Probe diffusion in phase-separated bicontinuous biopolymer gels
Journal article, 2014

Probe diffusion was determined in phase separated bicontinuous gels prepared by acid-induced gelation of the whey protein isolate-gellan gum system. The topological characterization of the phase-separated gel systems is achieved by confocal microscopy and the diffusion measurements are performed using pulsed field gradient (PFG) NMR and fluorescence recovery after photo-bleaching (FRAP). These two techniques gave complementary information about the mass transport at different time- and length scales, PFG NMR provided global diffusion rates in the gel systems, while FRAP enabled the measurements of diffusion in different phases of the phase-separated gels. The results revealed that the phase-separated gel with the largest characteristic wavelength had the fastest diffusion coefficient, while the gel with smaller microstructures had a slower probe diffusion rate. By using the diffusion data obtained by FRAP and the structural data from confocal microscopy, modelling through the lattice-Boltzmann framework was carried out to simulate the global diffusion and verify the validity of the experimental measurements. With this approach it was found that discrepancies between the two experimental techniques can be rationalized in terms of probe distribution between the different phases of the system. The combination of different techniques allowed the determination of diffusion in a phase-separated biopolymer gel and gave a clearer picture of this complex system. We also illustrate the difficulties that can arise if precautions are not taken to understand the system-probe interactions.

Author

Sophia Wassén

SuMo Biomaterials

SIK – the Swedish Institute for Food and Biotechnology

Romain Bordes

SuMo Biomaterials

Chalmers, Chemical and Biological Engineering, Applied Surface Chemistry

Tobias Gebäck

University of Gothenburg

Chalmers, Mathematical Sciences, Mathematics

SuMo Biomaterials

Diana Bernin

Swedish NMR Centre at the University of Gothenburg

SuMo Biomaterials

E. Schuster

SIK – the Swedish Institute for Food and Biotechnology

SuMo Biomaterials

Niklas Lorén

SIK – the Swedish Institute for Food and Biotechnology

SuMo Biomaterials

Anne-Marie Hermansson

SuMo Biomaterials

Chalmers, Chemical and Biological Engineering, Applied Surface Chemistry

Soft Matter

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

Vol. 10 41 8276-8287

Subject Categories

Physical Chemistry

Other Chemistry Topics

DOI

10.1039/c4sm01513d

More information

Latest update

11/27/2018