How the Supramolecular Nature of Lignohumate Affects Its Diffusion in Agarose Hydrogel

Abstract

Lignohumate, as an industrially produced analog of natural humic substances, is studied from the point of view of its diffusion properties. This work focuses on its permeation ability, important in agricultural and horticultural applications, connected with its penetration into plant organs as leaves and roots. The hydrogel based on agarose was used as a model material for the diffusion of lignohumate. Two types of experiments were realized: the diffusion of lignohumate in the hydrogel diffusion couple and the diffusion of lignohumate from its solution into hydrogel. The diffusion coefficient of lignohumate in the hydrogel was determined and used for the modelling of the time development of concentration profiles. It was found that the model agrees with experimental data for short times but an accumulation of lignohumate in front of the interface between donor and acceptor hydrogels was observed after several days. The particle size distribution of lignohumate and changes in the E4/E6 ratio used as an indicator of molecular weight of humic substances were determined. The results showed that the supramolecular structure of lignohumate can react sensitively to actual changes in its environs and thus affect their mobility and permeability into different materials. A filtration effect at the interface can be observed as an accompanying phenomenon of the re-arrangement in the lignohumate secondary structure.

Functional Hydrogels for Agricultural Application

“…Its main characteristics, such as elemental composition and structural features, can be found in refs. [26,28,34,40].…”

“…In this work, the amendment of manure was replaced by lignohumate as the source of organic carbon. It is an industrially produced analog of natural humic substances produced by the thermal processing of technical lignosulfonate, which is based on the oxidation and hydrolytic destruction of lignin-containing raw materials [26][27][28][29]. Due to its smaller molecular size and weight in comparison to humic substances isolated from native sources, it is more soluble and has a similar character to the most active fractions of humic substances dissolved in soil solution [30][31][32][33].…”

Hydrogel-Loaded Exosomes: A Promising Therapeutic Strategy for Musculoskeletal Disorders

“…Based on their excellent degradability, hydrophilicity, biocompatibility, water content, and excellent viscosity and elasticity, hydrogels are now widely used in regenerative medicine and various tissue engineering studies [105][106][107], showing good potential for clinical applications. Previous studies on hydrogels have focused on chemically cross-linked polymer networks to investigate their fundamental characteristics such as swelling/dissolution kinetics and equilibrium [108], difusion of solute [109], sliding friction [110], and volumetric phase transition [111]. In recent years, the focus of hydrogel research has gradually shifted from simple networks to "responsive" networks.…”