Towards antibacterial hydrogels. Synthesis, structural studies and biological activity

Abstract

The controlled release of bioactive molecules and the encapsulation of living cells are active areas of research in drug discovery. Hydrogels are attracting significant attention in the medical field, particularly in drug delivery applications, due to their unique physical and chemical properties. This study focuses on the design and study of three new low molecular weight gelators (LMWGs) derived from N-alkylamides derived from β-cyclohexanic amino acids. The study of their gel-forming properties was carried out by determining their minimum gelation concentration (mgc) in 14 solvents through a heating-cooling inversion test. Due to their potential applicability as drug delivery systems, the possibility of forming hydrogels was investigated, and it was only possible with two of the three gel-forming agents: Gt12-COOH and Gt12-NHNH2. These two hydrogels underwent structural studies using Infrared, X-ray and Scanning Electron Microscopy (SEM) to further understand their supramolecular organization and three-dimensional structures. Additionally, they were subjected to studies on the release of a model antibiotic, Ampicillin. These studies determined that the Gt12-COOH hydrogel formed with D-gluconolactone (GdL) established temporal control in drug release, prolonging its activity over time and positioning itself as a promising candidate for drug delivery applications. To conclude, the activity of both hydrogels was studied in biological cultures. A surprising inhibitory effect in the negative control of Gt12-COOH-GdL led to the consideration of various hypotheses regarding its interaction with different bacterial strains in the study. This antibacterial activity was ultimately linked to a tendency towards filamentation, observed exclusively in Gram-negative microorganisms.