Complete glutaraldehyde elimination during chitosan hydrogel drying by SC-CO2 processing

Baldino, Lucia; Concilio, Simona; Cardea, Stefano; Marco, Iolanda De; Reverchon, Ernesto

doi:10.1016/j.supflu.2015.04.020

Cited by 85 publications

(69 citation statements)

References 48 publications

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“…Also, the number of available amine reaction sites is limited; therefore, much glutaraldehyde probably remains in solution, even at 0.25% concentration. These theories match the previous CO 2 study, where residual glutaraldehyde did not increase considerably until a large excess of glutaraldehyde was used …”

Section: Discussionsupporting

confidence: 89%

“…Here, ethanol was mixed with CO 2 until ethanol fully dissolved (approximately 1 min); ethanol was added to increase the polarity of CO 2 and improve extraction efficiency. The CO 2 flow was set to 2.5 mL/min to ensure a residence time of 4 min . Temperature was again maintained at 37°C by the environmental chamber (4) and the pressure of CO 2 in the vessels was maintained at 20 MPa (2900 psi) using the back‐pressure regulator (10).…”

Section: Methodsmentioning

confidence: 99%

“…Of particular importance is a recent publication where supercritical CO 2 and an ethanol additive were used to extract residual glutaraldehyde from crosslinked chitosan aerogels . They found that an 8 h CO 2 treatment could reduce glutaraldehyde levels as low as 0.1 ppm.…”

Section: Introductionmentioning

confidence: 99%

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Eliminating glutaraldehyde from crosslinked collagen films using supercritical CO₂

Casali

Yost

Matthews

2017

J Biomedical Materials Res

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Collagen has received considerable attention as a biomaterial for tissue engineering because of its low immunogenicity, controllable biodegradation, and ability to influence cell growth and proliferation. Frequently, collagen scaffolds require crosslinking to improve mechanical strength, requiring agents like glutaraldehyde that have high residual cytotoxicity. A novel method for extracting residual glutaraldehyde from crosslinked collagen films with supercritical carbon dioxide (CO 2 ) is presented. CO 2 is a nontoxic, nonflammable substance that is relatively inert and can be used to process biomaterials at mild pressures and physiologic temperatures. In this work, it was first determined that type I collagen is chemically compatible with both liquid and supercritical CO 2 . Treated collagen showed minimal changes in physicochemical properties as determined by differential scanning calorimetry, gel electrophoresis, and circular dichroism. CO 2 was subsequently used to extract residual glutaraldehyde from crosslinked collagen films. Glutaraldehyde concentration was reduced by over 95%, from over 20 ppm before treatment to about 1 ppm, in only 1 h. CO 2 treatment caused negligible alteration of thermal stability but did significantly increase film stiffness and tensile strength. However, these changes were minor compared to heat-based removal of glutaraldehyde.

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Section: Discussionsupporting

confidence: 89%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Eliminating glutaraldehyde from crosslinked collagen films using supercritical CO₂

Casali

Yost

Matthews

2017

J Biomedical Materials Res

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“…Mechanistically, free pendant amine groups of chitosan react with the aldehydic group of GA and yield imine bonds [57], distinguishable as the 1600 cm −1 peak in the corresponding IR spectra and originating from the stretching vibration of the imine C=N bond [58]. This peak was observed in Ch hydrogels formed in a range of different Ch:GA weight ratios (16:1 to 1:1) [59], while the Ch:GA reaction is reported to reach equilibrium at Ch:GA = 1:1 conditions [57]. In this study we used GA as a cross-linker to a fivefold amount compared to the content of Ch (Ch:GA = 5:1).…”

Section: Resultsmentioning

confidence: 99%

Selective anticancer activity of hydroxyapatite/chitosan-poly(d,l)-lactide-co-glycolide particles loaded with an androstane-based cancer inhibitor

