Self-Healing Chitosan Hydrogels: Preparation and Rheological Characterization

The paper aims at the preparation of chitosan self-healing hydrogels, designed as carriers for local drug delivery by parenteral administration. To this aim, 30 hydrogels were prepared using chitosan and pyridoxal 5-phosphate (P5P), the active form of vitamin B6 as precursors, by varying the ratio of glucosamine units and aldehyde on the one hand and the water content on the other hand. The driving forces of hydrogelation were investigated by nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction, and polarized light microscopy (POM) measurements. NMR technique was also used to investigate the stability of hydrogels over time, and their morphological particularities were assessed by scanning electron microscopy (SEM). Degradability of the hydrogels was studied in media of four different pH, and preliminary self-healing ability was visually established by injection through a syringe needle. In-depth rheological investigation was conducted in order to monitor the storage and loss moduli, linear viscoelastic regime, and structural recovery capacity. It was concluded that chitosan crosslinking with pyridoxal 5-phosphate is a suitable route to reach self-healing hydrogels with a good balance of mechanical properties/structural recovery, good stability over time, and degradability controlled by pH.

Automated summary

This paper focuses on the preparation of chitosan self-healing hydrogels as carriers for local drug delivery. Through varying the ratio of glucosamine units and aldehyde and the water content, 30 hydrogels were prepared using chitosan and pyridoxal 5-phosphate (P5P). The driving forces of hydrogelation, stability, degradability, and self-healing ability were evaluated through various measurements. The results suggest that chitosan crosslinking with pyridoxal 5-phosphate is a suitable method to obtain self-healing hydrogels with good mechanical properties, structural recovery, stability, and pH-controlled degradability.