Interplay between flow and diffusion in capillary alginate hydrogels
Artikel i vetenskaplig tidskrift, 2016

Alginate gels with naturally occurring macroscopic capillaries have been used as a model system to study the interplay between laminar flow and diffusion of nanometer-sized solutes in real time. Calcium alginate gels that contain homogeneously distributed parallel-aligned capillary structures were formed by external addition of crosslinking ions to an alginate sol. The effects of different flow rates (0, 1, 10, 50 and 100 mu l min(-1)) and three different probes (fluorescein, 10 kDa and 500 kDa fluorescein isothiocyanate-dextran) on the diffusion rates of the solutes across the capillary wall and in the bulk gel in between the capillaries were investigated using confocal laser scanning microscopy. The flow in the capillaries was produced using a syringe pump that was connected to the capillaries via a tube. Transmission electron microscopy revealed an open aggregated structure close to the capillary wall, followed by an aligned network layer and the isotropic network of the bulk gel. The most pronounced effect was observed for the 1 nm-diameter fluorescein probe, for which an increase in flow rate increased the mobility of the probe in the gel. Fluorescence recovery after photobleaching confirmed increased mobility close to the channel, with increasing flow rate. Mobility maps derived using raster image correlation spectroscopy showed that the layer with the lowest mobility corresponded to the anisotropic layer of ordered network chains. The combination of microscopy techniques used in the present study elucidates the flow and diffusion behaviors visually, qualitatively and quantitatively, and represents a promising tool for future studies of mass transport in non-equilibrium systems.




Polymer Science


membrane dynamics




laser-scanning microscope


correlation spectroscopy

Materials Science


Erich Schuster

Chalmers University of Technology

SP Sveriges Tekniska Forskningsinstitut

Kristin Sott

Chalmers University of Technology

SP Sveriges Tekniska Forskningsinstitut

Anna Ström

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Farmaceutisk teknologi

Annika Altskar

Chalmers University of Technology

SP Sveriges Tekniska Forskningsinstitut

N. Smisdom

Vlaamse Instelling voor Technologisch Onderzoek (VITO)

Universiteit Hasselt

Tobias Gebäck

Göteborgs universitet

SuMo Biomaterials

Chalmers, Matematiska vetenskaper, Matematik

Niklas Lorén

Chalmers, Fysik, Eva Olsson Group

SuMo Biomaterials

Anne-Marie Hermansson

Chalmers, Biologi och bioteknik, Livsmedelsvetenskap

SuMo Biomaterials

Soft Matter

1744-683X (ISSN) 1744-6848 (eISSN)

Vol. 12 3897-3907






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