Using fluorescent probes and FRAP to investigate macromolecule diffusion in steam-exploded wood
Journal article, 2018

Diffusion of fluorescently labeled dextran of varying molecular weight in wood pretreated by steam explosion was studied with a confocal microscope. The steam explosion experiments were conducted at relatively mild conditions relevant for materials biorefinery at a pressure of 14 bars for 10 min. The method of fluorescence recovery after photobleaching (FRAP) was used to perform diffusion measurements locally in the wood microstructure. It was found that the FRAP methodology can be used to observe differences in the diffusion coefficient based on localization in the microstructure, i.e., earlywood, latewood, and cell wall. Microscopic changes due to steam explosion were seen to increase diffusion of the smaller 3-kDa dextran diffusion probe in the earlywood, while the latewood structure was not affected in any significant way. Macroscopic changes to the structure in the form of ruptures due to the steam explosion pretreatment were observed to increase the rate of diffusion for the larger 40-kDa dextran probe.


Patric Kvist

SuMo Biomaterials

Chemical Process and Reaction Engineering

Wallenberg Wood Science Center (WWSC)

Erich Schuster

RISE Research Institutes of Sweden

Niklas Lorén

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

SuMo Biomaterials

Anders Rasmuson

Wallenberg Wood Science Center (WWSC)

Chemical Process and Reaction Engineering

Wood Science and Technology

0043-7719 (ISSN) 1432-5225 (eISSN)

Vol. 52 5 1395-1410

Subject Categories


Composite Science and Engineering

Condensed Matter Physics



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