Production of Chitosan/Hyaluronan Complex Nanofibers. Characterization and Physical Properties as a Function of the Composition

Abstract

In this work, optimized conditions for preparation of chitosan and hyaluronan polyelectrolyte complex are proposed. The objective was to produce new biomaterials being biocompatible and bioresorbable in the body as well as approaching the extracellular matrix (ECM) structure. These materials will be tested for chondrocyte development in tissue engineering and wound healing applications. Nanofibers made of the polyelectrolyte complex (PEC) were successfully manufactured by electrospinning, and casted films were used as a model for properties comparison. To our knowledge, it is the first time that stable chitosan/hyaluronan fibers are produced, which were observed to be long-lasting in buffer at pH~7.4. The role of thermal treatment at 120 °C for 4 h is examined to control the degree of swelling by crosslinking of the two polysaccharides by H-bonds and amide bonds formation. The properties of the materials are tested for different PEC compositions at different pH values, based on swelling and solubility degrees, diameters of nanofibers and mechanical performances. The influence of the solvent (acidic potential and composition) utilized to process biomaterials is also examined. Acid formic/water 50/50 v/v is observed to be the more appropriated solvent for the carried-out procedures.

Electrospun Biomaterials from Chitosan Blends Applied as Scaffold for Tissue Regeneration

“…As proposed in the literature, amide linkage is formed between -NH 2 and -COOH under controlled thermal treatment at a temperature between 80 and 120 • C up to 4 h [71][72][73][74][75]. After testing the kinetic of the reaction at 120 • C, CS and CS/HA complexes under film and fiber mat morphologies were treated at 120 • C for 4 h in air [70].…”

“…Polyelectrolyte complex systems (PEC) are usually very difficult to process due to phase separation related to strong electrostatic interactions. The convenient solvent is essential; hence, W/AF mixture 50/50 v/v was selected [70]. Subsequently, HA and CS solutions were mixed at different volume ratios corresponding to charge ratios R C = 0.5, 1, 1.8, 2.35, and 3.0 under stirring, getting a homogeneous blend.…”

“…Comparison with chitosan alone shows that the weight loss is higher for free chitosan (18%) than for complexes (~14%) due to lower interaction between chains (thermal treatment of chitosan induces an increase of crystallinity) and a lower degree of reaction with residual formic acid used as solvent [70].…”

“…For the electrospinning process, the collector was designed to permit the recovery of the fiber matrix from a metal plate to avoid sticking on the support. For that purpose, aluminum foils cut in cross-section have been chosen as support to remove the mat after processing [70]. In these conditions, the probes for mechanical tests are easy to take out.…”

Novel Nanofibers Made of Chitosan/Hyaluronan Electrostatic Complex

“…From NMR, it is shown that the insoluble materials are made of pure complex. PEO is extracted in Ethanol (EtOH)/water mixture [18]. In phosphate buffer at pH = 7.4, the swelling degree is low (3-4 %) for higher charge ratios.…”