Effects of reaction pH on self-crosslinked chitosan-carrageenan polyelectrolyte complex gels and sponges

Abstract

Macromolecular biomaterials often require covalent crosslinking to achieve adequate stability for their given application. However, the use of auxiliary chemicals may be associated with long-term toxicity in the body. Oppositely-charged polyelectrolytes (PEs) have the advantage that they can selfcrosslink electrostatically and those derived from marine organisms such as chitosan (CS) and carrageenan (CRG) are inexpensive non-toxic alternatives to glycosaminoglycans present in the extracellular matrix of human tissues. The aim of this study was to explore the properties of crosslinker-free PEC gels and freeze-dried PEC sponges based on CS and CRG precursors. We offer new insights into the optimisation of conditions and mechanisms involved in the process and offer a systematic study of property changes across a full range of pH values. Zeta-potential measurements indicated that the PECs produced at pH 2-6 had a high strength of electrostatic interaction with the highest being at pH 4-5. This resulted in strong intra-crosslinking in the PEC gels which led to the formation of higher yield, viscosity, fibre content and lower moisture content. The weaker interaction between CS and CRG at pH 7-12 resulted in higher levels of CS incorporated into the complex and the formation of more inter-crosslinking through entanglements and secondary interactions between PEC units. This resulted in the production of stable PEC sponge materials compared with the PEC materials produced at pH 6 and below. From the range of samples tested, the PECs produced at pH 7.4 appeared to show the optimum combination of yield, stability and homogeneity.

Antimicrobial and antiviral activities with molecular docking study of chitosan/carrageenan@clove oil beads

“…On the other hand, the appearance of a new only after polyelectrolyte formation at 1529 cm−1 was thought to be due to OSO 3 -NH 3 + that is responsible for the electrostatic complexion. [13] Also a characteristic bands of NH and SH were shifted to a higher wavenumber and appeared at 2900-2800 cm -1 . [40] With encapsulation of oil in chitosan/carrageenan polyelectrolyte to verify that clove oil was introduced into polyelectrolyte, some absorption bands were disappeared and others were decreased in intensities.…”

“…The low costs of chitosan and carrageenan are mainly due to the abundance of farmed red seaweed, waste shrimp, simple extraction methods. [13] Essential oils are consisted of a complex mixture of volatile phytochemicals including sesqui terpenes, monoterpenes, and phenylpropanoids. Accordingly, researchers have studied the antifungal, antibacterial, antiviral, and antioxidant properties of these oils and they found them to be active against different viruses, like influenza, avian influenza, human herpes, human immunodeficiency, and yellow fever.…”

Determination of indicators allowing to evaluating the hemostatic activity of chitosan without a biological experiment

“…Because the rigid rod conformation is considered to be the most reactive, 20,21 we hypothesized that hemostatic activity will be higher in those samples the pH of the conformational transition rigid rod-globule which is as close as possible to the physiological pH value of 7.35-7.45. For the conformational transition took an abrupt decrease in light transmission of the solution not <30% of the initial values when you change pH by 0.3-0.4 units in the pH range of 3.96-9.61, indicating the transition of a significant part of the macromolecules in the other conformational state.…”

Chitosan as an Underrated Polymer in Modern Tissue Engineering

“…These features can be related to the synergistic effect of ionic and hydrogen bonds between κ-carrageenan and chitosan molecules. Additionally, the obtained blends had very good self-healing, biocompatible and anti-adhesive properties [135]. κ-carrageenan containing side sulphates can be used as an additional ionic cross-linking agent which gives a stable effect to chitosan hydrogels under acidic conditions [136].…”