Ignjatović

Penov-Gaši

et al. 2016

Colloids and Surfaces B: Biointerfaces

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In an earlier study we demonstrated that hydroxyapatite nanoparticles coated with chitosan-poly(D,L)-lactide-co-glycolide (HAp/Ch-PLGA) target lungs following their intravenous injection into mice. In this study we utilize an emulsification process and freeze drying to load the composite HAp/Ch-PLGA particles with 17β-hydroxy-17α-picolyl-androst-5-en-3β-yl-acetate (A), a chemotherapeutic derivative of androstane and a novel compound with a selective anticancer activity against lung cancer cells. 1H NMR and 13C NMR techniques confirmed the intact structure of the derivative A following its entrapment within HAp/Ch-PLGA particles. The thermogravimetric and differential thermal analyses coupled with mass spectrometry were used to assess the thermal degradation products and properties of A-loaded HAp/Ch-PLGA. The loading efficiency, as indicated by the comparison of enthalpies of phase transitions in pure A and A-loaded HAp/Ch-PLGA, equaled 7.47 wt.%. The release of A from HAp/Ch-PLGA was sustained, neither exhibiting a burst release nor plateauing after three weeks. Atomic force microscopy and particle size distribution analyses were used to confirm that the particles were spherical with a uniform size distribution of d50 = 168 nm. In vitro cytotoxicity testing of A-loaded HAp/Ch-PLGA using MTT and trypan blue dye exclusion assays demonstrated that the particles were cytotoxic to the A549 human lung carcinoma cell line (46±2%), while simultaneously preserving high viability (83±3%) of regular MRC5 human lung fibroblasts and causing no harm to primary mouse lung fibroblasts. In conclusion, composite A-loaded HAp/Ch-PLGA particles could be seen as promising drug delivery platforms for selective cancer therapies, targeting malignant cells for destruction, while having a significantly lesser cytotoxic effect on the healthy cells.

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“…In a more recent study, Baldino et al (2015) 15 evaluated the viability of scCO 2 extraction for the production and purification of CS scaffolds crosslinked with glutaraldehyde. In this case, CS solutions were crosslinked with glutaraldehyde, washed with water and subjected to solvent exchange by immersion in ethanol.…”

Section: Introductionmentioning

confidence: 99%

Supercritical CO₂ assisted process for the production of high‐purity and sterile nano‐hydroxyapatite/chitosan hybrid scaffolds

et al. 2017

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Hybrid scaffolds composed of hydroxyapatite (HAp), in particular in its nanometric form (n-HAp), and chitosan (CS) are promising materials for non-load-bearing bone graft applications. The main constraints of their production concern the successful implementation of the final purification/neutralization and sterilization steps. Often, the used purification strategies can compromise scaffold structural features, and conventional sterilization techniques can result in material's thermal degradation and/or contamination with toxic residues. In this context, this work presents a process to produce n-HAp/CS scaffolds mimicking bone composition and structure, where an innovative single step based on supercritical CO extraction was used for both purification and sterilization. A removal of 80% of the residual acetic acid was obtained (T = 75°C, p = 8.0 MPa, 2 extraction cycles of 2 h) giving rise to scaffolds exhibiting adequate interconnected porous structure, fast swelling and storage modulus compatible with non-load-bearing applications. Moreover, the obtained scaffolds showed cytocompatibility and osteoconductivity without further need of disinfection/sterilization procedures. Among the main advantages, the proposed process comprises only three steps (n-HAp/CS dispersion preparation; freeze-drying; and supercritical CO extraction), and the supercritical CO extraction show clear advantages over currently used procedures based on neutralization steps. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 965-975, 2018.

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Complete glutaraldehyde elimination during chitosan hydrogel drying by SC-CO2 processing

Cited by 85 publications

References 48 publications

Eliminating glutaraldehyde from crosslinked collagen films using supercritical CO₂

Eliminating glutaraldehyde from crosslinked collagen films using supercritical CO₂

Selective anticancer activity of hydroxyapatite/chitosan-poly(d,l)-lactide-co-glycolide particles loaded with an androstane-based cancer inhibitor

Supercritical CO₂ assisted process for the production of high‐purity and sterile nano‐hydroxyapatite/chitosan hybrid scaffolds

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Complete glutaraldehyde elimination during chitosan hydrogel drying by SC-CO2 processing

Cited by 85 publications

References 48 publications

Eliminating glutaraldehyde from crosslinked collagen films using supercritical CO2

Eliminating glutaraldehyde from crosslinked collagen films using supercritical CO2

Selective anticancer activity of hydroxyapatite/chitosan-poly(d,l)-lactide-co-glycolide particles loaded with an androstane-based cancer inhibitor

Supercritical CO2 assisted process for the production of high‐purity and sterile nano‐hydroxyapatite/chitosan hybrid scaffolds

Contact Info

Product

Resources

About

Eliminating glutaraldehyde from crosslinked collagen films using supercritical CO₂

Eliminating glutaraldehyde from crosslinked collagen films using supercritical CO₂

Supercritical CO₂ assisted process for the production of high‐purity and sterile nano‐hydroxyapatite/chitosan hybrid scaffolds