Modulating Alginate Hydrogels for Improved Biological Performance as Cellular 3D Microenvironments

Neves, Mariana I.; Moroni, Lorenzo; Barrias, Cristina C.

doi:10.3389/fbioe.2020.00665

Cited by 132 publications

(112 citation statements)

References 154 publications

(262 reference statements)

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“…The phage therapeutic cargo needs protection from environmental stresses such as the stomach acidic environment and exposure to digestive enzymes en route to the delivery site downstream in the small or large intestine. Biopolymers such as alginate have previously been used in pharmaceutical preparations due to their ease of biodegradability, biocompatibility and their ability to act as a carrier for the therapeutic agents [ 21 ]. Commercially available Eudragit polymers L-55, L100 and S100 have been specifically designed for enteric delivery applications with the aim of protecting therapeutics from gastric acidity and allowing controlled release of therapeutics utilising a pH-dependent trigger mechanism.…”

Section: Discussionmentioning

confidence: 99%

Microencapsulation of Bacteriophages Using Membrane Emulsification in Different pH-Triggered Controlled Release Formulations for Oral Administration

Richards¹,

Malik²

2021

Pharmaceuticals

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An E.coli-specific phage was encapsulated in three different pH responsive polymer formulations using the process of membrane emulsification. Small 100 µm capsules were fabricated and shown to afford phages suitable acid protection upon exposure to pH 1.5. Selection of polymer formulations allowed controlled release of phages at pH 5.5, pH 6 and pH 7. Other aspects of phage encapsulation including factors affecting encapsulation yield, release kinetics, acid and storage stability were evaluated. The work presented here would be useful for future evaluation of new therapeutic strategies including microbiome editing approaches allowing pH-triggered release of phages and delivery of encapsulated cargo to different intestinal compartments. The size of the capsules were selected to permit ease of delivery using small bore oral gavage tubes typically used in pre-clinical studies for evaluation of drug substances using small animal vertebrate models such as in mice and rats.

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Section: Discussionmentioning

confidence: 99%

Microencapsulation of Bacteriophages Using Membrane Emulsification in Different pH-Triggered Controlled Release Formulations for Oral Administration

Richards¹,

Malik²

2021

Pharmaceuticals

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“…The values determined are 30 ± 4, 46 ± 5, and 49 ± 4%, for Alg, Alg-PU 20, and Alg-PU 35, respectively. The carboxylic acid groups involve important crosslinking interactions with calcium (II) ions and intermolecular, generating the hydrogel state [1][2][3][4]. Statistically, significant differences are found when comparing the reticulation value of the Alg hydrogel with the IPN hydrogels.…”

Section: Structural and Physicochemical Characterizationmentioning

confidence: 99%

“…Alginate is a polysaccharide comprised of both guluronic and mannuronic acid units interconnected by β(1 → 4) glycosidic bonds, this is part of the extracellular matrix of different species of algae [1,2]. Alginate chains have the ability to physically crosslink in the presence of metal ions, such as Ca (II), Mg (II), Ba (II), Zn (II), generating hydrogels with high biocompatibility, they are widely used in the food industry, biomedicine, and tissue engineering [3,4].…”

Section: Introductionmentioning

confidence: 99%

Highly absorbent hydrogels comprised from interpenetrated networks of alginate–polyurethane for biomedical applications

Claudio‐Rizo

Escobedo-Estrada

Carrillo-Cortés

et al. 2021

J Mater Sci: Mater Med

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Developing new approaches to improve the swelling, degradation rate, and mechanical properties of alginate hydrogels without compromising their biocompatibility for biomedical applications represents a potential area of research. In this work, the generation of interpenetrated networks (IPN) comprised from alginate–polyurethane in an aqueous medium is proposed to design hydrogels with tailored properties for biomedical applications. Aqueous polyurethane (PU) dispersions can crosslink and interpenetrate alginate chains, forming amide bonds that allow the structure and water absorption capacity of these novel hydrogels to be regulated. In this sense, this work focuses on studying the relation of the PU concentration on the properties of these hydrogels. The results indicate that the crosslinking of the alginate with PU generates IPN hydrogels with a crystalline structure characterized by a homogeneous smooth surface with high capacity to absorb water, tailoring the degradation rate, thermal decomposition, and storage module, not altering the native biocompatibility of alginate, providing character to inhibit the growth of E. coli and increasing also its hemocompatibility. The IPN hydrogels that include 20 wt.% of PU exhibit a reticulation index of 46 ± 4%, swelling capacity of 545 ± 13% at 7 days of incubation at physiological pH, resistance to both acidic and neutral hydrolytic degradation, mechanical improvement of 91 ± 1%, and no cytotoxicity for monocytes and fibroblasts growing for up to 72 h of incubation. These results indicate that these novel hydrogels can be used for successful biomedical applications in the design of wound healing dressings.

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“…The mild gelation conditions with divalent cations such as Ca 2+ or Mg 2+ that enable the simultaneous incorporation of cells, is one of the reasons why alginate has been classically used for biomedical applications such as drug delivery [ 24 ], wound dressings [ 25 ] and tissue engineering [ 26 , 27 ]. This material is also biocompatible, has low toxicity and relatively low cost [ 21 , 28 ]. Ionic crosslinking typically occurs via fast and weakly controlled gelation due to the high solubility of calcium chloride in aqueous solutions.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Mechanical Control of Alginate-Fibronectin Hydrogels with Dual Crosslinking: Covalent and Ionic

et al. 2021

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Alginate is a polysaccharide used extensively in biomedical applications due to its biocompatibility and suitability for hydrogel fabrication using mild reaction chemistries. Though alginate has commonly been crosslinked using divalent cations, covalent crosslinking chemistries have also been developed. Hydrogels with tuneable mechanical properties are required for many biomedical applications to mimic the stiffness of different tissues. Here, we present a strategy to engineer alginate hydrogels with tuneable mechanical properties by covalent crosslinking of a norbornene-modified alginate using ultraviolet (UV)-initiated thiol-ene chemistry. We also demonstrate that the system can be functionalised with cues such as full-length fibronectin and protease-degradable sequences. Finally, we take advantage of alginate’s ability to be crosslinked covalently and ionically to design dual crosslinked constructs enabling dynamic control of mechanical properties, with gels that undergo cycles of stiffening–softening by adding and quenching calcium cations. Overall, we present a versatile hydrogel with tuneable and dynamic mechanical properties, and incorporate cell-interactive features such as cell-mediated protease-induced degradability and full-length proteins, which may find applications in a variety of biomedical contexts.

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Modulating Alginate Hydrogels for Improved Biological Performance as Cellular 3D Microenvironments

Cited by 132 publications

References 154 publications

Microencapsulation of Bacteriophages Using Membrane Emulsification in Different pH-Triggered Controlled Release Formulations for Oral Administration

Microencapsulation of Bacteriophages Using Membrane Emulsification in Different pH-Triggered Controlled Release Formulations for Oral Administration

Highly absorbent hydrogels comprised from interpenetrated networks of alginate–polyurethane for biomedical applications

Dynamic Mechanical Control of Alginate-Fibronectin Hydrogels with Dual Crosslinking: Covalent and Ionic

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