Exploring the Role of Aqueous Buffered Saline Solutions on the Macroscopic Properties of PEG/Carbomer/Agarose Hydrogels

Nowadays, during hydrogel formulation design, the focus is primarily on polymers and cross-linkers. It is crucial to ensure a high level of biocompatibility and degradability, along with appropriate physico-chemical properties. However, other ingredients can also influence hydrogel formation and performance. Therefore, this study examines the effect of different salt molarities in phosphate buffered saline (PBS) solutions, used as reaction solvents, on the properties of hydrogels mainly composed of polyethylene glycol, agarose, and carbomer. To conduct the study, two PBS solutions are prepared by varying the salt concentrations, and these mixtures are used as solvents in a bulk polycondensation reaction. Subsequently, the two hydrogel formulations obtained are characterized to analyze the effect of PBS concentration on the material properties. An increase in salt concentration reduced the swelling capacity and release ability of the hydrogel matrix, as well as decreased the porosity and interconnectivity of the material, contributing to non-homogeneity in the pore network. Consequently, these results highlight that the salinity and ionic strength of buffering solutions can affect various material properties, and therefore, careful consideration should be given during the preparation of these solutions.