Tracking of Short Distance Transport Pathways in Biological Tissues by Ultra-Small Nanoparticles

Abstract

In this work, ultra-small europium-doped HfO2 nanoparticles were infiltrated into native wood and used as trackers for studying penetrability and diffusion pathways in the hierarchical wood structure. The high electron density, laser induced luminescence, and crystallinity of these particles allowed for a complementary detection of the particles in the cellular tissue. Confocal Raman microscopy and high-resolution synchrotron scanning wide-angle X-ray scattering (WAXS) measurements were used to detect the infiltrated particles in the native wood cell walls. This approach allows for simultaneously obtaining chemical information of the probed biological tissue and the spatial distribution of the integrated particles. The in-depth information about particle distribution in the complex wood structure can be used for revealing transport pathways in plant tissues, but also for gaining better understanding of modification treatments of plant scaffolds aiming at novel functionalized materials.

Distribution and curing reactions of melamine formaldehyde resin in cells of impregnation-modified wood

“…7a). In addition to the direct transport from the lumen into the secondary cell wall, MF resin and other solutes may have diffused from the lumen over the pit membranes through the interconnected middle lamella and cell corners 19,[43][44][45] . Wet curing may have supported the cure of the MF resin to macromolecules in the cell corners before its diffusion into the secondary cell wall.…”

Solvent-Controlled Spatial Distribution of SI-AGET-ATRP Grafted Polymers in Lignocellulosic Materials

“…Scheme showing (A) the structure of spruce wood from macro-to micro-scale,(B) targeted initiator distribution into the wood structure and (C) SI-AGET-ATRP reaction process.In most chemical wood modifications, a solvent is used to transport the reagents to the reaction sites (-OH groups). The transport of fluids in wood may occur through different pathways: from one cell to another via natural features (pits for instance), from lumen to cell wall via diffusion, and in the longitudinal direction through the middle lamellae and through cut open cell walls 34. Although the importance of one or the other pathway is still debated, the nature of the solvent is widely accepted as a critical parameter determining the kinetics and the extent of wood impregnation and wood cell wall swelling 32.…”

Defensive strategies of Norway spruce and Kurile larch heartwood elucidated on the micron-level

“…According to Segmehl et al (2018), the porous wooden CW allows for two routes of transportation of extractives: via pits and the cell lumen to the lignin-rich S3 layer, and through the lignin-rich intra-cellular space of the CML and CCs 47 , possibly reaching this area via blind pits that end at the intra-cellular space 48 . This route may be kinetically favored, explaining the high accumulation of extractives in the CML.…”

“…A potential explanation could be the qualities of the micro-environment of the respective CW compartments, i.e. it seems reasonable that cell compartments rich in lignin are more hydrophobic than the cellulose-rich S2 layer, resulting in a higher affinity of phenolics towards this area 47 . Further, association with hydrophobic oleoresin may facilitate the diffusion of phenolics through this network 23 .…”