Preparation of gels of chitosan through a hydrothermal reaction in the presence of malonic acid and cinnamaldehyde: characterization and antibacterial activity

The preparation of composite gels through the hydrothermal reaction of a mixture of chitosan (CH), malonic acid (MLA), urea (UR) and cinnamaldehyde (CA), all of which are sustainable materials, is reported. The new material, CHMLAUR-CA, was characterized by C-13 solid-state NMR (SS NMR) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. The properties of the material were evaluated by rheometry and thermogravimetric analysis (TGA), while its morphology was assessed by SEM and AFM. The release of cinnamaldehyde by the composite gels displayed sustained release behavior. Also, the antibacterial study proves that composite gels exhibit a commendable and long-standing antibacterial activity against Escherichia coli (Gram-negative) bacteria and Staphylococcus aureus (Gram-positive). The outcome of the studies revealed that the prepared composite gels could be considered to be efficient long-term antibacterial materials.