate were determined. The morphology of the microspheres was observed by scanning electron microscopy. The pH and zeta potential were measured. The in vitro release of levofloxacin by the chitosan temperature-sensitive gel loaded with drug microspheres was determined using spectrophotometry. The eye retention time of the chitosan temperature-sensitive gel was calculated using a fluorescein sodium test. To assess the bioavailability and safety of the chitosan temperature-sensitive gel, a cell compatibility test, a cytotoxicity test and skin irritation test were performed. The entrapment rate of levofloxacin in the chitosan microspheres was determined to be 26.5%. The levofloxacin chitosan microspheres that were formed by chitosan and sodium tripolyphosphate were identified to be suitable for use in an ophthalmic particle dispersion system based on their physical and chemical properties. The pH of the levofloxacin chitosan microsphere suspension was 5.87±0.04, the average particle diameter was 2,452±342 nm, the polydispersity index was 0.168±0.028 and the ζ potential was 28.62±1.7 mV. The chitosan temperature-sensitive gel carrying microspheres loaded with drug prevented drug burst release at the initial stage and facilitated the slow release of the drug later on. Furthermore, this delivery system markedly prolonged the contact duration of levofloxacin with the eye. The chitosan temperature-sensitive hydrogel was safe and provided a good bioavailability of the drug. The results revealed that the chitosan temperature-sensitive gel had a cytotoxicity of grade 0, and no erythematous response was observed during the entire course of the skin irritation test. The present study provided a basis for the future development of the chitosan-based temperature-sensitive hydrogel in ophthalmic drug delivery.

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“…[17] For the biopolymer electrolyte membranes, CH and HPMC solutions were mixed together in 25:75 ratio to form the base matrix. All products described herein were purchased to Sigma-Aldrich Company, Ltd (St. Louis, MO) and were used as received without further purification.…”

Section: Methodsmentioning

confidence: 99%

“…[6] Moreover, with the growing commercialization of PEMFCs, the disposal of a large number of used Nafion membranes will become an important environmental issue. [17][18][19][20][21][22][23] In particular, chitosan (CH) and its derivatives are been extensively investigated as some of the most attractive "green" materials for power sources applications due to their biodegradability, biocompatibility, nontoxicity, and low-cost. [7][8][9][10] Recently, the aim to develop bio-solid polymer electrolytes (BioSPEs) based on natural polymers has arisen as alternative candidates to substitute synthetic polymer-based membranes due to their abundance, low-cost, and environmentally friendly nature.…”

Section: Introductionmentioning

confidence: 99%

“…[7][8][9][10] Recently, the aim to develop bio-solid polymer electrolytes (BioSPEs) based on natural polymers has arisen as alternative candidates to substitute synthetic polymer-based membranes due to their abundance, low-cost, and environmentally friendly nature. [17,23] One of The proliferation of portable electronic devices has resulted in an increase of e-waste that is generated after their use. [17][18][19][20][21][22][23] In particular, chitosan (CH) and its derivatives are been extensively investigated as some of the most attractive "green" materials for power sources applications due to their biodegradability, biocompatibility, nontoxicity, and low-cost.…”

Section: Introductionmentioning

confidence: 99%

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Biopolymer Electrolyte Membranes (BioPEMs) for Sustainable Primary Redox Batteries

Alday

Barros

Alves

et al. 2019

Advanced Sustainable Systems

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The proliferation of portable electronic devices has resulted in an increase of e‐waste that is generated after their use. One of the most hazardous components in e‐waste are batteries, due to their content of heavy metals and toxic chemicals. Fuel cells and redox flow batteries have been recognized as more sustainable alternatives to Li‐based batteries for powering portable applications. Although they provide comparable energy and power densities, they still face some challenges because they rely on proton exchange membranes based on nonenvironmentally friendly, high‐priced perfluorosulfonic acid copolymers that require energy‐intense manufacturing and recycling procedures. In this work, eco‐friendly and sustainable biopolymer electrolyte membranes (BioPEMs) are synthesized from biopolymers like chitosan, cellulose, and starch. These BioPEMs bring forth advantages in performance, sustainability, and cost. Additionally, they present good chemical and mechanical stability, high ionic conductivity in the same order of magnitude as Nafion membranes. Two alternatives of cellulose–chitosan based BioPEMs are successfully applied into primary redox batteries using benign eco‐friendly redox chemistries, delivering open circuit voltages above 0.75 V and power output up to 2.5 mW cm−2. These results demonstrate BioPEMs capability to improve biodegradable batteries in sectors requiring a transient electrical energy, such as environmental monitoring, agriculture, or packaging.

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Thermal–mechanical behaviour of chitosan–cellulose derivative thermoreversible hydrogel films

Cited by 58 publications

References 52 publications

Influence of Stereochemistry on Relative Reactivities of Glucosyl and Mannosyl Residues in Konjac Glucomannan (KGM)

Influence of Stereochemistry on Relative Reactivities of Glucosyl and Mannosyl Residues in Konjac Glucomannan (KGM)

Chitosan temperature‑sensitive gel loaded with drug microspheres has excellent effectiveness, biocompatibility and safety as an ophthalmic drug delivery system

Biopolymer Electrolyte Membranes (BioPEMs) for Sustainable Primary Redox Batteries

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