Modeling capillary formation in calcium and copper alginate gels.

Materials science & engineering. C, Materials for biological applications (2015-10-20)
Diego Caccavo, Anna Ström, Anette Larsson, Gaetano Lamberti
ABSTRACT

Alginate solutions in the presence of bivalent ions can form ionic cross-linked gels. In particular gelation conditions the gel structure can be characterized by great anisotropy with the presence of straight capillaries along a preferential direction. These materials can find applications mainly in high-tech sectors, like tissue engineering, where the gel characteristics play a crucial role. Despite the need of mastering the capillary formation and properties, the process remains a poorly known problem, and its development is left to trial and error procedures. In this work a quantitative approach to the description of the capillary formation process has been developed. The theory proposed by Treml et al. (2003) has been implemented and extended to an alginate different from the one used in that study and two different ions (calcium and copper). Some of the model parameters have been derived through simple measurements; others have been scaled using proper scaling equations. Experiments have been performed in different gelation conditions, varying alginate and ionic solution concentrations, to highlight the effects of these parameters on the anisotropic structure and to validate the model. In all the analyses done, the model has performed nicely showing a good reliability in the prediction of gel characteristics like capillary formation, capillary length and process time.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Calcium chloride dihydrate, ACS reagent, ≥99%
Sigma-Aldrich
Calcium chloride dihydrate, for molecular biology, ≥99.0%
Sigma-Aldrich
Calcium chloride dihydrate, BioReagent, suitable for cell culture, suitable for insect cell culture, suitable for plant cell culture, ≥99.0%
Sigma-Aldrich
Calcium chloride dihydrate, ReagentPlus®, ≥99.0%
Sigma-Aldrich
Copper(II) chloride dihydrate, ACS reagent, ≥99.0%
Sigma-Aldrich
Copper(II) chloride dihydrate, reagent grade
Sigma-Aldrich
Copper(II) chloride dihydrate, 99.999%
Sigma-Aldrich
Calcium chloride dihydrate, BioXtra, ≥99.0%
Sigma-Aldrich
Calcium chloride dihydrate, puriss. p.a., ACS reagent, reag. Ph. Eur., ≥99%
Sigma-Aldrich
Copper(II) chloride dihydrate, powder, BioReagent, suitable for cell culture
Sigma-Aldrich
Calcium chloride dihydrate, BioUltra, for molecular biology, ≥99.5% (KT)
Sigma-Aldrich
Calcium chloride dihydrate, puriss., meets analytical specification of Ph. Eur., USP, FCC, E509, 99-103%, ≤0.0001% Al
Sigma-Aldrich
Copper(II) chloride dihydrate, ≥99.95% trace metals basis