Ca(<scp>ii</scp>) and Ce(<scp>iii</scp>) homogeneous alginate hydrogels from the parent alginic acid precursor: a structural study

Sonego, Juan Manuel; Santagapita, Patricio R.; Perullini, Mercedes; Jobbágy, Matı́as

doi:10.1039/c6dt00321d

Cited by 29 publications

(28 citation statements)

References 38 publications

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“…Moreover, the Ca(II)-alginate structure can be obtained by cation exchange from a parent H-alginate hydrogel (Sonego, Santagapita, Perullini, & Jobbágy, 2016), 4 indicating a higher affinity of alginate polymer for Ca 2+ . It has been demonstrated that the combined use of alginate with sugars and/or other biopolymers such as arabic and guar gums allows to improve the stability of enzymes within the hydrogel (Traffano-Schiffo et al, 2017b).…”

Section: Introductionmentioning

confidence: 99%

Gums induced microstructure stability in Ca(II)-alginate beads containing lactase analyzed by SAXS

Traffano-Schiffo

Castro‐Giráldez

Fito

et al. 2018

Carbohydrate Polymers

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Previous works show that the addition of trehalose and gums in β-galactosidase (lactase) Ca(II)-alginate encapsulation systems improved its intrinsic stability against freezing and dehydration processes in the pristine state. However, there is no available information on the evolution in microstructure due to the constraints imposed by the operational conditions. The aim of this research is to study the time course of microstructural changes of Ca(II)-alginate matrices driven by the presence of trehalose, arabic and guar gums as excipients and to discuss how these changes influence the diffusional transport (assessed by LF-NMR) and the enzymatic activity of the encapsulated lactase. The structural modifications at different scales were assessed by SAXS. The incorporation of gums as second excipients induces a significant stabilization in the microstructure not only at the rod scale, but also in the characteristic size and density of alginate dimers (basic units of construction of rods) and the degree of interconnection of rods at a larger scale, improving the performance in terms of lactase activity.

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Section: Introductionmentioning

confidence: 99%

Gums induced microstructure stability in Ca(II)-alginate beads containing lactase analyzed by SAXS

Traffano-Schiffo

Castro‐Giráldez

Fito

et al. 2018

Carbohydrate Polymers

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“…All the alginate-Ca(II) beads analyzed showed isotropic scattering and were modeled as a fractal system composed of rod-like structures, although the rigorous interpretation of experimental results as indicating "fractality" requires many orders of magnitude of power-law scaling. 20 Three parameters were analyzed: i) α1, the fractal dimension at distances higher than R, which describes the multiplicity of the junction zone, at q < 0.28; ii) α2, the fractal dimension at distances lower than R, at q > 0.55,…”

Section: Microstructure Characterizationmentioning

confidence: 99%

Alginate Beads Containing Lactase: Stability and Microstructure

et al. 2017

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β-galactosidase (lactase) is a widely used enzyme in food industry; however, it has low stability against thermal and mechanical treatments. Due to this, the purpose of present research was to analyze the encapsulation of lactase in alginate-Ca(II) beads in order to maintain its enzymatic activity towards freezing, freezing/thawing and storage. Also, the effect of the addition of trehalose, arabic and guar gums and its influence in the microstructure as well as in thermal properties and molecular mobility were studied. Lactase was successfully encapsulated in alginate-Ca(II) beads and the inclusion of trehalose was critical for activity preservation towards treatments, being improved in guar gum-containing systems. The gums increased the Tm' values which represents a valuable technological improvement. Finally, the presence of secondary excipients affected the microstructure, showing rods with smaller outer diameter and with lower compactness than alginate-Ca(II) beads. Also, beads composition greatly affects the size, shape and relaxations times.

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“…In macroscopic systems, and likely here in the microfluidic system, external gelation creates a gradient of polymer and crosslinking concentration and makes control over total calcium content and gelation rates difficult to achieve. 40,57,58 In comparison, internal gelation allows for a consistent calcium to carboxyl molar ratio to be set. 40 The resulting microgels exhibited larger diameters, diminished storage moduli, and higher degrees of swelling in comparison to external gelation.…”

Section: Discussionmentioning

confidence: 99%

Microfluidic generation of alginate microgels for the controlled delivery of lentivectors

et al. 2016

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Microgels fabricated through distinct microfluidic procedures encapsulate and release functioning lentivectors in a controlled manner.Please check this proof carefully. Our staff will not read it in detail after you have returned it.Translation errors between word-processor files and typesetting systems can occur so the whole proof needs to be read. Please pay particular attention to: tabulated material; equations; numerical data; figures and graphics; and references. If you have not already indicated the corresponding author(s) please mark their name(s) with an asterisk. Please e-mail a list of corrections or the PDF with electronic notes attached -do not change the text within the PDF file or send a revised manuscript. Corrections at this stage should be minor and not involve extensive changes. All corrections must be sent at the same time.Please bear in mind that minor layout improvements, e.g. in line breaking, table widths and graphic placement, are routinely applied to the final version.Please note that, in the typefaces we use, an italic vee looks like this: n, and a Greek nu looks like this: n.We will publish articles on the web as soon as possible after receiving your corrections; no late corrections will be made.Please return your final corrections, where possible within 48 hours of receipt, by e-mail to: materialsB@rsc.orgQueries for the attention of the authors However, achieving safe, localized, and sufficient gene expression remain key challenges for effective lentivectoral therapy. Localized and efficient gene expression can be promoted by developing material systems to deliver lentivectors. Here, we address the utility of microgel encapsulation as a strategy for the controlled release of lentivectors. Three distinct routes for ionotropic gelation of alginate were incorporated into microfluidic templating to create lentivector-loaded microgels. Comparisons of the three microgels revealed marked differences in mechanical properties, crosslinking environment, and ultimately lentivector release and functional gene expression in vitro. Gelation with chelated calcium demonstrated low utility for gene delivery due to a loss of lentivector function with acidic gelation conditions. Both calcium carbonate gelation, and calcium chloride gelation, preserved lentivector function with a more sustained transduction and gene expression over 4 days observed with calcium chloride gelated microgels. The validation of these two strategies for lentivector microencapsulation may provide a platform for controlled gene delivery.

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Ca(ii) and Ce(iii) homogeneous alginate hydrogels from the parent alginic acid precursor: a structural study

Cited by 29 publications

References 38 publications

Gums induced microstructure stability in Ca(II)-alginate beads containing lactase analyzed by SAXS

Gums induced microstructure stability in Ca(II)-alginate beads containing lactase analyzed by SAXS

Alginate Beads Containing Lactase: Stability and Microstructure

Microfluidic generation of alginate microgels for the controlled delivery of lentivectors

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